It is therefore of great interest to identify targets of p53 (wild type and mutant) that are responsible for this phenotype during reprogramming, as these could be exploited for therapeutic use, that is, formation of induced pluripotent stem cells with high reprogramming efficiency, but no oncogenic potential. Here we studied the transcriptional changes of microRNA in a series of mouse embryonic fibroblasts that have undergone transition to induced pluripotent stem cells with wild type, knock out or mutant p53 status in order to identify microRNAs whose expression during reprogramming is dependent on p53. We identified a number of microRNAs, with known functions in differentiation and carcinogenesis, the expression of which was dependent on the p53 status of the cells. Furthermore, we detected several uncharacterised microRNAs that were regulated differentially in the different p53 backgrounds, suggesting a novel role of these microRNAs in reprogramming and pluripotency.The tumour suppressor p53 plays an important role in somatic cell reprogramming. While wild-type p53 reduces reprogramming efficiency, mutant p53 exerts a gain of function activity that leads to increased reprogramming efficiency. Furthermore, induced pluripotent stem cells expressing mutant p53 lose their pluripotency  Thus, p53 plays an important role in maintaining a pool of stem cells with an intact genome and moreover prevents of reprogramming cells with faulty genome.27Recently, p53 is emerging as a key regulator in the process of reprogramming from somatic to induced pluripotent stem (iPS) cells as well as being involved in stem cell maintenance.27 p53R172H (R175H in human) is a conformational mutant that results in a misfolded p53 protein. This study showed that p53 depletion or the expression mutant p53 increases reprogramming efficiency.27 However, cells expressing p53R172H in addition to their augmented pluripotency in vitro exhibited carcinogenic potential in vivo. When injected into nude mice, p53R172H expressing iPS cells lost their differentiation capacity and gave rise to aggressive sarcomas, while p53 KO iPS cells maintained pluripotency and led to the formation of benign teratomas, thus displaying a novel GOF for mutant p53.27We have previously studied the reprogramming efficiency of a series of MEFs with different p53 status, that is, p53 wt, p53 knock out (KO) and mutant p53R172H cells.43 but also influence reprogramming of stem cells and the maintenance of an undifferentiated cellular stage.45It is of great interest to generate iPS cells with a high reprogramming efficiency, but low tumorigenic potential for therapeutic use. As p53 was shown to be important in both reprogramming and maintaining genomic integrity of iPS cell, it provides an interesting target for manipulation of the reprogramming pathway. It is thus of interest to dissect the mechanisms and players regulated by p53 in these pathways. In addition to controlling the expression of protein coding genes, p53 was shown to control the transcription of a number of microRNAs (miRNAs). Expression of miRNAs is altered in many pathological conditions including cancer, where different miRNAs exhibit oncogenic and tumour suppressive properties. Moreover, miRNAs are key regulators of development; for example, miR-34a is fundamental for neuronal and muscle differentiation,In this study, we set out to examine miRNAs that are differentially regulated in cells during reprogramming depending on their p53 status, aiming to identify miRNAs that play a role in this process and that could be directly targeted to help optimise iPS cells. This would allow the generation of cells that have intact p53, which protects their genomic integrity, but at the same time exhibit high reprogramming efficiency. To this end, we performed a microarray screening of miRNA expression before and after three factors driven reprogramming of wt, KO and mutant p53 cells and identified several miRNAs whose expression is dependent on the p53 status of the cell.et al.27To identify miRNAs that are targeted by either wt or mutant p53 during reprogramming, we performed microarray analysis on a series of iPS cells and their parental MEFs with different p53 . The MEFs were reprogrammed by introduction of Oct4, Sox2, Klf4 as described in our previous study by Sarig All Cq values above 32 were considered noise background and excluded from the analysis. The results for a given sample were normalised by the geometric mean of the relative quantities of all targets expressed in the same sample . Targets that were up- or downregulated more than twofold were considered to be changed in the analysis.In a first step we looked at the miRNAs that were up- or downregulated in all three conditions during reprogramming . A high 47 Furthermore, several of these miRNAs have been implicated in both stemness and cancer , while in this study the iPS cells were generated using only three reprogramming factors  since c-Myc has been correlated with carcinogenesis of iPS cells in vivo.89Of note, our microarray screening did not highlight miR-34a as upregulated during reprogramming, as previously reported.In conclusion, our study highlighted a group of miRNAs driven by wt and mutant p53 that might be important for reprogramming, tumorigenesis and loss of genomic integrity. While a high number of miRNAs identified in our screen have already been associated with cancer development or differentiation and stemness , others 27 Briefly, MEFs were prepared from 13.5 days postcoitum embryos and maintained in DME, supplemented with 10% FCS, 1 mM sodium pyruvate, 2 mM l-glutamine, 0.1 mM nonessential amino acids, 0.1 mM β-mercaptoethanol and antibiotics. Reprogramming was induced using the three factor protocol  as described previously.27Primary MEFs were prepared from wt, p53 mutant or p53 KO E13.5 embryos as reported previously.RNA was extracted using Trizol , following manufacturer's instruction.n=3) were collected and pooled together for technical reasons; these were analysed with three technical replicates, obtaining always a mean error lower than 5% of the measure. Because this variation derives from a technical measure, and not from a biological replicate, it has not been reported on the histograms. Therefore, we did not show any statistics on these qualitative results.Microarray analysis was performed by Biogazelle . All Cq values above 32 were excluded as noise background. The results for a given sample were normalised by the geometric mean of the relative quantities of all targets that are expressed in that sample . Three biological samples .MicroRNAs targets were predicted by using the miRanda Software (microrna.org). Only target sites of conserved miRNAs and with good mirSVR score were taken into consideration.


Human immunodeficiency virus 1 (HIV-1) reverse transcriptase (RT)—a critical enzyme of the viral life cycle—undergoes a complex maturation process, required so that a pair of p66 precursor proteins can develop conformationally along different pathways, one evolving to form active polymerase and ribonuclease H (RH) domains, while the second forms a non-functional polymerase and a proteolyzed RH domain. These parallel maturation pathways rely on the structural ambiguity of a metamorphic polymerase domain, for which the sequence–structure relationship is not unique. Recent nuclear magnetic resonance (NMR) studies utilizing selective labeling techniques, and structural characterization of the p66 monomer precursor have provided important insights into the details of this maturation pathway, revealing many aspects of the three major steps involved: (1) domain rearrangement; (2) dimerization; and (3) subunit-selective RH domain proteolysis. This review summarizes the major structural changes that occur during the maturation process. We also highlight how mutations, often viewed within the context of the mature RT heterodimer, can exert a major influence on maturation and dimerization. It is further suggested that several steps in the RT maturation pathway may provide attractive targets for drug development. The accessory proteins negative regulatory factor (Nef) p66 have been interpreted to indicate the formation of a stable, symmetric p66/p66 homodimer containing two structurally and magnetically equivalent, stable RH domains -labeled p66 in our lab obtained under conditions similar to those of Sharaf et al. [Importantly, all of the NMR spectra that have been obtained for the Ile-labeled p66/p66’ homodimer reveal many subunit-specific chemical shift differences, consistent with the conclusion that the p66/p66’ homodimer exists as a structural heterodimer, and consistent with the above conformational selection process in which two conformationally distinct p66 monomers form an initial homodimer. Fortuitously, despite their close structural similarity, the RH and RH’ domains initially present in the p66/p66’ homodimer yield many separate resonances, allowing their separate conformational evolution to be individually tracked . In cont domains . Howeverf et al.  are domiM , many of these factors can exert their effects by influencing the earlier domain rearrangement process, rather than by directly influencing the monomer association step. Even perturbations that interfere with the subsequent subunit-specific RH domain unfolding step can influence the reversibility of the entire maturation pathway, and hence the fraction of p66 that is dimeric. Therefore, dimer stability provides a readout for multiple steps in the RT maturation pathway.extended conformation, and the second corresponding to dimerization of polymerase molecules in the E and M conformations p51MM and p51C conformations , this additional enhancement of the E/C ratio will enhance dimer formation  perturbations of the structure of the dimer interface that are transmitted from the NNRTI binding pocket ,83; and extended structure of the polymerase domain [In addition to the NNRTIs, other active site ligands, including dsDNA, hybrid RNA–DNA, and metal–nucleotide complexes are each expected to stabilize the dimer as a result of selective binding to the e domain ,88,89. Te domain ,90). In As in the case of symmetric multimers such as HIV protease, the metamorphic RT polymerase domain must accommodate a pair of mutations for each mutational variation in the p66 precursor. This constraint can be mitigated in protein regions with differential sensitivity to mutations. For example, the β7’–β8’ loop on p66’ (or p51) plays an important role at the dimer interface , while tNumerous studies have shown that RT mutations can influence dimer stability ,95,96,97E/M conformer ratio [M, Leu289 is solvent exposed, while in the structure of apo RT which serves as a model for p66E, Leu289 is located in a small fingers:thumb interface and makes hydrophobic contacts with fingers residues Phe61, Ile63, and Leu74 in the predominant closed conformation . Structural analysis indicates that the buried Asp110 and Asp186 residues in p51 make multiple H-bond and salt bridge contacts with other residues, while the buried Trp402 and Trp406 stabilize the compact conformation due to hydrophobic interactions. Trp406 Nε-H is also involved in stabilizing H-bond interactions in the compact p51 subunit. The role of the aspartyl residues of the YMDD motif in stabilizing the compact conformation of p51 has also been demonstrated by studies of Mulky et al. [extended conformation as neutral or slightly destabilizing with the additional possibility that W402R and W406R may be capable of dimer stabilization due to the formation of inter-subunit H-bond interactions. Consequently, while the L234A mutation is expected to lower the E/C conformational ratio of p66, the rescue mutations are expected to increase this ratio, primarily due to destabilization of the compact conformation. In summary, the effects of the dimerization inhibiting and rescue mutations studied by Tachedjian et al. [Tachedjian et al.  further am VADAR  for resiy et al. . Alternan et al.  appear tn et al.  and illuM and p66C, introduction of the larger side chains in the compact conformer will lead to local structural disruption that may be transmitted further into the structure, perturbing the dimer interface. The corresponding region in p66 in the apo structure is somewhat less crowded, but more importantly, exhibits substantial intrinsic flexibility that allows the accommodation of large NNRTIs. Movement of side chains in the NNRTI site of the E conformation can thus allow the accommodation of mutations requiring substantially greater side chain volume. It was determined that the most extreme side chain expansion (corresponding to a G190W mutation) was able to enhance dimer stability nearly as effectively as the NNRTI efavirenz (EFV) [E/C conformer ratio, similar to the mechanism discussed above for NNRTIs  . Consistnz (EFV)  shows thr NNRTIs . This exAs outlined above, subunit-specific RH domain unfolding is the final step in the maturation of the p66/p66’ homodimer. Mutations that significantly destabilize the RH domain can result in premature unfolding and proteolysis that effectively uncouples this step from dimer formation. Precursors containing mutations at the Phe440–Tyr441 cleavage site or in the segment between the domain N-terminal Tyr427 residue and the cleavage site have been reported to result in excessive formation of p51 and low or even absent levels of the RT heterodimer ,53,112. M illustrated in Abram et al. identified T477A as a rescue mutation for F440V and several other mutations that destabilize the RH domain and lead to premature processing ,113. BasThe RT maturation processes outlined above are mostly accomplished within the virion after it has separated from the host cell. Various lines of evidence indicate that the viral polyproteins exist primarily as a linear assembly of folded proteins and protein domains ,115, adoThe structures of the RT heterodimer and its p66/p66’ homodimer precursor A are arrThe polyprotein structure of pro-Pol results in cooperative dimerization, in which formation of an initial homodimer facilitates more extensive dimer formation . Since i20 lowers the equilibrium dissociation constant for p66 by about 30-fold. Formation of a complex with double-stranded RNA (dsRNA) formed from vRNA annealed with tRNA(Lys3) requires an extended conformation of the polymerase domain, which will stabilize the dimer and presumably accelerate the maturation of the p66’ subunit shown in In addition to the higher polyprotein concentration in the virion, other interactions are likely to facilitate RT dimerization. There is evidence that a pre-initiation reverse transcription complex (RTC) that includes viral RNA (vRNA), tRNA(Lys3), and RT is formed within the virion ,126. In In addition to supporting dimer formation, the high concentration of p66 within the virion can compensate for many p66 mutations that reduce but do not prevent dimer formation. Thus, Wapling et al.  observedThe virion pH is not well regulated, making the intra-virion pH subject to variations as a result of changes in the viral medium . Since Reverse transcriptases derived from HIV-1 and HIV-2 show only ~60% sequence identity ; howeverThe coding economy that results from reliance on a metamorphic RT comes at the cost of constraints on mutational variability and reliance on a complex maturation pathway. Recent NMR, crystallographic, and modeling studies have provided initial insights into this pathway, and suggest that maturation may be an attractive target for therapeutic intervention. In contrast, nucleoside drugs that target mature RT can also interfere with activities of host polymerases, and in some cases have been shown to inhibit the mitochondrial polymerase, leading to associated HIV lipodystrophy . In the The feasibility of targeting the final, subunit-specific RH domain unfolding step using an RH-active site-directed ligand has recently been demonstrated . As discThe RH:thumb’ interface—which is proposed to be absent in the initial homodimer structure A—represe


There is increasing importance placed upon noninvasive assessment of gut inflammation. These tools are likely to be the key in differentiating intestinal inflammatory disease from functional disorders and in monitoring the response to intervention in individuals with known inflammatory conditions. Although various noninvasive markers are currently available, they have limitations and do not provide ideal utility. This review focuses on emerging markers of gut inflammation, highlighting the potential of specific markers. Historically, noninvasive assessments of gut inflammation have utilized tests such as the detection of fecal white blood cells  and wholPyruvate kinase, a key enzyme in the glycolytic pathway , can be High levels of M2-PK were documented in 81 adults diagnosed with IBD  Table 1Table 1. Fecal M2-PK was assessed in a group of Polish children with IBD . Seventyp = 0.0007) [In a recent Australian study, mean fecal M2-PK levels were also higher in 17 children with active CD than in 21 healthy controls ( 0.0007) . HoweverHigh fecal M2-PK levels also were demonstrated in children with active UC . M2-PK aIn 2014, Czub et al.  who statOsteoprotegerin, also known as osteoprotegrin, (OPG) is a basic glycoprotein that is found either as a 60 kDa monomer or as a 120 kDa dimer. OPG is a cytokine receptor and belongs to the TNF superfamily , 17. OPGκB (RANK) and its ligand (RANKL). OPG acts as a decoy receptor for RANK [α) [OPG has a well-established role in bone turnover. The equilibrium of osteoclast and osteoblast activity is coordinated primarily by the receptor activator of nuclear factor-for RANK , 20–22. for RANK  promotinRANK [α) . This isRANK [α) . HoweverRANK [α) .OPG also may have a role in IBD pathogenesis, quite separate to the role in bone metabolism. The OPG/RANKL/RANK triad may contribute to mucosal and systemic inflammation , 20, 22.Recently, a small number of studies have demonstrated that OPG can be a useful marker of inflammation in the context of IBD. Nahidi et al.  evaluateα inhibitor infliximab in adult patients with IBD. In this study, OPG levels also decreased with treatment, in correlation with falling CRP levels. It is important to note that OPG levels did not fall acutely and were only significantly lower 22 weeks after the commencement of therapy. The authors suggest that in this setting, OPG is representative of the inflammatory response and not bone turnover.Galliera et al.  measuredIn addition, Sylvester et al.  recentlyThere are, however, conflicting reports on fecal OPG expression. In a preliminary investigation, Skinner et al.  report tMyeloperoxidase (MPO) is one of a number of proteins stored in and released from neutrophil secretory granules: it is stable for at least 3 days in stool . One potp < 0.001) [MPO levels were greatly increased in a cohort of 55 Indian patients with UC compared to 74 healthy controls (0.42 units versuss 0.06 units: < 0.001)  Table 1p < 0.001< 0.001)   1, is released from immune cells in the setting of inflammation. It has been described as an alarmin, with key inflammatory properties.r = 0.77). Furthermore, fecal concentrations reflected endoscopic severity in a subset of 16 children with clinically inactive disease but active mucosal findings. These results were reproduced by the same group in adult patients with IBD [r = 0.763, p < 0.001 for the Simple endoscopic score for Crohn's disease (SES-CD) and r = 0.44, p < 0.05 for endoscopic Mayo subscore). Palone et al. [One study has assessed HMGB1 in a cohort of children with IBD . Fecal lwith IBD . Howevere et al.  thereforHMGB1 has previously been shown to reflect intestinal inflammation in the context of enteric infection . In addiChitinase 3-like 1 (CHI3L1) binds chitin, an abundant polysaccharide. The expression of CHI3L1 is upregulated in various cell types such as colonocytes and lamina propria macrophages . This prp = 0.01). In addition to its presumed role in IBD, CHI3L1 was suggested by Chen et al. [Aomatsu et al.  demonstrn et al.  to play Although there is some rationale to consider that this protein may be a useful marker, further assessment and validation is required.β defensin group are produced in the colon by epithelial cells and plasma cells. An initial study completed in French children demonstrated that human β defensin (HBD) 2 could be measured in stool samples [p = 0.0002), especially those with UC   . HoweverThe matrix metalloproteinases (MMP) are a family of key biological mediators involved in tissue degradation and restitution. A number of studies have examined the roles of MMP proteins in IBD , 52: theMMPs are expressed in areas of inflammation and ulceration in the gut, and several MMPs are overexpressed in IBD , 53–57. MMP was also monitored in patients with CD managed with infliximab. Interestingly, MMP-2 serum levels increased, both in responders and nonresponders to treatment, and this was hypothesised to be due to increased intestinal cell turnover . Garg etp < 0.001 for both relationships) and were also associated with CRP levels (p = 0.002). Furthermore, MMP-9 levels correlated with fecal calprotectin (p = 0.014).Most interest in MMPs as disease markers of IBD has focused on MMP-9. Kofla-Dlubacz et al.  showed tDespite MMP-9 being elevated in both CD and UC, the performance of MMP-9 as a disease marker appears to be better in UC and pouchitis . Kolho eSeveral other MMP's are also elevated in IBD. MMP-7 and MMP-13 mRNA levels were elevated in biopsy specimens from CD and UC patients . Serum MOne study has assessed human deoxyribonucleic acid levels in stool of 36 individuals with UC . ExcretiIn addition to DNA, RNA or more specifically microRNA (miRNA) has the potential to be used as a disease marker in IBD. miRNAs are small noncoding RNA molecules that are capable of regulating gene expression at the posttranscriptional level. Expression patterns have been described in intestinal biopsies collected from IBD patients with a number of specific miRNA reported to be upregulated in both CD and UC –75. In CHowever, there are several difficulties that need to be overcome to compare these studies. For example, concurrent medications, the inflammatory status, and the location of the biopsy need to be considered when interpreting the role of miRNAs , 80. FurA biomarker can be described as a product that provides a measurable indication of the presence and/or severity of disease or physiological state of an organism. The holy grail of a biomarker is that it is disease specific, correlates highly with disease severity, and can provide both diagnostic and prognostic indications. To date, several promising fecal biomarkers for IBD have been identified. However, none of the currently described markers are disease specific so the search for better biomarkers of IBD continues. A number of promising novel biomarkers have been identified, and this article has described a portion of the most promising novel markers. However, there are many more potential biomarkers of IBD and further work is required to determine if any of the newly identified markers will be equal to, or surpass, the utility of currently available markers. The aims of the tables are to describe and compare the current knowledge in the use of novel markers: as markers of diagnostic tests for IBD , as markThe initial identification of calprotectin as a biomarker of IBD was greeted with great enthusiasm and promise that it would impact clinical care. However, after nearly 30 years of calprotectin research, the incorporation of this biomarker into a routine clinical care has been slow. Calprotectin has not replaced current nonspecific inflammatory markers, but when used, it is generally used as an adjunct disease marker. Therefore, it is reasonable to suspect a long wait for new IBD biomarkers to appear in the clinic. Nevertheless, biomarkers of IBD have a bright future, in research studies at least, as prognostic indicators and in the search for personalised and improved IBD clinical care.There also are several promising markers described here that likely reflect different cellular sources and different aspects of the IBD response. Currently, no single marker appears to be sought after highly sensitive, diagnostic, and prognostic IBD specific indicator. However, a number of novel biomarkers have been evaluated in just one or two cohorts: these all require more extensive assessments in various settings to establish their roles in identifying, monitoring, and predicting disease behaviour.More clinical studies are required to ascertain the full potential of fecal biomarkers in IBD. Although such evaluations should focus on specific biomarkers, comparative assessments are also required, yet there remains plenty of potential for novel biomarkers to impact clinical care.


TMEM230 has been associated with autosomal dominant Parkinson’s disease (PD). Subsequent studies have remained negative, and none of previous described mutation has been reported anymore. We investigated the implication of this gene in the PD in a population of 703 PD patients and 695 unrelated healthy controls from southern Spain. Thirteen variants were found, twelve of them observed only in controls or in patients and controls, and one (c.190A>G) observed only in one patient. Subsequent analysis of this variant indicates that probably it is not pathogenic. In addition, we found a variation in the 3’-UTR (rs183551373) and related with the miRNA hsa-miR-4299 but it was observed only in healthy controls. Our results suggest that variants in TMEM230 gene are not associated with the development of PD. PARK2, LRRK2 or SNCA, among others, are well documented as causative genes or risk factors for PD [Parkinson’s disease (PD) is a complex pathology in which both environmental and genetic factors are involved. More than 18 genes, like TMEM230 gene has been described to be a cause of autosomal dominant PD in a large family from North American [TMEM230 (p.*184ProGlyext5*) was identified as being related with PD in 7 familial cases. Several additional studies in different populations have failed to find neither causative mutation nor risk factors in TMEM230 associated with PD [Recently, a missense mutation (p.Arg141Leu) in  with PD   of the nature of the study and signed a written consent before blood collection.TMEM230 (NM_001009923 and NM_001009925) and their intron boundary regions were analyzed using high-resolution melting analysis in a LightCycler 480-II (Roche). Samples showing abnormal melting profiles were sequenced in an ABI3500 Genetic Analyzer (Applied Biosystem). The identified variants were annotated according to the longest isoform (NM_001009923). A variant call of sequenced samples was made using Variant Reporter software v1.1. (Applied Biosystem).We included a total of 703 PD patients from the Movement Disorders Unit of the Hospital Universitario Virgen del Rocío , and 695 healthy controls (HC). One hundred forty-eight patients had familial PD . PD was TMEM230. However, another variant found in the present study, c.191T>C, carrying the same effect was present in two healthy controls and in one PD patient. Another novel variant was identified in 3’UTR region, c.*670T>C but it was present in patients and control subjects. None of these variations were identified in the familial cases. Neither of the known variants previously related with PD have been found in this study.We detected a total of 13 genetic variants (two not reported before) in our population: two at 3’-untranslated region, one in 5’-untranslated region, one intronic variant, four synonymous variants, and five nonsynonymous variants . Ten werThree frequent variants  were present in PD case cohort and control cohort with similar frequencies.TMEM230 but neither of them seems to be related with the development of PD, since they are present only in HC or in both patients and HC. The exception has been c.190A>G, which is present in a single patient. This variation causes the loss of the ATG start codon in the isoform 2 of TMEM230 , therefore, it could be disease causing. However, the variant c.191T>C, with similar consequences in the protein , is present in healthy controls in this study and in previous ones [TMEM230 protein is also methionine, which would act as an alternative start codon to generate a novel protein that lacks only the first amino acid. So, it is expected that this variation does not cause a significant alteration of the protein. In addition, a variation in the 3’-UTR (rs183551373) has been related with the miRNA hsa-miR-4299 but it was found only in healthy controls in our population and, thereupon, the pathogenicity of this variant seems not be probable.In this study we have reported 13 variants in TMEM230 is very low and, therefore, TMEM230 do not play a major role in familial and sporadic PD patients in southern Spanish population which can have important implication in clinical investigation.Our findings suggest that the incidence of pathogenic variations in S1 Table(PDF)Click here for additional data file.


Economic bubbles are an empirical puzzle because they do not readily fit the notion of an efficient market. We argue that bubbles are associated with a conflict and a gap in the allocation of effort during negotiation by sellers and buyers. We examined 21 experimental asset markets where in one condition players could buy and sell and in the other they could either buy or sell. The results indicated that when making concurrent buying and selling decisions the mean number of asks for sellers was 71% higher than the number of bids for buyers. Similar findings emerge in a re-analysis of data from Lei et al. (2001). Importantly, bubbles only emerged in markets where the number of asks was larger than that of bids. These findings indicate that bubbles are associated with increased negotiation effort when acting as a seller and diminished effort when acting as a buyer. Economic bubbles are an empirical puzzle because they do not readily fit the notion of an efficient market . BubbIn light of the surprising ubiquity of economic bubbles, understanding the formation and mitigation of bubbles has been the subject of extensive experimental research. Still, most studies of experimental asset markets have focused on processes shared by buyers and sellers –7, 10–15Buyers and sellers’ effort is for all likelihood associated with their pricing performance. There is an extensive literature in psychology on the relationship between effort and performance –23, whicSeveral empirical findings support the notion that selling is associated with greater effort. First, the literature suggests that sellers view the task of trading more from the point of view of preventing a loss (of the object) than from that of obtaining a gain, while buyers view the task more from a gain than a loss perspective , 25. ForConsistent with the notion that selling is associated with more cognitive effort, studies have shown that in pricing of lotteries participants acting as sellers tend to be more sensitive to the lottery’s expected value than those acting as buyers e.g., –38) and  and 38])These theoretical accounts also suggest some moderators for the postulated cognitive differences between buyers and sellers. Increased attention and effort on the part of sellers should be more impactful when attentional resources are limited. This is implied by the diminishing marginal benefit of attentional investment ,23. AddiIn the current study we evaluated these predictions in an experimental asset market. In order to study the effect of concurrent buying and selling we compared a market where traders either buy or sell versus one where they can perform both tasks. As a proxy for negotiation efforts, we examined the volume of price proposals  which is considered to reflect the extent of one’s efforts at negotiating different prices ,40. ConsTo pilot these research questions, we re-analyzed data from a standard experimental asset market  collectet(27) = 2.75, p = .01). There was no significant difference between the number of asks and bids in the Buy OR Sell condition (t(21) = 0.65, p = .52).Using Lei et al.’s  data, wet(36) = 1.94, p = .07). High buying proposals significantly predicted excessive transaction prices above the fundamental value  = 0.38, p = .02); however, there was no direct relation between the market’s asks minus bids index and excessive transaction prices (r(48) = 0.15, p = .30). The latter analyses are sensitive to confounds since they are pooled across the two experimental conditions (Buy AND Sell vs. Buy OR Sell). However, the sample size was too small to conduct an analysis controlling for condition (n’s ≤ 10 in some of the cells). In our main study we conducted a more thorough analysis that controls for experimental condition.We then compared markets where the mean number of asks was larger than that of bids, to those where the number of bids was larger (there were five markets in the former and two in the latter category). Buying price proposals in markets dominated by asks were somewhat higher compared to their counterparts, though the effect was only marginally significant  and none had prior experience in asset market experiments. Their average age was 24.7; ages ranged between 18 and 40. Experimental sessions lasted approximately 75 minutes, and payment ranged between NIS 25 and 100 depending on performance. There were eight participants in each session; three sessions included only seven participants each due to insufficient show ups.Following Lei et al. (2001 ) particit equaled the expected value of the dividend (30 tokens) multiplied by the remaining rounds (30 × (13-t)). The number of assets in one’s possession and the cash balance were accumulated during rounds. The asset had no value for the participants after the experiment had ended, while experimental currency was converted into real currency at a rate of NIS 1 per 200 tokens.The experimental asset market was based on the parameters of Lei et al.’s (2001 ) experimIn the Buy OR Sell condition participants were assigned to the role of either buyers or sellers. Buyers were only permitted to purchase, while sellers were only permitted to sell. At the beginning of the experiment, each seller was endowed with 20 units of the asset (referred to as “stocks”) but no experimental tokens. Each buyer was endowed with 7,200 tokens  and no units of the asset. Because each unit of the asset paid on average 360 tokens during the 12 rounds, the expected value of the initial endowment was identical for buyers and sellers in this condition. In the Buy AND Sell condition all participants could buy and sell, and each participant was endowed with 10 units of the asset and 3,600 tokens at the beginning of the experiment. The expected value of the initial endowment in this condition was thus the same as in the Buy OR Sell condition.The sequence of events in all sessions was as follows. Upon arrival, participants completed an informed consent statement and received written instructions consisting of a description of the task and an explanation of the dividend structure. The instructions were based on those described in Lei et al. (2001 ), translThe experimenter read these instructions out loud. Participants were then encouraged to ask questions. This was followed by a short quiz regarding the value of a single asset one round ahead and 12 rounds ahead. If participants did not complete the test properly they were given further explanation until they were able to answer correctly. Next, there was a 4 minute training session in which participants practiced using their designated perspective in the experimental task . The initial endowment in the training session was identical to that given in the main experiment but monetary decisions were not incentivized. Participants then received a piece of paper stating their initial endowments and the possible actions available to them . This was followed by the 12 rounds asset market experiment with continuous double-auction rules.A accepted a pending bid from participant B then all asks for A and all bids for B were removed. Thus, each price proposal pertained to a single unit of the asset . At theAs in our re-analysis of Lei et al. (2001 ), we calt) refers to the mean transaction price in round t, and FV(t) refers to the fundamental value in round t.For descriptive purposes, we also calculated two common market-level indices of bubbles , 40: Bubt(21) = 2.79, p = .01). The results are thus consistent with those of Smith et al. (1998 [The mean prices in each trading round appear in l. (1998 ) in thatt(19) = 1.82, p = .084; Amplitude: t(19) = 1.84, p = .091).We also examined whether differences in the market indices of bubbles emerged between conditions. For both indices of bubble duration and bubble amplitude there was a marginally significant difference between conditions, with longer and more varied bubbles in the Buy OR Sell condition than in the Buy AND Sell condition (Duration: t(21) = 8.14, p < .001).Another difference between market conditions was the number of transactions in each condition, which was considerably higher in the Buy AND Sell condition (3.78±0.36) than in the Buy OR Sell condition (0.72±0.07). This difference was significant even at the market level (t(69) = 4.80, p < .001). There was also a significant difference in responsiveness in the predicted direction, with buyers being 32% more likely to accept an ask than sellers were to accept a bid (paired-sample t(69) = 2.81, p = .006). As in the data of Lei et al. (2001 [t(93) = 0.74, p = .46) and their responsiveness (t(93) = .07, p = 0.94).As shown in l. (2001 ), these W = 4.92, p < .001). Similarly, the median buyer responsiveness was 1.65 compared to 0.92 for sellers, a significant difference . An analysis of changes in the mean number of bids and asks over time (in different rounds) appears in the S1 Supplementary section.The effects in the Buy AND Sell condition did not seem to be due to extreme values. The median number of asks in the Buy AND Sell condition was 6.71 compared to 3.58 for bids, and the main effect was replicated in a non-parametric test  characterized by more asks than bids, versus those with more bids than asks. This enabled a direct contrast of an environment where selling or buying proposals are more dominant. In all, there were 13 markets where asks outnumbered bids and 8 markets where bids outnumbered asks . The mean pricing characteristics of the two groups are shown in F = 6.07, p = 0.01) and also by higher selling proposals  = 4.04, p = 0.047). Buyers in these markets also accepted higher price proposals  = 6.34, p = .01), as did sellers  = 6.49, p = .01).As in the data of Lei et al. (2001 ), marketF = 11.26, p = .001), as well as by sellers  = 16.65, p < .001). Indeed, for markets dominated by higher number of asks transaction prices were significantly above the FV (transactions accepted by buyers: t(81) = 2.72, p = 0.008; by sellers: t(81) = 3.53, p = 0.010). In contrast, in markets dominated by higher numbers of bids transaction prices accepted by either buyers or sellers were not significantly different from the FV (t(33) = -1.50, p = 0.14; t(33) = -1.36, p = 0.18, respectively). Thus, transaction prices significantly exceeded the FV only in those sessions that had greater numbers of asks than bids. As shown in Markets with higher number of asks were further characterized by higher positive deviations from the FV (price—FV), both when transactions were accepted by buyers  = 6.51, p = .01). No such effect emerged for transactions accepted by buyers  = 2.68, p = .11). We also looked at the mean price of the transactions at the market level in markets with more asks than bids and vice versa. FV. When regressing market price on condition and market type, there was a positive association between asks-dominated markets and mean market price . The effect was not significant, however, likely due to poor statistical power (df = 19).Finally, in line with the differences observed at the market level for bubble duration and amplitude, there was also an effect of condition on excessive prices for transactions accepted by sellers: The positive disparity between transaction prices and the FV was higher in the Buy Or Sell condition than in the Buy AND Sell condition . However, the Buy OR Sell condition was associated with higher accepted prices both for buyers and for sellers  = 15.39, p < .001; F = 4.46, p = .04). With respect to the magnitude of buying proposals, there was also an interaction between condition and selling to buying volume  = 9.57, p = .002) with the effect of market type being stronger in the Buy AND Sell condition. A similar interaction emerged for the price accepted as a seller  = 7.00, p = .01) and for excessive prices above the FV in transactions accepted by buyers  = 5.26, p = .02).There was no effect of condition on the magnitude of buying and selling proposals (r(67) = 0.40, p < .001) and showed a marginally significant correlation with the average price accepted as a buyer (r(63) = 0.21, p = 0.08). The difference between the number of asks and bids was also marginally correlated with excessive prices above the FV (price—FV) in transactions accepted by buyers (r(67) = 0.21, p = .08), but not sellers (r(68) = 0.05, p = 0.68).The Buy AND Sell condition allows assessment of the relation between individuals’ pricing decisions and the volume of their bids and asks. We therefore examined whether individuals’ pricing decisions were predicted by the disparity between their own number of asks compared to bids (#Asks–#Bids). The results indicated that the difference between the number of asks and bids was strongly correlated with the magnitude of buying proposals for a given individual (r(163) = 0.25, p = 0.001).Given these individual differences it was interesting to evaluate to what extent the tendency of transaction prices to exceed the FV in the Buy AND Sell condition was predicted by the individual’s index of #Asks–#Bids, or by the markets’ (session’s). To examine this, we conducted a regression analysis for predicting excessive transaction prices (price—FV) using two variables: 1) whether a session had higher number of asks or bids , 2) the individual’s #Asks–#Bids. The results are presented in The current findings indicate a basic difference between the volume of buying and selling proposals: When individuals can act as both sellers and buyers, the number of asks far exceeds the number of bids. Secondly, in our new study the disparity between the number of asks and bids appeared to predict the magnitude of bubbles. In markets dominated by asks, buyers as well as sellers had higher price proposals and accepted higher prices, and extant bubbles developed, as evidenced in transaction prices being above the fundamental value of the asset. In markets dominated by bids, there were no significant differences between transaction prices and the fundamental value of the asset. These findings echo those observed in our re-analysis of Lei et al.’s (2001 ) experimDifferences in the numbers of bids and asks did not emerge when participants could only buy or only sell. This is consistent with notion that a selling perspective captures more attention when there is a competition in priorities owing to the limited cognitive resources available . Still, Interestingly, despite the fact that larger differences between numbers of bids and asks emerged in the Buy AND Sell condition than in the Buy OR Sell condition, excessive transaction prices were higher in the Buy OR Sell condition (for transactions accepted by buyers). This indicates that other factors besides the volume of proposals modulate the difference between conditions with respect to excessive pricing. One relevant factor may be trading experience. Because assets in Buy AND Sell condition could be rebought and resold, participants gained much more trading experience in this condition (as reflected in the larger number of transactions). It is well known that experience moderates the emergence of bubbles ,13,46. FThe present findings constitute a departure from the standard assumptions about buying and selling proposals in economic theory. The standard way to interpret price proposals in economics is that a surplus of asks represents high supply, leading to reduced prices; whereas a surplus of bids represents high demand, leading to increased prices ,48. We fOne clear implication based on the current findings therefore concerns the relation between price proposals and bubbles. The findings suggest that reducing the gap between the numbers of bids and asks might be helpful in reducing bubbles. Obviously, in actual asset markets involving non-algorithmic trading, it is not possible to affect differences in the number of bids and asks without regulating the market. However, one could potentially reduce asymmetries by modifying the salience of bids and asks, for instance by using distributed averaging algorithms or a closed order book wherein only the current bid/ask spread is presented. Examining the effect of such presentation changes on asymmetries in pricing is an interesting endeavor for future studies.An obvious limitation of our research is that it focuses on experimental asset markets. First, in this setting participants have relatively little experience: With extended experience, differences between buyers and sellers, such as the endowment effect, tend to diminish –53. SecoIn sum, in the studied experimental asset markets, the outcome of one’s effort in negotiating prices through price proposals depended on one’s trading perspective. Greater numbers of asks than bids were predictive of the emergence of bubbles, whereas greater numbers of bids than asks were not. More markets conformed to the former type, however, giving way to bubbles on the aggregate level. The findings highlight the relevance of theories of attention and effort to studies of economic markets.S1 Text(DOCX)Click here for additional data file.


The ubiquitin–proteasome system (UPS) and autophagy are two distinct and interacting proteolytic systems. They play critical roles in cell survival under normal conditions and during stress. An increasing body of evidence indicates that ubiquitinated cargoes are important markers of degradation. p62, a classical receptor of autophagy, is a multifunctional protein located throughout the cell and involved in many signal transduction pathways, including the Keap1–Nrf2 pathway. It is involved in the proteasomal degradation of ubiquitinated proteins. When the cellular p62 level is manipulated, the quantity and location pattern of ubiquitinated proteins change with a considerable impact on cell survival. Altered p62 levels can even lead to some diseases. The proteotoxic stress imposed by proteasome inhibition can activate autophagy through p62 phosphorylation. A deficiency in autophagy may compromise the ubiquitin–proteasome system, since overabundant p62 delays delivery of the proteasomal substrate to the proteasome despite proteasomal catalytic activity being unchanged. In addition, p62 and the proteasome can modulate the activity of HDAC6 deacetylase, thus influencing the autophagic degradation. Nearly 30% of newly synthesized proteins in the cell are misfolded under normal conditions . Two sysp62 is an autophagy substrate that is used as a reporter of autophagy activity. Recently, p62 was also shown to deliver ubiquitinated proteins, such as tau, to the proteasome for degradation. In addition, it can shuttle between the nucleus and cytoplasm to bind with ubiquitinated cargoes and facilitate nuclear and cytosolic protein quality control. Other functions of p62 are gradually being revealed, emphasizing its importance in the proteolytic system. This review focuses on the role of p62 in linking the ubiquitin–proteasome system and autophagy pathway upon ubiquitinated protein degradation Fig. .Fig. 1ThThe ubiquitin–proteasome system (UPS) plays a critical role in the degradation of short-lived, misfolded and damaged proteins. This is necessary to maintain protein homeostasis, cell cycle control , inflammThe progress of proteolysis also requires ubiquitin to covalently attach to substrates. This 76-amino acid protein can form an isopeptide bond between its C-terminal glycine (G76) and a lysine residue within the target molecules or ubiquitin itself . UbiquitAutophagy is a highly evolutionarily conserved degradation system in eukaryotes . It was The autophagic degradation model of eukaryotes is emerging through more recent research . AutophaAutophagy-related gene (Atg) proteins play essential roles in autophagy. They are known as the ‘core machinery’ . More thp62 was the first selected autophagy adaptor discovered in mammals , 21, 22.p62 is a multifunctional protein consisting of an N-terminal Phox-BEM1 domain (PB1), a ZZ-type zinc finger domain, a nuclear localization signal (NLS), an export motif (NES), an LC3-interacting region (LIR), a Keap1-interacting region (KIR), and a C-terminal ubiquitin-associated domain (UBA) , 25 , the Ras/MAPK pathway, the JNK/c-Jun pathway and some chemical compounds  . ProteasUbiquitination is integral to the proteolytic system. Ubiquitin possesses 76 amino acid residues and is highly conserved from yeast to humans. It also possesses some non-proteolytic functions, including vesicle trafficking via ubiquitination of membrane proteins, protein kinase activation, DNA repair and chromatin dynamics through monoubiquitinated histone. A common mechanism involves ubiquitin or polyubiquitin chains recruiting ubiquitin receptors to perform biological functions .Ubiquitin is involved in three degradation pathways . The triage of ubiquitinated proteins is probably based on their location, the ubiquitin chain length and the linkage types. The three degradation pathways may be interdependent on the ubiquitin pool in the cell . Based oThe K48 chain is a classical sign of proteasomal degradation . K63 is It should be noted that K48 is still the common linkage targeting proteins to the proteasome. During proteasomal degradation, the length of the substrate proteins determines whether the process is mediated by mono- or polyubiquitination . The exiThe UBA domain of p62 can bind K48 and K63 (with a higher affinity for K63) , 44, 45.Drosophila to mice suggest that the inactivation of autophagy by pharmacological or genetic inhibition causes the accumulation of ubiquitinated proteins in the brain [Determining the overall contribution of UPS and autophagy to ubiquitinated protein degradation is a topic of considerable interest. Studies with subjects ranging from he brain , 49, skehe brain . In theihe brain , 50. DifDrosophila [As mentioned previously, p62 delivers ubiquitinated cargoes for autophagic degradation via the C-terminal UBA domain or the LIR domain, and then the PB1 domain promotes the process . Activatosophila ).In HeLa cells, p62 overexpression has no influence on the autophagic vacuole number and p62 knockdown does not have an effect on autophagic flux , 56, 57.Drosophila [p62 is localized to ubiquitin-positive inclusions, which is a common phenomenon that can be observed in some diseases, such as neurodegeneration . Collectosophila . The totosophila . Therefoosophila , 21, 55.p62 is widely used as a predictor of autophagic flux , since iAnother issue is the degradation process. It has been reported that Pan-cathepsin inhibitors and bafilomycin A1 can stop the degradation of p62 . We shouDuring starvation, the expression level of p62 does not always inversely correlate with autophagy activity. Not only can autophagy be induced, but p62 transcriptional synthesis is also active upon starvation , 66. p62The significance of p62 restoration might be the integration of different proteins to fulfill specific functions, since the other domains of p62 get involved in many signal pathways. Besides, p62 knockdown likely activates autophagy through mTORC1 inhibition in response to starvation, since p62 is a positive regulator of mTORC1 . This crNatura et al. used the proximity ligation assay (PLA) to reveal that p62 and the proteasome are co-localized in situ under basal conditions. They also found that p62 aggregates contain inactive proteasome, ubiquitinated proteins and autophagosome upon proteasome inhibition . It has The N-terminal PB1 domain of p62 might interact with Rpt1 and S5a/Rpn10 of the 26S proteasome and collaborate with the C-terminal UBA domain of p62 by binding ubiquitinated proteins to facilitate UPS degradation , 68. p62These studies indicate that p62 is also involved in the proteasomal degradation of ubiquitinated proteins in the nucleus via its NLS and NES domains and in the cytosol via its PB1 domain. Therefore, it naturally contributes to both nuclear and cytosolic protein quality control. Besides, the PEST domain serves as a proteolytic signal for rapid degradation, leading to short intracellular half-lives, which may relate to proteasome function . For insPharmacological inhibition of UPS enhances p62 transcription , 71 and Overexpressed p62 can enhance protein aggregation and has a protective effect on cell survival as described above. p62 deletion barely decreases the amount of ubiquitinated puncta in autophagy normal cells. Although p62 is not necessary for all the formation of ubiquitinated aggregation, it still plays a crucial role in aggregate degradation.Proteasome inhibition can activate autophagy, in which p62 is the bridge . First, The S351 of KIR is phosphorylated, leading to a rising affinity of p62 for Keap1 and followed by sequestration of Keap1 on the cargoes . SubsequNF-E2-related factor 2 (Nrf2), a transcription factor that controls the expression of an abundance of anti-oxidant genes, is degraded by the proteasome via the Cul3–Keap1–E3 ligase complex under basal conditions. However, during oxidative stress, p62 expression is upregulated by the nuclear import of Nrf2 resulting from the blocked interaction between Keap1 (a negative regulator of Nrf2) and Nrf2. The increased p62 can compete with Nrf2 for Keap1 at the Nrf2-binding site, forming a positive feedback loop . All of While proteasome deficiency enhances autophagy, autophagy inactivation compromises the ubiquitin–proteasome system due to surplus p62, which delays proteasomal substrate delivery to the proteasome with no changes shown in proteasomal catalytic activity . It is pThe terms ‘aggresome’, ‘aggregate’, and ‘inclusion bodies’ are used to describe misfolded protein granules in cells. In 1998, the aggresome was defined as a ‘pericentriolar membrane-free, cytoplasmic inclusion containing misfolded ubiquitinated proteins encased in a cage of intermediate filament proteins that co-localize with the microtubule organizing center (MTOC)’, in which the autophagosome and lysosome fuse . The ‘agAlthough the aggresome was initially used to describe the disease-associated inclusion bodies formed in neurodegenerative diseases, e.g., Lewy bodies in Parkinson’s disease and hyaline inclusion bodies in amyotrophic lateral sclerosis (ALS), the relevance of the aggresome to inclusions in disease is still disputable . Almost There is a common consensus that misfolded proteins aggregate and are concentrated in the aggresome, which is removed via the autophagy–lysosome pathway . DegradaBecause the UPS, autophagy and p62 are the interdependent elements of the protein quality control system, they must act in a networked manner to maintain proteostasis. p62 may serve as an integration center for multiple functions, including the formation of the autophagosome, the delivery of ubiquitinated proteins to the proteasome, and aggregate formation for autophagic clearance. It is also involved in several signaling pathways , 89. In


In normally proliferating cells, p53 protein levels and function are tightly controlled by main regulators, i.e., MDM2 (mouse double minute 2) and MDM4 proteins. p53 plays an important role due to its ability to mediate tumor suppression. In addition to its importance as a tumor suppressor, p53 coordinates diverse cellular responses to stress and damage and plays an emerging role in various physiological processes, including fertility, cell metabolism, mitochondrial respiration, autophagy, cell adhesion, stem cell maintenance and development. Interestingly, it has been recently implicated in the suppression of autoimmune and inflammatory diseases in both mice and humans. In this review based on current knowledge on the functional properties of p53 and its regulatory pathways, we discuss the potential utility of p53 reactivation from a therapeutic perspective in oncology and chronic inflammatory disorders leading to autoimmunity. The promdm4 and mdm2 KO mice is accomplished by an apoptotic outcome in the mdm2 KO and mostly by a growth arrest response in the mdm4 KO [In normally proliferating cells, p53 is tightly controlled by the function of its main regulators, MDM2 (mouse double minute 2) and MDM4 proteins, which perform non-redundant activities . Indeed, mdm4 KO ,24,25. T mdm4 KO .The role of p53 in human cancer has been the object of intensive investigations. Leading to evidence on the different mechanisms by which this protein mediates tumor suppression . Recent A variety of tumor suppressive mechanisms underlie the onset and progression of cancers. To inhibit tumor proliferation effectively, fine sensors are needed to single out the normal versus neoplastic growth . p53 serAs evidence of its protective role against tumor development, loss or mutation of p53 predisposes to a variety of spontaneous and induced tumors in animal models ,45. MostIn those tumors that retain the wild-type p53 protein, its pathway is, however, abrogated, leading to aberrant p53 inactivation and avoidance of the tumor suppressor response . These iRegarding the different approaches to reactivate p53, whenever this protein is found as awild type in tumors and the p53-regulatory pathways are defective, the approach to its reactivation is the use of small molecules or peptides to inhibit the N-terminal interaction between p53 and MDM2 or MDM4. Most of these molecules induce p53 activation by disruption of its binding to MDM2, either acting in the p53 binding cleft of MDM2  or by dWhenever p53 is mutated, such mutations lead to structural defects that prevent its appropriate folding, thus abolishing its binding to DNA. The ability of a molecule that acts as a chaperone to restore and stabilize the correct protein conformation was exploited . This aIt must be emphasized that other strategies in the field of cancer therapeutics might be linked to the p53 pathway. One example is evident in the reactivation of the tumor suppressor retinoblastoma susceptibility gene (RB) through RB-inducing agents. RB protein plays an important role in faithful chromosome segregation, checkpoint control, apoptosis, senescence and terminal differentiation. This protein suppresses tumor formation by means of its multiple biological functions. Moreover, RB has been shown to bind to MDM2, the negative regulator of p53. By doing so, RB positively regulates p53 apoptotic activity . AnotherThe role of p53 in inflammation has been extensively in experimental animal models especially in reference to non-organ specific autoimmune diseases ,67,68,69−/−p53 macrophages exhibited a higher innate immune response to lipopolysaccharide (LPS) and interferon γ (IFN γ) compared to +/+p53 mice. They provide evidence that p53 deficiency increases the incidence of T1D caused by p53-mediated inhibition of proinflammatory cytokines and of total and phosphorylated signal transducer and activator of transcription STAT-1.As regards to organ-specific autoimmune diseases, the putative role of the p53 protein has been investigated in insulin-dependent diabetes  . In moreCD4-Cre p53 fl/fl mice or p53 conditional KO mice. They found that aged p53/cKO mice spontaneously developed several inflammatory diseases such as thyroiditis, sialoadenitis, interstitial pneumonitis, hepatis, gastritis and glomerulonephritis. Moreover, they observed that in p53/KO mice the development of inflammatory lesions was paralleled by the reduction of FoxP3 CD4+CD25+ Treg. These data strongly support the putative effect of p53 in inducing the expression of FoxP3, i.e., a master regulator of Treg, by binding to the promoter and the conserved noncoding DNA sequence-2 of the Foxp3 gene. Interestingly, p53’s effects appeared to be on the development and maintenance of Treg rather than on their suppressive function [In the light of the foregoing, the mechanism by which p53 is involved in the suppression of autoimmunity development remains to be further elucidated. While unravelling this issue, we have to bear in mind that, as for many transcription factors, the net effect of the protein comes from the balance of its expression in cells of the immune system as well as in non-immune cells such as the pancreatic islets in T1D. As regards several functionally distinct peripheral T cell subpopulations, they play a pivotal role in the control of the immunological response, i.e., effector, regulatory and memory T cells. In normal conditions, T regulatory cells (Treg) are present in the peripheral blood where they represent approximately 2%–5% of the total pool. FoxP3 (forkhead box P3) Treg originate in the thymus as a naturally arising subset and in the peripheral compartment as an inducible population . Treg plfunction .−/−p53 mice decreased the activity of signal transducer and activator of transcription 5 (STAT-5), lowered the level of STAT-5 and compromised Treg cell differentiation. CD4+ T cells from −/−p53 mice were less prone to differentiate toward Treg expressing lower FoxP3 levels. They also demonstrated that p53 regulates Treg cell differentiation by interacting directly with STAT-5. In inflammatory conditions p53 suppressed Th17 cell differentiation skewing T cells toward Treg through STAT-5 signaling. In mice affected by collagen-induced arthritis, administration of a p53 overexpression vector or an antagonist of MDM2 controlled arthritis development [Of note, Park et al.  investigelopment . Consistelopment .Interestingly, activation-induced cell death (AIDC) of T lymphocytes is a recognized mechanism of immune regulation ensuring the control of the size of the activated pool of T cells subsequent to its expansion . CaspaseSeveral studies also document the effect of p53 in human experimental models of inflammation. NK-κB and p53, known to exert opposite effects in cancer cells, coregulate proinflammatory cytokine secretion in primary human monocytes and macrophages, thus modulating their control on tissue microenvironment . A novelGene expression microarrays analysis of patients with benign multiple sclerosis (BMS) revealed a signature with 30 p53 target genes. Among these, 19 had expression consistent with activation of p53 protein . FurtherIn recent years, longitudinal observational studies have highlighted a bidirectional and dynamic link between cancer and autoimmunity, especially for non-organ-specific rheumatic diseases . The assThe underlying reason for this increased risk remains to be elucidated at the molecular level although in some patients a common inciting trigger may act for both cancer and “paraneoplastic” autoimmune disease .Skp2 (S-phase kinase associated protein 2) and ErbB2  involved in cancer progression, was detected in p53-dependent DNA damage responses in human breast and colon cancer cells [Recent evidences further support the double role of p53 in cancer and autoimmunity. As regards the expression of FoxP3, as master regulator suppressing breast cancer oncogenes er cells . In the Remarkably, to further unravel this issue, it is interesting to observe the secondary autoimmune responses detected in cancer patients. In relation to this phenomenon, p53 Abs were detected in the sera of patients affected by pancreatic adenocarcinoma, serous ovarian and breast cancer . These hDiscovery of new molecular targets for treatment of pathological conditions at increased incidence worldwide is an area in which considerable efforts are being employed to develop new and safe therapeutic agents . In the Recently, in addition to reactivating p53 by targeting the interface between the protein and MDM2 or MDM4, novel strategies have been proposed that interfere with MDM2/MDM4 heterodimerization  Figure . These cNevertheless, as for every new area of drug discovery, safety and efficacy concerns must be addressed both in preclinical and clinical settings, especially when a certain cell type has to be targeted and/or a biological effect is desired. Side effects can be produced by inappropriate dosing, such as suppressive effects on wound healing or tissue repair following toxic or ischemic damage or impaired host defense responses . Thus, aIn the light of the foregoing, activation or restoring of p53 pathway has already reached the step of clinical trial exploitation . As rega


S. cerevisiae or TER94 in Drosophila) is one of the most abundant cytosolic ATPases. It is highly conserved from archaebacteria to eukaryotes. In conjunction with a large number of cofactors and adaptors, it couples ATP hydrolysis to segregation of polypeptides from immobile cellular structures such as protein assemblies, membranes, ribosome, and chromatin. This often results in proteasomal degradation of extracted polypeptides. Given the diversity of p97 substrates, this “segregase” activity has profound influence on cellular physiology ranging from protein homeostasis to DNA lesion sensing, and mutations in p97 have been linked to several human diseases. Here we summarize our current understanding of the structure and function of this important cellular machinery and discuss the relevant clinical implications.p97/VCP (known as Cdc48 in  ATPases associated with various cellular activities) ATPase family, which functions generally as essential chaperones to promote protein folding or unfolding. Cdc48 was initially identified in S. cerevisiae as a cell cycle regulator, which upon inactivation, leads to a cell cycle arrest at the G2-M transition stage  has been used given the partial localization of this enzyme to the endoplasmic reticulum (ER) surface , Golgi, mitochondria, and endosomes  for these domains   to the overall ATPase activity  that threads polypeptides through a central tunnel  present in gp78  domain of the peptide-N-glycanase (PNGase) bound by a 10-residue peptide from the p97 C-terminus dubbed as PUB-interacting motif (PIM) Figure . PNGase Several p97-adaptor assemblies have also been examined by Cryo-EM  or that bound by p47 (PDB:1S3S) or other adaptors showed no obvious change in the structure of p97 upon adaptor binding  can act in conjunction with Ufd1 and Npl4 to recruit substrates to Cdc48 in MAD  by extracting polypeptides from mitochondrial outer membrane   for lysosomal degradation via autophagasomes. However, the precise function of p97 in this process is controversial, mainly because the substrate(s) regulated by p97 is unclear. Several studies suggest p97 as a positive autophagy regulator because its inhibition causes a phenotype reminiscent of what appears to be an autophagasome maturation defect  [also named IBMPFD ], FALS , CMT2Y  , the bones , and/or the brain . To date, more than 40 mutations covering 29 different positions in p97 have been reported in MSP1/IBMPFD patients   is a progressive neurodegenerative disease. It mainly affects the motor neurons in the brain and spinal cord, resulting in death from respiratory failure. While most ALS cases were caused by sporadic mutations, about 10% are considered “familial” because often more than one individual in a family develops the disease. Mutations in at least 18 genes have been identified in familial ALS. Among them, p97 mutations account for less than 2%  is an autosomal dominant axonal peripheral neuropathy characterized by distal muscle weakness and atrophy associated with length-dependent sensory loss. Like ALS, CMT is a clinically and genetically heterogeneous disorder and is divided into subtypes based on genetics, pathology, and electrophysiology of the disease (Dyck and Lambert, in vitro as it preferentially kills cancer cells isolated from patients; and it can synergize with the proteasome inhibitor Bortezomib to induce apoptosis in cancer cells (Wang et al., Given the important roles played by p97 in diverse cellular processes, specific inhibitors of p97 can be useful tools for dissecting the mechanism of p97 action. Early chemical screens focusing on compounds that inhibit ERAD identified two structurally related chemicals (Fiebiger et al., More recently, chemical screens in search of compounds directly targeting p97 have been conducted. Chou and colleagues reported the first reversible p97 D2 inhibitor, DBeQ (Chou et al., In addition to the above-mentioned inhibitors, efforts from several groups have resulted in a large collection of p97 inhibitors Figure  Yi et a. Among tin vitro GFP unfolding assay represent a major step toward fully elucidating the mechanism of this important enzyme. Another key question is to understand the hierarchical organization of cofactor binding in the context of the ATPase cycle and substrate binding cycle. Moreover, animal models bearing disease-associated mutations are needed in order to better appreciate the connections between p97 dysfunction and human diseases. The recent advance in CRISPR technology should dramatically ease the development of these animal models. Finally, given the promising anti-cancer effect of p97 inhibitors, it is anticipated that more p97 inhibitors will be sought, and studies in this direction may one day produce a new class of anti-cancer agent.Through years of studies, we have accumulated a large body of knowledge on the structure and function of p97/Cdc48. Specifically, the identification of new p97 cofactors and substrates has revealed a whole new set of biological functions for this essential chaperone system, and it is anticipated that future studies will further expand the p97 functional repertoire. By contrast, mechanistic dissection of the molecular nature of the “segregase” activity has lagged behind, and many fundamental questions remain unresolved. Among them, the most intriguing one is how conformational changes in p97 generate the proposed “segregase” activity. The recently developed TZ and WT prepared the figures and tables, prepare part of the manuscript. DX and YY wrote the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.