bluuebunny/crossref_metadata_2025_split huggingface dataset:
The RNA‐binding protein Staufen from rat brain interacts with protein phosphatase‐1
Authors: Monshausen Michaela , Rehbein Monika , Richter Dietmar , Kindler Stefan 
Published: March 2003

AbstractIn mammalian neurones, homologues of the Drosophila RNA‐binding protein Staufen are part of ribonucleoprotein complexes that move bidirectionally along dendritic microtubules and appear to regulate mRNA translocation and translation. In this study, putative components of Staufen granules were identified in a yeast two‐hybrid screen of a rat brain cDNA library with a rat Staufen bait. Protein phosphatase‐1 was found as an interacting partner. Binding appears to be mediated by a five amino acid residue sequence motif (R‐K‐V‐T‐F) in Staufen that is conserved in a number of proteins interacting with the phosphatase. A two amino acid residue mutation within this motif (R‐K‐V‐G‐A) disrupted the interaction. A cytoplasmic interaction of both proteins was shown by coimmunoprecipitation of rat Staufen and protein phosphatase‐1 from the cytoplasm of transfected cells and rat brain homogenates. In mammalian brain, the phosphatase represents the first described endogenous interaction partner of Staufen. In primary hippocampal neurones, both proteins partially colocalize in somata and neuronal processes. Staufen does not modulate the in vitro protein phosphatase activity. These findings show that protein phosphatase‐1 is a native component of Staufen particles. Cellular functions of Staufen may be regulated via phosphorylation or Staufen may recruite the phosphatase into specific ribonucleoprotein complexes.
ProSAP/Shank proteins – a family of higher order organizing molecules of the postsynaptic density with an emerging role in human neurological disease
Authors: Boeckers Tobias M. , Bockmann Jürgen , Kreutz Michael R. , Gundelfinger Eckart D. 
Published: March 2003

AbstractThe postsynaptic density (PSD) is a specialized electron‐dense structure underneath the postsynaptic plasmamembrane of excitatory synapses. It is thought to anchor and cluster glutamate receptors exactly opposite to the presynaptic neurotransmitter release site. Various efforts to study the molecular structure of the PSD identified several new proteins including membrane receptors, cell adhesion molecules, components of signalling cascades, cytoskeletal elements and adaptor proteins with scaffolding functions to interconnect these PSD components. The characterization of a novel adaptor protein family, the ProSAPs or Shanks, sheds new light on the basic structural organization of the PSD. ProSAPs/Shanks are multidomain proteins that interact directly or indirectly with receptors of the postsynaptic membrane including NMDA‐type and metabotropic glutamate receptors, and the actin‐based cytoskeleton. These interactions suggest that ProSAP/Shanks may be important scaffolding molecules of the PSD with a crucial role in the assembly of the PSD during synaptogenesis, in synaptic plasticity and in the regulation of dendritic spine morphology. Moreover the analysis of a patient with 22q13.3 distal deletion syndrome revealed a balanced translocation with a breakpoint in the human ProSAP2/Shank3 gene. This ProSAP2/Shank3 haploinsufficiency may cause a syndrome that is characterized by severe expressive language delay, mild mental retardation and minor facial dysmorphisms.
Comparison of huntingtin proteolytic fragments in human lymphoblast cell lines and human brain
Authors: Toneff Thomas , Mende‐Mueller Liane , Wu Ying , Hwang Shin‐Rong , Bundey Richard , Thompson Leslie M. , Chesselet Marie‐Francoise , Hook Vivian 
Published: March 2003

AbstractProteolytic fragments of huntingtin (htt) in human lymphoblast cell lines from HD and control cases were compared to those in human HD striatal and cortical brain regions, by western blots with epitope‐specific antibodies. HD lymphoblast cell lines were heterozygous and homozygous for the expanded CAG triplet repeat mutations, which represented adult onset and juvenile HD. Lymphoblasts contained NH2‐ and COOH‐terminal htt fragments of 20–100 kDa, with many similar htt fragments in HD compared to control lymphoblast cell lines. Detection of htt fragments in a homozygous HD lymphoblast cell line demonstrated proteolysis of mutant htt. It was of interest that adult HD lymphoblasts showed a 63–64 kDa htt fragment detected by the NH2‐domain antibody, which was not found in controls. In addition, control and HD heterozygous cells showed a common 60–61 kDa band (detected by the NH2‐domain antibody), which was absent in homozygous HD lymphoblast cells. These results suggest that the 63–64 kDa and 60–61 kDa NH2‐domain htt fragments may be associated with mutant and normal htt, respectively. In juvenile HD lymphoblasts, the presence of a 66‐kDa, instead of the 63–64 kDa N‐domain htt fragment, may be consistent with the larger polyglutamine expansion of mutant htt in the juvenile case of HD. Lymphoblasts and striatal or cortical regions from HD brains showed similarities and differences in NH2‐ and COOH‐terminal htt fragments. HD striatum showed elevated levels of 50 and 45 kDa NH2‐terminal htt fragments [detected with anti(1–17) serum] compared to controls. Cortex from HD and control brains showed similar NH2‐terminal htt fragments of 50, 43, 40, and 20 kDa; lymphoblasts also showed NH2‐terminal htt fragments of 50, 43, 40, and 20 kDa. In addition, a 48‐kDa COOH‐terminal htt band was elevated in HD striatum, which was also detected in lymphoblasts. Overall, results demonstrate that mutant and normal htt undergo extensive proteolysis in lymphoblast cell lines, with similarities and differences compared to htt fragments observed in HD striatal and cortical brain regions. These data for in vivo proteolysis of htt are consistent with the observed neurotoxicity of recombinant NH2‐terminal mutant htt fragments expressed in transgenic mice and in transfected cell lines that may be related to the pathogenesis of HD.
Substantial sulfatide deficiency and ceramide elevation in very early Alzheimer's disease: potential role in disease pathogenesis
Authors: Han Xianlin , M. Holtzman David , W. McKeel Daniel , Kelley John , Morris John C. 
Published: March 2003

AbstractIn addition to pathology in the gray matter, there are also abnormalities in the white matter in Alzheimer's disease (AD). Sulfatide species are a class of myelin‐specific sphingolipids and are involved in certain diseases of the central nervous system. To assess whether sulfatide content in gray and white matter in human subjects is associated with both the presence of Alzheimer's disease (AD) pathology as well as the stage of dementia, we analyzed the sulfatide content of brain tissue lipid extracts by electrospray ionization mass spectrometry from 22 subjects whose cognitive status at time of death varied from no dementia to very severe dementia. All subjects with dementia had AD pathology. The results demonstrate that: (i) sulfatides were depleted up to 93% in gray matter and up to 58% in white matter from all examined brain regions from AD subjects with very mild dementia, whereas all other major classes of lipid (except plasmalogen) in these subjects were not altered in comparison to those from age‐matched subjects with no dementia; (ii) there was no apparent deficiency in the biosynthesis of sulfatides in very mild AD subjects as characterized by the examination of galactocerebroside sulfotransferase activities in post‐mortem brain tissues; (iii) the content of ceramides (a class of potential degradation products of sulfatides) was elevated more than three‐fold in white matter and peaked at the stage of very mild dementia. The findings demonstrate that a marked decrease in sulfatides is associated with AD pathology even in subjects with very mild dementia and that these changes may be linked with early events in the pathological process of AD.
Transient changes in mesolimbic dopamine and their association with ‘reward’
Authors: Wightman R. Mark , Robinson Donita L. 
Published: March 2003

AbstractMesolimbic dopaminergic neurons modulate complex circuitry in the ventral forebrain involved in reward processing, although the precise function of the dopaminergic input is debated. Electrophysiological measurements have revealed that mesolimbic dopaminergic neurons can fire in either tonic or phasic modes, and that phasic firing accompanies the alerting or anticipatory phases of reward. However, the neurochemical relevance of this rapid neuronal discharge within the reward processing circuitry is not yet clear, in part because of difficulty in interpretation of extracellular dopamine measurements. Herein, the nature of the information provided by different neurochemical techniques is critically discussed. Classical methods of monitoring dopamine reveal changes in extracellular dopamine resulting from tonic neuronal activity, but do not have the temporal resolution to distinguish concentration transients. However, recent advances in dopamine sensors now enable transient dopamine concentrations resulting from phasic firing to be positively identified and followed on a physiologically relevant timescale. This has enabled demonstrations of discrete, phasic dopamine signals accompanying rewarding or alerting stimuli. Thus, enhanced dopamine release at terminals appears to be coincident with phasic electrical activity at cell bodies. These accumulating data promise to help unravel the precise role of phasic dopamine transmission in reward processing.
The dopamine D1 receptor is a critical mediator for cocaine‐induced gene expression
Authors: Zhang Dongsheng , Zhang Lu , Lou Dan Wen , Nakabeppu Yusaku , Zhang Jianhua , Xu Ming 
Published: March 2003

AbstractThe dopamine D1 receptor plays a major role in mediating behavioral responses to cocaine administration. The time course for the acquisition and the relative stability for the expression of behavioral responses suggest the involvement of enduring neuroadaptations in response to repeated cocaine exposure. Changes in gene expression through the D1 receptors may accompany and mediate the development of such neuroadaptations to repeated cocaine stimulation. To test this possibility, we systematically compared the expression of the fos and Jun family immediate early genes in the nucleus accumbens and caudoputamen in D1 receptor mutant and wild‐type control mice after acute and repeated cocaine exposure. Moreover, we compared the expression of three molecules that have been implicated in mediating the actions of cocaine, Gαolf, β‐catenin and brain‐derived neurotrophic factor, in the two groups of mice before and after cocaine administration. We found that there is a lack of induction of c‐Fos, FosB, Fra‐2 and JunB by acute cocaine exposure, and of ΔFosB by repeated cocaine administration in both the NAc and CPu of D1 receptor mutant mice compared with wild‐type control mice. Moreover, the D1 receptor is differentially required for mediating Gαolf, β‐catenin and BDNF expression in the NAc and CPu upon cocaine exposure. These results suggest that the D1 receptor is a critical mediator for cocaine‐induced expression of these genes.
DLGdifferentially localizes Shaker K+‐channels in the central nervous system and retina of Drosophila
Authors: Ruiz‐Cañada C. , Koh Y. H. , Budnik V. , Tejedor F. J. 
Published: March 2003

AbstractSubcellular localization of ion channels is crucial for the transmission of electrical signals in the nervous system. Here we show that Discs‐Large (DLG), a member of the MAGUK (membrane‐associated guanylate kinases) family in Drosophila, co‐localizes with Shaker potassium channels (Sh Kch) in most synaptic areas of the adult brain and in the outer membrane of photoreceptors. However, DLG is absent from axonal tracts in which Sh channels are concentrated. Truncation of the C‐terminal of Sh (including the PDZ binding site) disturbs its pattern of distribution in both CNS and retina, while truncation of the guanylate kinase/C‐terminal domain of DLG induces ectopic localization of these channels to neuronal somata in the CNS, but does not alter the distribution of channels in photoreceptors. Immunocytochemical, membrane fractionation and detergent solubilization analysis indicate that the C‐terminal of Sh Kch is required for proper trafficking to its final destination. Thus, several major conclusions emerge from this study. First, DLG plays a major role in the localization of Shchannels in the CNS and retina. Second, localization of DLG in photoreceptors but not in the CNS seems to depend on its interaction with Sh. Third, the guanylate kinase/C‐terminal domain of DLG is involved in the trafficking of Shaker channels but not of DLG in the CNS. Fourth, different mechanisms for the localization of Sh Kch operate in different cell types.
Proteomic identification of oxidatively modified proteins in Alzheimer's disease brain. Part II: dihydropyrimidinase‐related protein 2, α‐enolase and heat shock cognate 71
Authors: Castegna Alessandra , Aksenov Michael , Thongboonkerd Visith , Klein Jon B. , Pierce William M. , Booze Rosemarie , Markesbery William R. , Butterfield D. Allan 
Published: March 2003

AbstractAlzheimer's disease (AD) is a neurodegenerative disorder in which oxidative stress has been implicated as an important event in the progression of the pathology. In particular, it has been shown that protein modification by reactive oxygen species (ROS) occurs to a greater extent in AD than in control brain, suggesting a possible role for oxidation‐related decrease in protein function in the process of neurodegeneration. Oxidative damage to proteins, assessed by measuring the protein carbonyl content, is involved in several events such as loss in specific protein function, abnormal protein clearance, depletion of the cellular redox‐balance and interference with the cell cycle, and, ultimately, neuronal death. The present investigation represents a further step in understanding the relationship between oxidative modification of protein and neuronal death in AD. Previously, we used our proteomics approach, which successfully substitutes for labor‐intensive immunochemical analysis, to detect proteins and identified creatine kinase, glutamine synthase and ubiquitin carboxy‐terminal hydrolase L−1 as specifically oxidized proteins in AD brain. In this report we again applied our proteomics approach to identify new targets of protein oxidation in AD inferior parietal lobe (IPL). The dihydropyrimidinase related protein 2 (DRP‐2), which is involved in the axonal growth and guidance, showed significantly increased level in protein carbonyls in AD brain, suggesting a role for impaired mechanism of neural network formation in AD. Additionally, the cytosolic enzyme α‐enolase was identified as a target of protein oxidation and is involved the glycolytic pathway in the pathological events of AD. Finally, the heat shock cognate 71 (HSC‐71) revealed increased, but not significant, oxidation in AD brain. These results are discussed with reference to potential involvement of these oxidatively modified proteins in neurodegeneration in AD brain.
Selective reduction by isolation rearing of 5‐HT1A receptor‐mediated dopamine release in vivo in the frontal cortex of mice
Authors: Ago Y. , Sakaue M. , Baba A. , Matsuda T. 
Published: March 2003

AbstractSerotonin (5‐HT)1A receptors modulate in vivo release of brain monoaminergic neurotransmitters which may be involved in isolation‐induced aggressive behavior. The present study examined the effect of isolation rearing on the 5‐HT1A receptor‐mediated modulation of dopamine (DA), 5‐HT and noradrenaline (NA) release in the frontal cortex of mice. The selective 5‐HT1A receptor agonist (S)‐5‐{3‐[(1,4‐benzodioxan‐2‐ylmethyl)amino]propoxy}‐1,3‐benzodioxole HCl (MKC‐242) increased the release of DA and NA and decreased the release of 5‐HT in the frontal cortex of mice. The effect of MKC‐242 on DA release was significantly less in isolation‐reared mice than in group‐reared mice, while effects of the drug on NA and 5‐HT release did not differ between both groups. The effect of the other 5‐HT1A receptor agonist 8‐hydroxy‐2‐(di‐n‐propylamino)tetralin on cortical DA release was also less in isolation‐reared mice than in group‐reared mice, and that of the drug on cortical 5‐HT release did not differ between both groups. In contrast to MKC‐242‐induced DA release, amphetamine‐induced increase in cortical DA release in vivo was greater in isolation‐reared mice. The present findings suggest that isolation rearing enhances the activity of cortical dopaminergic neurons and reduces selectively the 5‐HT1A receptor‐mediated release of DA in the cortex.
Stress‐mediated signaling in PC12 cells – the role of the small heat shock protein, Hsp27, and Akt in protecting cells from heat stress and nerve growth factor withdrawal
Authors: Mearow K. M. , Dodge M. E. , Rahimtula M. , Yegappan C. 
Published: March 2003

AbstractWe have investigated the role of stress‐activated signaling pathways and the small heat shock protein, Hsp27, in protecting PC12 cells from heat shock and nerve growth factor (NGF) withdrawal‐induced apoptosis. PC12 cells and a stable cell line overexpressing Hsp27 (HSPC cells) were subjected to heat shock. This resulted in the rapid activation of Akt followed by p38 mitogen‐activated protein kinase (MAPK) signaling, with phosphorylation and intracellular translocation of Hsp27 also detectable. Hsp27 was found to form an immunoprecipitable complex with Akt and p38 MAPK in both non‐stimulated and heat shocked cells, although after heat shock there was a gradual dissociation of Akt and p38 from the Hsp27. Cells were differentiated with NGF and then subjected to NGF withdrawal, a treatment which results in substantial cell death over 24–72 h. Hsp27 was shown to be protective against this treatment, since HSPC cells which overexpress Hsp27 showed significantly less cell death than the parental PC12 cells. In addition, we observed that phosphorylation of Akt was maintained in HSPC cells subjected to heat shock and NGF withdrawal compared with the parental cells. Taken together, our results suggest that Hsp27 may protect Akt from dephosphorylation and may also act in stabilizing Akt.
ProSAP/Shank postsynaptic density proteins interact with insulin receptor tyrosine kinase substrate IRSp53
Authors: Bockmann J. , Kreutz M. R. , Gundelfinger E. D. , Böckers T. M. 
Published: March 2003

AbstractThe ProSAP/Shank family of multidomain proteins of the postsynaptic density (PSD) can either directly or indirectly interact with NMDA‐type and metabotropic glutamate receptors and the actin‐based cytoskeleton. In a yeast two hybrid screen utilizing a proline‐rich domain that is highly conserved among the ProSAP/Shank family members, we isolated several cDNA clones coding for the insulin receptor substrate IRSp53. The specificity of this interaction was confirmed in transfected COS cells. Co‐immunoprecipitation of IRSp53 and ProSAP2 solubilized from rat brain membranes indicates that the interaction occurs in vivo. The C‐terminal SH3 domain of IRSp53 is responsible for the interaction with a novel proline‐rich consensus sequence of ProSAP/Shank that was characterized by mutational analysis. IRSp53 is a substrate for the insulin receptor in the brain and acts downstream of small GTPases of the Rho family. Binding of Cdc42Hs to IRSp53 induces actin filament assembly, reorganization and filopodia outgrowth in neuronal cell lines. Our data suggest that IRSp53 can be recruited to the PSD via its ProSAP/Shank interaction and may contribute to the morphological reorganization of spines and synapses after insulin receptor and/or Cdc42Hs activation.
Regulation of taurine transport at the blood–brain barrier by tumor necrosis factor‐α, taurine and hypertonicity
Authors: Kang Young‐Sook , Ohtsuki Sumio , Takanaga Hitomi , Tomi Masatoshi , Hosoya Ken‐ichi , Terasaki Tetsuya 
Published: March 2003

AbstractTaurine is the abundant sulfur‐containing β‐amino acid in brain where it exerts a neuroprotective effect. Although it is known that the blood–brain barrier (BBB) mediates taurine transport, the regulation of taurine transport have not been clarified yet. A conditionally immortalized rat brain capillary endothelial cells (TR‐BBB13), an in vitro model of the BBB, exhibited [3H]taurine uptake, which was dependent on both Na+ and Cl–, and inhibited by β‐alanine. Taurine transporter (TAUT) mRNA was detected in TR‐BBB13 cells, and TAUT protein was also expressed at 70 kDa. TR‐BBB13 cells exposed to 20 ng/mL TNF‐α and under hypertonic conditions showed a 1.7‐fold and 3.2‐fold increase in [3H]taurine uptake, respectively. In contrast, lipopolysaccharide and diethyl maleate did not significantly affect taurine uptake. The taurine uptake was reduced by pre‐treatment with excess taurine (50 mm). The mRNA level of the TAUT in TNF‐α and following hypertonic treatment was greater than that in control cells, whereas that under excess taurine conditions was lower than in controls. Therefore, taurine transport activity at the BBB appears to be regulated at the transcriptional level by cell damage, osmolality and taurine in the brain.
Oxidative modulation of nuclear factor‐κB in human cells expressing mutant fALS‐typical superoxide dismutases
Authors: Casciati Arianna , Ferri Alberto , Cozzolino Mauro , Celsi Fulvio , Nencini Monica , Rotilio Giuseppe , Carrì Maria Teresa 
Published: March 2003

AbstractPrevious evidence supports the notion of a redox regulation of protein phosphatase calcineurin that might be relevant for neurodegenerative processes where an imbalance between generation and removal of reactive oxygen species occurs. We have recently observed that calcineurin activity is depressed in human neuroblastoma cells expressing Cu,Zn superoxide dismutase (SOD1) mutant G93A and in brain areas from G93A transgenic mice, and that mutant G93A‐SOD1 oxidatively inactivates calcineurin in vitro. We have studied the possibility that, by interfering directly with calcineurin activity, mutant SOD1 can modulate pathways of signal transduction mediated by redox‐sensitive transcription factors. In this paper, we report a calcineurin‐dependent activation of nuclear factor‐κB (NF‐κB) induced by the expression of familial amyotrophic lateral sclerosis (fALS)‐SOD1s in human neuroblastoma cell lines. Alteration of the phosphorylation state of IκBα (the inhibitor of NF‐κB translocation into the nucleus) and induction of cyclooxygenase 2 are consistent with the up‐regulation of this transcription factor in this system. All of these modifications might be relevant to signaling pathways involved in the pathogenesis of fALS.