bluuebunny/crossref_metadata_2025_split huggingface dataset:
A domain of synapsin I involved with actin bundling shares immunologic cross‐reactivity with villin
Authors: Petrucci Tamara C. , Mooseker Mark S. , Morrow Jon S. 
Published: December 2004

AbstractSynapsin I is a neuronal phosphoprotein that can bundle actin filaments in vitro. This activity is under phosphorylation control, and may be related to its putative in vivo role of regulating the clustering and release of small synaptic vesicles. We have compared human and bovine synapsin I by peptide mapping, and have used NTCB (2‐nitro‐5‐thiocyano benzoic acid) cleavage to generate a series of peptide fragments from bovine synapsin I. After chymotryptic digestion, 88% of the tyrosine‐containing fragments appear to be structurally identical in human and bovine synapsin I, as judged by their positions on high‐resolution two‐dimensional peptide maps. The alignment of the NTCB peptides within the parent protein have been determined by peptide mapping, and the ability of these fragments to precipitate with actin bundles has been measured. Only peptides that are derived from regions near the ends of the protein are active. One such 25‐kDa peptide which sediments with actin also cross‐reacts with antibodies to chicken villin, an actin binding and bundling protein derived from the intestinal microvillus. Since in other respects villin appears to be an unrelated protein, these results suggest the possibility that certain actin binding proteins may show immunologic cross‐reactivity due to convergent evolution within the acting binding domain.
Structure‐function studies on Acanthamoeba myosins IA, IB, and II
Authors: Korn Edward D. , Atkinson Mark A. L. , Brzeska Hanna , Hammer John A. , Jung Goeh , Lynch Thomas J. 
Published: December 2004

AbstractMyosins IA and IB are globular proteins with only a single, short (for myosins) heavy chain (140,000 and 125,000 daltons for IA and IB, respectively) and are unable to form bipolar filaments. The amino acid sequence of IB heavy chain shows 55% similarity to muscle myosins in the N‐terminal 670 residues, which contain the active sites, and a unique 500‐residue C‐terminus highly enriched in proline, glycine, and alanine. The C‐terminal region contains a second actin‐binding site which allows myosins IA and IB to cross‐link actin filaments and support contractile activity. Myosins IA and IB are regulated solely by phosphorylation of one serine on the heavy chain positioned between the catalytic site and the actin‐binding site that activates ATPase.Myosins II is a more conventional myosin in composition (two heavy chains and two pairs of light chains), heavy chain sequence (globular head 45% identical to muscle myosins and a coiled‐coil helical tail), and structure (bipolar filaments). The tail of myosin II is much shorter than that of other conventional myosins, and it contains a 25 amino acid sequence in which helical structure is predicted to be weak or absent. The position of this sequence corresponds to the position of a bend in the monomer. Myosin II heavy chains also have a 29‐residue nonhelical tailpiece which contains three regulatory, phosphorylatable serines. Phosphorylation at the tip of the tail regulates ATPase activity in the globular head apparently through an effect on filament structure.
Simultaneous transfer of tumorigenic and metastatic phenotypes by transfection with genomic DNA from a human cutaneous squamous cell carcinoma
Authors: Ananthaswamy Honnavara N. , Price Janet E. , Goldberg Leonard H. , Bales Elise S. 
Published: December 2004

AbstractHigh‐molecular‐weight genomic DNA isolated from a human cutaneous squamous cell carcinoma (AS) was assayed for its ability to induce tumorigenic transformation of NIH 3T3 cells. Subcutaneous injection of NIH 3T3 cells cotransfected with DNAs from AS tumor and pSV2‐neo plasmid not only induced tumors at the site of injection, but also metastasized spontaneously to the lungs in 100% of nude mice injected. DNA isolated from a representative primary tumor and a metastasis was again used in a second round of transfection. Injection of secondary transfectants into nude mice again resulted in induction of both subcutaneous tumors and spontaneous long metastases. Southern blot hybridization with ras‐specific probes revealed that DNA from both primary tumors and metastases induced by AS tumor DNA contained highly amplified Ha‐ras oncogene. Furthermore, DNAs from secondary tumors and metastases induced by DNA from a primary tumor and a metastasis also contained similar highly amplified Ha‐ras oncogene. These results suggest that the amplified Ha‐ras oncogene may be responsible for induction of both tumorigenic and metastatic phenotypes in NIH 3T3 cells transfected with DNA from AS tumor.
Posttranslational modification of ras proteins: Detection of a modification prior to fatty acid acylation and cloning of a gene responsible for the modification
Authors: Tamanoi F. , Hsueh E. C. , Goodman L. E. , Cobitz A. R. , Detrick R. J. , Brown W. R. , Fujiyama A. 
Published: December 2004

AbstractProducts of ras genes are synthesized as precursors in the cytosol and transported to the plasma membrane by a process which involves posttranslational modification by fatty acid. In this paper, we present evidence for the occurrence in the cytosol of an intermediate modification of ras proteins prior to the fatty acid acylation. The modification is detected by a slight shift in the mobility of the protein on SDS polyacrylamide gel. The fatty acid acylation does not contribute to this mobility shift. This modification is affected by the dpr1 mutation which has recently been shown to affect the processing of yeast RAS proteins. To further characterize the nature of the modification event, we have cloned DPR1 gene from the DNA of Saccharomyces cerevisiae. The gene is actively transcribed in yeast cells producing mRNA of approximately 1.6 kb. Genes related to the DRP1 appear to be present in a distantly related yeast, Schizosaccharomyces pombe as well as in guinea pig and human cells.
Gene expression and tumor cell escape from host effector mechanisms in murine large cell lymphoma
Authors: LaBiche Ronald A. , Yoshida Mitsuzi , Gallick Gary E. , Irimura Tatsuro , Robberson Donald L. , Klostergaard Jim , Nicolson Garth L. 
Published: December 2004

AbstractUsing in vivo selection methods, we obtained metastatic sublines of the murine RAW 117 large cell lymphoma that form multiple liver metastases. The highly metastatic subline RAW117‐H10 has a low number of gp70 molecules expressed at the cell surface and low cytostatic sensitivity to activated syngeneic macrophages. This subline was infected with endogenous RNA tumor virus isolated from a high virus‐expressing RAW117‐P subline of low metastatic potential. After superinfection the H10 subline gradually increased its expression of cell surface gp70 and showed enhanced sensitivity to macrophage‐mediated cytostasis, suggesting that gp70 might be involved in host macrophage‐mediated surveillance. Culture of RAW117‐P and H10 cells in media conditioned by activated macrophages indicated that parental cells are severely growth inhibited in a dose dependent fashion while H10 cells showed almost no effect. Examination of differentially expressed genes in the highly metastatic RAW117‐H10 cells by analysis of RNA blots indicated that a mitochondrial gene was expressed at a level that was ∼ 10 times higher in H10 cells than in parental cells. This gene was identified as ND5, which codes for a subunit of NADH dehydrogenase (complex I of the mitochondrial electron transport chain); this complex is the target for an activated macrophage‐released cytostatic factor. Among other possibilities, the results are consistent with the suggestion that highly metastatic RAW 117 cells may escape macrophage surveillance by decreasing the synthesis of specific cell‐surface receptors for cytostatic molecules and increasing the synthesis of specific cellular targets for such molecules.
Comparison of N‐acetylglucosaminyltransferase V activities in Rous sarcoma‐transformed baby hamster kidney (RS‐BHK) and BHK cells
Authors: Arango Juan , Pierce Michael 
Published: December 2004

AbstractRecent studies have desmonstrated that Rous sarcoma virus‐transformed baby hamster kidney (RS‐BHK) cells express twofold higher levels of those N‐linked oligosac‐charides that contain the sequence [GlcNAc‐β(1,6)Man (1,6)] compared to nontrans‐formed parental BHK cells (Pierce and Arango, J. Biol. Chem. 261, 10772 [1986]). We have investigated in RS‐BHK and BHK cells the activity of UDP‐GlcNAc:α‐D‐mannoside β(l,6)N‐acetylglucosaminyltransferase V, the enzyme that begins the synthesis of the sequence that is increased in the RS‐BHK cells. We have measured GnT V activity using UDP‐ [3H]‐ GlcNAc and a synthetic oligosaccharide acceptor, GlcNAcβ(1,2)Man α(1,6)Manβ‐O‐ (Ch2)8COOCH3, separating the radioactive product by a newly devised reverse‐phase chromatographic technique. Assayed under optimal conditions, the specific activity of GnT V is about fourfold higher in RS‐BHK sonicates than in BHK sonicates, suggesting that this increase in activity may be the primary mechanism that causes the increase in [GlcNAcβ(1,6) Man] sequences in the RS‐BHK cells. The apparent Km, values of the enzymes in RS‐BHK and BHK cell sonicates for UDP‐GIcNAc and the synthetic acceptor are similar, as are the pH optima. These results suggest that the increase in GnT V‐specific activity in RS‐BHK cells is not caused by the presence in these cells of a GnT V with markedly different kinetic properties.
Extracellular matrix receptors, ECMRII and ECMRI, for collagen and fibronectin correspond to VLA‐2 and VLA‐3 in the VLA family of heterodimers
Authors: Takada Yoshikazu , Wayner Elizabeth A. , Carter William G. , Hemler Martin E. 
Published: December 2004

AbstractThe Very Late Activation Antigen (VLA) proteins are a family of five related heterodimers, which also are part of the integrin superfamily of cell adhesion molecules. Except for the identification of VLA‐5 as a fibronectin receptor structure, the functions of the VLA proteins have remained unclarified. In this paper, immuno‐precipitation experiments with both anti‐α and anti‐β subunit antibodies showed that the previously identified cell adhesion receptor for collagen, extracellular matrix receptor II (ECMRII), is equivalent to VLA‐2. At the same time a previously described multispecific cell adhesion receptor for collagen, fibroncclin, and laminin (ECMRI) has been shown to be identical to VLA‐3. Although the mAb 12F1 and P1H5 both recognized VLA‐2 (ECMRII), they appeared to define distinct epitopes on the α2 subunit. On the other hand, the mAb PIB5 and J143 recognized the α3 subunit of VLA‐3 (ECMRI) at or near the same site. Consistent with the collagen receptor functions of VLA‐2 (ECMRII) and VLA‐3 (ECMRI), anti‐VLA β antiserum blocked cell attachment to collagen.
Recombinant human granulocyte‐colony stimulating factor and recombinant human macrophage colony stimulating factor synergize in vivo to enhance proliferation of granulocyte‐macrophage, erythroid, and multipotential progenitor cells in mice
Authors: Broxmeyer Hal E. , Williams Douglas E. , Cooper Scott , Hangoc Giao , Ralph Peter 
Published: December 2004

AbstractCombinations of low dosages of purified recombinant human (rh) macrophage colony stimulating factor (M‐CSF; also termed CSF‐1) and rh granulocyte‐colony stimulating factor (G‐CSF) were compared alone and in combination for their influence on the cycling rates and numbers of bone marrow and splenic granulocyte macrophage, erythroid, and multipotential progenitor cells in vivo in mice pretreated with iron‐saturated human lactoferrin (LF). LF was used to enhance detection of the stimulating effects of exogenously added CSFs. Concentrations of each CSF that were not active in vivo when given alone were active when given together, with the other CSF. The concentrations of rhM‐CSF and rhG‐CSF needed to increase progenitor cell cycling in the marrow and spleen were reduced by factors of 40‐200 when these CSFs were administered in combination with low dosages of the other CSF. At the concentrations of rhM‐CSF and rhG‐CSF tested, synergism was not noted on absolute numbers of progenitor cells or total nucleated cell counts per organ o circulating in the blood. These findings may have potential relevance when considered in a clinical setting where the CSFs might be used in combination with other biotherapy and/or chemotherapy.
Colony‐stimulating factor‐1 receptor (c‐fms)
Authors: Sherr Charles J. , Roussel Martine F. , Rettenmier Carl W. 
Published: December 2004

AbstractThe macrophage colony‐stimulating factor, CSF‐1 (M‐CSF), is a homodimeric glycoprotein required for the lineage‐specific growth of cells of the mononuclear phagocyte series. Apart from its role in stimulating the proliferation of bone marrow‐derived precursors of monocytes and macrophages, CSF‐1 acts as a survival factor and primes mature macrophages to carry out differentiated functions. Each of the actions of CSF‐1 are mediated through its binding to a single class of high‐affinity receptors expressed on monocytes, macrophages, and their committed progenitors. The CSF‐1 receptor (CSF‐1R) is encoded by the c‐fms proto‐oncogene, and is one of a family of growth factor receptors that exhibits an intrinsic tyrosine‐specific protein kinase activity. Transduction of c‐fms sequences as a viral oncogene (v‐fms) in the McDonough (SM) and HZ‐5 strains of feline sarcoma virus has resulted in alterations in receptor coding sequences that affect its activity as a tyrosine kinase and provide persistent signals for cell growth in the absence of its ligand. The genetic alterations in the c‐fms gene that unmask its latent transforming potential abrogate its lineage‐specific activity and enable v‐fms to transform a variety of cells that do not normally express CSF‐1 receptors.
Biological functions of serine proteases in mast cells in allergic inflammation
Authors: Katunuma Nobuhiko , Kido Hiroshi 
Published: December 2004

AbstractSerine proteases in mast cell granules, such as chymase, atypical chymase, and tryptase, which are major proteins in the granules, may play important roles in the process of immunoglobulin E (IgE)‐mediated degranulation and in pathobiological alterations in tissues. Indeed, inhibitors of chymase, substrate analogs, and antichymase F(ab′)2, but not inhibitors of tryptase, markedly inhibited histamine release induced by IgE‐receptor bridging but not that induced by Ca ionophore. In contrast, inhibitors of metalloprotease inhibited histamine release induced not only by IgE‐receptor bridging but also by Ca ionophore. These results suggest that chymase and metalloprotease are involved at different steps in the process of degranulation. The extents of inhibition of histamine release were closely correlated with the amounts of the inhibitors of chymase accumulated in the granules. After degranulation, the released proteases may in part contribute to pathobiological alterations in allergic disorders through generations of C3a anaphylatoxin and thrombin by human and rat tryptase, respectively, and those of angiotensin n and a chemotactic factor of neutrophils by human and rat chymase, respectively. Moreover, chymase and atypical chymase from rat were shown to destroy type IV collagen, and human tryptase was found to hydrolyze various plasma proteins, such as fibrinogen and high‐molecular‐weight kininogen. The biological activities of tryptase and chymase from rat may be regulated by their dissociation from and association with trypstatin, an endogenous inhibitor of these proteases.
Pharmacological profile of the substituted beta‐lactam L‐659,286: A member of a new class of human PMN elastase inhibitors
Authors: Bonney R. J. , Ashe B. , Maycock A. , Dellea P. , Hand K. , Osinga D. , Fletcher D. , Mumford R. , Davies P. , Frankenfield D. , Nolan T. , Schaeffer L. , Hagmann W. , Finke P. , Shah S. , Dorn C. , Doherty J. 
Published: December 2004

AbstractHuman polymorphonuclear leukocyte elastase (PMN elastase) is inhibited by L‐659, 286 (7α‐methoxy‐8‐oxo‐3‐[[(1,2,5,6‐tetrahydro‐2‐methyl‐5,6‐dioxo‐1,2,4‐triaz‐in‐3‐yl)thio]methyl]‐5‐thia‐1‐aza‐6R‐bicyclo [4.2.O]oct‐2‐ene‐2‐pyrrolidine carboxamide‐5,‐dioxide) with a Ki of 0.4 μM. This inhibition is time‐dependent, rapid, and only slowly reversible, with a t1/2 of > 3 days at 25°C. L‐659, 286 is also highly selective for PMN elastase, as it does not inhibit thrombin, trypsin, papain, plasmin, chymotrypsin, or cathepsin G. L‐659, 286 administered intratracheally inhibits lung damage caused by administration via the same route of human PMN elastase into hamsters. In marmosets, L‐659, 286 is cleared from blood very rapidly after an intravenous injection but is recovered in bronchoalveolar lavage fluid for several hours after intratracheal administration.
Proteolytic regulation of neurite outgrowth from neuroblastoma cells by thrombin and protease nexin‐1
Authors: Cunningham Dennis D. , Gurwitz David 
Published: December 2004

AbstractThis review summarizes studies on the reciprocal regulation of neuroblastoma neurite outgrowth by thrombin and protease nexin‐1 (PN‐1). PN‐1 recently was shown to possess the same deduced amino acid sequence as the glial‐derived neurite‐promoting factor. The neurite outgrowth activity of PN‐1 depends on its ability to inhibit thrombin. Thrombin not only blocks the neurite outgrowth activity of PN‐1, but it also brings about neurite retraction in the presence of PN‐1. Thrombin also produces neurite retraction in the absence of PN‐1 and other regulatory factors. This suggests that its activity is due to a direct action on cells. The neurite retraction by thrombin depends on its proteolytic activity. It does not occur with the other serine proteases that have been tested, indicating that it is a specific effect and is not due to a general proteolytic effect that could detach neurites from the culture dish. Serum brings about neurite retraction in certain neuroblastoma cells and primary neuronal cultures; most of this activity is due to residual thrombin in the serum. Together, these results suggest that PN‐1 and thrombin (or a thrombin‐like protease) play a role in regulation of neurite outgrowth.
Augmented nuclease activity during cellular senescence in vitro
Authors: Dayton Mark A. , Nahreini Piruz , Srivastava Arun 
Published: December 2004

AbstractThe molecular correlates of the limited proliferative potential of normal human diploid fibroblasts and extensive single‐strand braks in the genomic DNA of these cells were examined by transfection analyses in which DNA replication could be uncoupled from DNA damage and repair. Both supercoiled (fmI), and restriction endonuclease‐cleaved, linear (fmIII) molecules of a well‐defined bacterial plasmid DNA, pBR322, were transfected into, and subsequently recovered from, early and late passage fibroblasts. Southern blot analysis revealed that fmI DNA was converted by random nicks into fmII DNA slightly more rapidly in late passage cells compared with cells at early passage. Similarly, fmII and fmIII DNAs also sustained multiple random nicks and no appreciable net religation of free ends of fmIII DNA could be detected at either passage. In addition, the efficiency of in vitro ligation of fmIII DNA recovered from late passage cells was also reduced, compared with that from early passage cells, as determined by Southern blotting. These data suggest that in the absence of DNA replication, a putative nuclease activity may contribute to DNA damage observed in senescent cells, which, in turn, may be causally related to their limited replicative potential.
Identification of tyrosine‐phosphorylated colony‐stimulating factor 1 (CSF‐1) receptor and a 56‐kilodalton protein phosphorylated in intact human cells in response to CSF‐1
Authors: Huhn Richard D. , Cicione Mary Elizabeth , Frackelton A. Raymond 
Published: December 2004

AbstractColony‐stimulating factor 1 (CSF‐1) selectively supports the survival, proliferation, and maturation of hemopoietic cells of the monocyte/macrophage lineage. Although the cellular receptor for CSF‐1, (the c‐fms protein) is a protein‐tyrosine kinase activated by the binding of CFS‐1, the role of phosphorylation of cellular proteins in CSF‐1 signal transduction is poorly understood. Therefore, we examined the CSF‐1‐stimulated phosphorylation of cellular proteins in human BeWo choriocarcinoma cell line (known to express the c‐fms protein). BeWo cells were metabolically labeled with 32Pi, stimulated with recombinant human CSF‐1, and extracted with detergent. Phosphotyrosyl proteins were isolated from detergent extracts by affinity chromatography on a highly specific antibody to phosphotyrosine. Rapid phosphorylation of 170‐kd protein, followed closely by the phosphorylation of a 56‐kd protein, was observed in response to CSF‐1. The 170‐kd phosphotyrosyl protein bound to wheat germ agglutinin and was secondarily immunoprecipitated with a specific anti‐fms serum, consistent with its identity as the CSF‐1 receptor. Although purified human macrophages that proliferate in culture in response to CSF‐1 are not generally accessible, CSF‐1 did stimulate the phosphorylation of a 56‐kd protein in intact mononuclear leukocytes from human peripheral blood. Thus, the BeWo cell line may represent a good model for the study of CSF‐1‐stimulated cellular protein phosphorylation.
The role of Asp‐49 and other conserved amino acids in phospholipases A2 and their importance for enzymatic activity
Authors: van den Bergh Carel J. , Slotboom Arend J. , Verheij Hubertus M. , de Haas Gerard H. 
Published: December 2004

AbstractThe role of aspartic acid‐49 (Asp‐49) in the active site of porcine pancreatic phospholipase A2 was studied by recombinant DNA techniques: two mutant proteins were constructed containing either glutamic acid (Glu) or lysine (Lys) at position 49. Enzymatic characterization indicated that the presence of Asp‐49 is essential for effective hydrolysis of phospholipids. Conversion of Asp‐49 to either Glu or Lys strongly reduces the binding of Ca2+ ions, in particular for the lysine mutant, but the affinity for substrate analogues is hardly affected. Extensive purification of naturally occurring Lys‐49 phospholipase A2 from the venom of Agkistrodon piscivorus piscivorus yielded a protein that was nearly inactive. Inhibition studies showed that this residual activity was due to a small amount of contaminating enzyme and that the Lys‐49 homologue itself has no enzymatic activity. Our results indicate that Asp‐49 is essential for the catalytic action of phospholipase A2. The importance of Asp‐49 was further evaluated by comparison of the primary sequences of 53 phospholipases A2 and phospholipase homologues showing that substitutions at position 49 are accompanied by structural variations of otherwise conserved residues. The occurrence of several nonconserved substitutions appeared to be a general characteristic of nonactive phospholipase A2 homologues.