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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Src homology 2 (SH2) domain is a noncatalytic region which is conserved among a number of signaling and transforming proteins, including cytoplasmic protein-tyrosine kinases and Ras GTPase-activating protein (GAP). Genetic and biochemical data indicate that the SH2 domain of the p60v-src (v-Src) protein-tyrosine kinase is required for full v-src transforming activity and may direct the association of v-Src with specific tyrosine-phosphorylated proteins. To test the ability of the v-Src SH2 domain to mediate protein-protein interactions, v-Src polypeptides were expressed as fusion proteins in Escherichia coli. The bacterial v-Src SH2 domain bound a series of tyrosine-phosphorylated proteins in a lysate of v-src-transformed Rat-2 cells, including prominent species of 130 and 62 kDa (p130 and p62). The p130 and p62 tyrosine-phosphorylated proteins that complexed v-Src SH2 in vitro also associated with v-Src in v-src-transformed Rat-2 cells; this in vivo binding was dependent on the v-Src SH2 domain. In addition to binding soluble p62 and p130, the SH2 domains of v-Src, GAP, and v-Crk directly recognized these phosphotyrosine-containing proteins which had been previously denatured and immobilized on a filter. In addition, the SH2 domains of GAP and v-Crk bound to the GAP-associated protein p190 immobilized on a nitrocellulose membrane. These results show that SH2 domains bind directly to tyrosine-phosphorylated proteins and that the Src SH2 domain can bind phosphorylated targets of the v-Src kinase domain.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Cell Biol 1992 Mar
PMID:Multiple SH2-mediated interactions in v-src-transformed cells. 154 18

The p21ras GTPase-activating protein (GAP) down-regulates p21ras by stimulating its intrinsic GTPase activity. GAP is found predominantly as a monomer in the cytosol of normal cells. However, in cells expressing an activated cytoplasmic protein-tyrosine kinase, p60v-src, or stimulated with epidermal growth factor, GAP becomes phosphorylated on tyrosine and serine and forms distinct complexes with two phosphoproteins of 62 and 190 kDa (p62 and p190). In v-src-transformed Rat-2 cells, a minor fraction of GAP associates with the highly tyrosine phosphorylated p62 to form a complex that is localized at the plasma membrane and in the cytosol. In contrast, the majority of GAP enters a distinct complex with p190 that is exclusively cytosolic and contains predominantly phosphoserine. Epidermal growth factor stimulation also induces a marked conversion of monomeric GAP to higher-molecular-weight species in rat fibroblasts. The GAP-p190 complex is dependent on phosphorylation and shows reduced GAP activity. These results indicate that protein-tyrosine kinases induce GAP to form multiple heteromeric complexes, which are strong candidates for regulators or targets of p21ras.
Mol Cell Biol 1991 Apr
PMID:Protein-tyrosine kinases regulate the phosphorylation, protein interactions, subcellular distribution, and activity of p21ras GTPase-activating protein. 200 83

Antibodies to c-fos oncoprotein were produced in rabbits by immunization with synthetic peptides, corresponding to the sequences 6-15 of N-end and 371-380 of C-end of c-fos oncoprotein. C-fos expression was tested with immunoprecipitation and immunoblotting in various transformed cell lines with antibodies to N- and C-decapeptides. It was shown that antibodies to C-terminal decapeptide revealed a c-fos gene product and also some fos-related antigens FRAs 36 kD, 46 kD, 75 kD and 90 kD in rat pheochromocytoma PC-12 cells and mouse carcinoma cell lines MAC-3 and LL. In some cell lines 46 kD FRA was expressed in the absence of p62 c-fos. Besides, different clones of the same cell line cultivated in identical conditions revealed differences in the 46 kD FRA expression. Antibodies to sequence 6-15 of N-end revealed only c-fos products and no FRAs were detected. Therefore FRAs have homology with the c-fos product in the C-terminal region and differ from it in the N-terminal region.
Mol Biol (Mosk)
PMID:[Tumor cell proteins, detected using antibodies to the S- and N-terminal fragments of the fos proto-oncogene product]. 212 73

The interactions of the macrophage colony-stimulating factor 1 (CSF-1) receptor with potential targets were investigated after ligand stimulation either of mouse macrophages or of fibroblasts that ectopically express mouse CSF-1 receptors. In Rat-2 cells expressing the mouse CSF-1 receptor, full activation of the receptor and cellular transformation require exogenous CSF-1, whereas NIH 3T3 cells expressing mouse c-fms are transformed by autocrine stimulation. Activated CSF-1 receptors physically associate with a phosphatidylinositol (PI) 3'-kinase. A mutant CSF-1 receptor with a deletion of the kinase insert region was deficient in its ability to bind functional PI 3'-kinase and to induce PI 3'-kinase activity precipitable with antiphosphotyrosine antibodies. In fibroblasts, CSF-1 stimulation also induced the phosphorylation of the GTPase-activating protein (GAP)-associated protein p62 on tyrosine, although GAP itself was a relatively poor substrate. In contrast to PI 3'-kinase association, phosphorylation of p62 and GAP was not markedly affected by deletion of the kinase insert region. These results indicate that the kinase insert region selectively enhances the CSF-1-dependent association of the CSF-1 receptor with active PI 3'-kinase. The insert deletion mutant retains considerable transforming activity in NIH 3T3 cells (G. Taylor, M. Reedijk, V. Rothwell, L. Rohrschneider, and T. Pawson, EMBO J. 8:2029-2037, 1989). This mutant was more seriously impaired in Rat-2 cell transformation, although mutant-expressing Rat-2 cells still formed small colonies in soft agar in the presence of CSF-1. Therefore, phosphorylation of GAP and p62 through activation of the CSF-1 receptor does not result in full fibroblast transformation. The interaction between the CSF-1 receptor and PI 3'-kinase may contribute to c-fms fibroblast transformation and play a role in CSF-1-stimulated macrophages.
Mol Cell Biol 1990 Nov
PMID:Interactions of phosphatidylinositol kinase, GTPase-activating protein (GAP), and GAP-associated proteins with the colony-stimulating factor 1 receptor. 217 81

UV irradiation of human and murine cells enhances the transcription of several genes. Here we report on the primary target of relevant UV absorption, on pathways leading to gene activation, and on the elements receiving the UV-induced signal in the human immunodeficiency virus type 1 (HIV-1) long terminal repeat, in the gene coding for collagenase, and in the cellular oncogene fos. In order to induce the expression of genes. UV radiation needs to be absorbed by DNA and to cause DNA damage of the kind that cannot be repaired by cells from patients with xeroderma pigmentosum group A. UV-induced activation of the three genes is mediated by the major enhancer elements (located between nucleotide positions -105 and -79 of HIV-1, between positions -72 and -65 of the collagenase gene, and between positions -320 and -299 of fos). These elements share no apparent sequence motif and bind different trans-acting proteins; a member of the NF kappa B family binds to the HIV-1 enhancer, the heterodimer of Jun and Fos (AP-1) binds to the collagenase enhancer, and the serum response factors p67 and p62 bind to fos. DNA-binding activities of the factors recognizing the HIV-1 and collagenase enhancers are augmented in extracts from UV-treated cells. The increase in activity is due to posttranslational modification. While AP-1 resides in the nucleus and must be modulated there, NF kappa B is activated in the cytoplasm, indicating the existence of a cytoplasmic signal transduction pathway triggered by UV-induced DNA damage. In addition to activation, new synthesis of AP-1 is induced by UV radiation.
Mol Cell Biol 1989 Nov
PMID:UV-induced DNA damage is an intermediate step in UV-induced expression of human immunodeficiency virus type 1, collagenase, c-fos, and metallothionein. 255 47

Expression of the Semliki Forest virus p62/E2 protein was studied in the polarized epithelial cell line Madin-Darby canine kidney (MDCK). After infection this transmembrane protein, together with the other spike subunit E1, accumulates at the basolateral surface of MDCK cells (Fuller, S. D., C.-H. von Bonsdorff, and K. Simons, 1985, EMBO (Eur. Mol. Biol. Organ.) J., 4:2475-2485). The cDNAs encoding truncated forms of the protein were used to stably transform MDCK cells to examine the role of subunit oligomerization (E1-E2) and the cytoplasmic domain of p62/E2 in directed transport to the basolateral surface. The biochemical characteristics and polarity of the expressed proteins were studied using cell monolayers grown on nitrocellulose filters. A wild-type form of p62/E2, in the absence of E1, and two forms having either 15 or 3 of the wild-type 31-amino acid carboxyl cytoplasmic domain were all localized to the basolateral surface. These results indicate that the cytoplasmic domain of E2 does not contain the information essential for directed transport to the plasma membrane, and imply that this information resides in either the lumenal and/or membrane-spanning segments of this transmembrane protein.
 ...
PMID:Alteration of the cytoplasmic domain of the membrane-spanning glycoprotein p62 of Semliki Forest virus does not affect its polar distribution in established lines of Madin-Darby canine kidney cells. 353 42

Synthesis of the c-myc gene product was measured during the entire cell cycle of subconfluent mouse 3T3 cells with an antibody raised against a human c-myc synthetic peptide. The antiserum recognized two mouse c-myc-encoded proteins with apparent molecular weights in sodium dodecyl sulfate-polyacrylamide gels of 62,000 and 60,000. Cell-derived p62 was compared with the mouse c-myc gene product synthesized in vitro. Immunoprecipitation, electrophoretic analyses, and peptide mapping provided evidence that p62 is encoded by the mouse c-myc gene. The rate of synthesis of the c-myc proteins was tightly coupled to the cellular growth state of nontransformed A31 3T3 cells, but not to that of their benzo(a)pyrene-transformed derivative (BPA31). Furthermore, the synthesis of the c-myc proteins was stimulated by the exposure of confluent, density-arrested A31 cells to platelet-derived growth factor or fibroblast growth factor. Tightly synchronized cell populations were obtained on the addition of serum factors to subconfluent, serum-deprived A31 cells, and c-myc expression could be monitored for more than one complete cell cycle. One hour after stimulation the steady-state level of the 2.2 kilobase c-myc transcript increased 30-fold relative to that of quiescent cells and decreased thereafter to the level observed during exponential growth. The rate of synthesis of c-myc-encoded proteins was determined by immunoprecipitation after a 2-h labeling period. After an initial sevenfold increase detectable 2 h after serum addition, the rate of synthesis remained constant throughout the rest of the cell cycle. No further changes associated with the late prereplicative period, S phase, G2, or mitosis could be demonstrated. Pulse-chase and long-term labeling experiments revealed different half-lives for the two c-myc-encoded proteins. The half-lives of the c-myc proteins, however, were independent of the cellular growth state. The sustained expression observed throughout the cell cycle suggests that the growth-related function of c-myc may be required during the G0-G1 transition and in all phases of the cycle of the growing cell.
Mol Cell Biol 1985 Nov
PMID:Growth-dependent synthesis of c-myc-encoded proteins: early stimulation by serum factors in synchronized mouse 3T3 cells. 391 69

Tyrphostins are synthetic compounds that have been described as in vitro and in vivo inhibitors of epidermal growth factor receptor tyrosine kinase activity. In NIH/3T3 cells transfected with the c-src/F527 gene, an increase in the level of tyrosine phosphorylation of several proteins, including pp125FAK, within a group of proteins of 120 kDa, of p85 (cortactin), and of p62 is observed, which is due to the elevated kinase activity of the resulting encoded pp60F527 protein. In the transfected cells, we showed that the tyrphostins we used, i.e., AG18, AG34, and AG82, strongly diminished the tyrosine phosphorylation of these proteins. Analysis of the steady state level of pp60F527 in tyr-phostin-treated cells revealed that AG34 and AG82, the two most potent compounds, also induced 30 and 48% decreases, respectively, in the amount of pp60F527, while having no action on the levels of other proteins, especially the pp60F527 kinase substrates. Measurement of the rates of pp60F527 synthesis and degradation showed that this decreased level was due to a slower rate of synthesis in the presence of AG34 and AG82. Tyrphostins also reversed the pp60F527-induced transformed morphology of NIH/3T3 cells and also inhibited the pp60F527 kinase activity in vitro. We conclude that the effects elicited by the tyrphostins occurred not only through the inhibition of the pp60F527 protein kinase activity but also through a selective reduction of the Src protein steady state level in the cases of AG34 and AG82. This is a novel mode of action for these two tyrphostins, which were the most active compounds in this system.
Mol Pharmacol 1994 May
PMID:Effects of tyrphostins on the activated c-src protein in NIH/3T3 cells. 751 14

Src homology 3 (SH3) domains mediate protein-protein interactions necessary for the coupling of cellular proteins involved in intracellular signal transduction. We previously established solution-binding conditions that allow affinity isolation of Src SH3-binding proteins from cellular extracts (Z. Weng, J. A. Taylor, C. E. Turner, J. S. Brugge, and C. Seidel-Dugan, J. Biol. Chem. 268:14956-14963, 1993). In this report, we identified three of these proteins: Shc, a signaling protein that couples membrane tyrosine kinases with Ras; p62, a protein which can bind to p21rasGAP; and heterogeneous nuclear ribonucleoprotein K, a pre-mRNA-binding protein. All of these proteins contain proline-rich peptide motifs that could serve as SH3 domain ligands, and the binding of these proteins to the Src SH3 domain was inhibited with a proline-rich Src SH3 peptide ligand. These three proteins, as well as most of the other Src SH3 ligands, also bound to the SH3 domains of the closely related protein tyrosine kinases Fyn and Lyn. However, Src- and Lyn-specific SH3-binding proteins were also detected, suggesting subtle differences in the binding specificity of the SH3 domains from these related proteins. Several Src SH3-binding proteins were phosphorylated in Src-transformed cells. The phosphorylation of these proteins was not detected in cells transformed by a mutant variant of Src lacking the SH3 domain, while there was little change in tyrosine phosphorylation of other Src-induced phosphoproteins. In addition, the coprecipitation of v-Src with two tyrosyl-phosphorylated proteins with M(r)s of 62,000 and 130,000 was inhibited by incubation with a Src SH3 peptide ligand, suggesting that the binding of these substrate proteins is dependent on interactions with the SH3 domain. These results strongly suggest a role for the Src SH3 domain in the recruitment of substrates to this protein tyrosine kinase, either through direct interaction with the SH3 domain or indirectly through interactions with proteins that bind to the SH3 domain.
Mol Cell Biol 1994 Jul
PMID:Identification of Src, Fyn, and Lyn SH3-binding proteins: implications for a function of SH3 domains. 751 69

p62 is a highly tyrosyl phosphorylated protein that was first identified in immunoprecipitates of the GTPase-activating protein (GAP) of p21ras from cells transformed by oncogenic nonreceptor tyrosine kinases or stimulated through tyrosine kinase receptors (C. Ellis, M. Moran, F. McCormick, and T. Pawson, Nature 343:377-381, 1991). In this article we describe a highly related 62-kDa protein that becomes tyrosyl phosphorylated and associated with phospholipase C gamma (PLC gamma) in C3H10T1/2 cells stimulated with epidermal growth factor (EGF) or transformed by v-src. GAP-associated and PLC gamma-associated p62 comigrated in one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis and exhibited nearly identical phosphotryptic peptide patterns. That the association of p62 with PLC gamma was direct and not mediated through binding of GAP-p62 to PLC gamma or to the EGF receptor (and coprecipitation of the receptor with PLC gamma) was demonstrated by (i) the inability to detect GAP in PLC gamma immunocomplexes or PLC gamma in GAP immunocomplexes, (ii) the association of p62 with PLC gamma in v-src-transformed cells in the absence of EGF stimulation, and (iii) in vitro solution binding and direct blotting of p62 with a glutathione S-transferase fusion protein containing the Src homology 2 (SH2) domains of PLC gamma. Unlike GAP, whose N-terminal SH2 mediates the interaction between GAP and p62, PLC gamma was found to require both its N- and C-terminal SH2 regions for p62 binding. These studies demonstrate that a protein identical to or highly related to GAP-associated p62 binds PLC gamma and suggest a means by which "cross-talk" between PLC gamma- and GAP-mediated signalling may occur.
Mol Cell Biol 1994 Aug
PMID:A protein that is highly related to GTPase-activating protein-associated p62 complexes with phospholipase C gamma. 751 63


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