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Query: EC:2.7.10.2 (focal adhesion kinase)
 44,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We show in this report that two v-src substrate proteins, p130Cas and cortactin, become tyrosine-phosphorylated during integrin-mediated cell adhesion to extracellular matrix substrata and upon cell attachment onto immobilized anti-integrin antibodies. This tyrosine phosphorylation does not occur when cells attach to polylysine or through antibodies against major histocompatibility complex. It also does not take place when adhesion-mediated reorganization of the actin cytoskeleton is inhibited with cytochalasin D. Tyrosine phosphorylation of p130Cas and cortactin coincides with tyrosine phosphorylation of focal adhesion kinase during integrin-mediated cell adhesion but is independent of cell adhesion in v-src-transformed cells. The tyrosine-phosphorylated sites in p130Cas and cortactin may serve as binding sites for proteins containing Src homology 2 domains, as is the case with two other integrin-regulated docking proteins, focal adhesion kinase and paxillin. Thus, these results suggest that ligand binding of integrins regulates the tyrosine phosphorylation state of multiple docking proteins. These proteins may mediate anchorage dependence of growth; their misregulation in v-src-transformed and other tumorigenic cells may be responsible for the anchorage independence of such cells.
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PMID:Tyrosine phosphorylation of p130Cas and cortactin accompanies integrin-mediated cell adhesion to extracellular matrix. 754 76

The intracellular protein tyrosine kinase FAK (focal adhesion kinase) was originally identified gy its high level of tyrosine phosphorylation in v-src-transformed cells. FAK is also highly phosphorylated during early development. In cultured cells it is localized to focal adhesion contacts and becomes phosphorylated and activated in response to integrin-mediated binding of cells to the extracellular matrix, suggesting an important role in cell adhesion and/or migration. We have generated FAK-deficient mice by gene targeting to examine the role of FAK during development. Mutant embryos displayed a general defect of mesoderm development, and cells from these embryos had reduced mobility in vitro. Surprisingly, the number of focal adhesions was increased in FAK-deficient cells, suggesting that FAK may be involved in the turnover of focal adhesion contacts during cell migration.
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PMID:Reduced cell motility and enhanced focal adhesion contact formation in cells from FAK-deficient mice. 756 54

As cells adhere to extracellular matrix proteins, several focal adhesion proteins become tyrosine phosphorylated. One of the most prominent of these has been identified as the tyrosine kinase p125FAK (focal adhesion kinase, FAK). An interaction between FAK and members of the Src family tyrosine kinases p59fyn, pp60v-src, and activated pp60c-src (527F) has been demonstrated, raising the possibility that these kinases may regulate FAK activity. To explore the role of Src family kinases in focal adhesions and in the regulation of FAK activity, we isolated fibroblasts from transgenic mice that lack either pp60c-src, p59fyn, or pp62c-yes. These primary fibroblasts, and those of a control mouse, were passaged numerous times and resulted in spontaneously immortalized cell lines without the addition of transforming agents. After confirming the absence of the appropriate nonreceptor tyrosine kinases in the fyn-, src- and yes- fibroblasts, the ability of these fibroblasts to form focal adhesions and stress fibers was assessed by immunofluorescence microscopy and found to be comparable to that of normal fibroblasts. We investigated phosphotyrosine levels in response to adhesion to fibronectin and identified the pp60src substrate p130 as the one major protein with reduced levels of tyrosine phosphorylation in the cells lacking p59fyn and pp62c-yes, and particularly in those lacking pp60c-src. We examined FAK phosphorylation and kinase activity and found that there were no significant differences between these cells.
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PMID:An examination of focal adhesion formation and tyrosine phosphorylation in fibroblasts isolated from src-, fyn-, and yes- mice. 758 9

Effects of various types of protein kinase inhibitor on the adhesion and spreading of BALB/c mouse 3T3 cells and on the phosphorylation and stability of focal adhesion kinase (FAK) in the cells were studied. Inhibitors of protein tyrosine kinases, methyl 2,5-dihydroxycinnamate and herbimycin A, inhibited tyrosine-phosphorylation of FAK and the adhesion of 3T3 cells to fibronectin. Among inhibitors of serine/threonine kinases tested, calphostin C, a specific inhibitor of protein kinase C, inhibited cell spreading rather than cell adhesion, and it induced the decrease of intracellular FAK within 30 min. Inhibitors of tyrosine kinase, A kinase, G kinase, and myosin light chain kinase did not induce such a rapid and specific decrease of FAK. When calphostin C (20 microM) was added to sub-confluent monolayer cultures, serine-phosphorylation of FAK was inhibited by 67% within 2 h, and decrease in the amount of FAK and rounding up of the cells began after 4 h. Label-chase experiments indicated that about 60% of 35S-labeled FAK degraded within 1-2 h after addition of calphostin C to monolayer cultures. These results indicated that serine-phosphorylation of FAK induced by protein kinase C was important in the regulation of metabolic stability of FAK.
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PMID:Possible role of protein kinase C in the regulation of intracellular stability of focal adhesion kinase in mouse 3T3 cells. 758 52

Involvement of tyrosine phosphorylation in osteoclastic bone resorption was examined using osteoclast-like multinucleated cells prepared from co-cultures of mouse osteoblastic cells and bone marrow cells in the presence of 1 alpha,25-dihydroxyvitamin D3. When osteoclast-like cells were plated on culture dishes in the presence of 10% fetal bovine serum, they were sharply stained in their peripheral region by anti-phosphotyrosine antibody. Western blot analysis revealed that 115- to 130-kD proteins were tyrosine-phosphorylated in osteoclast-like cells. Using immunoprecipitation and immunoblotting, one of the proteins with 115-130 kD was identified as focal adhesion kinase (p125FAK), a tyrosine kinase, which is localized in focal adhesions. Immunostaining with anti-p125FAK antibody revealed that p125FAK was mainly localized at the periphery of osteoclast-like cells. Herbimycin A, a tyrosine kinase inhibitor, not only suppressed tyrosine phosphorylation of p125FAK but also changed the intracellular localization of p125FAK and disrupted a ringed structure of F-actin-containing podosomes in osteoclast-like cells. Antisense oligodeoxynucleotides to p125FAK inhibited dentine resorption by osteoclast-like cells, whereas sense oligodeoxynucleotides did not. These results suggest that p125FAK is involved in osteoclastic bone resorption and that tyrosine phosphorylation of p125FAK is critical for regulating osteoclast function.
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PMID:Possible involvement of focal adhesion kinase, p125FAK, in osteoclastic bone resorption. 759 64

Macrophage colony-stimulating factor (M-CSF) is required for the growth and differentiation of mononuclear phagocytes. In the present studies using human monocytes, we show that M-CSF induces interaction of the Grb2 adaptor protein with the focal adhesion kinase pp125FAK. The results demonstrate that tyrosine-phosphorylated pp125FAK directly interacts with the SH2 domain of Grb2. The findings indicate that a pYENV site at Tyr-925 in pp125FAK is responsible for this interaction. We also demonstrate that the Grb2-FAK complex associates with the GTPase dynamin. Dynamin interacts with the SH3 domains of Grb2 and exhibits M-CSF-dependent tyrosine phosphorylation in association with pp125FAK. These findings suggest that M-CSF-induced signaling involves independent Grb2-mediated pathways, one leading to Ras activation and another involving pp125FAK and a GTPase implicated in receptor internalization.
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PMID:Stimulation of human monocytes with macrophage colony-stimulating factor induces a Grb2-mediated association of the focal adhesion kinase pp125FAK and dynamin. 759 91

The family of protein kinases includes many oncogenes and growth factor receptors, many of which have been linked to the pathogenesis and progression of cancer. Protein tyrosine kinases such as HER-2/c-erbB-2 and the epidermal growth factor receptor (EGFR) have been linked specifically to breast cancer, and perturbations of HER-2 affect response to chemotherapy. We have reviewed the biology of protein kinases in human breast cancer, as well as their translational applications to breast cancer patients. We have studied the spectrum of protein kinases expressed in human breast cancer cells and have identified four protein kinases with potentially important functions in breast cancer: rak (src-related), TK5 (which we now designate JAK3), the focal adhesion kinase (FAK), and STK1 (human M015/CAK). We describe the potential significance of these genes in breast cancer, as well as our methodology for identifying and characterizing novel genes in breast cancer.
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PMID:Protein kinases in human breast cancer. 761 97

The concomitant tyrosine phosphorylation of the focal adhesion protein, paxillin, and the tyrosine kinase, focal adhesion kinase (FAK), in response to multiple stimuli including integrin-mediated cell adhesion suggests that paxillin phosphorylation is closely coupled to FAK activity. In the present study, we have identified a specific tyrosine residue within paxillin, tyrosine 118 (Tyr-118), that represents the principle site of phosphorylation by FAK in vitro. The identification of this site as a target for FAK phosphorylation was accomplished by immunoprecipitating FAK and performing in vitro kinase assays, using as substrate either glutathione S-transferase (GST)-paxillin fusion proteins containing truncations in paxillin sequence or fusion proteins with phenylalanine substitutions for tyrosine residues. GST-paxillin containing a phenylalanine substitution at Tyr-118 (Y118F) was not phosphorylated by FAK immunoprecipitates; however, this mutant was shown to bind FAK equally as well as the wild type fusion protein. As a first step toward assessing the function of paxillin phosphorylation on Tyr-118, a Y118F paxillin cDNA construct was transiently transfected into NIH 3T3 cells. Similar to wild type paxillin, mutated paxillin localized to focal adhesions, indicating that the phosphorylation of paxillin on Tyr-118 is not essential for the recruitment of paxillin to sites of cell adhesion.
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PMID:Characterization of tyrosine phosphorylation of paxillin in vitro by focal adhesion kinase. 761 49

Mouse embryos lacking Csk, a negative regulator of Src family kinases, exhibit defects in neurulation and die at mid-gestation. To determine the role of activated Src family kinases in the csk- phenotype, we have introduced mutations in the src and fyn genes into the csk- mutant background. Genetic analysis reveals that src, but not fyn, is partly epistatic to the csk gene. Biochemical analysis indicates that several cytoskeletal proteins are hyperphosphorylated on tyrosine residues in csk- cells. Regulation of cortactin and tensin hyperphosphorylation is Src-dependent, whereas focal adhesion kinase and paxillin hyperphosphorylation is partly dependent on both Src and Fyn. Furthermore, the src- mutation can restore the normal distribution of cortactin and partly correct filamentous actin organization in csk-cells. Thus, Src family kinases have both specific and overlapping functions in regulation of the cytoskeleton. The disturbance of these functions may be a molecular basis for the phenotype exhibited by csk- mutants.
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PMID:Specific and redundant roles of Src and Fyn in organizing the cytoskeleton. 761 39

The interaction of cells with extracellular matrix proteins plays a critical role in a variety of biological processes. Recent studies suggest that cell-matrix interactions mediated by integrins can transduce biochemical signals to the cell interior that regulate cell proliferation and differentiation. These studies have placed the focal adhesion kinase (FAK), an intracellular protein tyrosine kinase, in a central position in integrin-initiated signal transduction pathways (Zachary, I., and Rozengurt, E. (1992) Cell 71, 891-894; Schaller, M., and Parsons, J. T. (1993) Trends Cell Biol. 3, 258-262). Here, we report data suggesting a possible association of FAK with the cytoskeletal protein talin in NIH 3T3 cells. We have identified a 48-amino acid sequence in the carboxyl-terminal domain of FAK necessary for talin binding in vitro. Furthermore, we have correlated the ability of integrin to induce FAK phosphorylation with its ability to bind talin using a mutant integrin lacking the carboxyl-terminal 13 amino acids. These studies suggest talin may be a mediator for FAK activation in signaling initiated by integrins and may provide an explanation for the dependence on the integrity of actin-cytoskeleton of multiple intracellular signaling pathways converging to FAK activation and autophosphorylation.
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PMID:Interaction of focal adhesion kinase with cytoskeletal protein talin. 762 20


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