Gene/Protein Disease Symptom Drug Enzyme Compound
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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)

Incubation of human platelets with EGTA under conditions that dissociate the alphaIIbbeta3-integrin stimulated tyrosine phosphorylation of pp72(syk) (6.8-fold) and of proteins of 62 (2. 2-fold), 68 (2.5-fold) and 130 kDa (1.4-fold). Stimulation of tyrosine phosphorylation of pp72(syk) was associated with an increase of pp72(syk) kinase activity. In contrast to pp72(syk), tyrosine phosphorylation of the focal adhesion kinase pp125(FAK) was not stimulated by EGTA. Preincubation of platelets with the monoclonal antibody P2, which binds to the alphaIIbbeta3 complex and thus stabilizes it, strongly reduced the increase of tyrosine phosphorylation of pp72(syk), p62, and p68 induced by EGTA. The Y2/51 monoclonal antibody, which recognizes only the beta3 glycoprotein, did not inhibit the stimulation of protein tyrosine phosphorylation evoked by EGTA. Stimulation of tyrosine phosphorylation of pp72(syk), p62, p68, and p130 induced by EGTA was not observed in thrombasthenic platelets, which lack the alphaIIbbeta3-integrin. The results indicate that the dissociation of the alphaIIbbeta3 complex in intact platelets activates pp72(syk). The mechanism of activation was found to be insensitive to inhibition by cAMP and cGMP and only partially dependent on cytosolic Ca2+, suggesting a close functional coupling of alphaIIbbeta3-integrin and pp72(syk). Since platelets retain their discoid shape after EGTA treatment, we further conclude that pp72(syk) stimulation alone is not sufficient for platelet activation.
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PMID:Dissociation of the alphaIIbbeta3-integrin by EGTA stimulates the tyrosine kinase pp72(syk) without inducing platelet activation. 890 Jan 25

The focal adhesion kinase (FAK) and Crk-associated substrate, p130(Cas) (Cas), have been implicated in diverse signaling pathways including those mediated by integrins, G-protein-coupled receptors, tyrosine kinase receptors, and the v-src and v-crk oncogenes. The recent identification of a direct interaction between FAK and Cas prompted the examination of potential regulation of FAK.Cas complexes by factors that result in concomitant increase in their phosphotyrosine content, namely cell adhesion and transformation by Src. Both conditions resulted in elevated FAK.Cas complex levels in nonionic detergent-insoluble fractions, indicating increased association with the cytoskeleton. For activated Src, this effect requires an active Src catalytic domain but not its Src homology 2 (SH2) or Src homology 3 (SH3) domains. FAK kinase domain tyrosines 576 and 577 are also required, suggesting that direct phosphorylation of these sites by Src may influence the solubility and/or stability of the complex. FAK-Cas association was only observed in the context of Cas binding to at least one of two distinct proline-rich sites on FAK. These findings firmly establish a direct interaction between FAK and Cas and demonstrate that Src can influence the subcellular localization of the complex by a tyrosine phosphorylation-dependent mechanism.
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PMID:Complexes of focal adhesion kinase (FAK) and Crk-associated substrate (p130(Cas)) are elevated in cytoskeleton-associated fractions following adhesion and Src transformation. Requirements for Src kinase activity and FAK proline-rich motifs. 903 54

We and others have recently cloned a non-receptor, calcium-dependent tyrosine kinase (CADTK; also known as PYK2, CAKbeta, and RAFTK) that shares both overall domain structure and 45% amino acid identity with p125(FAK). We have studied the signaling, activation, and potential function of these related enzymes in GN4 rat liver epithelial cells that express CADTK and p125(FAK) at roughly similar levels. p125(FAK) is nearly fully tyrosine-phosphorylated in resting GN4 cells. In contrast, while CADTK is not tyrosine-autophosphorylated in untreated cells, angiotensin II increases CADTK Tyr(P) by 5-10-fold. With regard to signaling, CADTK activation is correlated with stimulation of c-Jun N-terminal kinase and p70(S6K) pathways but not with the stimulation of mitogen-activated protein kinase or p90(RSK). In this report we assessed the contribution of CADTK and p125(FAK) to tyrosine phosphorylation of focal contact proteins. In adherent GN4 cells, the constitutive activity of p125(FAK) was correlated with basal paxillin, tensin, and p130(CAS) tyrosine phosphorylation. A rapid increase in the tyrosine phosphorylation of each protein was detected after treatment with angiotensin II or other agonists that stimulate CADTK; the prolonged 3-4-fold increase in paxillin tyrosine phosphorylation was the most substantial change. In the WB cell line that expresses 3-fold less CADTK than GN4 cell line agonist-dependent paxillin tyrosine phosphorylation is similarly reduced. Immunoprecipitation of CADTK from GN4 cells revealed CADTK. paxillin complexes that persisted in 500 mM NaCl but not in 0.1% SDS cell lysis buffer. The complexes were largely independent of the tyrosine phosphorylation state of either protein. Surprisingly, we did not detect p125(FAK).paxillin complexes in immunoprecipitates using either of two p125(FAK) antibodies. When CADTK and p125(FAK) were transiently overexpressed in 293(T) cells, both enzymes associated with paxillin, but the avidity of CADTK appeared to be greater. In addition, in transfected 293(T) cells, complexes between CADTK and another potential substrate, p130(CAS), were detected. In summary, in GN4 rat liver epithelial cells stimulation of CADTK was highly correlated with paxillin tyrosine phosphorylation; in addition, CADTK but not p125(FAK) was complexed to paxillin at detectable levels. This suggests that agonist-dependent cytoskeletal changes in epithelial cells might proceed, in part, by CADTK-dependent mechanisms.
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PMID:Paxillin is tyrosine-phosphorylated by and preferentially associates with the calcium-dependent tyrosine kinase in rat liver epithelial cells. 916 70

pp125(FAK) and CAKbeta/Pyk2/CadTK/RAFTK are related protein-tyrosine kinases. It is therefore of interest whether CAKbeta shares some of the properties of pp125(FAK). Using recombinant glutathione S-transferase fusion proteins, we show that the C-terminal domains of both proteins bind paxillin in vitro. The C-terminal domain of CAKbeta was engineered to be autonomously expressed in chicken embryo cells and, like pp125(FAK) and p41/43(FRNK) (the C-terminal noncatalytic domain of pp125(FAK)), was found to localize to cellular focal adhesions. In contrast, full-length CAKbeta was generally found diffusely distributed throughout the cell, although a fraction of the cells exhibited focal adhesion localization. Vanadate treatment of pp125(FAK)- and CAKbeta-overexpressing CE cells induced a dramatic increase in the phosphotyrosine content of a common set of proteins including tensin, paxillin, and p130(Cas), but some of these substrates, particularly p130(Cas), appeared to be differentially phosphorylated by pp125(FAK) and CAKbeta. Levels of tyrosine phosphorylation were higher in CAKbeta-overexpressing cells, and additional phosphotyrosine-containing species were specifically immunoprecipitated. In addition, vanadate treatment of CE cells overexpressing CAKbeta, but not pp125(FAK) overexpressors, induced a profound morphological change, which could be a consequence of the observed differences in substrate phosphorylation.
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PMID:Differential signaling by the focal adhesion kinase and cell adhesion kinase beta. 931 50

Similar to insulin, osmotic shock of 3T3L1 adipocytes stimulated an increase in glucose transport activity and translocation of GLUT4 protein from intracellularly localized vesicles to the plasma membrane. The docking/fusion of GLUT4 vesicles with the plasma membrane appeared to utilize a similar mechanism, since expression of a dominant interfering mutant of syntaxin-4 prevented both insulin- and osmotic shock-induced GLUT4 translocation. However, although the insulin stimulation of GLUT4 translocation and glucose transport activity was completely inhibited by wortmannin, activation by osmotic shock was wortmannin-insensitive. Furthermore, insulin stimulated the phosphorylation and activation of the Akt kinase, whereas osmotic shock was completely without effect. Surprisingly, treatment of cells with the tyrosine kinase inhibitor, genistein, or microinjection of phosphotyrosine antibody prevented both the insulin- and osmotic shock-stimulated translocation of GLUT4. In addition, osmotic shock induced the tyrosine phosphorylation of several discrete proteins including Cbl, p130(cas), and the recently identified soluble tyrosine kinase, calcium-dependent tyrosine kinase (CADTK). In contrast, insulin had no effect on CADTK but stimulated the tyrosine phosphorylation of Cbl and the tyrosine dephosphorylation of pp125(FAK) and p130(cas). These data demonstrate that the osmotic shock stimulation of GLUT4 translocation in adipocytes occurs through a novel tyrosine kinase pathway that is independent of both the phosphatidylinositol 3-kinase and the Akt kinase.
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PMID:Osmotic shock stimulates GLUT4 translocation in 3T3L1 adipocytes by a novel tyrosine kinase pathway. 934 Nov 92

Integrin-ligand binding induces the tyrosine phosphorylation of various proteins including focal adhesion kinase (pp125(FAK)) and Crk-associated substrate (Cas). FAK is activated and autophosphorylated by the ligation of integrins, although the substrate of FAK has not been revealed. We show here that p130(Cas) and Cas-L are FAK substrates. FAK directly phosphorylates Cas proteins primarily at the YDYVHL sequence that is conserved among all Cas proteins. Furthermore, the phosphorylated YDYVHL sequence is a binding site for Src family protein-tyrosine kinases, and the recruited Src family kinase phosphorylates the other tyrosine residues within Cas. The Cas-L YDYVHL sequence is phosphorylated upon integrin-ligand binding, and this integrin-mediated tyrosine phosphorylation is inhibited by the cotransfection of the FAK COOH-terminal domain that does not contain a kinase domain. These findings strongly suggest that FAK initiates integrin-mediated tyrosine phosphorylation of Cas proteins; then, Src family tyrosine kinases, which are recruited to phosphorylated Cas and FAK, further phosphorylate Cas proteins.
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PMID:Tyrosine phosphorylation of Crk-associated substrates by focal adhesion kinase. A putative mechanism for the integrin-mediated tyrosine phosphorylation of Crk-associated substrates. 936 Sep 83

BCR/ABL is considered responsible for the development of Philadelphia chromosome-positive leukemia. Experimental animal models, such as transgenic mice, have demonstrated unambiguously that Bcr/Abl is capable of inducing leukemogenesis. The adaptor molecule Crkl is a major in vivo substrate of the deregulated Bcr/Abl tyrosine kinase and functions as a molecular link with other signaling proteins. While associated in vivo with Bcr/Abl through its SH3 domain, Crkl can interact simultaneously via its SH2 domain with other tyrosine-phosphorylated proteins. Here we report the identification of prominently tyrosine-phosphorylated proteins with a molecular mass of approximately 110 kDa, which bind specifically to the Crkl SH2 domain in leukemic tissues of P190BCR/ABL transgenic mice. We demonstrate that these proteins are identical to Hef1/Cas-L, which is related to p130(Cas). The proto-oncoprotein p120(Cbl) and Hef1, but not p130(Cas), were detectably phosphorylated on tyrosine in P190Bcr/Abl-expressing leukemic cells and were found in complex with Crkl, showing the existence of protein complexes in P190Bcr/Abl leukemic cells, consisting of P190Bcr/Abl, Crkl, and Hef1 or p120(Cbl). This supports a model in which Crkl acts as mediator between Bcr/Abl and downstream effectors. Since Hef1 is involved in the beta1-integrin signaling pathway, our study demonstrates that Bcr/Abl could specifically interfere with normal beta1-integrin signaling.
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PMID:BCR/ABL-induced leukemogenesis causes phosphorylation of Hef1 and its association with Crkl. 940 82

Previously we have demonstrated that focal adhesion kinase (FAK)-promoted migration on fibronectin (FN) by its overexpression in CHO cells is dependent on FAK autophosphorylation at Y397 and subsequent binding of Src to this site. In this report, we have examined the role of FAK association with Grb2 and p130(Cas), two downstream events of the FAK/Src complex that could mediate integrin-stimulated activation of extracellular signal-regulated kinases (Erks). We show that a Y925F FAK mutant was able to promote cell migration as efficiently as FAK and that the transfected FAK demonstrated no detectable association with Grb2 in CHO cells. In contrast, cells expressing a FAK P712/715A mutant demonstrated a level of migration comparable to that of control cells. This mutation did not affect FAK kinase activity, autophosphorylation, or Src association but did significantly reduce p130(Cas) association with FAK. Furthermore, FAK expression in CHO cells increased tyrosine phosphorylation of p130(Cas) and its subsequent binding to several SH2 domains, which depended on both the p130(Cas) binding site and the Src binding site. However, we did not detect increased activation of Erks in cells expressing FAK, and the MEK inhibitor PD98059 did not decrease FAK-promoted cell migration. Finally, we show that coexpression of p130(Cas) further increased cell migration on FN and coexpression of the p130(Cas) SH3 domain alone functioned as a dominant negative mutant and decreased cell migration. Together, these results demonstrate that p130(Cas), but not Grb2, is a mediator of FAK-promoted cell migration and suggest that FAK/ p130(Cas) complex targets downstream pathways other than Erks in mediating FAK-promoted cell migration.
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PMID:Identification of p130Cas as a mediator of focal adhesion kinase-promoted cell migration. 942 68

Cell adhesion kinase beta (CAKbeta) is a protein tyrosine kinase closely related to focal adhesion kinase (FAK) in structure. CAKbeta contains two proline-rich sequences within its C-terminal region. Since proline-rich sequences present in the corresponding region of FAK are known to mediate protein-protein interactions by binding to SH3 domains, we investigated binding of CAKbeta to a panel of SH3 domains. Affinity precipitation from rat brain lysate revealed selective interactions of CAKbeta with glutathione S-transferase (GST)-fused SH3 domains of p130(Cas)(Cas)-related proteins and Graf. Mutational analysis indicated that the proline-rich sequences of CAKbeta mediate this interaction. Each of the two proline-rich sequences fused to GST bound directly to these SH3 domains in dot blot analysis. A competitive binding assay revealed that the first proline-rich sequence of CAKbeta preferentially associated with the SH3 domain of Cas. The second proline-rich sequence of CAKbeta bound to the SH3 domain of Graf with higher specificity than the corresponding proline-rich sequence of FAK. Finally, we showed co-immunoprecipitation of CAKbeta with Graf from rat brain lysate. These results indicate that CAKbeta associates in vivo with Graf through its SH3 domain.
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PMID:Interaction of two proline-rich sequences of cell adhesion kinase beta with SH3 domains of p130Cas-related proteins and a GTPase-activating protein, Graf. 949 93

Cas-L (pp105), a Crk-associated substrate (p130(Cas))-related protein, was first identified as a 105-kDa protein that is tyrosine-phosphorylated following beta1 integrin cross-linking in T cells. Cas-L contains possible multiple binding sites for the Src homology (SH) 2 domains of various signaling molecules, and appears to be involved in signal transduction through phosphorylated tyrosine-mediated protein-protein interaction. Since Cas-L is preferentially expressed in lymphocytes, it is conceivable that Cas-L plays an important role in lymphocyte-specific signals. Here, we show the involvement of Cas-L in the T cell receptor (TCR)/CD3 signaling pathway. Cas-L is transiently phosphorylated following CD3 cross-linking, and tyrosine-phosphorylated Cas-L binds to Crk and C3G. Furthermore, a Cas-L mutant that lacks the SH3 domain, the binding site for focal adhesion kinase (FAK), is also tyrosine-phosphorylated upon CD3 cross-linking, but not upon beta1 integrin crosslinking, suggesting that FAK is not involved in CD3-dependent Cas-L phosphorylation. Taken together, the present study indicates a novel signaling pathway mediated by tyrosine-phosphorylated Cas-L upon the TCR/CD3 stimulation.
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PMID:T cell receptor-mediated tyrosine phosphorylation of Cas-L, a 105-kDa Crk-associated substrate-related protein, and its association of Crk and C3G. 949 77


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