Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

In rabbit aortic vascular smooth muscle cells (VSMC) platelet-derived growth factor BB (PDGF-BB) stimulated the tyrosine phosphorylation of phospholipase C-gamma, p120 GTPase-activating protein, and the p85 alpha subunit of phosphatidylinositol 3'-kinase only at high concentrations (5-25 ng/ml). In contrast, PDGF-BB induced a rapid and concentration-dependent increase in p125 focal adhesion kinase (p125FAK) tyrosine phosphorylation, which was half-maximal and maximum at 1 and 2.5 ng/ml, respectively. Saliently, stimulation of p125FAK tyrosine phosphorylation was sustained at up to 100 ng/ml PDGF-BB and for prolonged times of treatment. With similar concentration dependence, PDGF-BB stimulated the tyrosine phosphorylation of the 68-kDa focal adhesion-associated protein, paxillin. PDGF-BB also induced p125FAK and paxillin tyrosine phosphorylation in human aortic VSMC. PDGF-BB caused no detectable disruption of the actin cytoskeleton in VSMC. PDGF-BB stimulated rabbit VSMC migration with a very similar concentration dependence to that for p125FAK and paxillin tyrosine phosphorylation. PDGF-BB was equally effective in stimulating p125FAK and paxillin tyrosine phosphorylation under conditions similar to those used for cell migration. In Swiss 3T3 fibroblasts, PDGF-BB and -AA stimulated p125FAK tyrosine phosphorylation and cell migration only at low concentrations, and stimulation was abolished at 10-25 ng/ml. PDGF-AA failed to stimulate tyrosine phosphorylation, mitogenesis, and chemotaxis in rabbit VSMC, and immunoblot analysis showed that rabbit VSMC expressed PDGF beta-receptors but no alpha-receptors. These results implicate p125FAK in the chemotactic response to PDGF-BB and suggest that the ability of PDGF-BB to trigger the p125FAK pathway may be dependent both upon cell type and receptor isotype expression.
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PMID:Differential effects of platelet-derived growth factor BB on p125 focal adhesion kinase and paxillin tyrosine phosphorylation and on cell migration in rabbit aortic vascular smooth muscle cells and Swiss 3T3 fibroblasts. 753 14

Identification of the signal transduction pathways used by PRL is essential for understanding the role of PRL receptors in growth and differentiation processes. Early cellular mediators of PRL receptor activation include tyrosine kinases of the Janus kinase (JAK) and SRC families, with rapid nuclear signaling via tyrosine phosphorylated signal transducers and activators of transcription. In the present study we provide the first demonstration of PRL-induced activation of Ras, an oncogenic protein that supports an alternative signaling route from the membrane to the nucleus. PRL stimulated Ras in rat Nb2-SP lymphoma cells, as detected by a 2.0-fold increase in the GTP-bound state of the molecule (P < 0.01). This activation was associated with marked tyrosine phosphorylation and increased membrane association of the 52-kilodalton form of SHC. Moreover, PRL induced binding of SHC to growth factor receptor bound 2 and the guanine-nucleotide exchange factor son of sevenless, a common method used by growth factor receptors to activate Ras. In contrast, no apparent regulation by PRL of Ras via VAV or p120 Ras-guanosine triphosphatase-activating protein was detected, based upon an absence of PRL-inducible tyrosine phosphorylation of these proteins. Collectively, these results provide a molecular bridge between activation of PRL receptor-associated tyrosine kinases and subsequent stimulation of the serine/threonine kinase Raf-1, an established Ras target that was recently shown to be activated by PRL in Nb2 cells. We conclude that PRL is able to activate Ras via recruitment of the signaling proteins SHC, growth factor receptor bound 2, and son of sevenless in Nb2 cells. Moreover, PRL induced tyrosine phosphorylation of SHC in two of three PRL-responsive human breast cancer cell lines, suggesting that SHC-mediated Ras activation is a commonly used signaling strategy by PRL.
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PMID:Prolactin activates Ras via signaling proteins SHC, growth factor receptor bound 2, and son of sevenless. 762 88

JK32.1 and SKW6.4 are Epstein-Barr virus (EBV)-positive human B cell lines that undergo spontaneous, lymphocyte function-associated antigen 1 (LFA-1) dependent homotypic adhesion in culture. This process is associated with induction of tyrosine phosphoproteins of molecular mass 90, 106, and 120 kDa and could be reproduced when these cells were centrifugationally aggregated. Antibodies to the beta 2 (CD18) chain of LFA-1 interfered with induction of p120, p106, and p90 during cellular aggregation. Response induction was abrogated when cells were incubated with protein tyrosine kinase (PTK) inhibitors (erbstatin, genistein, and geldanomycin) or cytochalasin B prior to aggregation. An in vitro kinase assay did not reveal activation of focal adhesion kinase. Although the role of LFA-1-dependent tyrosine phosphorylation in B cells is uncertain, patients with the leukocyte adhesion defect (LAD) exhibit humoral abnormalities. Moreover, aggregation did not induce specific tyrosine phosphoproteins in an EBV-transformed B cell line from a LAD patient. These results suggest that an LFA-1-dependent PTK pathway may play an important role in human B cell function.
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PMID:Evidence for LFA-1/ICAM-1 dependent stimulation of protein tyrosine phosphorylation in human B lymphoid cell lines during homotypic adhesion. 785 49

In the present study, we have identified several proteins in Swiss 3T3 cells that are phosphorylated on tyrosine in response to platelet-derived growth factor (PDGF) and exhibit an unusual bell-shaped dose-response curve with a maximum at 5 ng/ml platelet-derived growth factor (PDGF). These proteins include two that are associated with focal adhesions, namely the focal adhesion kinase (p125FAK), a novel cytosolic tyrosine kinase, and paxillin. At low concentrations of PDGF (1-5 ng/ml), these proteins are the predominant tyrosine-phosphorylated species. At 30 ng/ml PDGF, however, there was no stimulation of their phosphorylation over control levels. In contrast, tyrosine phosphorylation of previously described substrates of the PDGF receptor tyrosine kinase, namely the p21ras GTPase-activating protein, p120, phosphatidyl inositol 3' kinase, and phospholipase C gamma exhibited sigmoidal dose-response curves with PDGF and were all efficiently phosphorylated on tyrosine at 30 ng/ml PDGF. Cytochalasin D, which disrupts the actin cytoskeleton, completely inhibited the tyrosine phosphorylation of p125FAK and paxillin by PDGF. Examination of the actin cytoskeleton after stimulation of cells with different concentrations of PDGF revealed that at 5 ng/ml PDGF, actin appears in stress fibers and in membrane ruffles, while at 30 ng/ml, PDGF disrupts the actin cytoskeleton. Bombesin stimulates actin stress fiber formation with no evidence of disruption of stress fibers at high concentrations. When cells were stimulated with bombesin (10 nM) in the presence of 30 ng/ml PDGF, however, the actin cytoskeleton was completely disrupted. Further, the tyrosine phosphorylation of both p125FAK and paxillin induced by bombesin (10 nM) was completely prevented when cells were stimulated with bombesin in the presence of 30 ng/ml PDGF. We propose that the inhibitory limb in the bell-shaped dose-response curve of PDGF and the novel cross-talk between PDGF and bombesin on tyrosine phosphorylation may be explained by the ability of PDGF at 30 ng/ml to disrupt the actin cytoskeleton.
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PMID:Platelet-derived growth factor modulation of focal adhesion kinase (p125FAK) and paxillin tyrosine phosphorylation in Swiss 3T3 cells. Bell-shaped dose response and cross-talk with bombesin. 827 72

The Philadelphia chromosome, detected in virtually all cases of chronic myelogenous leukemia, is formed by a reciprocal translocation between chromosomes 9 and 22 that fuses BCR encoded sequences upstream of exon 2 of c-ABL. This oncogene produces a fusion protein, p210BCR-ABL, in which the ABL tyrosine kinase activity is elevated. This elevated kinase activity is essential for transformation, but the mechanisms involved are unknown. To investigate p210BCR-ABL function we constructed a model system in which the tyrosine kinase activity of p210BCR-ABL was inducible. Two amino acid substitutions, Arg to His at amino acid 457 and Tyr to His at amino acid 469 of c-abl, modeled on mutations known to render v-src temperature-sensitive for tyrosine kinase activity, were introduced into p210BCR-ABL. This mutant was characterized in an IL-3 growth factor dependent murine myeloid cell line, 32Dc13. Cell lines expressing the temperature-sensitive mutant remained factor dependent at the non-permissive temperature, but at the permissive temperature displayed a marked reduction in cell death in the absence of growth factor and an exaggerated proliferative response to low levels of IL-3. Both the kinase activity of the mutant and the levels of tyrosine phosphorylated proteins are increased in the temperature-sensitive mutant at the permissive temperature. Further, tyrosine phosphorylation of potential substrates of the p210BCR-ABL tyrosine kinase, p120 rasGAP and its associated proteins of p190 and p62, only occurs at the permissive temperature in cells expressing the temperature-sensitive mutant.
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PMID:Use of a temperature-sensitive mutant to define the biological effects of the p210BCR-ABL tyrosine kinase on proliferation of a factor-dependent murine myeloid cell line. 830 74

Lysophosphatidic acid (LPA) added to serum-starved Swiss 3T3 cells induced, in a time- and concentration-dependent manner, tyrosine phosphorylation of multiple proteins, including proteins of 43, 64, 88 kDa and a group of proteins between 110 and 130 kDa. Among them, two proteins, p43 and p120, were identified as mitogen-activated protein kinase (MAP-kinase) and focal adhesion kinase (FAK), respectively, by immunoprecipitation and immunoblot analysis. Tyrosine phosphorylation of p64 peaked at 1 min and declined rapidly, whereas that of MAP-kinase and FAK peaked at 5 and 10 min after the addition of LPA, respectively. The activity of MAP-kinase determined as phosphorylation of myelin basic protein increased transiently about 3-fold at 5 min, and correlated with tyrosine phosphorylation. These results indicate that tyrosine phosphorylation of these proteins is a part of the signal transduction by LPA and may be involved in its mitogenic responses.
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PMID:Lysophosphatidic acid induces tyrosine phosphorylation and activation of MAP-kinase and focal adhesion kinase in cultured Swiss 3T3 cells. 836 68

The immature erythroid J2E cell line proliferates and terminally differentiates following erythropoietin stimulation. In contrast, the mutant J2E-NR clone does not respond to erythropoietin by either proliferating or differentiating. Here we show that erythropoietin can act as a viability factor for both the J2E and J2E-NR lines, indicating that erythropoietin-initiated maturation is separable from the prevention of cell death. The inability of J2E-NR cells to mature in response to erythropoietin was not due to a defect in the erythropoietin receptor sequence, although surface receptor numbers were reduced. Both the receptor and Janus kinase 2 were phosphorylated after erythropoietin stimulation of J2E-NR cells. However, protein interactions with the erythropoietin receptor and Grb2 were restricted in the mutant cells. Subsequent investigation of several other signaling molecules exposed numerous alterations in J2E-NR cells; phosphorylation changes to phosphatidylinositol 3-kinase, phospholipase Cgamma, p120 GAP, and mitogen-activated protein kinases (p42 and p44) observed in erythropoietin-stimulated J2E cells were not seen in the J2E-NR line. These data indicate that some pathways activated during erythropoietin-induced differentiation may not be essential for the prevention of apoptosis.
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PMID:Disrupted signaling in a mutant J2E cell line that shows enhanced viability, but does not proliferate or differentiate, with erythropoietin. 863 47

Stimulation of small cell lung cancer (SCLC) cells with neuropeptides bombesin, bradykinin, gastrin, and neurotensin resulted in increased tyrosine kinase activity and tyrosine phosphorylation of a number of polypeptides including a p120 kDa polypeptide identified by immunoblotting as focal adhesion kinase (p125FAK). The neuropeptides stimulated a rapid, concentration-dependent phosphorylation of p125FAK (EC50 of 1 nM, 5 nM, and 2 nM for bombesin, bradykinin, and gastrin, respectively), which was receptor mediated and inhibited by both specific and broad-spectrum neuropeptide receptor antagonists. Specific inhibition of protein tyrosine kinase activity by tyrphostin-25 inhibited both basal and neuropeptide-stimulated SCLC cell growth. These results identify a novel neuropeptide-stimulated growth signaling event in SCLC cells.
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PMID:Neuropeptides stimulate tyrosine phosphorylation and tyrosine kinase activity in small cell lung cancer cell lines. 880 78

The Philadelphia chromosome (Ph) translocation generates a chimeric tyrosine kinase oncogene, BCR/ABL, which causes chronic myelogenous leukemia (CML) and a type of acute lymphoblastic leukemia (ALL). In primary samples from virtually all patients with CML or Ph+ALL, the CRKL adapter protein is tyrosine phosphorylated and physically associated with p210(BCR/ABL). CRKL has one SH2 domain and two SH3 domains and is structurally related to c-CRK-II (CRK) and the v-Crk oncoprotein. We have previously shown that CRKL, but not the related adapter protein c-CRK, is tyrosine phosphorylated in cell lines transformed by BCR/ABL, and that CRKL binds to BCR/ABL through the CRKL-SH3 domains. Furthermore, the CRKL-SH2 domain has been shown to bind one or more cellular proteins, one of which is p120(CBL). Here we demonstrate that another cellular protein linked to BCR/ABL through the CRKL-SH2 domain is p130(CAS). p130(CAS) was found to be tyrosine phosphorylated and associated with CRKL in BCR/ABL expressing cell lines and in samples obtained from CML and ALL patients, but not in samples from controls. In both normal and BCR/ABL transformed cells, p130(CAS) was detected in focal adhesion-like structures, as was BCR/ABL. In normal cells, the focal adhesion proteins tensin, p125(FAK), and paxillin constitutively associated with p130(CAS). However, in BCR/ABL transformed cells, the interaction between p130(CAS) and tensin was disrupted, while the associations between p130(CAS), p125(FAK), and paxillin were unaffected. These results suggest that the BCR/ABL oncogene could alter the function of p130(CAS) in at least three ways: tyrosine phosphorylation, inducing constitutive binding of CRKL to a domain in p130(CAS) containing Tyr-X-X-Pro motifs (substrate domain), and disrupting the normal interaction of p130(CAS) with the focal adhesion protein tensin. These alterations in the structure of signaling proteins in focal adhesion like structures could contribute to the known adhesion abnormalities in CML cells.
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PMID:p130CAS forms a signaling complex with the adapter protein CRKL in hematopoietic cells transformed by the BCR/ABL oncogene. 881 Feb 78

Breast cancer antigens RAK-p120, -p42, -p25 were detected in 100% of breast cancer cases tested (71 cases). Only 10% of adjacent tissue cases tested positive for all three cancer antigens, and 17.5% of the cases tested positive for two antigens only. Eighty-five percent of histologically normal breast tissue samples, isolated either from breast cancer patients or patients with advanced fibrocystic disease, tested RAK-negative, with the exception of low expression of p25, observed in some patients. Polymerase chain reaction (PCR) with HIV-1 gp 41-derived primers revealed cancer-associated DNA fragments of similar size (140 bp) as in HIV-1 genome. Fifty-four percent of cancer adjacent tissues, and 50% of malignancy-free breast tissue samples, tested PCR-negative. It is suggested that genetic predisposition to cancer may be associated with the presence of RAK genes, while expression of RAK antigens marks an already ongoing process of malignant changes.
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PMID:New protein and PCR markers RAK for diagnosis, prognosis and surgery guidance for breast cancer. 902 74


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