Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.10.2 (focal adhesion kinase)
 44,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The accumulation and organization of extracellular matrix (ECM) components play critical roles in development, maintenance, and pathogenesis of most organ systems. These processes are regulated by the precisely orchestrated expression of ECM components, their receptors, and matrix proteases. The collagen gel culture system has been extensively used as a model to examine ECM remodeling similar to that which occurs during development and wound healing. Growth factors, including transforming growth factor-beta, platelet-derived growth factor, insulin-like growth factor, and angiotensin II, have been shown to stimulate collagen gel contraction. The present studies were undertaken to begin to examine the mechanisms through which angiotensin II stimulates collagen remodeling and gel contraction. These studies indicate that angiotensin II stimulates collagen gel contraction by isolated heart fibroblasts in a dose-dependent manner and that this response is inhibited by the AT1 receptor antagonist Losartan. Furthermore, stimulation of collagen gel contraction by angiotensin II is also blocked by the src-related tyrosine kinase inhibitors genistein and herbimycin, indicating that activation of tyrosine kinases plays critical roles in this process. Stimulation of gel contraction by angiotensin II also involves the activation of JAK2, a member of the JAK/STAT pathways of transcriptional activation. Immunoprecipitation of surface-labeled fibroblasts indicate that cell surface levels of collagen-binding integrins also increase in response to angiotensin II treatment. Determining the underlying mechanisms regulating ECM remodeling is essential to understanding the role of ECM organization in development and disease.
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PMID:Angiotensin II-stimulated collagen gel contraction by heart fibroblasts: role of the AT1 receptor and tyrosine kinase activity. 976 19

In cardiac fibroblasts, angiotensin II (Ang II) induced a rapid increase in extracellular signal regulated kinase (ERK) activity in a pertussis toxin insensitive manner. This ERK activation was abolished by the Gq-associated phospholipase C inhibitor U73122 but was insensitive to protein kinase C (PKC) inhibitors or PKC downregulation by phorbol ester. Intracellular Ca2+ chelation by BAPTA-AM or TMB-8 abolished Ang II induced ERK activation, whereas treatment with EGTA or nifedipine did not affect it. Ca2+ ionophore A23187 also induced a rapid increase in ERK activity to an extent similar to that of Ang II stimulation. Calmodulin inhibitors (W7 and calmidazolium) and tyrosine kinase inhibitors (genistein and ST638) completely blocked ERK activation by Ang II and A23187. Both Ang II and A23187 caused a rapid increase in the binding of GTP to p21(Ras), which was nearly abolished by genistein and calmidazolium. Transfection with the dominant negative mutant of Ras and the Ras inhibitor manumycin completely inhibited Ang II induced ERK activation. It was also found for the first time that cardiac fibroblasts abundantly expressed Ca2+-sensitive tyrosine kinase Pyk2/CAKbeta/RAFTK and that Ang II markedly induced its activation in a Ca2+/calmodulin-sensitive manner. Overexpression of the dominant negative mutant of Pyk2 significantly attenuated Ang II or A23187-induced ERK activities (36% and 38% inhibition compared with that in mock-transfected cells, respectively) and ERK tyrosine phosphorylation levels, as well as an increase in the binding of GTP to p21(Ras). These findings demonstrate that in cardiac fibroblasts, Ang II induced Ras/ERK activation is dominantly regulated by Gq-coupled Ca2+/calmodulin signaling and that Pyk2 plays an important role in the signal transmission for efficient activation of the Ang II induced Ras/ERK pathway.
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PMID:Role of calcium-sensitive tyrosine kinase Pyk2/CAKbeta/RAFTK in angiotensin II induced Ras/ERK signaling. 977 61

The increase in vascular wall stress imposed by hypertension has been strongly implicated in the pathogenesis of cardiovascular disease. Much of this chronic cyclical mechanical strain is experienced by the vascular smooth (VSM) cells of the vascular media. The cellular mechanisms whereby VSM cells sense and respond to changing mechanical forces are poorly understood. This review focuses on an emerging field of cardiovascular research in which the direct effects of mechanical strain on VSM cells and isolated blood vessels in organ culture have been characterized, in vitro. Cyclical mechanical strain profoundly influences cultured VSM cell orientation, growth and phenotype. Mechanical strain also increases the secretory function of VSM cells leading to increased extracellular matrix protein production. Vasoactive mediators such as angiotensin II potentiate these effects. Mechanical strain increases VSM cell release of platelet derived growth factor, transforming growth factor beta1, fibroblast growth factor and vascular endothelial growth factor, which act in autocrine or paracrine loops to influence VSM and endothelial cell growth and function. Mechanical strain may also activate local tissue renin-angiotensin systems and regulate expression of angiotensin II receptors within the cardiovascular system. The mechanism whereby VSM cells transduce mechanical stimuli into an intracellular signal and biological response, i.e. 'mechanotransduction', is strongly dependent on integrins. Moreover, specific matrix protein:integrin engagements lead to differential VSM cells responses via the selective activation of numerous intracellular signalling pathways including; mitogen-activated protein kinase, focal adhesion kinase and c-Src. The study of vascular mechanotransduction has begun to delineate the complex cellular basis of cardiovascular structural and functional modification in hypertension.
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PMID:Mechanical influences on vascular smooth muscle cell function. 988 78

In this review, the signal events regulated by angiotensin II (AngII) in vascular smooth muscle are analyzed based on activation of specific tyrosine kinases. AngII has been shown to play a critical role in the pathogenesis of hypertension, inflammation, atherosclerosis, and congestive heart failure. The expanding role of AngII indicates that multiple signal transduction pathways are likely to be activated in a tissue-specific manner. Although at least three AngII receptors have been characterized, it seems that the AngII type I receptor (AT1R) is physiologically most important since pharmacologic inhibitors of the AT1R block most AngII signal events and have beneficial effects on cardiovascular disease. The AT1R is a seven transmembrane-spanning G protein-coupled receptor that regulates intracellular signal events by activation of Gq and Gi. However, many recent data indicate that activation of tyrosine kinases by several different mechanisms contributes to AngII effects in target tissues. Tyrosine kinases activated by AngII include c-Src, focal adhesion kinase (FAK), Pyk2 (CADTK), Janus kinases (JAK2 and TYK2), and the receptor tyrosine kinases Ax1, epidermal growth factor, and platelet-derived growth factor. Finally, unknown tyrosine kinases may mediate tyrosine phosphorylation of paxillin, Shc, Raf, and phospholipase C-gamma after AngII stimulation. These AngII-regulated tyrosine kinases seem to be required for AngII effects such as vasoconstriction, proto-oncogene expression, and protein synthesis based on studies with tyrosine kinase inhibitors. Thus, understanding AngII-stimulated signaling events, especially those related to tyrosine kinase activity, may form the basis for the development of new therapies for cardiovascular diseases.
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PMID:Angiotensin II signal transduction in vascular smooth muscle: pathways activated by specific tyrosine kinases. 989 42

-PYK2, a recently identified Ca2+-sensitive tyrosine kinase, has been implicated in extracellular signal-regulated kinase (ERK) activation via several G protein-coupled receptors. We have reported that angiotensin II (Ang II) induces Ca2+-dependent transactivation of the epidermal growth factor receptor (EGFR) which serves as a scaffold for preactivated c-Src and downstream adaptors (Shc/Grb2), leading to ERK activation in cultured rat vascular smooth muscle cells (VSMC). Herein we demonstrate the involvement of PYK2 in this cascade. Ang II rapidly induced tyrosine phosphorylation of PYK2, whose effect was completely inhibited by an AT1 receptor antagonist and an intracellular Ca2+ chelator. A Ca2+ ionophore also induced PYK2 tyrosine phosphorylation to a level comparable with that by Ang II, whereas phorbol ester-induced phosphorylation was less than that by Ang II. Moreover, PYK2 formed a complex coprecipitable with catalytically active c-Src after Ang II stimulation. Although a selective EGFR kinase inhibitor completely abolished Ang II-induced recruitment of Grb2 to EGFR and markedly attenuated Ang II-induced ERK activation, it had no effect on Ang II-induced PYK2 tyrosine phosphorylation or its association with c-Src and Grb2. These data suggest that the AT1 receptor uses Ca2+-dependent PYK2 to activate c-Src, thereby leading to EGFR transactivation, which preponderantly recruits Grb2 in rat VSMC.
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PMID:Involvement of PYK2 in angiotensin II signaling of vascular smooth muscle cells. 993 Nov 5

Chronic stimulation of norepinephrine (NE) neuromodulation by angiotensin II (Ang II) involves activation of the Ras-Raf-MAP kinase signal transduction pathway in Wistar Kyoto (WKY) rat brain neurons. This pathway is only partially responsible for this heightened action of Ang II in the spontaneously hypertensive rat (SHR) brain neurons. In this study, we demonstrate that the MAP kinase-independent signaling pathway in the SHR neuron involves activation of PI3-kinase and protein kinase B (PKB/Akt). Ang II stimulated PI3-kinase activity in both WKY and SHR brain neurons and was accompanied by its translocation from the cytoplasmic to the nuclear compartment. Although the magnitude of stimulation by Ang II was comparable, the stimulation was more persistent in the SHR neuron compared with the WKY rat neuron. Inhibition of PI3-kinase had no significant effect in the WKY rat neuron. However, it caused a 40-50% attenuation of the Ang II-induced increase in norepinephrine transporter (NET) and tyrosine hydroxylase (TH) mRNAs and [3H]-NE uptake in the SHR neuron. In contrast, inhibition of MAP kinase completely attenuated Ang II stimulation of NET and TH mRNA levels in the WKY rat neuron, whereas it caused only a 45% decrease in the SHR neuron. However, an additive attenuation was observed when both kinases of the SHR neurons were inhibited. Ang II also stimulated PKB/Akt activity in both WKY and SHR neurons. This stimulation was 30% higher and lasted longer in the SHR neuron compared with the WKY rat neuron. In conclusion, these observations demonstrate an exclusive involvement of PI3-kinase-PKB-dependent signaling pathway in a heightened NE neuromodulatory action of Ang II in the SHR neuron. Thus, this study offers an excellent potential for the development of new therapies for the treatment of centrally mediated hypertension.
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PMID:Role of phosphatidylinositol 3-kinase in angiotensin II regulation of norepinephrine neuromodulation in brain neurons of the spontaneously hypertensive rat. 1008 56

Human mesangial cells (HMCs) respond to angiotensin II stimulation, which modulates their physiological activities, i.e., contraction and proliferation. It has been revealed that focal adhesion kinase (FAK) and paxillin participate in the angiotensin II-mediated signaling and cytoskeletal rearrangements at focal adhesion. We investigated the influences of cell adhesion upon angiotensin II effects in HMCs. In adherent cells, both FAK and paxillin were tyrosine phosphorylated by angiotensin II, while the cell detachment completely inhibited the tyrosine phosphorylation of paxillin. Activation of p44/42 mitogen-activated protein (MAP) kinase by angiotensin II was accentuated in suspended cells. Moreover, p190, a member of Rho GTPase activating protein (GAP), and RasGAP were coprecipitated with paxillin in adherent cells and angiotensin II stimulation reduced the formation of paxillin-p190 and paxillin-RasGAP complexes. These results suggest that the formation of focal adhesion complexes accelerated by accumulation of mesangial matrices may inhibit the proliferation of HMCs by modulating MAP kinase activity and be related to mesangial cell depletion.
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PMID:Signaling transduction pathway of angiotensin II in human mesangial cells: mediation of focal adhesion and GTPase activating proteins. 1009 39

This study was designed to determine whether mechanical stretch activates the Janus kinase (JAK)/signal transducers and activators of transcription (STAT) pathway in cardiomyocytes and, if so, by what mechanism. Neonatal rat/murine cardiomyocytes were cultured on malleable silicone dishes and were stretched by 20%. Mechanical stretch induced rapid phosphorylation of JAK1, JAK2, Tyk2, STAT1, STAT3, and glycoprotein 130 as early as 2 minutes and peaked at 5 to 15 minutes. It also caused gel mobility shift of sis-inducing element, which was supershifted by preincubation with anti-STAT3 antibody. Preincubation with CV11974 (AT1 blocker) partially inhibited the phosphorylation of STAT1, but not that of STAT3. Preincubation with TAK044 (endothelin-1-type A/B-receptor blocker) did not attenuate this pathway. RX435 (anti-glycoprotein 130 blocking antibody) inhibited the phosphorylation of STAT3 and partially inhibited that of STAT1. Phosphorylation of STAT1 and STAT3 was strongly inhibited by HOE642 (Na+/H+ exchanger inhibitor) and BAPTA-AM (intracellular calcium chelator), but not by gadolinium (stretch-activated ion channel inhibitor), EGTA (extracellular Ca2+ chelator), or KN62 (Ca2+/calmodulin kinase II inhibitor). Chelerythrine (protein kinase C inhibitor) partially inhibited the phosphorylation of STAT1 and STAT3. Mechanical stretch also augmented the mRNA expression of cardiotrophin-1, interleukin-6, and leukemia inhibitory factor at 60 to 120 minutes. These results indicated that the JAK/STAT pathway was activated by mechanical stretch, and that this activation was partially dependent on autocrine/paracrine-secreted angiotensin II and was mainly dependent on the interleukin-6 family of cytokines but was independent of endothelin-1. Moreover, certain levels of intracellular Ca2+ were necessary for stretch-induced activation of this pathway, and protein kinase C was also partially involved in this activation.
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PMID:Mechanical stretch activates the JAK/STAT pathway in rat cardiomyocytes. 1034 87

Ligand binding to the angiotensin II (Ang II) AT1 receptor on vascular smooth muscle cells (VSMCs) activates the Janus-activated kinase (JAK)/signal transducers and activators of transcription (STAT) pathway. We have shown previously that the JAK2 tyrosine kinase and the Src family p59 Fyn tyrosine kinase are required for Ang II-induced STAT1 tyrosine phosphorylation in VSMCs. The mitogen-activated protein kinase phosphatase, MKP-1, is required for STAT1 tyrosine dephosphorylation. In the present study, using specific enzyme inhibitors and antisense oligonucleotides, we show that Ang II-induced tyrosine phosphorylation and nuclear translocation of STAT3 in VSMCs is mediated by p60 c-Src, whereas tyrosine dephosphorylation is mediated by calcineurin. Calcineurin is activated in response to Ang II stimulation of VSMCs and is translocated to the nucleus. In addition, we show that Ang II-induced serine phosphorylation of STAT3 in VSMCs is mediated by mitogen-activated protein kinase and that dephosphorylation is mediated by protein phosphatase 2A (PP2A). PP2A translocates to the nucleus in response to Ang II stimulation of VSMCs and forms a complex with STAT3 in an Ang II-dependent manner.
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PMID:Regulation of angiotensin II-induced phosphorylation of STAT3 in vascular smooth muscle cells. 1039 29

Previously, we showed that the JAK/STAT pathway was activated in pressure-overloaded rat heart, and that angiotensin II was partially involved in this activation. The present study was designed to investigate whether gp130-mediated signaling is involved in this activation, and if so, which interleukin (IL)-6 family cytokine is involved. Pressure overload was produced by ligation of the abdominal aorta of Wistar rats or ICR mice. IP-Western blot was performed to detect tyrosine phosphorylation of STATs, gp130, and the association of gp130 with JAK kinases. The serum concentration of IL-6 was measured by enzyme-linked immunosorbent assay. Expression of IL-6, IL-11, leukemia inhibitory factor (LIF), ciliary neurotrophic factor (CNTF), oncostatin M (OSM), and cardiotrophin-1 (CT-1) mRNA was quantitated. After pressure overload, rapid phosphorylation of STAT1 and STAT3 was observed at 5 min, STAT1 was rephosphorylated at 60 min, and intense phosphorylation of STAT3 was observed at 60 min. Both the phosphorylation of gp130 and the association of gp130 with JAK1 and JAK2 were increased after pressure overload. IL-6 was significantly increased by two-fold in the pressure-overloaded rats. Only CT-1 mRNA expression could be detected by Northern blot, and it increased after pressure overload. Reverse transcription-polymerase chain reaction revealed that IL-6 mRNA expression was increased 9.5-fold. IL-11, LIF, CNTF, and OSM expression were unaffected by pressure overload. These results suggested that gp130-mediated signaling was involved in the pressure overload-induced activation of the JAK/STAT pathway, and that IL-6 and CT-1 might be involved in this activation.
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PMID:Involvement of gp130-mediated signaling in pressure overload-induced activation of the JAK/STAT pathway in rodent heart. 1044 2


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