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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)
The human placenta is an invasive structure in which highly proliferative, migratory, and invasive extravillous trophoblast (EVT) cells migrate and invade the uterus and its vasculature. Using in vitro propagated normal first-trimester EVT cells and immortalized EVT cells, which share all of the phenotypic and functional characteristics of the normal EVT cells, it has been shown that migration/invasion of human EVT cells is stringently regulated by many growth factors, their binding proteins, extracellular matrix (ECM) components, and some adhesion molecules in an autocrine/paracrine manner at the fetal-maternal interface in human pregnancy. Transforming growth factor beta (TGF-beta), decorin (a proteoglycan in the ECM), and melanoma cell adhesion molecule (Mel-CAM) inhibit, and insulin-like growth factor II (IGF-II), IGF-binding protein 1 (IGFBP-1), and endothelin 1 (ET-1) stimulate EVT cell migration/invasion. Inhibition of EVT cell migration by TGF-beta has been suggested to be due to upregulation of integrins, which make the cells more adhesive to the ECM. Its antiinvasive action is due to an upregulation of tissue inhibitor of matrix metalloprotease 1 (TIMP-1) and plasminogen activator inhibitor (PAI-1) and a downregulation of urokinase-type plasminogen activator (uPA). Molecular mechanisms of inhibition of migration/invasion of EVT cells by decorin and Mel-CAM remain to be identified. IGF-II action has been shown to be mediated by IGF type I receptors (IGF-RII) independently of IGF type I receptors (IGF-RI) and IGFBPs. This action of IGF-II appears to involve inhibitory G proteins and phosphorylation of mitogen-activated protein kinase (MAPK) (extracellular signal-regulated protein kinases 1 and 2 (ERK-1 and
ERK-2
)). IGFBP-1 stimulation of EVT cell migration appears to occur by binding its Arg-Gly-Asp (RGD) domain to alpha5beta1 integrin, leading to phosphorylation of
focal adhesion kinase
(
FAK
) and MAPK (ERK-1 and
ERK-2
). These studies may improve our understanding of diseases related to abnormal placentation, viz. hypoinvasiveness in preeclampsia and hyperinvasiveness in trophoblastic neoplasms.
...
PMID:Regulation of human trophoblast migration and invasiveness. 1193 54
The ets transcription factor, TEL, undergoes chromosomal rearrangements with the tyrosine kinase
JAK2
. TEL-
JAK2
is constitutively active, confers cell line factor independence, and activates signal transducer and activator of transcription-1 (STAT1), STAT3, and STAT5. Data from bone marrow transplantation models suggest that STAT5 activation does not account for the entire disease phenotype induced by TEL-
JAK2
. This study examined additional signaling pathways that are activated by TEL-
JAK2
. TEL-
JAK2
expression in Ba/F3 cells results in constitutive association and tyrosine phosphorylation of Shc and Ship-1 and, consequently, recruitment of Grb2 to TEL-
JAK2
. Direct Grb2 recruitment is also possible because a putative Grb2 binding site, Tyr314, is present on TEL-
JAK2
(5-19) and TEL-
JAK2
(5-12). Studies with a TEL-
JAK2
(5-19)Tyr314Phe mutant support a role for Tyr314 in Grb2 recruitment, because Grb2 association with TEL-
JAK2
(5-19)Tyr314Phe is significantly reduced. Interestingly, TEL-
JAK2
(5-19)Tyr314Phe shows reduced Ras activation when compared with TEL-
JAK2
(4-17), TEL-
JAK2
(5-12), and TEL-
JAK2
(5-19). Analysis of extracellular signal-regulated kinase-1/2 (ERK1/2), stress-activated protein/Jun kinase (SAPK/JNK), and p38 demonstrates the activation of SAPK/JNK and phosphorylation of p38 by all TEL-
JAK2
isoforms. TEL-
JAK2
(5-12) and TEL-
JAK2
(5-19) preferentially phosphorylate
ERK2
, whereas TEL-
JAK2
(4-17) phosphorylated
ERK2
at lower levels. Inhibition studies demonstrated that ERK1/2 activation was necessary for Ba/F3 factor independence mediated by TEL-
JAK2
(5-19), while inhibition of SAPK/JNK or p38 activity had no effect. Our data reveal the requirement of ERK activation by TEL-
JAK2
(5-19) in Ba/F3 cells and suggest that TEL-
JAK2
leukemogenic potential may be mediated in part through ERK1/2.
...
PMID:TEL-JAK2 constitutively activates the extracellular signal-regulated kinase (ERK), stress-activated protein/Jun kinase (SAPK/JNK), and p38 signaling pathways. 1214 29
A role for alpha/beta interferon (IFN-alpha/beta) in the IFN-gamma antiviral response has long been suggested. Accordingly, possible roles for autocrine or double-stranded-RNA (dsRNA)-induced IFN-alpha/beta in the IFN-gamma response were investigated. Use was made of wild-type and a variety of mutant human fibrosarcoma cell lines, including mutant U5A cells, which lack a functional IFN-alpha/beta receptor and hence an IFN-alpha/beta response. IFN-gamma did not induce detectable levels of IFN-alpha/beta in any of the cell lines, nor was the IFN-gamma response per se dependent on autocrine IFN-alpha/beta. On the other hand, a number of responses to dsRNA [poly(I). poly(C)] and encephalomyocarditis virus were greatly enhanced by IFN-gamma pretreatment (priming) of wild-type cells or of mutant cells lacking an IFN-alpha/beta response; these include the primary induction of dsRNA-inducible mRNAs, including IFN-beta mRNA, and, to a lesser extent, the dsRNA-mediated activation of the p38 mitogen-activated protein (MAP) kinase(s). IFN-gamma priming of mRNA induction by dsRNA is dependent on
JAK1
and shows biphasic kinetics, with an initial rapid (<30-min) response being followed by a more substantial effect on overnight incubation. The IFN-gamma-primed dsRNA responses appear to be subject to modulation through the p38, phosphatidylinositol 3-kinase, and ERK1/
ERK2
MAP kinase pathways. It can be concluded that despite efficient priming of IFN-beta production, the IFN-alpha/beta pathways play no significant role in the primary IFN-gamma antiviral response in these cell-virus systems. The observed IFN-gamma priming of dsRNA responses, on the other hand, will likely play a significant role in combating virus infection in vivo.
...
PMID:The antiviral response to gamma interferon. 1218 89
Phosphoinositide-3-kinase (PI3K) is a lipid kinase, which phosphorylates the D3 position of phosphoinositides, and is known to be activated by a host of protein tyrosine kinases. PI3K plays an important role in mitogenesis in several cell systems. However, whether parathyroid hormone (PTH) affects the activity and functional roles of PI3K in intestinal cells remain to be determined. The objective of this study was to identify and characterize the PI3K pathway, and its relation to other non-receptor tyrosine kinases in mediating PTH signal transduction in rat enterocytes. PTH dose- and time-dependently increased PI3K activity with a peak occurring at 2 min. The tyrosine kinase inhibitor genistein, c-Src inhibitor PP1 and two structurally different inhibitors of PI3K, LY294002 and wortmannin, suppressed PI3K activity dependent on PTH. Co-immunoprecipitation analysis showed a constitutive association between c-Src and PI3K, which was enhanced by PTH treatment, suggesting that the cytosolic tyrosine kinase forms an immunocomplex with PI3K probably via the N-SH2 domain of the p85alpha regulatory subunit. In response to PTH, tyrosine phosphorylation of p85alpha was enhanced, effect that was abolished by PP1, the inhibitor of c-Src kinase. PTH causes a rapid (0.5-5 min) phosphorylation of Akt/
PKB
, effect that was abrogated by PI3K inhibitors, indicating that in rat enterocytes, PI3K is an upstream mediator of Akt/
PKB
activation by PTH. We report here that PI3K is also required for PTH activation of the mitogen-activated protein kinases ERK1 and
ERK2
. Taken together, the present study demonstrate, for the first time, that PTH rapidly and transiently stimulates PI3K activity and its down effector Akt/
PKB
in rat enterocytes playing c-Src kinase a central role in PTH-dependent PI3K activation and that PI3K signaling pathway contributes to PTH-mediated MAPK activation.
...
PMID:Involvement of PI3-kinase and its association with c-Src in PTH-stimulated rat enterocytes. 1221 Jul 43
The chicken retina was exposed to 20% hyposmotic or ischaemia-like (54 mM KCl and 1 mM ouabain) conditions and changes in cell volume, amino acid release and activation of protein tyrosine kinases measured. To investigate possible connection between these cellular events, the effect of tyrosine kinase blockers on (3)H-taurine, (3)H-GABA and (3)H- D-aspartate (as a tracer for glutamate) efflux was examined. Both hyposmotic and ischaemic conditions increased phosphorylation of the tyrosine kinase p125
focal adhesion kinase
(p125(
FAK
)) and the mitogen-activated protein kinase-p38 (MAPK-p38), but not of the extracellular-signal-related kinases-1/2 (ERK1/
ERK2
), and markedly activated the tyrosine kinase target enzyme phosphatidylinositide 3-kinase (PI3K). Hyposmolarity and ischaemia both led to rapid retinal swelling followed by active volume recovery of 84% (hyposmolarity) and 40% (ischaemia), together with rapid release of taurine, GABA and D-aspartate. Taurine and GABA efflux under both conditions was reduced markedly by tyrosine kinase and PI3K blockers (50 microM tyrphostin A23, 50 microM genistein, 100 nM wortmannin, 25 microM LY294002) and was decreased by 85% when ischaemia-induced swelling was prevented. About 65% of D-aspartate efflux occurred irrespective of swelling in ischaemia and was either less sensitive (hyposmotic) or largely resistant (ischaemia) to the blockers. These results suggest that in ischaemia, GABA and taurine react primarily to swelling with a typical osmolyte response, while glutamate differs in its release mechanisms under both hyposmotic and ischaemic conditions. These findings suggest new strategies for evaluating the contribution of swelling to excitotoxicity in ischaemia.
...
PMID:Tyrosine kinases and amino acid efflux under hyposmotic and ischaemic conditions in the chicken retina. 1239 92
Estradiol and insulin-like growth factor-I (IGF-I) interact in the hypothalamus to regulate neuronal function, synaptic plasticity and neuroendocrine events. However, the molecular mechanisms involved in these interactions are still unknown. In the present study, the effect of estradiol on the signaling pathways of IGF-I receptor has been assessed in the hypothalamus of young adult ovariectomized rats, using specific antibodies for the phosphorylated forms of extracellular-signal regulated kinase (ERK) 1 and
ERK2
and Akt/protein kinase B (Akt/
PKB
). Estradiol treatment resulted, between 6 and 24 h after systemic administration, in dose-dependent effects on the phosphorylation of ERK and Akt/
PKB
. Estradiol did not modify the level of ERK phosphorylation induced by intracerebroventricular administration of IGF-I. However, both hormones had a synergistic effect on the phosphorylation of Akt/
PKB
. These findings suggest that estrogen effects in the hypothalamus may be mediated in part by the activation of the signaling pathways of the IGF-I receptor.
...
PMID:Synergistic interaction of estradiol and insulin-like growth factor-I in the activation of PI3K/Akt signaling in the adult rat hypothalamus. 1241 26
Signal transducers and activators of transcription (STAT) factors are cytoplasmic proteins that can be activated by Janus kinases (JAK) and that modulate gene expression in response to cytokine receptor stimulation. STAT proteins dimerize, translocate into the nucleus, and activate specific target genes. In the present study, we show for the first time that interleukin-6 (IL), in the presence of its soluble receptor (sIL-6R), induces activation of
JAK1
,
JAK2
, and STAT1/STAT3 proteins in bovine articular chondrocytes. Western blotting and mobility shift assays demonstrated that this effect is accompanied by the DNA binding of the STAT proteins. The mitogen-activated protein kinase pathway was also activated in response to IL-6/sIL-6R association, as reflected by phosphorylation of ERK1 and
ERK2
proteins. In these conditions, the expression of cartilage-specific matrix genes, type II collagen, aggrecan core, and link proteins was found to be markedly down-regulated. This negative effect was abolished by addition of parthenolide, an inhibitor of the STAT activation, whereas blockade of the MAP kinases with PD098059 was without significant effect. Thus, activation of the STAT signaling pathways, but not ERK-dependent pathways, is essential for down-regulation of the major cartilage-specific matrix genes by IL-6. In addition, a parallel reduction of Sox9 expression, a key factor of chondrocyte phenotype, was found in these experimental conditions. These IL-6 effects might contribute to the phenotype loss of chondrocytes in joint diseases and the alteration of articular cartilage associated with this pathology.
...
PMID:JAK/STAT but not ERK1/ERK2 pathway mediates interleukin (IL)-6/soluble IL-6R down-regulation of Type II collagen, aggrecan core, and link protein transcription in articular chondrocytes. Association with a down-regulation of SOX9 expression. 1241 23
Through the production of cytokines and growth factors the endothelium of secondary lymphoid organs plays a crucial role in controlling lymphocyte migration to the lymphoid microenvironment, an essential step in the initiation of the immune response. Here we demonstrate that direct contact of B cell lines with tonsil-derived human endothelial cells resulted in changes in the phosphorylation state of endothelial cells, causing their functional activation. We found a rapid (<15-s) and transient dephosphorylation, followed by a rapid rephosphorylation of tyrosine residues of the
focal adhesion kinase
, paxillin, and
ERK2
. Maximal rephosphorylation occurred after 15-30 min of B cell contact. Preincubation of lymphoid B cells with an adhesion-blocking Ab directed against alpha(4)beta(1) integrin abrogated adhesion-mediated changes of endothelial cell tyrosine phosphorylation, suggesting that cell contact was essential. Similar patterns of tyrosine phosphorylation, but with slightly different kinetics were induced after cross-linking of beta(1) integrin or CD40 on endothelial cells. Functional activation of endothelial cells by B cell adhesion was confirmed by the production of IL-6, IL-8, monocyte chemoattractant protein-1, M-CSF, and macrophage inflammatory protein-1beta mRNA. However, direct cross-linking of beta(1) integrin and CD40 failed to accomplish the same functional activation. These data indicate that direct contact of lymphoid B cells with the endothelium from lymphoid tissue induce endothelial cell signaling, resulting in chemokine and cytokine production. This phenomenon may provide a mechanism for the remodeling of the endothelium from lymphoid tissues, thus contributing to the free migration of lymphocytes and other cells into the lymphoid organs.
...
PMID:Adhesion of B cell lines to endothelial cells from human lymphoid tissue modulates tyrosine phosphorylation and endothelial cell activation. 1242 71
Integrin beta(3) is polymorphic at residue 33 (Leu(33) or Pro(33)), and the Pro(33) variant exhibits increased outside-in signaling to
focal adhesion kinase
and greater actin reorganization. Because
focal adhesion kinase
activation and an intact cytoskeleton are critical links for integrin-mediated signaling to MAPK, we explored the role of integrin alpha(IIb)beta(3) in this signaling using Chinese hamster ovary and human kidney 293 cell lines expressing either the Leu(33) or Pro(33) isoform of beta(3). Compared with Leu(33) cells, Pro(33) cells demonstrated substantially greater activation of
ERK2
(but not MAPK family members JNK and p38) upon adhesion to immobilized fibrinogen (but not fibronectin) and upon integrin cross-linking.
ERK2
activation was mediated through MAPK kinase and required phosphoinositide 3-kinase signaling and an intact actin cytoskeleton. Human platelets and Chinese hamster ovary cells expressing the Pro(33) isoform showed enhanced activation of the
ERK2
substrate myosin light chain kinase (MLCK) upon adhering to fibrinogen. Furthermore, compared with platelets and cells expressing the Leu(33) isoform, the Pro(33) variant showed greater alpha-granule release, clot retraction, and adhesion to fibrinogen under shear stress, and these functional differences were abolished by MLCK and MAPK kinase inhibition. Post-integrin occupancy signaling through MAPK and MLCK after alpha(IIb)beta(3) cross-linking may explain in part the increased adhesive properties of the Pro(33) variant of integrin beta(3).
...
PMID:Enhanced activation of mitogen-activated protein kinase and myosin light chain kinase by the Pro33 polymorphism of integrin beta 3. 1246 Sep 91
Because gonadotropin releasing hormone analogue (GnRHa) therapy often causes leiomyoma regression, in part through alteration of growth factor and receptor expression, we determined whether GnRHa therapy alters the expression of extracellular signal-regulated kinase (ERK) and
focal adhesion kinase
(
FAK
), which are linked to intracellular signaling pathways activated by ovarian steroids, growth factors, and adhesion molecules. Leiomyoma and matched unaffected myometrium were collected from women who received GnRHa therapy (n = 5) and untreated women (n = 10). We determined the expression of ERK1,
ERK2
,
FAK
, phosphorylated ERK (pERK1/2), and pFAK using Western blotting and immunohistochemical analysis. Leiomyoma and myometrium expressed ERK1 (44 kD),
ERK2
(42 kD), and
FAK
(125 kD) at variable levels with increased
ERK2
, pERK, and
FAK
expression in leiomyoma. We found that GnRHa therapy resulted in a noticeable decrease in
ERK2
and
FAK
, with significant reduction in pERK1/2 and low or undetectable levels of pFAK in both leiomyoma and myometrium compared with the untreated group (P <.05). Immunohistochemically ERK1,
ERK2
,
FAK
, pERK1/2, and pFAK were localized in smooth muscle cells and connective tissue fibroblasts in GnRHa-treated and untreated leiomyoma and myometrium, with considerable reduction in their intensity as indicated by HScore in GnRHa-treated tissues. The data provide further evidence that leiomyoma regression induced by GnRHa is mediated in part through a mechanism involving suppression of signal transduction pathways involving growth factors or ovarian steroid and adhesion molecules.
...
PMID:Gonadotropin releasing hormone analogue therapy alters signal transduction pathways involving mitogen-activated protein and focal adhesion kinases in leiomyoma. 1251 89
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