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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)
Endostatin, a fragment of collagen XVIII, is a potent anti-angiogenic protein, but the molecular mechanism of its action is not yet clear. We examined the effects of endostatin on the biological and biochemical activities of vascular endothelial growth factor (VEGF). Endostatin blocked VEGF-induced tyrosine phosphorylation of KDR/Flk-1 and activation of ERK,
p38
MAPK, and p125(
FAK
) in human umbilical vein endothelial cells. Endostatin also inhibited the binding of VEGF(165) to both endothelial cells and purified extracellular domain of KDR/Flk-1. Moreover, the binding of VEGF(121) to KDR/Flk-1 and VEGF(121)-stimulated ERK activation were blocked by endostatin. The direct interaction between endostatin and KDR/Flk-1 was confirmed by affinity chromatography. However, endostatin did not bind to VEGF. Our findings suggest that a direct interaction of endostatin with KDR/Flk-1 may be involved in the inhibitory function of endostatin toward VEGF actions and responsible for its potent anti-angiogenic and anti-tumor activities in vivo.
...
PMID:Endostatin blocks vascular endothelial growth factor-mediated signaling via direct interaction with KDR/Flk-1. 1202 87
We have previously established that insulin-like growth factor (IGF)-I, -II and insulin exert a strong protective effect against tumor necrosis factor-alpha (TNF)-induced apoptosis in interferon-gamma (IFN)-sensitized HT29-D4 human colon carcinoma cells. In this study, we report that this effect was still operative when cells were cultured in the absence of integrin- and E-cadherin-mediated cell-extracellular matrix and cell-cell interactions. In this model, IGF-I did not activate the
focal adhesion kinase
, whereas it induced tyrosine phosphorylation of the insulin receptor substrate-1 and activation of the extracellular signal-related kinase 1 and 2,
p38
, phosphatidylinositol 3'-kinase and protein kinase B/Akt. However, the use of specific inhibitors indicated that these pathways did not play a role in the adhesion-independent IGF-I anti-apoptotic signal. In contrast, inhibition of the NF-kappaB activation induced a complete reversal of the IGF-I anchorage-independent protective effect. Correspondingly, IGF-I markedly enhanced the TNF- and IFN/TNF-induced NF-kappaB-dependent interleukin-8 production. Our results provide evidence that IGF-I induces resistance against cytokine-induced cell death even in the absence of cell adhesion-mediated signaling. NF-kappaB appears to be a key mediator of this anti-apoptotic effect that should contribute to the resistance of colon cancer cells to immune-destruction during metastasis.
...
PMID:Prevention of cytokine-induced apoptosis by insulin-like growth factor-I is independent of cell adhesion molecules in HT29-D4 colon carcinoma cells-evidence for a NF-kappaB-dependent survival mechanism. 1205 82
IL (interleukin)-22 is an IL-10-related cytokine; its main biological activity known thus far is the induction of acute phase reactants in liver and pancreas. IL-22 signals through a receptor that is composed of two chains from the class II cytokine receptor family: IL-22R (also called ZcytoR11/CRF2-9) and IL-10Rbeta (CRF2-4), which is also involved in IL-10 signaling. In this report, we analyzed the signal transduction pathways activated in response to IL-22 in a rat hepatoma cell line, H4IIE. We found that IL-22 induces activation of
JAK1
and Tyk2 but not
JAK2
, as well as phosphorylation of STAT1, STAT3, and STAT5 on tyrosine residues, extending the similarities between IL-22 and IL-10. However our results unraveled some differences between IL-22 and IL-10 signaling. Using antibodies specific for the phosphorylated form of MEK1/2, ERK1/2, p90RSK, JNK, and
p38
kinase, we showed that IL-22 activates the three major MAPK pathways. IL-22 also induced serine phosphorylation of STAT3 on Ser(727). This effect, which is not shared with IL-10, was only marginally affected by MEK1/2 inhibitors, indicating that other pathways might be involved. Finally, by overexpressing a STAT3 S727A mutant, we showed that serine phosphorylation is required to achieve maximum transactivation of a STAT responsive promoter upon IL-22 stimulation.
...
PMID:Interleukin-22 (IL-22) activates the JAK/STAT, ERK, JNK, and p38 MAP kinase pathways in a rat hepatoma cell line. Pathways that are shared with and distinct from IL-10. 1208
Tumor necrosis factor-alpha (TNFalpha, 10-100 ng/ml) provokes a dramatic cell death in differentiated PC12 cells (dPC12), but it does not affect the viability and the proliferation of naive PC12 cells (nPC12). We have analyzed the molecular alterations of the TNFalpha-signal cascade underlying this developmental switch toward propagation of apoptosis. The transcriptional inhibitor actinomycin D rendered nPC12 responsive for TNFalpha-induced death, but was hardly effective in dPC12, suggesting that TNFalpha evokes its harmful action in dPC12 predominantly by posttranslational modification of existing molecules. This suggestion was supported by the finding that differentiation of PC12 per se went along with the increased expression of the proapoptotic TNFalpha-receptor I (p55) and its adapter protein Traf-2, whereas expression and phosphorylation of the antiapoptotic Akt (
PKB
) declined. We could demonstrate that the c-Jun N-terminal kinases (JNKs) mediate this enhanced capacity of apoptotic signaling in dPC12. TNFalpha induced in dPC12, but not nPC12, a biphasic activation of JNKs with a rapid transient JNK1 activation and a second persistent activation of JNK1 and JNK2 paralleled by phosphorylation of c-Jun; in contrast, TNFalpha did not activate
p38
kinase. Block of JNKs by CEP-11004, a MLK antagonist and subsequently indirect inhibitor of JNK activation, or L-JNK11, a direct peptidergic inhibitor of JNK activity, almost completely rescued dPC12. Summarizing, the NGF-triggered formation of neurites during differentiation of PC12 includes the reinforced propensity for apoptosis, with JNK2 as the effector in JNK3-negative PC12. These findings offer novel insights into the increased risk of neuronal death, which is linked to the potential to regenerate.
...
PMID:Fatal shift of signal transduction is an integral part of neuronal differentiation: JNKs realize TNFalpha-mediated apoptosis in neuronlike, but not naive, PC12 cells. 1209 55
The mechanism of proinflammatory activation of human monocytes by plasmin is unknown. Here we demonstrate that in human primary monocytes, plasmin stimulates mitogen-activated protein kinase (MAPK) signaling via phosphorylation of MAPK kinase 3/6 (MKK3/6) and
p38
MAPK that triggers subsequent DNA binding of transcription factor activator protein-1 (AP-1). The AP-1 complex contained phosphorylated c-Jun and ATF2, and its DNA binding activity was blocked by the
p38
MAPK inhibitor SB203580. In addition, plasmin elicits Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling, as detected by phosphorylation of
JAK1
tyrosine kinase and STAT1 and STAT3 proteins. Plasmin-induced DNA binding of STAT1 and STAT3 was blocked by SB203580 and AG490, inhibitors of
p38
MAPK and JAK, respectively, but not by U0126, an inhibitor of MKK1/2. DNA binding of NF-kappaB remained unaffected by any of these inhibitors. The plasmin-induced signaling led to expression of monocyte chemoattractant protein-1 (MCP-1) and CD40, which required activation of both
p38
MAPK and JAK/STAT signaling pathways. Additionally, signaling through both
p38
MAPK and JAK is involved in the plasmin-mediated monocyte migration, whereas the formylmethionylleucylphenylalanine-induced chemotaxis remained unaffected. Taken together, our data demonstrate a novel function of the serine protease plasmin in a proinflammatory signaling network.
...
PMID:The serine protease plasmin triggers expression of MCP-1 and CD40 in human primary monocytes via activation of p38 MAPK and janus kinase (JAK)/STAT signaling pathways. 1209 96
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
It is well established that IFNalpha has significant clinical activity in the treatment of chronic myelogenous leukemia (CML). This cytokine has been used for many years in the management of patients in the chronic phase of the disease, but the mechanisms by which it induces growth inhibitory effects in CML-cells have not been elucidated. Understanding the signaling mechanisms by which the Type I IFN receptor transduces growth inhibitory signals in BCR-
ABL
expressing cells should prove very valuable, as it may result in the design of new, more specific pharmacological compounds that target the same cellular cascades. Recent evidence indicates that, in addition to the classic IFN-activated Jak-Stat pathway, the Type I IFN receptor engages in its signaling cascade the CrkL-adapter protein, which is also a substrate for the kinase activity of the BCR-
ABL
oncogene. In addition, it appears that activation of a member of the Map kinase (MAPK) family of proteins, the
p38
MAPK, is essential for the generation of the antileukemic effects of IFNalpha. This review summarizes the recent advances in the-field of interferon signaling in CML cells and discusses the implications of identifying signaling proteins that mediate IFNalpha-induced growth inhibition.
...
PMID:Signaling via the interferon-alpha receptor in chronic myelogenous leukemia cells. 1215 54
Kaposi's sarcoma-associated herpes virus (KSHV) infects B cells and microvascular endothelium,and is linked to both lymphoid and endothelial neoplasms. KSHV encodes a G protein-coupled receptor (v-GPCR) that can bind several CC and CXC chemokines but is able to signal in the absence of known ligands. This signaling can transform cultured fibroblasts, promote angiogenesis in vitro and in vivo, and activate the mitogen-activated protein kinase, c-Jun-NH(2)-terminal kinase, and
p38
pathways. To assess the potential impact of v-GPCR signaling on host cell biology we have examined cellular gene expression in v-GPCR-transfected cells using DNA microarrays. v-GPCR expression up-regulated numerous cellular transcripts in both BJAB B cells and
SLK
endothelial cells, but with a remarkable degree of cell-type specificity. Among the most highly regulated genes in endothelial cells were the cytokines interleukin 6 and GRO alpha; several genes affecting endothelial/vascular growth and remodeling were also induced, including plasminogen, thrombomodulin, the urokinase-type plasminogen activator receptor, and to a modest extent vascular endothelial growth factor C. By contrast, the most highly regulated genes in B cells were the CC chemokines macrophage inflammatory protein 1 alpha and macrophage inflammatory protein 1 beta. No genes other than members of the dual-specificity phosphatase family were induced in both cell lines. The results indicate that the effects of KSHV GPCR expression in these two target cell types differ considerably and suggest that signaling by this molecule may make different contributions to the pathogenesis of KSHV-related endothelial and lymphoproliferative lesions.
...
PMID:Modulation of host gene expression by the constitutively active G protein-coupled receptor of Kaposi's sarcoma-associated herpesvirus. 1215 65
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
Neuronal cell membranes are particularly rich in gangliosides, which play important roles in brain physiology and pathology. Previously, we reported that gangliosides could act as microglial activators and are thus likely to participate in many neuronal diseases. In the present study we provide evidence that JAK-STAT inflammatory signaling mediates gangliosides-stimulated microglial activation. Both in rat primary microglia and murine BV2 microglial cells, gangliosides stimulated nuclear factor binding to GAS/ISRE elements, which are known to be STAT-binding sites. Consistent with this, gangliosides rapidly activated
JAK1
and
JAK2
and induced phosphorylation of STAT1 and STAT3. In addition, gangliosides increased transcription of the inflammation-associated genes inducible nitric-oxide synthase, ICAM-1, and MCP-1, which are reported to contain STAT-binding elements in their promoter regions. AG490, a JAK inhibitor, reduced induction of these genes, nuclear factor binding activity, and activation of STAT1 and -3 in gangliosides-treated microglia. AG490 also inhibited gangliosides-induced release of nitric oxide, an inflammation hallmark. Furthermore, AG490 markedly reduced activation of ERK1/2 MAPK, indicating that ERKs act downstream of JAK-STAT signaling during microglial activation. However, AG490 did not affect activation of
p38
MAPK. We also report that the sialic acid residues present on gangliosides may be one of the essential components in activation of JAK-STAT signaling. The present study indicates that JAK-STAT signaling is an early event in gangliosides-induced brain inflammatory responses.
...
PMID:JAK-STAT signaling mediates gangliosides-induced inflammatory responses in brain microglial cells. 1219 95
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