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)

Self-incompatibility in Brassica is controlled by the S locus which contains at least two genes. SLG encodes a secreted S locus glycoprotein whilst SRK encodes a putative S locus receptor kinase which consists of three domains: an extracellular domain sharing extensive sequence identity with SLG, transmembrane region, and a cytoplasmic domain exhibiting a serine/threonine protein kinase activity. Here, the existence of truncated forms of the SRK protein corresponding to the extracellular domain of the putative receptor is reported. These proteins were detected by an antibody which recognizes the N-terminus of SRK3 and, in an F2 progeny segregating for the S3 haplotype, were only expressed in plants possessing the S3 haplotype. The truncated SRK proteins were expressed specifically in stigmas but, unlike the membrane-spanning SRK3 protein, were soluble and occurred as four different glycoforms sharing the same amino acid backbone as shown by deglycosylation experiments. Several SRK3 transcripts that may code for these truncated SRK3 proteins have been identified by RACE PCR, stigma cDNA library screening and RNA blot analysis. These transcripts are apparently generated by a combination of alternative splicing and the use of alternative polyadenylation signals. The existence of truncated forms of the S locus receptor kinase highlights some similarities between plant and animal receptor kinases. In animals, soluble extracellular domains of receptors have been described and, in some cases, have been shown to play a role in the modulation of signal transduction. By analogy, the soluble, truncated SRK proteins may play a similar role in the self-incompatibility response.
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PMID:The S locus receptor kinase gene encodes a soluble glycoprotein corresponding to the SKR extracellular domain in Brassica oleracea. 858 Sep 56

The photodynamic inhibitory effect of hypericin and a number of hypericin-derivatives were investigated in vitro using numerous growth-factor regulated protein kinases including receptor-bound (Insulin-R, EGF-R) and non-receptor (Lyn, c-Fgr, CSK, Syk) protein tyrosine kinases as well as Ser/Thr (PK-C, protein kinase CK-2, CK-1) protein kinases. Modification of the hypericin structure altered significantly the specificity of the protein kinase inhibition. In particular, methylation or attachment of long lipophilic chains to both methyl groups of the hypericin molecule strongly enhanced the specificity toward PK-C.
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PMID:A comparative analysis of the photosensitized inhibition of growth-factor regulated protein kinases by hypericin-derivatives. 860 12

A human myeloid leukemia cell line, KBM-7, was developed from a patient in the blastic phase of chronic myeloid leukemia (CML). We characterized its morphology, immunophenotype, cytogenetics, and proliferative capacity. Developed in the absence of exogenous lymphokines, KBM-7 in vitro cloning capacity actually decreased when colony-stimulating factors were added. The cells had an aberrant immature myeloid phenotype, a doubling time of 22 h in suspension cultures and a high cloning efficiency in semisolid system (24 +/- 3)%. Early passages contained one near-haploid (predominant) and one hyperdiploid stem line. Gradually the hyperdiploid stem line became predominant, reaching an average of 49 chromosomes per cell. Cells from passage 89 had two Philadelphia chromosomes [t(9;22)(q34;q11)] and lacked normal copies of chromosomes 9 and 22. Detailed molecular characterization of the breakpoint in the t(9;22)(q34;q11) revealed that KBM-7 had the BCR 2/ABL II splice junction. The cells had high protein kinase (p210BCR-ABL) activity and carried two identified variants of an ABL-BCR message. There was no evidence that normal BCR or c-ABL messages were expressed, assessed with the reverse-transcriptase polymerase chain reaction. When KBM-7 cells were heterotransplanted into nude mice without immunosuppressive pretreatment, one of three mice injected with 1 x 10(7) cells and all mice injected with 1 x 10(8) cells developed slowly growing granulocytic sarcomas within 6-8 weeks. These tumors were locally invasive but did not metastasize. We conclude that the KBM-7 cell line will be of value for investigating molecular events underlying neoplastic transformation in CML, in particular for studying the effects of BCR-ABL and ABL-BCR on the proliferation of CML cells in the absence of normal BCR and c-ABL messages.
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PMID:KBM-7, a human myeloid leukemia cell line with double Philadelphia chromosomes lacking normal c-ABL and BCR transcripts. 860 23

Signal transduction of two mitogens for pancreatic beta-cells, GH and PRL, was investigated using the differentiated insulin-secreting cell line, INS-1. Addition of human GH (hGH) or ovine PRL in a serum-substitute medium increased growth, insulin content, and nutrient metabolism evaluated by tetrazolium salt reduction. hGH, bovine GH (bGH), and PRL also stimulated [3H]thymidine incorporation in a dose-dependent manner (1 pM - 1 nM). hGH induced cytosolic Ca2+ ([Ca2+]i) rises, which were transient, dependent on the presence of extracellular Ca2+, blocked by verapamil, calciseptine, and the hyperpolarizing agent diazoxide, suggesting that hGH stimulates Ca(2+)-influx through L-type Ca(2+)-channels. Similar effects on [Ca2+]i were observed with bGH or PRL. hGH caused membrane depolarization in a small proportion of the cells ( < 25%) as detected by cell-attached patch-clamp analysis. However, hGH failed to stimulate acute insulin secretion. hGH, bGH, and PRL promoted tyrosine phosphorylation of JAK2 tyrosine kinase. Verapamil inhibited neither [3H]thymidine incorporation nor JAK2 phosphorylation stimulated by hGH, whereas a tyrosine kinase inhibitor, lavendustin A, blocked the mitogenic effect. Involvement of cAMP is suggested because Rp-cyclic adenosine-3', 5'-monophosphorothioate, a competitive inhibitor of protein kinase A, abolished hGH-induced [Ca2+]i rises and DNA synthesis. cAMP appears to play a permissive role, although hGH failed to raise cellular cAMP levels. These results support the idea that activation of JAK2 is a major signaling event, whereas the [CA2+]i rise is not a prerequisite, for the mitogenic effects of GH and PRL in insulin-secreting cells.
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PMID:Postreceptor signalling of growth hormone and prolactin and their effects in the differentiated insulin-secreting cell line, INS-1. 861 23

The first exon of the BCR gene encodes a new serine/threonine protein kinase. Abnormal fusion of the BCR and ABL genes, resulting from the formation of the Philadelphia chromosome (Ph), is the hallmark of Ph-positive leukemia. We have previously demonstrated that the Bcr protein is tyrosine phosphorylated within first-exon sequences by the Bcr-Abl oncoprotein. Here we report that in addition to tyrose 177 (Y-177), Y-360 and Y283 are phosphorylated in Bcr-Abl proteins in vitro. Moreover, Bcr tyrosine 360 is phosphorylated in vivo within both Bcr-Abl and Bcr. Bcr mutant Y177F had a greatly reduced ability to transphosphorylate casein and histone H1, whereas Bcr mutants Y177F and Y283F had wild-type activities. In contrast, the Y360F mutation had little effect on Bcr's autophosphorylation activity. Tyrosine-phosphorylated Bcr, phosphorylated in vitro by Bcr-Abl, was greatly inhibited in its serine/threonine kinase activity, impairing both auto- and transkinase activities of Bcr. Similarly, the isolation of Bcr from cells expressing Bcr-Abl under conditions that preserve phosphotyrosine residues also reduced Bcr's kinase activity. These results indicate that tyrosine 360 of Bcr is critical for the transphosphorylation activity of Bcr and that in Ph-positive leukemia, Bcr serine/threonine kinase activity is seriously impaired.
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PMID:Inhibition of Bcr serine kinase by tyrosine phosphorylation. 862 3

The integrins are a family of cell surface receptors that mediate adhesive interactions with the extracellular matrix and also generate signals that influence cell growth and differentiation. Ligation and clustering of integrins causes activation and autophosphorylation of focal adhesion kinase (FAK), a cytoplasmic tyrosine kinase, and results in the transient activation of p42 and p44 mitogen-activated protein (MAP) kinases. Initial evidence has suggested that the integrin signaling pathway may share common elements with the canonical Ras signal transduction cascade activated by peptide mitogens such as epidermal growth factor (EGF). In this report we demonstrate that Raf-1 and MAP or extracellular signal-related kinase kinase (MEK), key cytoplasmic kinases of the Ras cascade, are activated subsequent to integrin-mediated adhesion of mouse NIH 3T3 fibroblasts. We also show that MAP kinase is downstream of MEK in the integrin signaling pathway. However, in contrast to the receptor tyrosine kinase signaling cascade, integrin-mediated signal transduction seems to be largely independent of Ras. Dominant negative inhibitors of Ras-dependent signaling failed to block integrin-mediated activation of MEK. In addition, while treatment with the peptide mitogen EGF clearly increased GTP-loading of Ras, little effect was observed in response to integrin-dependent cell adhesion. Thus, integrin-mediated activation of MEK and MAP kinase in 3T3 cells occurs primarily by a mechanism that is distinct from the Ras signal transduction cascade.
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PMID:Integrin-mediated activation of MEK and mitogen-activated protein kinase is independent of Ras [corrected]. 866 36

Fluid shear stress regulates endothelial cell function, but the signal transduction mechanisms involved in mechanotransduction remain unclear. Recent findings demonstrate that several intracellular kinases are activated by mechanical forces. In particular, members of the mitogen-activated protein (MAP) kinase family are stimulated by hyperosmolarity, stretch, and stress such as heat shock. We propose a model for mechanotransduction in endothelial cells involving calcium-dependent and calcium-independent protein kinase pathways. The calcium-dependent pathway involves activation of phospholipase C, hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2), increases in intracellular calcium and stimulation of kinases such as calcium-calmodulin and C kinases (PKC). The calcium-independent pathway involves activation of a small GTP-binding protein and stimulation of calcium-independent PKC and MAP kinases. The calcium-dependent pathway mediates the rapid, transient response to fluid shear stress including activation of nitric oxide synthase (NOS) and ion transport. In contrast, the calcium-independent pathway mediates a slower response including the sustained activation of NOS and changes in cell morphology and gene expression. We propose that focal adhesion complexes link the calcium-dependent and calcium-independent pathways by regulating activity of phosphatidylinositol 4-phosphate (PIP) 5-kinase (which regulates PIP2 levels) and p125 focal adhesion kinase (FAK, which phosphorylates paxillin and interacts with cytoskeletal proteins). This model predicts that dynamic interactions between integrin molecules present in focal adhesion complexes and membrane events involved in mechanotransduction will be integrated by calcium-dependent and calcium-independent kinases to generate intracellular signals involved in the endothelial cell response to flow.
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PMID:Protein kinases as mediators of fluid shear stress stimulated signal transduction in endothelial cells: a hypothesis for calcium-dependent and calcium-independent events activated by flow. 866 84

Interleukin-11 is a stromal derived cytokine important in hematopoiesis. IL-11 intracellular signaling travels through cytoplasmic kinases of the Janus family. How JAKs accomplish the multiple functions of IL-11 has not been determined and until recently only a few associated downstream proteins have been identified. We present evidence here for the IL-11 induced association of PP2A, P13K, and Yes to JAK2. Reciprocal immunoprecipitations support the mutual involvement of these signaling components in IL-11 mediated signal transduction. This novel finding of JAK2/PP2A binding and release may have relevance to many serine/threonine regulated mechanisms such as P13K, Stat, and MAPK activation. These associations support a model of JAK2 as a protein kinase docking protein of IL-11 signal transduction that may be applicable to other gp130 and JAK signal transduction systems.
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PMID:Complex formation of JAK2 with PP2A, P13K, and Yes in response to the hematopoietic cytokine interleukin-11. 870 85

Using chronic myelogenous leukemia (CML) as a model, we tested the hypothesis that cytokine-independent growth of leukemia cells results from aberrant activation of cytokine signaling pathways. The STAT5 (signal transducer and activator of transcription) protein, which is activated transiently in normal myeloid cells by cytokines such as GM-CSF (granulocyte-macrophage colony stimulating factor), was constitutively activated in cell lines derived from CML patients, even in the absence of GM-CSF. STAT5 was also activated in primary mouse bone marrow cells acutely transformed by the CML-specific BCR-ABL oncogene, but not by the serine kinase oncogene v-MOS. Reconstitution experiments in non-hematopoietic cells show that STAT5 activation by BCR-ABL occurs independent of cytokines. Results using BCR-ABL mutants which specifically uncouple connections to known signal transduction pathways show that STAT5 activation is kinase dependent and correlates directly with ability to confer cytokine independent growth in hematopoietic cells. BCR-ABL also activates JAK kinases, which may provide a mechanism for STAT activation. These findings are consistent with a role for STAT5 in hematopoietic transformation by BCR-ABL.
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PMID:Constitutive activation of STAT5 by the BCR-ABL oncogene in chronic myelogenous leukemia. 871 Mar 63

Anandamide is an endogenous ligand for central cannabinoid receptors and is released after neuronal depolarization. Anandamide increased protein tyrosine phosphorylation in rat hippocampal slices and neurons in culture. The action of anandamide resulted from the inhibition of adenylyl cyclase and cyclic adenosine 3', 5'-monophosphate-dependent protein kinase. One of the proteins phosphorylated in response to anandamide was an isoform of pp125-focal adhesion kinase (FAK+) expressed preferentially in neurons. Focal adhesion kinase is a tyrosine kinase involved in the interactions between the integrins and actin-based cytoskeleton. Thus, anandamide may exert neurotrophic effects and play a role in synaptic plasticity.
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PMID:Regulation of a neuronal form of focal adhesion kinase by anandamide. 878 Dec 36


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