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)

Polyclonal antibodies have been raised against two synthetic peptides reproducing the 48-64 and 353-369 sequences of CSK, a protein tyrosine kinase implicated in the down-regulation of src-related protein kinases. Both antibodies specifically recognize recombinant CSK and a CSK-related 49 kDa protein tyrosine kinase present in spleen but they do not cross-react with purified TPK-IIB, a spleen protein tyrosine kinase sharing with CSK catalytic activity toward src kinases and incapability to autophosphorylate. CSK and TPK-IIB once resolved from each other by heparin-Sepharose affinity chromatography, display opposite specificities toward synthetic peptides reproducing the sequences around the main phosphoacceptor residues of pp60c-src, namely Tyr-416 and Tyr-527. These data support the view that TPK-IIB and CSK may exert opposite effects on the activity of src-related protein tyrosine kinases.
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PMID:Spleen protein tyrosine kinases TPK-IIB and CSK display different immunoreactivity and opposite specificities toward c-src-derived peptides. 128 Feb 30

The translocation between chromosome 9 and chromosome 22 which creates the Philadelphia chromosome moves the ABL oncogene from its normal location on chromosome 9 and fuses it with a portion of the BCR gene on chromosome 22. This new BCR/ABL fusion gene generates a unique 8.7 kilobase (kb) RNA which codes for a new 210 kilodalton (kd, p210) protein which has a protein tyrosine kinase activity that is greatly increased in comparison to the normal ABL protein. The human K562 cell line was derived from a patient with CML, and serves as one model for the regulation of expression of the ABL and BCR/ABL genes. This study examines the expression of the BCR/ABL fusion gene and the normal ABL gene in relation to differentiation and changes in proliferative state. The expression of both the normal ABL transcripts and the BCR/ABL fusion transcript decrease approximately ten-fold when the cells are induced to differentiate with hemin. In contrast, expression of the MYC oncogene is unaffected by hemin-induced differentiation. The results suggest that both ABL and BCR/ABL expression vary in proportion to the differentiation of the cells, but minimally if at all as a function of the cells' proliferative state.
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PMID:ABL oncogene expression during erythroleukemia cell differentiation. 199 45

We have cloned a protein tyrosine kinase, MATK, which is expressed abundantly in megakaryocytes and the brain. We investigated whether MATK participates in the c-Kit ligand/stem cell factor (KL/SCF) signaling pathway in the megakaryocytic cell line CMK. After KL/SCF stimulation, five major proteins of molecular masses of 145, 113, 92, 76, and 63 kDa were rapidly and transiently tyrosine-phosphorylated in a time-dependent manner, peaking within 5 min, and returning to basal levels within 60 min. To study the role of MATK in the KL/SCF signaling pathway, glutathione S-transferase (GST) fusion proteins containing SH2 and SH3 domains of MATK were cloned, expressed in Escherichia coli, and purified. MATK-SH2, but not MATK-SH3, precipitated the tyrosine-phosphorylated c-Kit (molecular mass of 145 kDa) in KL/SCF-stimulated CMK cells. Other GST fusion proteins containing the SH2 domain of p85 of phosphatidylinositol 3-kinase, phospholipase C gamma-1, and ras-GAP also precipitated c-Kit. The tyrosine-phosphorylated c-Kit was co-immunoprecipitated with anti-MATK and anti-p85 antibodies in KL/SCF-stimulated CMK cells, but not in granulocyte-macrophage colony stimulating factor or interleukin-6-stimulated cells, suggesting receptor specificity. These results indicate that MATK associates with the c-Kit receptor following specific stimulation by KL/SCF via its SH2 domain and likely participates in transduction of growth signals induced by this cytokine in megakaryocytes.
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PMID:The MATK tyrosine kinase interacts in a specific and SH2-dependent manner with c-Kit. 753 44

Focal adhesion kinase (p125FAK; FAK) is a protein tyrosine kinase that is tyrosine-phosphorylated in response to v-src-mediated transformation, cell adhesion, and stimulation with neuropeptides. To elucidate a possible functional relationship between FAK and BCR-ABL oncoprotein detected in Philadelphia chromosome-positive (Ph+) leukemias, we investigated the tyrosine phosphorylation state of FAK in a murine growth factor-dependent cell line and in its stable human bcr-abl cDNA transfectant. In interleukin-3 (IL-3)-dependent NFS/N1.H7 cells, tyrosine phosphorylation of FAK was not detected after stimulation with either IL-3 or Steel factor (SLF), both of which involve Ras-mediated signaling pathways. However, stable gene transfection with p210bcr-abl cDNA into H7 cells made these cells growth factor-independent for proliferation and resulted in constitutive tyrosine phosphorylation and kinase activation of FAK. Constitutive phosphorylation and activation of FAK was also observed in all Ph+ leukemia cell lines examined--that is, K562, TS9;22, and YS9;22, which express p210BCR-ABL, and NALM-21 and OM9;22, which express p185BCR-ABL. Ph-negative (Ph-) cell lines, such as MO7e and JM, did not show any detectable tyrosine phosphorylation of FAK. FAK phosphorylation in BCR-ABL-expressing cells was inhibited in a dose-dependent manner by cytochalasin D, a reagent that disrupts the intracellular network of actin filaments. However, no suppression of kinase activity or protein expression of BCR-ABL was observed after treatment with cytochalasin D. A physical association between BCR-ABL and FAK was not apparent. These data suggest that BCR-ABL may be involved in the activation of FAK. Moreover, FAK may be distinct from components in Ras-mediated signaling cascades that are activated by stimulation of myeloid cells with various cytokines.
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PMID:Tyrosine phosphorylation and activation of focal adhesion kinase (p125FAK) by BCR-ABL oncoprotein. 755 24

T-cell antigen receptor (TCR), which is not itself a protein tyrosine kinase (PTK), is thought to be associated with at least two SRC-like PTKs, P59fyn and ZAP-70. Activation of these PTKs is required for T-cell signal transduction. The aim of the present study was to determine the roles of PTKs in peripheral T-cell activation, induced by in vivo bacterial superantigen administration. We demonstrated that in vivo staphylococcal enterotoxin B (SEB) administration induced an enhanced tyrosine phosphorylation in peripheral spleen T cells undergoing a programmed cell death. In vitro immunecomplex kinase assay using antibody against P59fyn showed increased fyn kinase activity in SEB-stimulated spleen T cells. We examined the effect of PTK-specific inhibitors on DNA fragmentation and programmed cell death of V beta 8 positive T cells following in vitro culture of SEB-primed spleen T cells. Our results indicated that pretreatment of SEB-activated T cells with PTK inhibitors reduced DNA fragmentation and programmed cell death of V beta 8 positive T cells. These findings suggest that PTK plays an important role in activation and apoptosis of peripheral T cells induced by in vivo SEB administration.
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PMID:Tyrosine phosphorylation participates in peripheral T-cell activation and programmed cell death in vivo. 755 48

The integrin family of heterodimeric cell surface receptors play critical roles in multiple biological processes by mediating cellular adhesion to the extracellular matrix (ECM). Adhesion triggers intracellular signaling cascades, including tyrosine phosphorylation and elevation of [Ca2+]i. The Focal Adhesion Kinase (FAK or pp125FAK), a protein tyrosine kinase that colocalizes with integrins in cellular focal adhesions, is a prime candidate for a mediator of integrin signaling events. Here we report an analysis of the domain structure of FAK in which we have identified a contiguous stretch of 159 amino acids within the COOH terminus essential for correct subcellular localization. When placed in the context of an unrelated cytosolic protein, this Focal Adhesion Targeting (FAT) sequence functions to efficiently mediate the focal adhesion localization of this fusion protein. Furthermore, this analysis suggests that pp125FAK cannot be activated oncogenically by mutation. This result could be explained if pp125FK either exhibits a narrow substrate specificity or is diametrically opposed by cellular phosphatases or other cellular processes.
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PMID:Identification of sequences required for the efficient localization of the focal adhesion kinase, pp125FAK, to cellular focal adhesions. 822 54

The integrin family of cell surface receptors mediates cell adhesion to components of the extracellular matrix (ECM). Integrin engagement with the ECM initiates signaling cascades that regulate the organization of the actin-cytoskeleton and changes in gene expression. The Rho subfamily of Ras-related low-molecular-weight GTP-binding proteins and several protein tyrosine kinases have been implicated in mediating various aspects of integrin-dependent alterations in cell homeostasis. Focal adhesion kinase (FAK or pp125FAK) is one of the tyrosine kinases predicted to be a critical component of integrin signaling. To elucidate the mechanisms by which FAK participates in integrin-mediated signaling, we have used expression cloning to identify cDNAs that encode potential FAK-binding proteins. We report here the identification of a cDNA that encodes a new member of the GTPase-activating protein (GAP) family of GTPase regulators. This GAP, termed Graf (for GTPase regulator associated with FAK), binds to the C-terminal domain of FAK in an SH3 domain-dependent manner and preferentially stimulates the GTPase activity of the GTP-binding proteins RhoA and Cdc42. Subcellular localization studies using Graf-transfected chicken embryo cells indicates that Graf colocalizes with actin stress fibers, cortical actin structures, and focal adhesions. Graf mRNA is expressed in a variety of avian tissues and is particularly abundant in embryonic brain and liver. Graf represents the first example of a regulator of the Rho family of small GTP-binding proteins that exhibits binding to a protein tyrosine kinase. We suggest that Graf may function to mediate cross talk between the tyrosine kinases such as FAK and the Rho family GTPase that control steps in integrin-initiated signaling events.
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PMID:An SH3 domain-containing GTPase-activating protein for Rho and Cdc42 associates with focal adhesion kinase. 864 27

IL-4 and IL-13 each act on human endothelial cells (ECs) to induce expression of vascular cell adhesion molecule-1. On hematopoietic cells. IL-4 responses may be mediated either through a pathway involving gc, the common signaling subunit of the IL-2, IL-4, IL-7, IL-9, and IL-15 receptors, or through a gc-independent pathway that may be alternatively activated by IL-13. We find that human ECs do not express gc, as detected by indirect immunofluorescence and FACS analysis or by a reverse transcription-PCR method. Like IL-4, IL-13 activates a protein tyrosine kinase that phosphorylates the IL-4R binding protein. In addition, we find that IL-4 and IL-13 each induce tyrosine phosphorylation of the JAK2 tyrosine kinase. Furthermore, both IL-4 and IL-13 induce binding of the Stat6 transcription factor to a consensus sequence oligonucleotide. We conclude that the IL-4 response of human ECs involves the IL-13 shared pathway that is independent of gc, and uses JAK2-Stat6 signaling.
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PMID:IL-4 and IL-13 activate the JAK2 tyrosine kinase and Stat6 in cultured human vascular endothelial cells through a common pathway that does not involve the gamma c chain. 869 49

pp125FAK (focal adhesion kinase) a protein tyrosine kinase that may mediate cellular responses to adhesion, is activated and tyrosine-phosphorylated when platelets adhere to fibrinogen via the integrin, alpha IIb beta 3. To determine whether either of the cytoplasmic tails of alpha IIb beta 3 regulates FAK phosphorylation, CHO cells were stably transfected with alpha IIb beta 3 or various cytoplasmic tail truncation mutants. Cells expressing wild-type alpha IIb beta 3 or alpha IIb beta 3 that lacked the COOH-terminal 13 or 18 residues of the 20 residue alpha IIb tail adhered to and spread on fibrinogen or on an anti-alpha IIb antibody, and FAK became tyrosine-phosphorylated. FAK also became phosphorylated in adherent cells lacking the COOH-terminal 35 or 39 residues of the 47 residue beta 3 tail, although the extent of phosphorylation was reduced by about 50% in the latter mutant. Little or no FAK phosphorylation was observed if 46 residues were deleted from the beta 3 tail. None of these beta 3 truncation mutants spread on the anti-alpha IIb antibody. When cells with wild-type alpha IIb beta 3 or truncated beta 3 were detached from a surface, FAK became rapidly dephosphorylated. In contrast, FAK remained phosphorylated in the two alpha IIb truncation mutants for up to 90 minutes in suspension. This persistent phosphorylation was not due to occupancy of alpha IIb beta 3 by adhesive ligands because it was also observed with an alpha IIb tail truncation mutant that contained an additional mutation in the extracellular portion of the receptor that prevents ligand binding. These studies demonstrate that: (1) the beta 3 cytoplasmic tail, including the membrane-proximal portion, is involved in initiation of FAK phosphorylation; (2) FAK phosphorylation can be initiated by cell adhesion in the absence of cell spreading; and (3) the membrane-distal portion of the alpha IIb cytoplasmic tail may normally function to dampen FAK phosphorylation in non-anchored cells.
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PMID:Integrin signaling: roles for the cytoplasmic tails of alpha IIb beta 3 in the tyrosine phosphorylation of pp125FAK. 871 88

pp125FAK, a protein tyrosine kinase (PTK) co-localized with integrins in focal adhesion plaques, is known to transduce signals involved in the regulation of cell adhesion and motility as well as the anchorage-independent growth of transformed cells. We investigated whether pp125FAK could be part of a signalling pathway that contributes to the progression of human prostate carcinoma (PCa). Up-regulation of pp125FAK expression, its activation by phosphorylation on tyrosine and its association with paxillin and p50csk were preferentially observed in PCa tissues from patients with metastases, whereas normal and hyperplastic prostates and localized PCa tissues showed undetectable or low levels of both FAK mRNA and protein and an absence of pp125FAK signalling complexes. The increase in expression and activation of pp125FAK in metastatic PCa tissues was also corroborated by our findings in human PCa cell lines. Indeed, higher levels of pp125FAK and FAK mRNA were observed in highly tumorigenic PC-3 cells as was the presence of activated pp125FAK, as opposed to an inactive form in LNCaP cells, which have a lower tumorigenic ability. In addition, pp125FAK formed signalling complexes with both paxillin and p50csk in PC-3 cells as in metastatic PCa tissues. Together, our results show that an increase in FAK mRNA and protein, as well as pp125FAK activation and association with signalling proteins, correlates with progression and invasion in human PCa tissues and cells.
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PMID:Focal adhesion kinase (pp125FAK) expression, activation and association with paxillin and p50CSK in human metastatic prostate carcinoma. 890 Apr 22


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