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)

We have investigated mechanisms involved in integrin-mediated signal transduction in platelets by examining integrin-dependent phosphorylation and activation of a newly identified protein tyrosine kinase, pp125FAK (FAK, focal adhesion kinase). This kinase was previously shown to be localized in focal adhesions in fibroblasts, and to be phosphorylated on tyrosine in normal and Src-transformed fibroblasts. We show that thrombin and collagen activation of platelets causes an induction of tyrosine phosphorylation of pp125FAK and that pp125FAK molecules isolated from activated platelets display enhanced levels of phosphorylation in immune-complex kinase assays. pp125FAK was not phosphorylated on tyrosine after thrombin or collagen treatment of Glanzmann's thrombasthenic platelets deficient in the fibrinogen receptor GPIIb-IIIa, or of platelets pretreated with an inhibitory monoclonal antibody to GP IIb-IIIa. Fibrinogen binding to GP IIb-IIIa was not sufficient to induce pp125FAK phosphorylation because pp125FAK was not phosphorylated on tyrosine in thrombin-treated platelets that were not allowed to aggregate. These results indicate that tyrosine phosphorylation of pp125FAK is dependent on platelet aggregation mediated by fibrinogen binding to the integrin receptor GP IIb-IIIa. The induction of tyrosine phosphorylation of pp125FAK was inhibited in thrombin- and collagen-treated platelets preincubated with cytochalasin D, which prevents actin polymerization following activation. Under all of these conditions, there was a strong correlation between the induction of tyrosine phosphorylation of pp125FAK in vivo and stimulation of the phosphorylation of pp125FAK in vitro in immune-complex kinase assays. This study provides the first genetic evidence that tyrosine phosphorylation of pp125FAK is dependent on integrin-mediated events, and demonstrates that there is a strong correlation between tyrosine phosphorylation of pp125FAK in platelets, and the activation of pp125FAK-associated phosphorylating activity in vitro.
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PMID:Integrin-dependent phosphorylation and activation of the protein tyrosine kinase pp125FAK in platelets. 138 45

Recently we described the establishment in culture and the immunophenotypic and functional characteristics of a human T-leukemia line TALL-103/2 derived from the T-cell receptor (TCR)-gamma/delta subset of T-lymphocytes. TALL-103/2 cells are absolutely dependent on interleukin 2 (IL-2) for their growth and survival in culture and thus provide a model cell line for studies of IL-2 signal transduction in a TCR-gamma/delta T-cell. In this report, we focus on the regulation of SRC-family protein tyrosine kinases (PTKs) by IL-2. TALL-103/2 cells were found to contain p56-LCK, p59-FYN, p62-YES and p53/56-LYN. Stimulation of growth factor-deprived TALL-103/2 cells with IL-2, however, induced increases in the relative activity only of the p56-LCK kinase. This IL-2-mediated increase in LCK kinase activity was manifested both by increased kinase autophosphorylation and by increased phosphorylation of the exogenous substrate enolase during in vitro kinase assays. Furthermore, immunoblot assays determined that the levels of p56-LCK protein were unaltered by IL-2-treatment, indicating that the measured elevations in LCK kinase activity reflected an increase in the specific activity of this PTK. In TALL-103/2 cells, IL-2 stimulated concentration-dependent increases in p56-LCK activity that displayed rapid and transient kinetics: detectable increases occurred within 1 minute after IL-2 stimulation, peaked at 10 minutes, and declined to baseline levels by 30 minutes. Treatment of TALL-103/2 cells with IL-4 abrogated IL-2-initiated proliferation, but did not inhibit IL-2-mediated activation of p56-LCK.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Interleukin 4 inhibits IL-2-induced proliferation of a human T-leukemia cell line without interfering with p56-LCK kinase activation. 142 Sep 98

IL-2 is one of the principal growth factors regulating the proliferation of T lymphocytes. Although two independent IL-2-binding molecules have been molecularly cloned and shown to participate in the formation of a high affinity receptor complex, their primary structures do not suggest a specific mechanism for IL-2 growth signal transduction across the cell membrane. Neither IL-2 receptor subunit contains an intrinsic kinase domain; nevertheless, tyrosine phosphorylation of various intracellular substrates is one of the first biochemical changes observed following activation of the IL-2 receptor (IL-2R). Both serine/threonine and tyrosine kinases can be co-precipitated as part of the IL-2R complex suggesting that the IL-2 signalling may involve the activation of non-covalently associated intracellular kinases. However, controversy exists as to which kinases are involved in IL-2 signal transduction; in particular, which kinase(s) mediates the first or proximal event(s) in the signalling process. Activation of the IL-2R leads to serine and threonine phosphorylation of the SRC tyrosine kinase family member, LCK, and an increase in LCK tyrosine kinase activity. Furthermore, LCK can be co-immunoprecipitated with the beta chain of the IL-2R indicating its association with the receptor complex. IL-2 has also been reported to increase FYN kinase activity and to alter its association with the 85 kDa subunit of phosphatidylinositol-3 kinase thus suggesting a role for FYN in IL-2 signal transduction. However, in this report, we now demonstrate that neither LCK nor FYN are obligatory for IL-2-induced growth of HTLV-I-infected human T cells. Lack of expression of LCK or FYN in the HTLV-I-infected T cell lines was demonstrated by a combination of Northern blotting, polymerase chain reaction, Western blotting, and in vitro kinase activity. Despite the absence of LCK or FYN, IL-2 induced similar patterns of rapid tyrosine phosphorylation. Similar results were observed in cell lines lacking expression of the LYN, FGR, HCK, and LTK tyrosine kinases. Thus, none of these tyrosine kinases alone appears to be required for growth signalling through the IL-2R in the HTLV-I-infected T cell lines analyzed. The findings raise the possibility that an, as yet, unidentified tyrosine kinase is involved. Alternatively, this biological signalling system may exhibit remarkable redundancy whereby several different tyrosine kinases may be capable of associating with the IL-2R complex and mediating intracellular signalling.
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PMID:Neither the LCK nor the FYN kinases are obligatory for IL-2-mediated signal transduction in HTLV-I-infected human T cells. 147 76

Chromosome Philadelphia (Ph) which originated from translocation 9;22 is an aberration connected with chronic myelogenous leukaemia (CML) and with part of the cases of acute lymphoblastic leukaemia (ALL). The analysis on the molecular level has shown that the rearrangement of ABL and BCR genes is the most important consequence of this translocation. The new hybrid gene translates the protein p210, which shows tyrosine phosphokinase activity. This protein could play an important role in the pathogenesis of CML. The investigations of BCR/ABL rearrangement on molecular level are an important tool for differential diagnosis of lymphoblastic crisis of CML and ALL and also are very valuable in detection of residual Ph positive cells in cytogenetic conversion of CML.
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PMID:[Molecular biology of chronic myeloid leukemia]. 148 67

Fractionation of a cytosolic extract of HeLa cells revealed the existence of a highly active protein tyrosine kinase. Chromatographic fractionation of the extract resulted in partial purification of a single enzymatic activity that coeluted with a 94-kDa polypeptide. In vitro phosphorylation of the isolated enzyme showed that p94 was the only polypeptide phosphorylated and only the tyrosine residue(s) was (were) modified. The fractionated enzyme (p94 kinase) also phosphorylated a number of other nonspecific substrates exclusively on tyrosine residues. Unlike other protein tyrosine kinases that have been characterized, p94 kinase is relatively insensitive to inhibition by the isoflavone genistein. Using two different antisera, we provided evidence that the HeLa p94 kinase is most likely the FER gene product, which was previously shown to be expressed in a wide variety of cell types. These results represent the first biochemical characterization of the cellular FER gene product and also provide a basis for studying the biochemistry of tyrosine kinase function in HeLa cells.
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PMID:Identification and characterization of a cytosolic protein tyrosine kinase of HeLa cells. 155 92

The Philadelphia chromosome (Ph1), detected in virtually all cases of chronic myelogenous leukemia, is formed by a reciprocal translocation between chromosomes 9 and 22 that fuses BCR encoded sequences upstream of exon 2 of c-ABL. This oncogene produces a fusion protein (p210BCR/ABL) in which the ABL tyrosine kinase activity is elevated. This elevated kinase activity is essential for transformation, but the mechanisms involved are unknown. We report here that p21ras GTPase activating protein (rasGAP) or rasGAP-associated proteins p190 and p62 are phosphorylated on tyrosine in Ph1 (+) cell lines. Further, rasGAP coimmunoprecipitates with p210BCR/ABL in these cell lines. These results suggest that rasGAP or associated proteins are potential substrates for p210BCR/ABL kinase and thus directly link p210BCR/ABL with a signal transduction pathway known to be activated by hematopoietic growth factors (p21ras).
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PMID:Tyrosine phosphorylation of rasGAP and associated proteins in chronic myelogenous leukemia cell lines. 157 36

Protein tyrosine kinases (PTKs) are implicated in the control of cell growth by virtue of their frequent appearance as products of retroviral oncogenes, as intracellular signal transducers, and as growth factor receptors or components thereof. The knowledge of the structure and sequence of family genes encoding PTKs is still limited. To date, the complete genomic structure of human src family members is only available for the C-FGR gene (encoding p55 Fgr, PTK). Sequence analysis and characterization of the intron/exon organization of the human HCK gene, encoding a hemopoietic-specific cell PTK of the src-related family, revealed a length of over 16 kb for the seven 3'-exons. All intron/exon splice junctions agree with the GT/AG rule. In each case where a boundary occurs at a Gly codon, GGG or GGA, the triplet is split between the first and second nucleotide (nt). A total of eight complete and one partial Alu repeats were identified within the introns. The nt sequence of the genomic clones resolves existing discrepancies among two published sequences of HCK cDNAs. Human HCK, C-SRC (encoding p60 Src PTK), C-FGR and LCK (encoding p56 Lck, PTK) genes thus share very similar exon/intron structures for the conserved exons. These results provide additional evidence that the different PTKs of the src-like family most likely arose by duplication of an ancestral src-like gene.
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PMID:The genomic locus of the human hemopoietic-specific cell protein tyrosine kinase (PTK)-encoding gene (HCK) confirms conservation of exon-intron structure among human PTKs of the src family. 157 49

A member of a new class of protein tyrosine kinases, JAK1, has been mapped to 1p31.3 by in situ hybridization and Southern blot analysis of a panel of mouse-human hybrid cell lines. A murine protein tyrosine kinase, related to, but distinct, from JAK1, was mapped by in situ hybridization to human Chromosome (Chr) 9p24 and 1p31.3.
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PMID:Two members of the JAK family of protein tyrosine kinases map to chromosomes 1p31.3 and 9p24. 158 31

Expression of the Rous sarcoma virus-encoded oncoprotein, pp60v-src, subverts the normal regulation of cell growth, which results in oncogenic transformation. This process requires the intrinsic protein-tyrosine kinase activity of pp60v-src and is associated with an increase in tyrosine phosphorylation of a number of cellular proteins, candidate substrates for pp60v-src. We report here the isolation of a cDNA encoding a protein, pp125, that is a major phosphotyrosine-containing protein in untransformed chicken embryo cells and exhibits an increase in phosphotyrosine in pp60v-src-transformed chicken embryo cells. This cDNA encodes a cytoplasmic protein-tyrosine kinase which, based upon its predicted amino acid sequence and structure, is the prototype for an additional family of protein-tyrosine kinases. Immunofluorescence localization experiments show that pp125 is localized to focal adhesions; hence, we suggest the name focal adhesion kinase.
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PMID:pp125FAK a structurally distinctive protein-tyrosine kinase associated with focal adhesions. 159 31

Unlike many other growth factor receptors, the known subunits of the receptors for the Interleukins IL-2 and IL-3 lack intrinsic tyrosine kinase activity, and yet increases in the phosphorylation of proteins on tyrosines is a rapid event in hematolymphoid cells following stimulation with these lymphokines. Here we show that IL-2 and IL-3 regulate the activity of specific members of the SRC-family of non-receptor protein tyrosine kinases (PTKs). In IL-2-dependent T-cell lines, IL-2 induced rapid and transient increases in the activity of the p56-LCK kinase without influencing the activities of other SRC-like PTKs (p59-FYN, p62-YES) in these T-lymphocytes. In contrast to IL-2's effects on p56-LCK in T-cells, studies of an IL-2-responsive cell line of the B-cell lineage that lacks p56-LCK revealed that IL-2 specifically regulates the activity of the p53/56-LYN kinase. Thus, some flexibility exists in the ability of various SRC-like PTKs to functionally couple to IL-2 signalling pathways. In several IL-3-dependent myeloid-committed leukemic cell lines, IL-3 was found to specifically regulate the activity of the p53/56-LYN kinase without affecting the activities of other SRC-like PTKs (p59/64-HCK, p59-FYN, p62-YES) in these hematopoietic cells. This finding that p53/56-LYN can be regulated by both IL-2 in B-lineage cells and IL-3 in myeloid-committed cells demonstrates that the same SRC-family PTK can participate in signal transduction events mediated via two independent receptor systems. Taken together, our findings imply that the specific combinations of lymphokine receptors and SRC-like PTKs available for coupling with those receptors are coordinately controlled during the differentiation of hematopoietic cells.
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PMID:Regulation of SRC-family protein tyrosine kinases by interleukins, IL-2, and IL-3. 160 36


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