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

---

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.
...
PMID:Spleen protein tyrosine kinases TPK-IIB and CSK display different immunoreactivity and opposite specificities toward c-src-derived peptides. 128 Feb 30

We describe the isolation and cDNA sequence of a novel human gene, which is distinct from all known members of the human src family of proto-oncogenes. In contrast to these, an autophosphorylation site corresponding to Tyr416, as well as the equivalent of Tyr527 in p60c-src, are missing in the amino acid (aa) sequence deduced from this gene. Furthermore, no N-terminal myristylation site is found. Our human clone is 98% identical at the aa level to a gene which was isolated independently from neonatal rat brain and was termed csk for c-src kinase. We, therefore, propose to designate the present human gene CSK. In Northern blot experiments, CSK was found to be expressed in human lung and macrophages. Due to its extreme conservation across species barriers, the CSK product is likely to exert important regulatory functions. On the basis of its expression in tissues, not typically expressing high c-src levels, it can be assumed that its regulatory role is more general and may also involve other tyrosine kinases.
...
PMID:Isolation and characterization of a human gene that encodes a new subclass of protein tyrosine kinases. 137 89

We have previously reported the cloning of a novel cytoplasmic tyrosine kinase, CSK. This tyrosine kinase has been shown to downregulate the tyrosine kinase activity of the c-src oncoprotein through tyrosine phosphorylation of the c-src carboxyl terminus. Cell transformation by src oncoproteins is caused by several oncogenic mechanisms, which interfere with this phosphorylation. The CSK gene could therefore potentially function as an antioncogene. We have here mapped the CSK gene to 15q23----q25 by in situ hybridization.
...
PMID:The c-src tyrosine kinase (CSK) gene, a potential antioncogene, localizes to human chromosome region 15q23----q25. 137 9

The functions of src family protein-tyrosine kinases are thought to be regulated negatively by the phosphorylation of highly conserved tyrosine residues close to their carboxyl termini. Recently we have purified and cloned a protein-tyrosine kinase (designated as CSK) that can specifically phosphorylate the negative regulatory site of p60c-src. To elucidate the relationship between CSK and other types of src family kinases, we investigated the tissue distribution of CSK and examined whether CSK could phosphorylate the negative regulatory sites of src family kinases other than p60c-src. Western blot analysis indicated that CSK was enriched at the highest level in lymphoid tissues in which the expression of p60c-src is considerably lower than those of other types of src family kinases. CSK phosphorylated p56lyn and p59fyn, which are known to be expressed in lymphoid tissues at a relatively high level. The putative regulatory site, tyrosine 508, was found to be essential for phosphorylation in p56lyn, and the kinase activities of these src family kinases were repressed by phosphorylation with CSK. These findings raise the possibility that CSK might act as a universal regulator for src family kinases.
...
PMID:CSK: a protein-tyrosine kinase involved in regulation of src family kinases. 172 1

Biochemical analysis of the kinetics of assembly of two cytoplasmic plaque proteins of the desmosome, desmoplakins I (250,000 Mr) and II (215,000 Mr), in Madin-Darby canine kidney (MDCK) epithelial cells, demonstrated that these proteins exist in a soluble and insoluble pool, as defined by their extract ability in a Triton X-100 high salt buffer (CSK buffer). Upon cell-cell contact, there is a rapid increase in the capacity of the insoluble pool at the expense of the soluble pool; subsequently, the insoluble pool is stabilized, while proteins remaining in the soluble pool continue to be degraded rapidly (Pasdar, M., and W. J. Nelson. 1988. J. Cell Biol. 106:677-685). In this paper, we have sought to determine the spatial distribution of the soluble and insoluble pools of desmoplakins I and II, and their organization in the absence and presence of cell-cell contact by using differential extraction procedures and indirect immunofluorescence microscopy. In the absence of cell-cell contact, two morphologically and spatially distinct patterns of staining of desmoplakins I and II were observed: a pattern of discrete spots in the cytoplasm and perinuclear region, which is insoluble in CSK buffer; and a pattern of diffuse perinuclear staining, which is soluble in CSK buffer, but which is preserved when cells are fixed in 100% methanol at -20 degrees C. Upon cell-cell contact, in the absence or presence of protein synthesis, the punctate staining pattern of desmoplakins I and II is cleared rapidly and efficiently from the cytoplasm to the plasma membrane in areas of cell-cell contact (less than 180 min). The distribution of the diffuse perinuclear staining pattern remains relatively unchanged and becomes the principal form of desmoplakins I and II in the cytoplasm 180 min after induction of cell-cell contact. Thereafter, the relative intensity of staining of the diffuse pattern gradually diminishes and is completely absent 2-3 d after induction of cell-cell contact. Significantly, double immunofluorescence shows that during desmosome assembly on the plasma membrane both staining patterns coincide with a subpopulation of cytokeratin intermediate filaments. Taken together with the preceding biochemical analysis, we suggest that the assembly of desmoplakins I and II in MDCK epithelial cells is regulated at three discrete stages during the formation of desmosomes.
...
PMID:Kinetics of desmosome assembly in Madin-Darby canine kidney epithelial cells: temporal and spatial regulation of desmoplakin organization and stabilization upon cell-cell contact. II. Morphological analysis. 327 50

CSK is a predominantly cytosolic protein-tyrosine kinase (PTK) that negatively regulates Src family PTKs by phosphorylation of a conserved tyrosine near their C termini. Little is known about how CSK itself is regulated. On the basis of immunofluorescence studies, a model has been proposed that when c-Src is activated, it is redistributed to podosomes, in which substrates become phosphorylated, creating binding sites for CSK. CSK is recruited to these sites of c-Src activation via its SH2 and SH3 domains and is then in a position to downregulate c-Src activity (B. W. Howell and J. A. Cooper, Mol. Cell. Biol. 14:5402-5411, 1994). To identify phosphotyrosine (P.Tyr)-containing proteins that may mediate translocation of CSK due to c-Src activation, we have examined the whole spectrum of P.Tyr-containing proteins that associate with CSK in v-Src NIH 3T3 cells by anti-P.Tyr immunoblotting. Nine P.Tyr-containing proteins coimmunoprecipitated with CSK from v-Src NIH 3T3 cells. One of these, an approximately 62-kDa protein, also associated with CSK in NIH 3T3 cells treated with vanadate prior to lysis and in NIH 3T3 cells expressing an activated c-Src mutant. This 62-kDa protein was shown to be identical to the GTPase-activating protein (GAP)-associated p62 (GAP-A.p62) protein. The interaction between CSK and GAP-A.p62 could be reconstituted in vitro with glutathione S-transferase fusion proteins containing full-length CSK or the CSK SH2 domain. Furthermore, our data show that CSK interacts directly with GAP.A-p62 and that the complex between the two proteins is localized in subcellular membrane or cytoskeletal fractions. Our results suggest that GAP-A.p62 may function as a docking protein and may mediate translocation of proteins, including GAP and CSK, to membrane or cytoskeletal regions upon c-Src activation.
...
PMID:The nonreceptor protein-tyrosine kinase CSK complexes directly with the GTPase-activating protein-associated p62 protein in cells expressing v-Src or activated c-Src. 754 35

We recently cloned a partial cDNA (35H) for a protein kinase C (PKC) binding protein from a rat kidney cDNA library and demonstrated that it is a PKC substrate in vitro (Chapline, C., Ramsay, K., Klauck, T., and Jaken, S. (1993) J. Biol. Chem. 268, 6858-6861). Additional library screening and 5' rapid amplification of cDNA ends were used to obtain the complete open reading frame. Amino acid sequence analysis, DNA sequence analysis, and Northern analysis indicate that 35H is a unique cDNA related to alpha-and beta-adducins. Antisera prepared to the 35H bacterial fusion protein recognized two polypeptides of 80 and 90 kDa on immunoblots of kidney homogenates and cultured renal proximal tubule epithelial cell extracts. The 35H-related proteins were similar to alpha- and beta-adducins in that they were preferentially recovered in the Triton X-100-insoluble (cytoskeletal, CSK) fraction of cell extracts and were predominantly localized to cell borders. Phorbol esters stimulated phosphorylation of CSK 35H proteins, thus emphasizing that sequences isolated according to PKC binding activity in vitro are also PKC substrates in vivo. The phosphorylated forms of the 35H proteins were preferentially recovered in the soluble fraction, thus demonstrating that phosphorylation regulates their CSK association and, thereby, their function in regulating cytoskeletal assemblies. We have isolated another PKC binding protein partial cDNA (clone 45) from a rat fibroblast library with substantial homology to alpha-adducin. Antisera raised against this expressed sequence recognized a protein of 120 kDa, the reported size of alpha-adducin, on immunoblots of renal proximal tubule epithelial cell extracts. A 120-kDa protein that cross-reacts with the clone 45 (alpha-adducin) antisera coprecipitated with 35H immunecomplexes, indicating that alpha-adducin associates with 35H proteins in vivo. Taken together, these results indicate that 35H is a new, widely expressed form of adducin capable of forming heterodimers with alpha-adducin. We propose naming this adducin homologue gamma-adducin.
...
PMID:35H, a sequence isolated as a protein kinase C binding protein, is a novel member of the adducin family. 759 23

In normal fibroblasts, the product of the cellular src gene, p60c-src or Src, is repressed by phosphorylation at its C-terminal tyrosine residue, Tyr 527. Mutations in Src that prevent phosphorylation cause enzymatic activation and malignant transformation. The tyrosine kinases that phosphorylate Src at Tyr 527 in vivo have not been identified, but a tyrosine kinase known as CSK is an excellent candidate. CSK has the unusual ability to phosphorylate Src in vitro only at Tyr 527. To examine whether CSK has the appropriate sequence specificy to explain the phosphorylation of Src at Tyr 527 in fibroblasts, we have made use of a set of C-terminal substitution mutants of Src. These mutants were previously characterized for their levels of Tyr 527 phosphorylation when expressed in Rat2 fibroblasts. The ability of CSK to phosphorylate selected mutants has now been tested, using both in vitro phosphorylation assays and co-expression of CSK with the Src mutants in a heterologous organism, Saccharomyces cerevisiae. We also tested whether the mutant Src molecules could autophosphorylate at Try 527, by examining the phosphorylation state of catalytically active forms expressed in the absence of CSK in yeast cells. The results show that CSK has strict sequence specificity for the normal Src sequence, although it can also phosphorylate the Lck sequence. The other mutant Src molecules tested were not phophorylated by CSK, even though some of these mutants are highly phosphorylated at Tyr 527 in Rat 2 cells. All the mutants that are phosphorylated at Tyr 527 in Rat2 cells are also able to autophosphorylate at Tyr 527. The results suggest that CSK, autophosphorylation, and phosphorylation by kinases other than CSK, may all contribution to repressing Src catalytic activity in fibroblasts.
...
PMID:Phosphorylation of Src mutants at Tyr 527 in fibroblasts does not correlate with in vitro phosphorylation by CSK. 767 1

The CSK-gene encodes an intracellular protein-tyrosine kinase (PTK). In contrast to members of the src-family, an autophosphorylation site corresponding to Tyr416, as well as the equivalent of the regulatory Tyr527 in p60c-src are missing in the amino acid sequence deduced from the gene. CSK phosphorylates other members of the src-family of tyrosine kinases at their regulatory carboxy-terminus. By regulating the activity of these kinases, CSK may play an important role in cell growth and development. Here we describe the structure of the human CSK gene. The entire coding region spans a genomic distance of only 4.9 kb. It encompasses 12 exons ranging between 66 and 220 bp in size. The introns between coding exons vary between 76 and 920 bp in length. An exon coding for the 5'-untranslated region of CSK is separated from the first coding exon by an intron of more than 6400 bp. Based on comparisons of sequence homologies within the catalytic domains, the intracellular PTKs are divided into the src-family, the fes/fer- and the abl/arg-group. The genomic structure of four members of the SRC-family revealed nearly identical exon/intron boundaries within the catalytic domain of this family. They differ from those described for FES. Comparing the genomic structure of CSK with the exon/intron organisation of both, it is obvious that the exon/intron boundaries are in common either with those of the SRC-type or the FES boundaries. This intermediate exon/intron structure of CSK between FES and the SRC-family agrees with the position of CSK in a phylogenetic tree based on sequence homology within the kinase domain.
...
PMID:Characterization of the human CSK locus. 768 31

The naphthodianthrone hypericin causes a photosensitized inhibition of protein kinases involved in growth factor signalling pathways. Nanomolar concentrations of hypericin inhibit the protein tyrosine kinase activities (PTK) of the epidermal growth factor receptor and the insulin receptor, while being ineffective towards the cytosolic protein tyrosine kinases Lyn, Fgr, TPK-IIB and CSK. Photosensitized inhibition by hypericin is not restricted to receptor-PTKs since the Ser/Thr protein kinases (protein kinase CK-2, protein kinase C and mitogen-activated kinase) are also extremely sensitive to inhibition (IC50 value for protein kinase CK-2 = 6 nM). A comparison of the hypericin-mediated inhibition of the epidermal growth factor-receptor PTK and protein kinase CK-2 revealed that the inhibition is irreversible, strictly dependent upon irradiation of the enzyme-inhibitor complex with fluorescent light and likely mediated by the formation of radical intermediates (type I mechanism). Although the exact molecular basis for the selectivity of enzyme inhibition by hypericin remains unknown, our results suggest that distantly related protein kinases could still share common reactive domains for the interaction with hypericin.
...
PMID:Photosensitized inhibition of growth factor-regulated protein kinases by hypericin. 778 2


1 2 3 4 5 6 7 8 9 10 Next >>

---