Identification and Characterization of a Novel Related Adhesion Focal Tyrosine Kinase (RAFTK) from Megakaryocytes and Brain
Autor: | Dan Hiregowdara, Shuxian Jiang, Linda M. Pasztor, Shalom Avraham, Yigong Fu, Hava Avraham, Robert A. White, Setsuo Ota, Jerome E. Groopman, Junzhi Li, Roanna London |
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Rok vydání: | 1995 |
Předmět: |
DNA
Complementary Immunoprecipitation Molecular Sequence Data Hybrid Cells Biology Polymerase Chain Reaction Biochemistry Gene Expression Regulation Enzymologic Homology (biology) Cell Line Focal adhesion Mice chemistry.chemical_compound Fetus Bone Marrow Complementary DNA Animals Humans Amino Acid Sequence Cloning Molecular Molecular Biology Cells Cultured Conserved Sequence Crosses Genetic DNA Primers Recombination Genetic Base Sequence Sequence Homology Amino Acid Brain Chromosome Mapping Tyrosine phosphorylation Cell Biology Protein-Tyrosine Kinases Focal Adhesion Kinase 2 Molecular biology Mice Inbred C57BL Muridae chemistry Organ Specificity Signal transduction Megakaryocytes Tyrosine kinase |
Zdroj: | Journal of Biological Chemistry. 270:27742-27751 |
ISSN: | 0021-9258 |
DOI: | 10.1074/jbc.270.46.27742 |
Popis: | We have isolated a cDNA encoding a novel human intracytoplasmic tyrosine kinase, termed RAFTK (for a related adhesion focal tyrosine kinase). In addition, we have cloned and characterized the murine homolog of the human RAFTK cDNA. Comparison of the deduced amino acid sequences of human RAFTK and murine Raftk cDNAs revealed 95% homology, indicating that RAFTK is highly conserved between these species. The RAFTK cDNA clone, encoding a polypeptide of 1009 amino acids, has closest homology (48% identity, 65% similarity) to the focal adhesion kinase (pp125FAK). Comparison of the deduced amino acid sequences also indicates that RAFTK, like pp125FAK, lacks a transmembrane region, myristylation sites, and SH2 and SH3 domains. In addition, like pp125FAK, RAFTK contains a kinase domain flanked by large N-terminal (426 residues) and C-terminal (331 residues) domains, and the C-terminal region contains a predicted proline-rich stretch of residues. In fetal tissues, RAFTK expression was abundant in brain, and low levels were observed in lung and liver. In adult tissues, it was less restricted, indicating that RAFTK expression is developmentally up-regulated. Expression of RAFTK was also observed in human CD34+ marrow cells, primary bone marrow megakaryocytes, platelets, and various areas of brain. The human RAFTK gene was assigned to human chromosome 8 using genomic DNAs from human/rodent somatic cell hybrid lines. The mouse Raftk gene was mapped to chromosome 14, closely linked to gonadotropin-releasing hormone. Using specific antibodies for RAFTK, a approximately 123-kDa protein from the human megakaryocytic CMK cell line was immunoprecipitated. Treatment of the megakaryocytic CMK cells with thrombin caused a rapid induction of tyrosine phosphorylation of RAFTK protein. The structural features of RAFTK suggest that it is a member of the focal adhesion kinase gene family and may participate in signal transduction in human megakaryocytes and brain as well as in other cell types. |
Databáze: | OpenAIRE |
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