Cell adhesion kinase beta forms a complex with a new member, Hic-5, of proteins localized at focal adhesions.
Cell adhesion kinase beta (CAKbeta/PYK2) is the second protein-tyrosine kinase of the focal adhesion kinase subfamily. We identified a cDNA that encodes a CAKbeta-binding protein. This cDNA clone encodes the human homologue of Hic-5, the cDNA of which was cloned in 1994 as transforming growth factor beta1- and hydrogen peroxide-inducible ... mRNA. We found that Hic-5 exclusively localized at focal adhesions in a rat fibroblast line, WFB. This localization of Hic-5 was confirmed in WFB cells expressing Myc-tagged Hic-5. The amino acid sequence of Hic-5 is highly similar to that of paxillin in the four LD motifs as well as in the four contiguous LIM domains. The Hic-5 N-terminal domain directly associated in vitro with the extreme C-terminal region (residue 801 to the end) of CAKbeta. CAKbeta was coimmunoprecipitated with Hic-5 from the WFB cell lysate. The coimmunoprecipitation of CAKbeta with Hic-5 was markedly inhibited by the addition of the extreme C-terminal region of CAKbeta. Coimmunoprecipitation of Hic-5 with CAKbeta, which was shown in COS-7 cells doubly transfected with cDNA constructs of CAKbeta and Myc-tagged Hic-5, was lost when the CAKbeta amino acid residues 741-903 were deleted. Hic-5 was tyrosine-phosphorylated in Src-transformed 3Y1 cells and in cells treated with pervanadate. Hic-5 associated with CAKbeta was selectively tyrosine-phosphorylated in WFB cells exposed to hypertonic osmotic stress. These results indicate that Hic-5 is a paxillin-related component of focal adhesions and binds to CAKbeta, implying possible involvement of Hic-5 in the downstream signaling of CAKbeta.
Mesh Terms:
Amino Acid Sequence, Animals, COS Cells, Cell Line, Child, Preschool, Cloning, Molecular, Cytoskeletal Proteins, DNA, Complementary, DNA-Binding Proteins, Female, Focal Adhesion Kinase 2, Glutathione Transferase, Humans, Intracellular Signaling Peptides and Proteins, Lysophospholipids, Molecular Sequence Data, Oxidative Stress, Paxillin, Phosphoproteins, Precipitin Tests, Protein-Tyrosine Kinases, Rats, Recombinant Fusion Proteins, Sequence Homology, Amino Acid
Amino Acid Sequence, Animals, COS Cells, Cell Line, Child, Preschool, Cloning, Molecular, Cytoskeletal Proteins, DNA, Complementary, DNA-Binding Proteins, Female, Focal Adhesion Kinase 2, Glutathione Transferase, Humans, Intracellular Signaling Peptides and Proteins, Lysophospholipids, Molecular Sequence Data, Oxidative Stress, Paxillin, Phosphoproteins, Precipitin Tests, Protein-Tyrosine Kinases, Rats, Recombinant Fusion Proteins, Sequence Homology, Amino Acid
J. Biol. Chem.
Date: Jan. 09, 1998
PubMed ID: 9422762
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