Abstract
A 62 kDa protein is highly phosphorylated in many cells containing activated tyrosine kinases. This protein, characterized mainly by its avid association with rasGAP, has proved elusive. Anti-phosphotyrosine antibody was used to purify p62. From peptide sequence, molecular cloning revealed a cDNA encoding a novel protein, p62dok, with little homology to others but with a prominent set of tyrosines and nearby sequences suggestive of SH2 binding sites. In cells, v-Abl tyrosine kinase binds and strongly phosphorylates p62dok, which then binds rasGAP. A monoclonal antibody, 2C4, to the rasGAP-associated p62 reacts with p62dok. Thus, p62dok appears to be the long-sought major substrate of many tyrosine kinases.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Animals
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Antibodies, Monoclonal / immunology
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Binding Sites
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Blotting, Northern
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Cell Line
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Cell Line, Transformed
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Cloning, Molecular
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DNA, Complementary / genetics
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DNA-Binding Proteins / immunology
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GTPase-Activating Proteins
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Mice
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Molecular Sequence Data
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Oncogene Proteins v-abl / metabolism*
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Phosphoproteins / chemistry
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Phosphoproteins / genetics
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Phosphoproteins / immunology
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Phosphoproteins / isolation & purification
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Phosphoproteins / metabolism*
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Phosphorylation
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Phosphotyrosine / metabolism
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Protein-Tyrosine Kinases / metabolism
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Proteins / metabolism*
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RNA-Binding Proteins / immunology
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Sequence Homology, Amino Acid
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Transfection
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src Homology Domains
Substances
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Antibodies, Monoclonal
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DNA, Complementary
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DNA-Binding Proteins
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Dok1 protein, mouse
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GAP-associated protein p62
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GTPase-Activating Proteins
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Oncogene Proteins v-abl
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Phosphoproteins
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Proteins
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RNA-Binding Proteins
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Phosphotyrosine
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Protein-Tyrosine Kinases