Association of a tyrosine kinase activity with GAP complexes in v-src transformed fibroblasts

p21ras GAP is phosphorylated on tyrosine residues and associates with 62 kDa and 190 kDa tyrosine phosphorylated proteins in v-src-transformed fibroblasts. We were interested in identifying the tyrosine kinase responsible for phosphorylation of GAP and the two associated proteins. Here, we report th...

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Bibliographic Details
Published inOncogene Vol. 7; no. 2; p. 389
Main Authors Pronk, G J, Polakis, P, Wong, G, de Vries-Smits, A M, Bos, J L, McCormick, F
Format Journal Article
LanguageEnglish
Published England 01.02.1992
Subjects
3T3 Cells
Animals
Cell Transformation, Viral
GTPase-Activating Proteins
Macromolecular Substances
Mice
Oncogene Protein pp60(v-src) - metabolism
Peptide Mapping
Phosphoproteins - metabolism
Phosphorylation
Protein-Tyrosine Kinases - metabolism
Proteins - metabolism
Recombinant Proteins - metabolism
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Summary:p21ras GAP is phosphorylated on tyrosine residues and associates with 62 kDa and 190 kDa tyrosine phosphorylated proteins in v-src-transformed fibroblasts. We were interested in identifying the tyrosine kinase responsible for phosphorylation of GAP and the two associated proteins. Here, we report that GAP-immunoprecipitates from v-src transformed cells contain a tyrosine kinase activity that phosphorylates GAP, p62 and p190. Tryptic peptide analysis indicated that the sites phosphorylated in vitro and in vivo are indistinguishable, suggesting that the precipitated kinase could be responsible for tyrosine phosphorylation of GAP in vivo. The GAP-associated kinase activity might be due to v-src itself, because pp60v-src is able to associate with GAP in vitro and GAP can be phosphorylated by pp60v-src immunecomplexes.
ISSN:0950-9232
1476-5594