Caveolin-1 and a 29-kDa caveolin-associated protein are phosphorylated on tyrosine in cells expressing a temperature-sensitive v-Abl kinase.
Caveolin-1 was originally identified as a tyrosine-phosphorylated protein in v-Src-transformed cells and it was suggested that phosphorylation of this protein could mediate transformation by the tyrosine kinase class of oncogenes (J. R. Glenney, 1989, J. Biol. Chem. 264, 20163--20166). We found that caveolin-1 is also phosphorylated on tyrosine in v-Abl-transformed cells. In fact, caveolin-1 and a caveolin-associated protein of 29 kDa are among the strongest phosphotyrosine signals detected in the Abl-expressing cells. In addition, v-Abl shows a preferential phosphorylation of caveolin-1 and the 29-kDa caveolin-associated protein over other proteins in the caveolin-enriched Triton-resistant cell fraction. These data indicate that caveolin-1 and the 29-kDa caveolin-associated protein may be preferred substrates of the Abl kinase. Caveolin-1 is phosphorylated at tyrosine 14 in v-Abl-expressing cells as has been observed previously in v-Src-expressing cells. However, using a temperature-sensitive allele of v-Abl (ts120 v-Abl) we provide evidence that caveolin-1 phosphorylation is not sufficient to mediate the loss of caveolin expression or loss of cell adhesion induced by v-Abl.
Corley Mastick
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Department of Biochemistry, University of Nevada, Reno, Nevada 89557, USA. cmastick@med.unr.edu
Sanguinetti
A R
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Knesek
J H
JH
Mastick
G S
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Newcomb
L F
LF
D000199:Actins / Q000378:metabolism; D000595:Amino Acid Sequence / Q000502:physiology; D051242:Caveolin 1; D022461:Caveolins / Q000378:metabolism*; D002448:Cell Adhesion / Q000502:physiology; D002461:Cell Line, Transformed / Q000166:cytology / Q000378:metabolism; D048429:Cell Size / Q000502:physiology; D002478:Cells, Cultured / Q000166:cytology / Q000201:enzymology*; D006801:Humans; D008970:Molecular Weight; D016374:Oncogene Proteins v-abl / Q000378:metabolism*; D010641:Phenotype; D010766:Phosphorylation; D011108:Polymers / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism*; D013696:Temperature; D014443:Tyrosine / Q000378:metabolism*
D000199:Actins; C495540:CAV1 protein, human; D051242:Caveolin 1; D022461:Caveolins; D016374:Oncogene Proteins v-abl; D011108:Polymers; D014443:Tyrosine; D011494:Protein Kinases