Tyr527 is phosphorylated in pp60c-src: implications for regulation.
The Rous sarcoma virus oncogene product, pp60v-src, transforms cultured fibroblasts but its corresponding proto-oncogene product, pp60c-src, does not. Both proteins are known to be protein-tyrosine kinases. Published results suggest that the kinase activity of pp60c-src is inhibited relative to that of pp60v-src, due perhaps to phosphorylation of a tyrosine in pp60c-src that is not phosphorylated in pp60v-src. In this study, it was observed that the tyrosine phosphorylated in pp60c-src is Tyr527, six residues from the COOH-terminus of the protein. The region of pp60c-src from residue 515 to the COOH-terminus, including Tyr527, has been replaced with a different sequence in pp60v-src. Thus, the increase in transforming ability and kinase activity that occurred in the genesis of pp60v-src may have resulted from the loss of a tyrosine involved in negative regulation.
Cooper
J A
JA
Gould
K L
KL
Cartwright
C A
CA
Hunter
T
T
D000818:Animals; D001358:Avian Sarcoma Viruses / Q000235:genetics; D002471:Cell Transformation, Neoplastic / Q000378:metabolism; D002642:Chick Embryo; D002645:Chickens; D005347:Fibroblasts / Q000378:metabolism; D015688:Oncogene Protein pp60(v-src); D009857:Oncogenes; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D016392:Proto-Oncogene Proteins pp60(c-src); D011519:Proto-Oncogenes; D012191:Retroviridae Proteins / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism*
D011518:Proto-Oncogene Proteins; D012191:Retroviridae Proteins; D014443:Tyrosine; D011494:Protein Kinases; D015688:Oncogene Protein pp60(v-src); D016392:Proto-Oncogene Proteins pp60(c-src)