Phosphorylation of tyrosine in the carboxyl-terminal tryptic peptide of pp60c-src.
The major site of tyrosine phosphorylation of the transforming protein of Rous sarcoma virus, pp60v-src (tyrosine-416), is different from the major site of tyrosine phosphorylation of its nontransforming normal cellular counterpart, pp60c-src. We have shown that antibodies against a synthetic peptide modeled on the carboxyl-terminal 13 residues of pp60c-src specifically immunoprecipitate the major phosphotyrosine tryptic peptide of pp60c-src from both chicken and rat fibroblasts. These experiments localize the major site of tyrosine phosphorylation to one or more of the three tyrosine residues in the carboxyl-terminal tryptic peptide at positions 511, 519, and 527 of the amino acid sequence of chicken pp60c-src. Tyrosines-519 and -527 are in the carboxyl-terminal 19-amino acid segment of pp60c-src that is deleted and replaced by an unrelated sequence in pp60v-src. It is possible that phosphorylation of tyrosine in the carboxyl-terminal tryptic peptide may be involved in the normal regulation of pp60c-src. The absence of this phosphorylation site in pp60v-src may, in part, contribute to its oncogenic properties.
A P
AP
Laudano
J M
JM
Buchanan
D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D005347:Fibroblasts / Q000378:metabolism; D010446:Peptide Fragments / Q000378:metabolism; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D016392:Proto-Oncogene Proteins pp60(c-src); D051381:Rats; D014443:Tyrosine / Q000378:metabolism*
D010446:Peptide Fragments; D011518:Proto-Oncogene Proteins; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D016392:Proto-Oncogene Proteins pp60(c-src)