Identification of a cellular protein substrate phosphorylated by the avian sarcoma virus-transforming gene product.
The avian sarcoma virus-transforming gene product (pp60src) appears potentially able to mediate cell transformation via phosphorylation since it is tightly associated with a protein kinase activity. We have searched for and have been able to identify a normal cellular protein that appears to be a substrate of pp60src. The phosphorylation of this protein (34K) in transformation-specific in ASV-transformed cells of both avian and mammalian origin. Moreover, the 34K polypeptide serves as a substrate for the pp60src phosphotransferase activity in vitro and is phosphorylated at a site identical to the major site of phosphorylation in vivo. These data suggest that upon transformation the 34,000-dalton protein is phosphorylated directly as a result of pp60src activity.
D000818:Animals; D001358:Avian Sarcoma Viruses / Q000378:metabolism*; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D002472:Cell Transformation, Viral; D002642:Chick Embryo; D010750:Phosphoproteins / Q000032:analysis / Q000378:metabolism*; D010766:Phosphorylation; D014443:Tyrosine / Q000378:metabolism; D014764:Viral Proteins / Q000032:analysis / Q000378:metabolism*
D010750:Phosphoproteins; D014764:Viral Proteins; D014443:Tyrosine