Tyrosine protein kinase activity of the HZ4-feline sarcoma virus P80gag-kit-transforming protein.
The Hardy-Zuckerman 4 feline sarcoma virus (HZ4-FeSV), isolated from a feline fibrosarcoma, is a replication defective acute transforming feline retrovirus that originated by transduction of feline c-kit sequences with feline leukemia virus (FeLV). The v-kit sequences of the HZ4-FeSV, a segment of 1106 nucleotides, correspond to sequences of the cytoplasmic domain of the c-kit receptor kinase. The HZ4-FeSV is known to encode an 80-kilodalton protein with FeLV gag and kit determinants. The P80gag-kit protein and its associated activities from HZ4-FeSV-transformed mink cells were characterized. The P80gag-kit protein was found to be myristoylated, suggesting a membrane association for this protein. In agreement with the predicted relationship with tyrosine kinases, by using the in vitro immune complex-kinase procedure, the P80gag-kit protein was shown to display a tyrosine-specific autophosphorylation activity. In vivo, the P80 protein was found to be phosphorylated on serine and threonine and to a lesser degree on tyrosine. In addition, potential in vivo protein substrates for tyrosine-specific phosphorylation mediated by the P80gag-kit kinase were identified in HZ4-FeSV-transformed cells.
Majumder
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S
Molecular Biology Program, Sloan Kettering Institute, New York, New York.
Ray
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P
Besmer
P
P
D000818:Animals; D015153:Blotting, Western; D002415:Cats; D002461:Cell Line, Transformed; D004591:Electrophoresis, Polyacrylamide Gel; D015683:Gene Products, gag / Q000235:genetics; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D019009:Proto-Oncogene Proteins c-kit; D012190:Retroviridae / Q000201:enzymology*; D015682:Retroviridae Proteins, Oncogenic / Q000235:genetics / Q000378:metabolism*; D005253:Sarcoma Viruses, Feline / Q000201:enzymology* / Q000235:genetics
D015683:Gene Products, gag; D011518:Proto-Oncogene Proteins; D015682:Retroviridae Proteins, Oncogenic; D011505:Protein-Tyrosine Kinases; D019009:Proto-Oncogene Proteins c-kit