Myristylation of pp60c-src is not required for complex formation with polyomavirus middle-T antigen.
Middle-T antigen (middle-T), the transforming gene product of polyomavirus, associates with several cellular tyrosine kinases, such as pp60c-src. Complex formation leads to kinase activation and is essential for cell transformation. Middle-T-associated as well as uncomplexed pp60c-src is predominantly found in the plasma membrane. We transfected mouse 3T3 fibroblasts with a mutated c-src gene (2Ac-src), allowing the expression of a protein containing alanine instead of glycine in position 2 of the primary translation product. Contrary to the wild-type c-src gene product, pp60c-src(2A) was not myristylated and accumulated in the cytoplasm instead of being transferred to cellular membranes. The mutant protein was able to associate with middle-T and was activated similarly to the wild-type c-src gene product. Both wild-type and 2A mutant protein were membrane associated upon complex formation with middle-T. This finding suggests that the putative carboxy-terminal membrane anchor sequence of middle-T is sufficient to hold middle-T-associated pp60c-src(2A) in the plasma membrane.
Wyss
A
A
Friedrich Miescher Institute, Basel, Switzerland.
Kaech
S
S
Ballmer-Hofer
K
K
D000818:Animals; D000952:Antigens, Polyomavirus Transforming / Q000235:genetics; D002460:Cell Line; D015870:Gene Expression; D051379:Mice; D009154:Mutation; D019814:Myristic Acid; D009227:Myristic Acids / Q000378:metabolism*; D015688:Oncogene Protein pp60(v-src) / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids; D011120:Polyomavirus / Q000235:genetics* / Q000276:immunology; D011499:Protein Processing, Post-Translational; D014162:Transfection
D000952:Antigens, Polyomavirus Transforming; D009227:Myristic Acids; D019814:Myristic Acid; D015688:Oncogene Protein pp60(v-src)