Transformation-specific decrease of phosphorylation of 80K protein, a substrate of protein kinase C, in NIH3T3 cells.
Phosphorylation in normal and transformed NIH3T3 cells of the 80K protein, a specific substrate for protein kinase C, was compared by means of two-dimensional gel analysis. We obtained evidence that NIH3T3 cells transformed by the c-raf or H-ras oncogene maintained a decreased level of phosphorylation of the 80K protein, with or without phorbol ester (TPA)-stimulation, at all concentrations of serum tested while normal NIH3T3 cells maintained an elevated level of phosphorylation of the 80K protein. Furthermore, NIH3T3 cells transformed by N-ras, K-ras, src, mos or polyoma middle T antigen exhibited a decreased level of phosphorylation of the 80K protein. These events were confirmed by an analysis of a hormone-inducible H-ras transformant. Thus, phosphorylation of the 80K protein is inversely correlated with cellular transformation.
Oh-uchida
M
M
Department of Biology, Faculty of Science, Kyushu University, Fukuoka.
Yano
K
K
Kawamoto
S
S
Shimizu
K
K
D002461:Cell Line, Transformed; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D008970:Molecular Weight; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D011518:Proto-Oncogene Proteins; D019908:Proto-Oncogene Proteins c-raf; D013274:Stomach Neoplasms / Q000378:metabolism*; D013379:Substrate Specificity; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000378:metabolism
D011518:Proto-Oncogene Proteins; D019908:Proto-Oncogene Proteins c-raf; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate