Modulation of tyrosine phosphorylation of p36 and other substrates by the S-100 protein.
The inhibitory effects of Ca2+-binding proteins on tyrosine phosphorylation of p36 protein isolated from bovine intestinal epithelium by immunoprecipitated p130fps were investigated. S-100 protein dose dependently inhibited the p36 phosphorylation, and calmodulin weakly depressed the phosphorylation, whereas parvalbumin and troponin C had no significant effects. The S-100 preparation purified from bovine brain did not contain phosphatase activity or ATPase activity. The concentration of ATP did not affect the S-100-mediated inhibition of phosphorylation but the substrate protein, p36, reversed the inhibition. S-100 similarly inhibited the tyrosine phosphorylation of p36 by p60src but did not affect the p36 phosphorylation by protein kinase C. S-100 inhibited the tyrosine kinase activity of p130fps using the other substrates tested as well. These results suggest that S-100 interacts with the substrate binding site of retroviral tyrosine-specific protein kinases and may play a regulatory role in the tyrosine phosphorylation.
Hagiwara
M
M
Department of Molecular and Cellular Pharmacology, Mie University School of Medicine, Japan.
Ochiai
M
M
Owada
K
K
Tanaka
T
T
Hidaka
H
H
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D001358:Avian Sarcoma Viruses; D002135:Calcium-Binding Proteins / Q000494:pharmacology*; D002147:Calmodulin / Q000494:pharmacology*; D002417:Cattle; D002645:Chickens; D004305:Dose-Response Relationship, Drug; D008970:Molecular Weight; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011817:Rabbits; D009418:S100 Proteins / Q000494:pharmacology*; D014443:Tyrosine / Q000378:metabolism*; D014764:Viral Proteins / Q000378:metabolism*
D002135:Calcium-Binding Proteins; D002147:Calmodulin; D009418:S100 Proteins; D014764:Viral Proteins; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D000251:Adenosine Triphosphatases