pp60c-src kinase activity in bovine coronary extracts is stimulated by ATP.
pp60c-src kinase is believed to participate in regulating key cellular mechanisms including signal transduction and differentiation of smooth muscle during early embryogenesis. In this study, pp60c-src kinase activity was demonstrated in extracts from adult bovine coronary arterial smooth muscle. Activity, reflected by autophosphorylation of pp60c-src, phosphorylation of exogenous substrates, and phosphorylation of several endogenous substrates, was enhanced about 2 fold when added Mg2+ was replaced by Mn2+. Unexpectedly, activity was dramatically stimulated 20-50 fold by prior incubation with ATP. Such stimulation appears to be mediated through a novel mechanism which is independent of ATP-induced phosphorylation of reaction components. These new observations strongly suggest that a unique mechanism exists for regulation of coronary arterial pp60c-src kinase activity. Conceivably, this mechanism may serve important roles in modulating signal transduction and contractility of vascular smooth muscle.
Di Salvo
J
J
Department of Physiology and Biophysics, University of Cincinnati, College of Medicine, Ohio 45267-0576.
Gifford
D
D
Kokkinakis
A
A
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000266:Adenylyl Imidodiphosphate / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D003331:Coronary Vessels / Q000201:enzymology*; D008274:Magnesium / Q000378:metabolism; D008345:Manganese / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000201:enzymology; D011494:Protein Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D016392:Proto-Oncogene Proteins pp60(c-src); D014661:Vasoconstriction
D011518:Proto-Oncogene Proteins; D000266:Adenylyl Imidodiphosphate; D008345:Manganese; D000255:Adenosine Triphosphate; D011494:Protein Kinases; D016392:Proto-Oncogene Proteins pp60(c-src); D008274:Magnesium