Possible involvement of a phosphatidylinositol-type signaling pathway in glucose-induced activation of plasma membrane H(+)-ATPase and cellular proton extrusion in the yeast Saccharomyces cerevisiae.
Addition of glucose to cells of the yeast Saccharomyces cerevisiae causes rapid activation of plasma membrane H(+)-ATPase and a stimulation of cellular H+ extrusion. We show that addition of diacylglycerol and other activators of protein kinase C to intact cells also activates the H(+)-ATPase and causes at the same time a stimulation of H+ extrusion from the cells. Both effects are reversed by addition of staurosporine, a protein kinase C inhibitor. Addition of staurosporine or calmidazolium, an inhibitor of Ca2+/calmodulin-dependent protein kinases, separately, causes a partial inhibition of glucose-induced H(+)-ATPase activation and stimulation of cellular H+ extrusion; together they cause a more potent inhibition. Addition of neomycin, which complexes with phosphatidylinositol 4,5-bisphosphate, or addition of compound 48/80, a phospholipase C inhibitor, also causes near complete inhibition. Diacylglycerol and other protein kinase C activators had no effect on the activity of the K(+)-uptake system and the activity of trehalase and glucose-induced activation of the K(+)-uptake system and trehalase was not inhibited by neomycin, supporting the specificity of the effects observed on the H(+)-ATPase. The results support a model in which glucose-induced activation of H(+)-ATPase is mediated by a phosphatidylinositol-type signaling pathway triggering phosphorylation of the enzyme both by protein kinase C and one or more Ca2+/calmodulin-dependent protein kinases.
Brandão
R L
RL
Laboratorium voor Moleculaire Celbiologie, Katholieke Universiteit te Leuven, Heverlee, Belgium.
de Magalhães-Rocha
N M
NM
Alijo
R
R
Ramos
J
J
Thevelein
J M
JM
D000470:Alkaloids / Q000494:pharmacology; D002462:Cell Membrane / Q000201:enzymology; D004075:Diglycerides / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology*; D007093:Imidazoles / Q000494:pharmacology; D010716:Phosphatidylinositols / Q000378:metabolism*; D010766:Phosphorylation; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure; D015398:Signal Transduction; D019311:Staurosporine; D003189:p-Methoxy-N-methylphenethylamine / Q000494:pharmacology
D000470:Alkaloids; D004075:Diglycerides; D007093:Imidazoles; D010716:Phosphatidylinositols; C044295:1,2-dioctanoylglycerol; D003189:p-Methoxy-N-methylphenethylamine; C031938:calmidazolium; D006180:Proton-Translocating ATPases; D019311:Staurosporine; D005947:Glucose