The PLC1 encoded phospholipase C in the yeast Saccharomyces cerevisiae is essential for glucose-induced phosphatidylinositol turnover and activation of plasma membrane H+-ATPase.
Addition of glucose to glucose-deprived cells of the yeast Saccharomyces cerevisiae triggers rapid turnover of phosphatidylinositol, phosphatidylinositol-phosphate and phosphatidylinositol 4,5-bisphosphate. Glucose stimulation of PI turnover was measured both as an increase in the specific ratio of 32P-labeling and as an increase in the level of diacylglycerol after addition of glucose. Glucose also causes rapid activation of plasma membrane H+-ATPase. We show that in a mutant lacking the PLC1 encoded phospholipase C, both processes were strongly reduced. Compound 48/80, a known inhibitor of mammalian phospholipase C, inhibits both processes. However, activation of the plasma membrane H+-ATPase is only inhibited by concentrations of compound 48/80 that strongly inhibit phospholipid turnover. Growth was inhibited by even lower concentrations. Our data suggest that in yeast cells, glucose triggers through activation of the PLC1 gene product a signaling pathway initiated by phosphatidylinositol turnover and involved in activation of the plasma membrane H+-ATPase.
Sezione di Biochimica Comparata, Dipartimento di Fisiologia e Biochimica Generali, Università degli Studi di Milano, via Celoria 26, I-20133 Milan, Italy.
P
P
Coccetti
R
R
Tisi
E
E
Martegani
L
L
Souza Teixeira
R
R
Lopes Brandão
I
I
de Miranda Castro
J M
JM
Thevelein
D002455:Cell Division / Q000187:drug effects; D002462:Cell Membrane / Q000201:enzymology; D004075:Diglycerides / Q000096:biosynthesis; D004789:Enzyme Activation / Q000187:drug effects; D005800:Genes, Fungal; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010716:Phosphatidylinositols / Q000378:metabolism*; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D015398:Signal Transduction; D010738:Type C Phospholipases / Q000235:genetics* / Q000378:metabolism*; D003189:p-Methoxy-N-methylphenethylamine / Q000494:pharmacology
D004075:Diglycerides; D010716:Phosphatidylinositols; D003189:p-Methoxy-N-methylphenethylamine; D010738:Type C Phospholipases; D006180:Proton-Translocating ATPases; D005947:Glucose