Regulation of Clostridium perfringens alpha-toxin-activated phospholipase C in rabbit erythrocyte membranes.

The rapid phosphatidic acid (PA) formation induced by Clostridium perfringens alpha-toxin was stimulated by AlF4- in rabbit erythrocyte membranes. GTP[gamma S] [guanosine 5'-O-(3-thiotriphosphate)] stimulated the rapid 1,2-diacylglycerol formation and inositol 1,4,5-trisphosphate release induced by the toxin. On the other hand, treatment of erythrocyte lysates with phorbol 12-myristate 13-acetate (PMA) resulted in inhibition of toxin-induced PA production, and long-term PMA or 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7) treatment of the lysates led to stimulation of PA formation. Furthermore, treatment of erythrocytes with the toxin caused an increase of protein kinase C activity in membrane fractions. The results suggest that toxin-induced PA formation is mediated by endogenous phospholipase C regulated through GTP-binding protein and protein kinase C in rabbit erythrocytes.