Staphylococcus aureus alpha-toxin activates phospholipases and induces a Ca2+ influx in PC12 cells.

D Fink, M L Contreras, P I Lelkes, P Lazarovici

Index: Cell. Signal. 1 , 387-393, (1989)

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Abstract

Staphylococcal alpha-toxin at subcytotoxic concentrations stimulated phosphatidylinositol turnover and arachidonic acid release in undifferentiated cultures of pheochromocytoma PC12 cells. Stimulation of phospholipase A2 but not C was dependent on extracellular calcium. Addition of staphylococcal alpha-toxin to PC12 cells caused a dose-dependent, biphasic increase in intracellular calcium measured by fura-2 fluorescence technique. Elevation of intracellular Ca2+ content occurred with a time course similar to those observed for stimulation of phospholipase A2. Alteration of membrane structure and formation of staphylococcal alpha-toxin pores facilitating an influx of Ca2+, represent the probable mechanisms by which phospholipases C and A2 are activated, respectively. These results suggest a possible involvement of Ca2+, phosphoinositides and arachidonic acid metabolites in the pathogenic action of staphylococcus alpha-toxin and caution against the general usage of this toxin as a permeabilizing agent to study stimulus-secretion coupling in secretory cells.