Inhibition of phosphatidylinositol-specific phospholipase C activity by fluvirucin B2.

We isolated fluvirucin B2 from the culture broth of Streptomyces as an inhibitor of phosphatidylinositol-specific phospholipase C (PI-PLC). It inhibited PI-PLC of A431 cell cytosol with an IC50 of 1.6 micrograms/ml. Fluvirucin B2 also inhibited PI-PLC in cultured A431 cells, whereas it did not inhibit phosphatidylinositol synthesis and macromolecular synthesis markedly. It also inhibited epidermal growth factor-induced rapid rounding of A431 cells, in which PI turnover is involved.