Disappearance of Ca2+-sensitive, phospholipid-dependent protein kinase activity in phorbol ester-treated 3T3 cells.

Treatment of intact 3T3 cells with biologically active phorbol esters causes a progressive decline in the total activity of Ca2+-sensitive, phospholipid-dependent protein kinase (protein kinase C) measured in cell-free, detergent-solubilized, extracts. The effect is dose-dependent and reversible; protein kinase C activity reappears when the phorbol esters are removed from the medium.