Activation of calcium-activated, phospholipid-dependent protein kinase (protein kinase C) by new classes of tumor promoters: teleocidin and debromoaplysiatoxin

The new potent tumor promoters teleocidin and debromoaplysiatoxin , which are structurally unrelated to phorbol esters, activate Ca2+-activated, phospholipid-dependent protein kinase (protein kinase C). The concentrations of 12-O-tetradecanoylphorbol-13-acetate, teleocidin and debromoaplysiatoxin for half-maximum activation of protein kinase C were found to be approximately 3 ng/ml, 40 ng/ml and 400 ng/ml, respectively. These three types of tumor promoters bind to protein kinase C, and appear to exhibit their pleiotropic actions through activation of this Enzyme.