ISOFORM SPECIFICITY OF ACTIVATORS AND INHIBITORS OF PROTEIN-KINASE-C-GAMMA AND PROTEIN-KINASE-C-DELTA

Expression of certain mammalian protein kinase C (PKC) isoforms inhibi ts the proliferation of Schizosaccharomyces pombe (Goode et al., Mel. Biol, Cell 5 (1994) 907-920). We have taken advantage of this fact to determine the in vivo isoform preference of a number of PKC inhibitors , using a microtitre plate assay which allows rapid screening, This in vivo model has revealed previously unreported preferences; calphostin C is a more efficient inhibitor of the novel PKC delta than cheleryth rine chloride whereas the efficiencies are reversed for inhibition of the classical PKC gamma. We have also shown that the anti-leukaemic ag ent bryostatin 1 inhibits or activates in vivo in an isoform-specific manner, (C) 1997 Federation of European Biochemical Societies.