CHANGES IN PROTEIN-KINASE-C ISOENZYME EXPRESSION ASSOCIATED WITH APOPTOSIS IN U937 MYELOMONOCYTIC CELLS

Spontaneously apoptotic U937 cells from exponentially growing cell cul tures were enriched on discontinuous Percoll density gradients. Increa sed PKC-beta and reduced PKC-zeta expression were detected in apoptoti c cells by Western blotting. Using confocal microscopy, changes in the level of PKC isoenzymes were confirmed and in addition alterations in the subcellular location of PKC isoenzymes were detected in apoptotic cells compared with nonapoptotic cells. The data indicate that the ex pression of specific PKC isoenzymes is modulated during apoptosis and that PRC-beta and PKC-zeta may play specific roles in the regulation o f the apoptotic program. (C) 1995 Academic Press, Inc.