Differential redistribution of protein kinase C isoforms by cyclic AMP in HL60 cells

In this study we have analyzed the distribution of protein kinase C isoform s in cytosol, membrane, and nucleus in HL60 cells. Furthermore, we have stu died the redistribution of these isoforms after cyclic AMP treatment. Prote in kinase C localization and cyclic AMP-induced translocation was demonstra ted by Western blot analysis. Cytosol, membrane and nucleus in HL60 cells e xpressed the abundance of protein kinase C alpha, beta I, beta II, delta, l ambda, and zeta isoforms. After cyclic AMP treatment, the amount of protein kinase C beta I and zeta increased only in the nucleus, while protein kina se C delta increased in the three fractions tested. These effects were depe ndent on the cyclic AMP concentration and duration of action. Our results s uggest the existence of cross-talk between the cyclic AMP system and protei n kinase C in HL60 cells. Taking into account the processes regulated by pr otein kinase C, these findings also suggest that cyclic AMP plays a regulat ory role in various cellular responses in HL60 cells, such as differentiati on and gene expression. The increase observed in PRC delta was due to cycli c AMP-dependent protein kinase C activation, and the synthesis of enzyme wa s probably activated by the nucleotide, (C) 2000 Academic Press.