INTERLEUKIN-3 OR ERYTHROPOIETIN-INDUCED NUCLEAR-LOCALIZATION OF PROTEIN-KINASE-C BETA-ISOFORMS IN HEMATOPOIETIC TARGET-CELLS

Protein kinase C (PKC) has been implicated in the signal transduction pathways for the biological effect of both interleukin-3 (IL-3) and er ythropoietin (EPO) in hematopoietic target cells. The goal of this stu dy was to identify specific classical isoforms of PKC and their locali zation in hematopoietic cells in response to the growth factors, IL-3 or EPO. In addition to murine fetal liver cells as a source of normal erythroid progenitor cells, we have utilized the B6SUt.EP cell line, a non-transformed hematopoietic cell line that requires IL-3 for prolif eration, but for which EPO can substitute as a growth factor. With pol yclonal antibodies prepared against peptide sequences specific for the alpha, beta I, beta II and gamma isoforms of PKC, we have identified beta I and beta II as the predominant nuclear isoforms in target cells that proliferate in response to IL-3 or EPO.