Introduction of the β Isozyme of Protein Kinase C Accelerates Induced Differentiation of Murine Erythroleukemia Cells

Induction of differentiation in murine erythroleukemia cells (MELCs) involves a protein kinase C (PKC)-mediated step. Vincristine-resistant cells respond more rapidly to hybrid polar/apolar inducers than the parental cells. These vincristine-resistant MELCs contain elevated levels of the β isozyme of PKC (PKC-β). Exogenous homologous murine PKC-β, incorporated into permeabilized MELCs, accelerates induced differentiation. Neither rat PKC-β, nor mouse PKC-α, nor rat PKC-α, incorporated into permeabilized MELCs, is effective in altering the kinetics of induced differentiation. This provides direct evidence for a rate-limiting role for this PKC isozyme during N,N'-hexamethylenebisacetamide-mediated induced differentiation of a transformed cell.