Correlation between levels of δ protein kinase C and resistance to differentiation in murine erythroleukemia cells

It has been demonstrated that the level of δ protein kinase C is inversely correlated to the responsiveness of murine erythroleukemia cells to chemical induction to terminal erythroid differentiation. In these cells, δPKC is largely present in a membrane associated form, and thus in a constitutively active state, a condition which characterizes the undifferentiated phenotype. Accordingly, commitment to cell differentiation has been shown to be preceded by down regulation of δPKC, a process significantly accelerated and induced to almost completion by the differentiation enhancing factor (DEF) in a dose dependent manner. The present results provide a better understanding of the role of δPKC in characterizing the undifferentiated MEL cell phenotype, and suggest a relationship between the acceleration in the rate of differentiation induced by DEF and the down regulation of this kinase form.