CORRELATION BETWEEN LEVELS OF DELTA-PROTEIN-KINASE-C AND RESISTANCE TO DIFFERENTIATION IN MURINE ERYTHROLEUKEMIA-CELLS

It has been demonstrated that the level of delta protein kinase C is i nversely correlated ro the responsiveness of murine erythroleukemia ce lls to chemical induction to terminal erythroid differentiation. In th ese cells, delta PKC is largely present in a membrane associated form, and thus in a constitutively active state, a condition which characte rizes the undifferentiated phenotype. Accordingly, commitment to cell differentiation has been shown to be preceded by down regulation of de lta PKC. a process significantly accelerated and induced to almost com pletion by the differentiation enhancing factor (DEF) in a dose depend ent manner. The present results provide a better understanding of the role of delta PKC in characterizing the undifferentiated MEL cell phen otype, and suggest a relationship between the acceleration in the rare of differentiation induced by DEF and the down regulation of this kin ase form. (C) 1996 Academic Press, Inc.