Zeta PKC in rat preadipocytes: modulation by insulin and serum mitogenic factors and possible role in adipogenesis.

Several PKC isoforms belonging to the three PKCs' subfamilies cPKC alpha and beta isoforms, nPKC epsilon isoform and aPKC zeta isoform were detected by Western blot in rat preadipocytes. zeta PKC which appears involved in proliferation and differentiation of some cellular types was shown to display variations according to the preadipocyte anatomical origin and stage of differentiation. A rapid increase in zeta PKC in the cytosolic compartment and translocation into the nucleus were induced by mitogenic factors in proliferating preadipocytes and by insulin in differentiating preadipocytes. These findings suggest that zeta PKC could be involved i) in the post-receptor signaling pathway of serum mitogenic factors and insulin in preadipocytes, and ii) in the mechanisms underlying the variations in the proliferating and differentiating capacities of preadipocytes according to their anatomical localization.