Expression of protein kinase C isozymes in hippocampal neurones in culture

Several protein kinase C (PKC) isozymes were analyzed by immunoblot and immunocytochemistry in cultures of hippocampal neurones at several stages of differentiation. Our findings reveal the existence of two distinct patterns of expression. Firstly, conventional PKC isozymes α, β and γ, that are expressed at very low levels during the initial stages and then increase continuously with time of culture. Secondly, novel PKC isozymes δ, ϵ and ζ, whose contents increase very early to reach a maximum after three days of culture and then progressively decline. Specific proteolysis for PKC isozymes β and γ was observed throughout the period studied. The developmental profile obtained for the different PKC isozymes is discussed in relation to the differentiation of hippocampal neurones in culture.