Selective activation of the γ‐subspecies of protein kinase C from bovine cerebellum by arachidonic acid and its lipoxygenase metabolites

Abstract
The γ-subspecies of protein kinase C (PKC) apparently is expressed only in central nervous tissues, and at a high level in the cerebellum and hippocampus. γ-PKC from bovine cerebellum, but not the α-or βI/βII-subspecies, is activated by micromolar concentrations of arachidonic acid (AA), in the absence of both phospholipid and diacylglycerol. A significant component of this activation is also calcium independent. Other unsaturated fatty acids are much less active in this respect. Among the AA metabolites tested, lipoxin A (5(S),6(R),15(S)-11-cis-isomer) was a potent, selective activator of the γ-subspecies, and also, to a lesser extent, 12(S)-hydroxy-5,8,10,14-eicosatetraenoic acid could support activation. These results raise the possibility that AA and some of its lipoxygenase metabolites may function as messenger molecules in neurones to activate the γ-subspecies of PKC.