We investigated the differential role of protein kinase C (PKC) isoforms in the regulated proteolytic release of soluble amyloid precursor protein (sAPPa)inSH-SY5Y neuroblastoma cells. We used cells stably transfected with cDNAs encoding either PKCaor PKCein the antisense orientation, producing a reduction of the expression of PKCa and PKCe, respectively. Reduced expression of PKCaand/or PKCedid not modify the response of the kinase to phorbol ester stimulation, demonstrating translo.