Conventional protein kinase C (PKC)‐α and novel PKCε, but not ‐δ, increase the secretion of an N‐terminal fragment of Alzheimer's disease amyloid precursor protein from PKC cDNA transfected 3Y1 fibroblasts

摘要

>A large soluble N-terminal fragment of Alzheimer's disease amyloid precursor protein (secreted form of APP: APP_s) is produced by constitutive processing in the middle of the amyloid β-protein portion of APP. Recent studies indicate that the activation of endogenous protein kinase C (PKC) with phorbol ester raises the rate of secretion of APP_s. We constructed rat fibroblast 3Y1 cells that stably overexpress PKC isoenzymes α, δ, or ε, and analyzed the amount of APP_s released from these PKC transfectants. The levels of APP_s released from 3Y1 cells overexpressing PKCα and -ε were higher than those from PKCδ-transfected and control cells expressing vector only. These results suggest that specific isoforms of PKC regulate the secretion of APP_s through a signaling pathway.