Enhancement of calcium current in Aplysia neurones by phorbol ester and protein kinase C

Abstract

One of the molecular mechanisms capable of regulating the physiological properties of neurones is the phosphorylation of ion channels and other cellular components by cyclic AMP-dependent protein kinase1. Another protein kinase present in high concentrations in the mammalian brain is protein kinase C (a calcium/phosphatidylserine/diacylglycerol-dependent protein kinase) 2-5, but there is no direct evidence, as yet, for the involvement of this enzyme in the control of neuronal excitability. We now present evidence that activation of endogenous protein kinase C by the tumour-promoting phorbol ester TPA (12-O-tetradecanoyl-phorbol-13-acetate), or intracellular injection of the purified enzyme, enhances the voltage-sensitive calcium current in bag cell neurones of the mollusc Aplysia. © 1985 Nature Publishing Group.