Mode-switching of a voltage-gated cation channel is mediated by a protein kinase A-regulated tyrosine phosphatase.

Abstract

Tyrosine kinases and tyrosine phosphatases are abundant in central nervous system tissue, yet the role of these enzymes in the modulation of neuronal excitability is unknown. Patch-clamp studies of an Aplysia voltage-gated cation channel now demonstrate that a tyrosine phosphatase endogenous to excised patches determines both the gating mode of the channel and the response of the channel to protein kinase A. Moreover, a switch in gating modes similar to that triggered by the phosphatase occurs at the onset of a prolonged change in the excitability of Aplysia bag cell neurons.