Regulation of gap junction conductance by calcineurin through Cx43 phosphorylation: implications for action potential conduction.

Cardiac arrhythmias are associated with raised intracellular [Ca] and slowed action potential conduction caused by reduced gap junction (GJ) electrical conductance (Gj). Ventricular GJs are composed of connexin proteins (Cx43), with Gj determined by Cx43 phosphorylation status. Connexin phosphorylation is an interplay between protein kinases and phosphatases but the precise pathways are unknown.