Structural and Functional Characterization of a Na _v 1.5-Mitochondrial Couplon

Abstract

We describe an anatomic hub (a couplon) formed by sodium channel clusters and subjacent subsarcolemmal mitochondria. Preferential localization of NCLX to this domain allows for functional coupling where the extrusion of Ca²⁺ from the mitochondria is powered, at least in part, by the entry of sodium through Na_V1.5 channels. These results provide a novel entry-point into a mechanistic understanding of the intersection between electrical and structural functions of the heart.