Essential for maintaining proper cardiac intercalated disk (ICD) structure and function as well as cardiac conduction velocity in the heart. Its association with SCN1B is required for stabilizing the perinexus in the ICD and for localization of GJA1 and SCN5A to the ICD. May regulate the function of the gap junction protein GJA1 and may contribute to the stability and proper localization of GJA1 to cardiac intercalated disk thereby regulating gap junction communication (By similarity). May also play a role in the regulation of mitochondrial respiration and mitochondrial DNA copy number maintenance (PubMed:28295037).