The function of Ensembl gene identifier ENSG00000164983 (TMEM65, transmembrane protein 65) is as follows. Mitochondrial protein that plays a critical role in the sodium-dependent calcium efflux from mitochondrion (PubMed:40200126, PubMed:40691517). The precise role of TMEM65 in mitochondrial sodium/calcium exchange is however unclear: TMEM65 associates with the SLC8B1/NCLX antiporter and probably promotes the sodium/calcium exchange mediated by SLC8B1/NCLX (PubMed:40200126). According to another report, TMEM65 functions as the mitochondrial sodium/calcium antiporter itself: homodimerization drives formation of a pocket capable of binding calcium (PubMed:40691517). Essential for maintaining proper cardiac intercalated disk (ICD) structure and function as well as cardiac conduction velocity in the heart (By similarity). Its association with SCN1B is required for stabilizing the perinexus in the ICD and for localization of GJA1 and SCN5A to the ICD (By similarity). {ECO:0000250|UniProtKB:Q4VAE3, ECO:0000269|PubMed:40200126, ECO:0000269|PubMed:40691517}.