Fig. 3: TMEM65 mediates Na⁺-dependent mitochondrial Ca²⁺ efflux.

a–d [Ca²⁺]_mt measurements in digitonin-permeabilized HeLa cells. Representative [Ca²⁺]_mt traces of control, TMEM65 overexpressing and silenced cells in the absence (a) or presence (b) of 10 mM Na⁺. Histograms (mean ± s.d.) of maximal Na⁺-independent (c) and Na⁺-dependent (d) mitochondrial Ca²⁺ influx and efflux rates. Data were analyzed by one-way ANOVA followed by Holm–Sidak’s multiple comparisons test. * indicates p < 0.05. e–g [Ca²⁺]_mt measurements in control and TMEM65 overexpressing intact HeLa cells treated with either vehicle (DMSO) or 20 μM CGP-37157. e Representative [Ca²⁺]_mt traces. f Histograms (mean ± s.d.) of histamine-induced [Ca²⁺]_mt peak values. g Histograms (mean ± s.d.) of normalized mitochondrial Ca²⁺ efflux. Data were analyzed by two-way ANOVA followed by Holm–Sidak’s multiple comparisons test. * indicates p < 0.001, ns=not significant. Individual data points, descriptive statistics and exact p values are included in Source Data Table.