a, Expression profile of Slc25a family members in the inguinal WAT of mice acclimatized to 23 °C or 12 °C for 1 week. n = 3 per group. b, mRNA expression of UCP1, SLC25A44 and SLC25A39 normalized to TBP levels in the supraclavicular BAT from the same individuals (six pairs) at thermoneutrality (27 °C) and cold temperature (19 °C). c, Mitochondrial localization of SLC25A44 protein in differentiated mouse beige adipocytes. TOM20 was used as a mitochondrial marker. d, Immunoblotting for SLC25A44 in BAT and liver of control and Slc25a44-KD mice. GAPDH was used as a loading control. Red arrows indicate specific bands whose intensities were decreased in Slc25a44-KD mice. e, mRNA expression of Slc25a44 and indicated genes normalized to levels of 36B4 (also known as Rplp0) during mouse brown adipogenesis. n = 4 per group. f, Protein expression of SLC25A44 in mouse beige preadipocytes and differentiated adipocytes. β-actin was used as a loading control. g, Protein expression of UCP1 and SLC25A44 in immortalized human brown preadipocytes and differentiated adipocytes. β-actin was used as a loading control. a, b, e, Biologically independent samples. Data are mean ± s.e.m.; one-sided P values by paired t-test (b) and two-sided P values by unpaired Student’s t-test (a). c, d, f, g, Representative results from two independent experiments. Uncropped images are available in Supplementary Fig. 1.