Fig. 3: Translational regulation of OXPHOS- and TCA cycle component genes engenders distinct mitochondrial metabolism of thermogenic adipocytes.

a Heat maps showing ribosome density fold change of mtDNA-originated OXPHOS complex subunits and TCA cycle components. Early and late indicate 4 d and 8 d compared to 0 d, respectively. b Fold changes of mRNA and translated mRNA levels of TCA cycle components and SDH relative to OXPHOS complex I, III, IV, and V during beige, brown, and white adipocyte differentiation. Values of biological replicates were pooled for statistical tests. c Western blot of OXPHOS complex subunits with the mitochondrial fraction of beige and white adipocytes. The right bar plot shows the band intensity of SDHB relative to the total intensity of all five subunits. Representative image among four replicates is shown. d Percentage of Complex II protein level over total OXPHOS complex protein level in beige, brown, and white adipocytes. Replicate N = 5. e Percentage of TCA cycle enzymes’ protein level over total MitoCarta protein level in beige, brown, and white adipocytes. Replicate N = 5. f, g Measurement of SDH activity (f) and Complex I activity g with the mitochondrial fraction of beige and white adipocytes. The activity of SDH and Complex I are depicted by a decrease in absorbance at 600 nm and an increase in absorbance at 450 nm, respectively. Replicate N_Beige = 7, N_White = 8 for (f) N = 9 for g. h Activity of SDH relative to activity of Complex I in beige and white adipocytes. i A diagram describing the hypothesis to explain differential translational regulation of TCA cycle and OXPHOS complex components in thermogenic adipocytes. Statistical tests: one-sided Mann-Whitney U test for p-values of b and two-sided unpaired t-test for p-values of c–g. *p < 0.05, **p < 0.01, ***p < 0.001. Point plots of b are shown as median with 50% interval. Bar plots of c–g and point plots of f, g are shown as mean (SD). Source data are provided as a Source Data file.