Figure 3. Blockade of mitochondrial pyruvate transport activates glutamine-dependent citrate formation.

(A) Dose-dependent effects of UK5099 on citrate labeling from [U-¹³C]glucose and [U-¹³C]glutamine in SFxL cells.

(B) Time course of citrate labeling from [U-¹³C]glutamine with or without 200 μM UK5099.

(C) Abundance of total citrate and citrate m+6 in cells cultured in [U-¹³C]glutamine with or without 200 μM UK5099.

(D) Mass isotopologues of citrate in cells cultured for 6 hours in [U-¹³C]glutamine with or without 10 mM CHC or 200 μM UK5099.

(E) Effect of silencing ME2 on citrate m+6 after 6 hours of culture in [U-¹³C]glutamine. Relative abundances of citrate isotopologues were determined by normalizing total citrate abundance measured by mass spectrometry against cellular protein for each sample, then multiplying by the fractional abundance of each isotopologue.

(F) Effect of silencing MPC1 or MPC2 on formation of citrate m+6 after 6 hours of culture in [U-¹³C]glutamine.

(G) Citrate isotopologues in primary human fibroblasts of varying MPC1 genotypes after culture in [U-¹³C]glutamine.

Data are the average and SD of three independent cultures. *, p<0.05; **, p<0.01; ***, p<0.001.

See also Fig. S1.