Figure 6.

A FAMIN-Dependent PNC Controls Energy Metabolism

(A) Schematic of cellular energy metabolism in context of the PNC. PNC enzymes (blue circles), other enzymes (yellow circles), and transporters (gray circles) with gene names. Electron transfer from glycolysis to mitochondria by the glycerol-3-phosphate (G3PS; connected with red dotted lines) and malate-aspartate shuttle (MAS; connected with red dashed lines). Filled red circles depict fate of [¹³C₁₆] palmitic acid (C16:0)-derived carbons through fatty acid oxidation (FAO) into tricarboxylic acid (TCA) cycle citrate and by ATP citrate lyase (ACLY) into fatty acid synthesis (FASN); empty circles depict route of carbons from TCA oxaloacetate; labeling of α-ketoglutarate and succinyl-CoA depicted for M0 macrophages with intact TCA cycle. Complex II (CII) forward and reverse activity, blue and red arrowed arcs, respectively. CoQ, coenzyme Q; CI, complex I; branched chain amino and keto acids (BCAA, BCKA); DHAP, dihydroxyacetone phosphate; G-6-P, glucose-6-phosphate; F-6-P, fructose-6-phosphate; F-1,6-P, fructose-1,6-bisphosphate; Ga-3-P, glyceraldehyde-3-phosphate; 1,3-BPG, 1,3-bis-phosphoglycerate; 3-PG, 3-phosphoglycerate; 2-PG, 2-phosphoglycerate; 2-PEP, 2-phosphoenolpyruvate.

(B) OCR (left) and ECAR (right) of M0 macrophages treated (dotted line + fill) with L-alanosine for 3 h or vehicle (solid line). Basal OCR and ECAR followed by (arrows) oligomycin A (Oligo), FCCP, and rotenone plus antimycin A (Rot + ant) (n = 3).

(C) ECAR of M1 macrophages treated (dotted line + fill) with L-alanosine or vehicle (solid line). Basal ECAR followed by (arrows) Oligo and 2-deoxyglucose (2-DG) (n = 3).

(D) Cytoplasmic pH (pH_c) measured using pHrodo in M1 macrophages treated with L-alanosine or vehicle (n = 12 from 3 mice per genotype).

(E and F) Fraction of aspartate (E) or fumarate (F) labeled as the indicated isotopomer in M0 macrophages after a [¹³C₁₆] palmitate pulse (n = 6). (G) OCR (left) and ECAR (right) of M0 macrophages treated (dotted line + fill) with SB204990 (ACLY inhibitor) or vehicle (solid line). (n = 3).

Data represented as mean ± SEM. ^∗p < 0.05, ^∗∗p < 0.01, and ^∗∗∗p < 0.001 (one-way ANOVA).