Figure 5.

RBF1-depleted animals' sensitivity to fasting is rescued by glutamine supplementation. Genotypes of animals used are described in the Materials and Methods. Error bars represent the C.I. of 95%. Statistical significance is designated as P-values as follows: (*) P < 0.06; (***) P < 0.001. Statistical differences are between effects from RBF1 depletion compared with control animals. (A) Mid-second instar larvae were fasted or fed only 25 mM L-glutamine over the course of 48 h. (B) Schematic of [U-¹³C]-glutamine (gray circles) metabolism depicts the expected amount of ¹³C labeling after glutamine is metabolized through the citric acid cycle (CAC). Molecular symmetry and cellular compartments are not depicted. Unlabeled carbon (¹²C) is shown by open circles. Molecular symmetry and cellular compartments are not depicted. (αKG) α-Ketoglutarate; (Cit) citrate; (Asp) aspartate; (Mal) malate; (Pyr) pyruvate; (Gly) glycine; (Cys) cysteine; (CDP) cytodine diphosphate; (dTDP) thymidine diphosphate; (dGDP) deoxyguanosine diphosphate. (C–I) Enrichment of the [U-¹³C₅]-glutamine tracer in metabolites associated with glutathione synthesis, the CAC, and nucleotide synthesis. All percentages are relative to the total amount of [U-¹³C₅]-glutamine tracer in each sample.