Figure 4

mTOR inhibition does not alter mitochondrial function. (a) HepG2 cells were treated with Rapa and Tor (left panel) or transfected with siRNA against Rap, Ric or both (right panel). Cells were then incubated with ¹⁴C-labeled glucose for 2 h and released¹⁴C-labeled CO₂ was trapped in the filter paper and counted as described in the Materials and Methods. Complete oxidation of glucose (GO) was normalized to cellular protein. (b) Cells were treated as described before and ATP levels were estimated in whole-cell lysates. (c) OCR was measured in the presence of 25 mM glucose as indicated. (d) HepG2 cells were treated as described before and incubated with ¹⁴C-labeled palmitic acid for 2 h. Fatty acid oxidation (FAO) was quantified as described in the Materials and Methods. (e) Citrate synthase (CS) activity was measured in the mitochondrial fraction of HepG2 cells treated as indicated. All panels: n≥3, *P<0.05, **P<0.01 compared with Con or sc cells.