Fig. 2.

Physical and functional links between purinosomes and mitochondria. (A) Western blot of purified mitochondria showing that purinosome proteins FGAMS and ASL co-isolate with mitochondria in a rapamycin-dependent manner. Mitochondria were isolated from HeLa cells grown under purine-depleted conditions that transiently expressed FGAMS-3×FLAG after treatment with 1 μM rapamycin (+) or vehicle control (−) for 1 h. Inhibition of mTOR was verified by observing a decrease in the phosphorylated form (pT389) of the mTOR target S6 kinase (p70-S6K). VDAC1 was used as a mitochondria loading control and p70-S6Kserved as a cytoplasmic loading control. (B) The percentage of cells with visible purinosomes (determined from at least 100 total cells) as a function of modulators of mitochondrial metabolism and glycolysis at their specified concentrations for 1 h. Values reflect mean ± standard deviation, N=3. (C) Intracellular malate (gray) and lactate (black) levels were determined by colorimetric assay after various drug treatments for 1 h (2 h for MKT-077). Values reflect mean ± standard deviation, N=3.