Landscape of the mitochondrial Hsp90 metabolome in tumours

Reprogramming of tumour cell metabolism contributes to disease progression and resistance to therapy, but how this process is regulated on the molecular level is unclear. Here we report that heat shock protein 90-directed protein folding in mitochondria controls central metabolic networks in tumour cells, including the electron transport chain, citric acid cycle, fatty acid oxidation, amino acid synthesis and cellular redox status. Specifically, mitochondrial heat shock protein 90, but not cytosolic heat shock protein 90, binds and stabilizes the electron transport chain Complex II subunit succinate dehydrogenase-B, maintaining cellular respiration under low-nutrient conditions, and contributing to hypoxia-inducible factor-1α-mediated tumorigenesis in patients carrying succinate dehydrogenase-B mutations. Thus, heat shock protein 90-directed proteostasis in mitochondria regulates tumour cell metabolism, and may provide a tractable target for cancer therapy. Tumour cells utilize a pool of the molecular chaperone heat shock protein 90 to ensure correct protein folding in mitochondria. Here, the authors demonstrate that mitochondrial heat shock protein 90 regulates the folding of a subunit of the electron transport chain and that this can contribute to tumorigenesis.