Mitochondrial VHL rewires cell metabolism in hypoxia.

Abstract

Under normoxia, von Hippel-Lindau (VHL) protein targets the oxygen-induced, hydroxylated α subunits of hypoxia-inducible factors (HIFs) for degradation to orchestrate mammalian oxygen sensing. However, whether VHL plays non-canonical roles in hypoxia, when protein hydroxylation is attenuated, remains elusive. Here, we show that most cytosolic VHL is degraded under chronic hypoxia, with the remaining VHL pool primarily translocating to the mitochondria. Mitochondrial VHL binds and inhibits 3-methylcrotonyl-coenzyme A carboxylase subunit 2 (MCCC2), an essential subunit of the leucine catabolic machinery. Accumulated leucine allosterically activates glutamate dehydrogenase to promote glutaminolysis, generating sufficient lipids and nucleotides to support hypoxic cell growth. Furthermore, SRC-mediated VHL phosphorylation and protein arginine methyltransferase 5 (PRMT5)-mediated MCCC2 methylation synergistically regulate the VHL-MCCC2 interaction and concomitant metabolic changes, which are recapitulated in animal models of ischemic injury and functionally associated with VHL mutations in cancer. Our study highlights VHL as a bona fide regulator of hypoxic metabolism within mitochondria, rather than a solely "standby adaptor" for HIFs under hypoxia.