Methylation-dependent regulation of HIF-1α stability restricts retinal and tumour angiogenesis
Yunho Kim, Hye Jin Nam, Junyeop Lee, Do Young Park, Chan Kim, Young Suk Yu, Dongha Kim, Se Won Park, Jinhyuk Bhin, Daehee Hwang, Ho Lee, Gou Young Koh & Sung Hee Baek
Hypoxia-inducible factor-1α (HIF-1α) mediates hypoxic responses and regulates gene expression involved in angiogenesis, invasion and metabolism. Among the various HIF-1α posttranslational modifications, HIF-1α methylation and its physiological role have not yet been elucidated. Here we show that HIF-1α is methylated by SET7/9 methyltransferase, and that lysine-specific demethylase 1 reverses its methylation. The functional consequence of HIF-1α methylation is the modulation of HIF-1α stability primarily in the nucleus, independent of its proline hydroxylation, during long-term hypoxic and normoxic conditions. Knock-in mice bearing a methylation-defective Hif1aKA/KA allele exhibit enhanced retinal angiogenesis and tumour vascularization via HIF-1α stabilization. Importantly, S28Y and R30Q mutations of HIF-1α, found in human cancers, are involved in the altered HIF-1α stability. Together, these results demonstrate a role for HIF-1α methylation in regulating protein stability, thereby modulating biological output including retinal and tumour angiogenesis, with therapeutic implications in human cancer.