HIF-2 alpha is a member of the heterodimeric hypoxia-inducible factors/HIFs family (HIF-1,HIF-2, and HIF-3) which contains a common beta subunit but differ in their alpha subunits.
HIF-2 alpha is one subunit within the HIF-2 nuclear protein that regulates cellular responses to hypoxia (low oxygen tension conditions). Hydroxylation post-translational modifications on particular HIF residues target them for degradation. Luo, et al.