HIF-2 alpha, also known as hypoxia-inducible factor 2, endothelial PAS domain protein-1, and member of PAS superfamily 2 is part of the HIF family of proteins. The HIF family is composed of HIF-1, HIF-2 and HIF-3, where HIF-2 is a dimeric protein that consists of an alpha and beta subunit.HIF-2 alphais activated in the presence of oxygen deprivation, or hypoxia, via prolyl hydroxylase-domain enzymes (PHD