Biology of hypoxia-inducible factor-2 alpha in development and disease

The transcriptional response to hypoxia is primarily mediated by two hypoxia-inducible factors -HIF-1 alpha and HIF-2 alpha. While these proteins are highly homologous, increasing evidence suggests they have unique transcriptional targets and differential impact on tumor growth. Furthermore, non-transcriptional effects of the HIF-alpha subunits, including effects on the Notch and c-Myc pathways, contribute to their distinct functions. HIF-2 alpha transcriptional targets include genes involved in erythropoiesis, angiogenesis, metastasis, and proliferation. Therefore, HIF-2 alpha contributes significantly to both normal physiology as well as tumorigenesis. Here, we summarize the function of HIF-2 alpha during development as well as its contribution to pathologic conditions, such as tumors and vascular disease.