Folate receptor alpha(FOLR) belongs to the folate receptor family, and is primarily expressed in tissues of epithelial origin. It is also expressed in kidney, lung and cerebellum. The secreted form is derived from the membrane-bound form either by cleavage of the GPI anchor, or/and by proteolysis catalyzed by a metalloprotease. FOLR1 binds to folate and reduced folic acid derivatives and mediates delivery of 5-methyltetrahydrofolate and folate analogs into the interior of cells. It has high affinity for folate and folic acid analogs at neutral pH. Exposure to slightly acidic pH after receptor endocytosis triggers a conformation change that strongly reduces its affinity for folates and mediates their release. It is required for normal embryonic development and normal cell proliferation.