PDGFRA, also known as CD140a, together with the structurally homolog protein PDGFRB (CD140b), are cell surface receptors for members of the platelet-derived growth factor family. PDGF R alpha (platelet-derived growth factor receptor alpha) is a type I transmembrane glycoprotein in the class III subfamily of receptor tyrosine kinases (RTK) . PDGF R alpha and PDGF R beta can form homo- or hetero-dimeric receptors when engaged by dimers of the PDGF family of growth factors, which include disulfide-linked homodimers of PDGF-A, B, C or D, or the heterodimer PDGF-AB that is mainly found in human platelets. PDGF R alpha autophosphorylates upon dimerization, activating signaling cascades in PI 3-kinase Ras‑MAP kinase, and PLC-gamma pathways. Signaling is down‑regulated by SHP-2 phosphatase activity and by receptor endocytosis and lysosomal degradation. This receptor binds to certain isoforms of platelet-derived growth factors (PDGFs) and thereby becomes active in stimulating cell signaling pathways that elicit responses such as cellular growth and differentiation. The receptor is critical for the development of certain tissues and organs during embryogenesis and for the maintenance of these tissues and organs, particularly hematologic tissues, throughout life.