Platelet-derived growth factor receptor A

Platelet-derived growth factor receptor A, also termed CD140a, is a receptor located on the surface of a wide range of cell types. The protein is encoded in the human by the PDGFRA gene. 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 embryonic development of certain tissues and organs, and for their maintenance, particularly hematologic tissues, throughout life. Mutations in PDGFRA, are associated with an array of clinically significant neoplasms, notably ones of the clonal hypereosinophilia class of malignancies, as well as gastrointestinal stromal tumors (GISTs). This gene encodes a typical receptor tyrosine kinase, which is a transmembrane protein consisting of an extracellular ligand binding domain, a transmembrane domain and an intracellular tyrosine kinase domain. The molecular mass of the mature, glycosylated PDGFRα protein is approximately 170 kDA. cell surface tyrosine kinase receptor for members of the platelet-derived growth factor family. Activation of PDGFRA requires de-repression of the receptor's kinase activity. The ligand for PDGFRα (PDGF) accomplishes this in the course of assembling a PDGFRα dimer. Four of the five PDGF isoforms activate PDGFRα (PDGF-A, PDGF-B, PDGF-AB and PDGF-C). The activated receptor phosphorylates itself and other proteins, and thereby engages intracellular signaling pathways that trigger cellular responses such as migration and proliferation. There are also PDGF-independent modes of de-repressing the PDGFRα's kinase activity and hence activating it. For instance, forcing PDGFRα into close proximity of each other by overexpression or with antibodies directed against the extracellular domain. Alternatively, mutations in the kinase domain that stabilize a kinase active conformation result in constitutive activation. Finally, growth factors outside of the PDGFR family (non-PDGFs) activate PDGFRα indirectly.