Platelet Derived Growth Factor Receptor alpha, Fc Chimera, Recombinant Human (PDGFRA, Platelet-Deriv

PDGF Ra (platelet-derived growth factor receptor alpha) is a type I transmembrane glycoprotein in the class III subfamily of receptor tyrosine kinases (RTK) (1-4). PDGF Ra and PDGF Rb 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. While multiple in vitro ligand-receptor combinations have been identified, in vivo evidence indicates that PDGF Ra primarily binds PDGF-AA and PDGF-CC, while PDGF Rb primarily binds PDGF-BB and probably PDGF-DD. Like all class III RTKs, the extracellular domain (ECD) of human PDGF Ra (aa24-524) contains five immunoglobulin-like domains, while the intracellular region contains a split tyrosine kinase domain (aa593-954) (1-4). Within the ECD, human PDGF Ra shares 85%, 83%, 95%, 93%, and 88% aa sequence identity with mouse, rat, equine, canine and bovine PDGF Ra respectively. PDGF Ra autophosphorylates upon dimerization, activating signaling cascades in PI 3-kinase Ras-MAP kinase, and PLC-g pathways (1, 2). Signaling is down-regulated by SHP-2 phosphatase activity and by receptor endocytosis and lysosomal degradation. PDGF Ra is expressed at low levels in most mesenchymal cells, but is strongly expressed in oligodendrocyte, lung, skin and intestinal progenitor cells and induced by inflammation or growth in culture (1-4). During development, mesenchymal cells expressing PDGF Ra respond to local gradients of epithelially produced PDGF-AA or PDGF-CC during formation of the cranial and cardiac neural crest, retina, gonads, lung alveoli, intestinal villi, skin, hair follicles, skeleton, teeth, palate, and interstitial kidney mesenchyme (1, 5). Deletion of PDGF Ra in mice severely impairs mesenchymal derivatives in both embryo and extraembryonic tissues, and high or low PDGF Ra signaling in humans may result in spina bifida or cleft palate-type malformations. Postnatally, PDGF Ra is implicated in gliomas and fibrotic disorders of lung, heart and skin (scleroderma) (6-8). Source: Recombinant corresponding aa1-524 from human PDGF Ra at N-terminus and C-terminus expressed in mouse myeloma cell line, NSO. Molecular Weight: ~82.8kD, Endotoxin: <1EU/1ug (LAL) , Biological Activity:, Measured by its ability to inhibit the biological activity of PDGF-AB or PDGF-AA using NR6R-3T3 mouse fibroblasts. Raines, E.W. et al. (1985) Methods Enzymol. 109:749. The ED50 for this effect is typically 0.2-1ug/ml in the presence of 100ng/ml recombinant human PDGF-AB. Storage and Stability: Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute with PBS. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Reconstituted product is stable for 6 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.