Human PDGF R alpha Biotinylated Antibody

PDGF is a major serum mitogen that can exist as a homo- or heterodimeric protein consisting of disulfide-linked PDGF-A and PDGF-B chains. The PDGF-AA, PDGF-BB and PDGF-AB isoforms have been shown to bind to two distinct cell surface PDGF receptors with different affinities. Whereas PDGF R alpha binds all three PDGF isoforms with high affinity, PDGF R beta binds PDGF-BB and AB, but not PDGF-AA. Both PDGF R alpha and PDGF R beta are members of the class III subfamily of receptor tyrosine kinases (RTK) that also includes the receptors for M-CSF, SCF and Flt3 ligand. All class III RTKs are characterized by the presence of five immunoglobulin-like domains in their extracellular region and a split kinase domain in their intracellular region. PDGF binding induces receptor homo-and heterodimerization and signal transduction. The expression of the alpha and beta receptors is independently regulated in various cell types. Only PDGF R alpha is expressed in oligodendrocyte progenitor cells, mesothelial cell and liver endothelial cells. Soluble PDGF-R alpha has been detected in cell conditioned medium and human plasma. Recombinant soluble PDGF R alpha binds PDGF with high affinity and is a potent PDGF antagonist (1).