Recombinant Rat PDGF-AA Protein, CF

The platelet-derived growth factor (PDGF) family consists of proteins derived from four genes (PDGF-A, -B, -C, and -D) that form four disulfide-linked homodimers (PDGF-AA, -BB, -CC, and -DD) and one heterodimer (PDGF-AB) (1, 2). These proteins regulate diverse cellular functions by binding to and inducing the homo- or hetero-dimerization of two receptors (PDGF R alpha and R beta). Whereas alpha/ alpha homo-dimerization is induced by PDGF-AA, -BB, -CC, and -AB, alpha/ beta hetero-dimerization is induced by PDGF-AB,-BB, -CC, and -DD, and beta/ beta homo-dimerization is induced only by PDGF-BB, and -DD (1 - 4). Both PDGF R alpha and R beta are members of the class III subfamily of receptor tyrosine kinases (RTK) that have five immunoglobulin-like domains in their extracellular region and a split kinase domain in their intracellular region. Ligand-induced receptor dimerization results in autophosphorylation in trans resulting in the activation of several intracellular signaling pathways that can lead to cell proliferation, cell survival, cytoskeletal rearrangement, cell migration and extracellular matrix production. Rat PDGF-A chain cDNA encodes a 204 amino acid (aa) residue precursor protein with a 20 aa signal peptide, a 65 aa propeptide that is removed by proteolysis, and a 119 aa mature protein. By alternative splicing, a short form lacking 8 C-terminal aa residues also exists. The long form contains the 8 aa basic insert which promotes intracellular cell retention and association with cell matrix. PDGF-A is expressed in multiple cell types and tissues. Based on PDGF-A knockout studies, PDGF-A appears to be important for the development of oligodendrocytes, testicular Leydig cells, alveolar smooth muscle cells, hair follicles and intestinal villus (1).