A tyrosinated peptide representing the alternatively spliced exon of the platelet-derived growth factor A-chain binds specifically to cultured cells and interferes with binding of several growth factors.

摘要: Platelet-derived growth factor (PDGF) is a potent mitogen for cells of mesenchymal origin. Alternative exon splicing responsible two forms the PDGF A-chain which differ at carboxyl terminus by highly basic region consisting 18 amino acids. To clarify function region, we synthesized an octadecapeptide corresponding to this extension (A194-211), incorporated tyrosine residue terminus, and used radioiodinated construct in binding studies with Balb/c3T3 variety human cell lines. 125I-(Y)A194-211 bound specifically, reversibly, saturably, low affinity large population sites on these cells. In addition, (Y)A194-211 markedly reduced its parent protein, 125I-PDGF-AAL, receptor. also attenuated epidermal several other isoforms PDGF, but did not interfere transferrin These observations were due competitive peptide directly known receptors respective factors, was likely interaction extracellular glycosaminoglycan. Thus, A194-211 may represent additional heparin domain mature PDGF-AAL, as isolate, capable modulating interactions between factors their receptors.