Platelet-derived growth factor binds specifically to receptors on vascular smooth muscle cells and the binding becomes nondissociable.
AUTOR(ES)
Williams, L T
RESUMO
Radioiodinated platelet-derived growth factor (125I-PDGF) was used in studies of PDGF binding sites on vascular smooth muscle cells. There was an excellent correlation between the ability of 125I-PDGF to stimulate cell proliferation and to bind specifically to cultured vascular smooth muscle cells. The half-maximal concentration for both processes was 0.1 nM. There were 50,000 binding sites per cell. Reduced PDGF, prepared by treatment of PDGF with 20 mM dithiothreitol, had neither the ability to bind to smooth muscle cells nor to stimulate cellular proliferation. Epidermal growth factor, nerve growth factor, fibroblast growth factor, and histone B did not compete for the binding sites at a concentration of 10 nM. 125I-PDGF binding was slowly reversible at 4 degrees C and was rapidly and totally reversible after a 1-min incubation at 37 degrees C. After continued incubation at 37 degrees C, the binding became irreversible. The half-time for formation of the nondissociable state of 125I-PDGF binding was approximately equal to 5 min at 37 degrees C. The nondissociable state of binding was not formed at 4 degrees C even after 1 hr of incubation. These data suggest that the sites we labeled are the PDGF receptors that mediate PDGF's mitogenic action and that a nondissociable state of PDGF binding is formed at 37 degrees C. It is likely that nondissociable PDGF represents internalized ligand or binding to sites that are converted to a high-affinity state after the ligand binds.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=347011Documentos Relacionados
- Platelet-derived growth factor stimulates the secretion of hyaluronic acid by proliferating human vascular smooth muscle cells.
- Attachment of smooth muscle cells to collagen and their migration toward platelet-derived growth factor.
- Coagulation factor Xa stimulates platelet-derived growth factor release and mitogenesis in cultured vascular smooth muscle cells of rat.
- Ca2+-channel blockers inhibit the action of recombinant platelet-derived growth factor in vascular smooth muscle cells.
- Endothelial and Smooth Muscle-derived Neuropilin-like Protein Regulates Platelet-derived Growth Factor Signaling in Human Vascular Smooth Muscle Cells by Modulating Receptor Ubiquitination*