Extracellular matrix assembly of cell-derived and plasma-derived fibronectins by substrate-attached fibroblasts.
Using a previously described model system for the incorporation of plasma fibronectin into the extracellular matrix (McKeown-Longo, P.J. and Mosher, D.F., 1985. J. Cell Biol., 100:364-374), we compared the binding of cell-derived and plasma-derived fibronectins to human fibroblast cell layers. Binding was measured in time course experiments using metabolically labeled cell-derived, iodinated cell-derived, and iodinated plasma-derived fibronectins. The kinetics of matrix assembly of cell- and plasma-derived fibronectins were the same. Competitive binding curves using intact fibronectin or the 70-kD amino-terminal fragment of fibronectin suggested that cell surface binding sites have equal affinity for cell- and plasma-derived fibronectins. Iodinated fibronectins did not bind to isolated matrices containing collagen type I, fibronectin, and thrombospondin. These results suggest that fibroblasts do not distinguish between cell-derived and plasma-derived fibronectins when assembling exogenous fibronectin into extracellular matrix.
Allio
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AE
Department of Physiology, Albany Medical College, New York 12208.
McKeown-Longo
P J
PJ
D001665:Binding Sites; D002448:Cell Adhesion; D003094:Collagen / Q000032:analysis; D005109:Extracellular Matrix / Q000187:drug effects*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D005353:Fibronectins / Q000494:pharmacology*; D005455:Fluorescent Antibody Technique; D006023:Glycoproteins / Q000032:analysis; D006801:Humans; D008970:Molecular Weight; D010949:Plasma; D019699:Thrombospondins
D005353:Fibronectins; D006023:Glycoproteins; D019699:Thrombospondins; D003094:Collagen