Five type I modules of fibronectin form a functional unit that binds to fibroblasts and Staphylococcus aureus.
Fibronectin is a cell-adhesive protein comprised of three types of repeating homologous sequences, I, II, and III (Petersen, T.E., Thøgersen, H.C., Skorstengaard, K., Vibe-Pedersen, K., Sahl, P., Sottrup-Jensen, L., and Magnusson, S. (1983) Proc. Natl. Acad. Sci. U.S.A. 80, 137-141). The amino-terminal portion of fibronectin is comprised of five type I modules and mediates assembly of dimeric soluble fibronectin into insoluble fibrils by cultured fibroblasts, binding and cross-linking of fibronectin to Staphylococcus aureus, and binding and cross-linking of fibronectin to fibrin. It is not known whether these binding activities require individual type I modules, several modules, or all five modules. To answer this question, we generated recombinant truncated fibronectin molecules with deletions of or mutations in the amino-terminal type I modules. Binding to cellular fibronectin assembly sites and S. aureus required all five type I modules. In contrast, proteins with deletions of type I modules interacted well with fibrin.
Department of Medicine, University of Wisconsin, Madison 53706.
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Sottile
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Schwarzbauer
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Selegue
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Mosher
D001483:Base Sequence; D001665:Binding Sites; D002478:Cells, Cultured; D002846:Chromatography, Affinity; D005337:Fibrin / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D005353:Fibronectins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D015345:Oligonucleotide Probes; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D013211:Staphylococcus aureus / Q000378:metabolism*; D011503:Transglutaminases / Q000378:metabolism
D005353:Fibronectins; D015345:Oligonucleotide Probes; D011994:Recombinant Proteins; D005337:Fibrin; D011503:Transglutaminases