Binding of fibronectin to the small proteoglycan decorin plays an important role in cell differentiation and cell migration. The cartilage-specific (V+C)- fibronectin isoform, in which nucleotides that normally encode the protein segments V, III15, and I10 are spliced out, is one of the major splice variants present in cartilage matrices. Full-length and truncated cDNA constructs were used to express recombinant versions of fibronectin. Results demonstrated that the (V+C)- isoform has a higher affinity for decorin. Dissociation constants for decorin and fibronectin interaction were calculated to be 93 nM for the V+C+ isoform and 24 nM and 223 nM for (V+C)- fibronectin. Because heparin competed with decorin competitively, binding of decorin to fibronectin likely occurs at a heparin-binding region. We propose that alternative splicing of the V and C regions changes the global conformation of fibronectin in such a way that it opens an additional decorin-binding site. This conformational change is responsible for the higher affinity of the (V+C)- fibronectin isoform for decorin.
|Number of pages||7|
|Journal||Journal of Biological Chemistry|
|State||Published - Mar 28 2003|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology