Fibronectin-binding 36 kDa protein in human fibroblasts

A 36 kDa fibronectin-binding protein was identified from electrophoretically separated proteins of the deoxycholate-soluble fraction of cultured fibroblasts by blotting with fibronectin and using poly- or monoclonal antibodies and immunoperoxidase staining to detect the bound fibronectin. The 36 kDa protein was purified by preparative electrophoresis and used to raise specific antibodies. Solid-phase 36 kDa protein bound plasma and fibroblast fibronectins equally well. The 36 kDa protein is an amphipathic protein with pI 5.9. It is monomeric with a tendency to dimerize and appears to be distinct from the cell surface fibronectin receptors which interact with the Arg-Gly-Asp recognition site in the fibronectin molecule.