Isolation and characterization of fibronectin-binding proteoglycan carrying both heparan sulfate and dermatan sulfate...

A proteoglycan was isolated from the human placenta by procedures including affinity chromatography with fibronectin immobilized on agarose. The glycosaminoglycan chains were found to be composed of heparan sulfate (86%) and dermatan sulfate (14%). The average molecular weights were estimated to be 1.8 X 10(5) for heparan sulfate and 1.2 X 10(5) for dermatan sulfate. Mouse monoclonal antibodies HS42 and HS47 were prepared against the proteoglycan, and examination of the specificity of these antibodies indicated that they recognized the core protein portion. The binding specificity, as studied by the solid phase enzyme-linked immunoassay with monoclonal antibody HS47, indicated that the proteoglycan bound to solid phase fibronectin and to laminin, but not to collagen types I, II, and IV or gelatin. Competitive immunoassays suggested that the proteoglycan bound weakly to the liquid phase-soluble fibronectin. These studies also indicated that the core protein was involved in the interaction between the proteoglycan and solid phase fibronectin. The ubiquitous distribution of this proteoglycan in the human tissues was demonstrated by the immunohistochemical method and thus suggested its important role in the tissue organization and function.