Nidogen: a new, self-aggregating basement membrane protein.

摘要: Nidogen was purified from a mouse tumor basement membrane where it accounted for 2-3% of the total proteins. It isolated as two forms (A and B) monomer (Mr = 80000) each consisting single polypeptide chain folded into globular head connected to small tail. The B form shown be capable aggregating nest-like structure greater than 250000). A smaller 45000) observed in some extracts. amino acid composition nidogen different that other contained about 10% carbohydrate, with N-linked O-linked oligosaccharide chains similar proportions. Isoelectrofocussing demonstrated limited heterogeneity pI range 6.5 - 7. Monomeric failed interact components heparin. Aggregation could induced by proteolysis reversed detergents or high salt concentrations. Together observation most solubilized only after destroying collagenous matrix, data indicate aggregation reflects an activity involved matrix assembly. Specific antibodies raised against did not distinguish between monomeric aggregated protein but showed fragment antigenically deficient. These cross-react collagen type IV, laminin, entactin heparansulfate proteoglycan. Immunofluorescence staining absorption studies is common component authentic membranes. Larger 100000 150000) were found organ cultures Reichert's suggesting synthesized precursor forms.