Assembly of fibronectin-containing extracellular matrix: a glimpse of the machinery

Soluble fibronectin binds specifically and saturably to surfaces of substrate-attached cells. Bound fibronection is then transferred to the deoxycholate-insoluble extracellular matrix. During transfer, fibronectin is translocated from the cell surface and organized into disulfide-bonded multimers by disulfide exchange. Binding is mediated by disulfidelooped, type I homology “fingers” in the amino-terminal region. Exchange involves disulfides in the same amino-terminal region.