FN1 and intervertebral disk degenerative disorder: In particular, fibronectin binding to integrin receptors promotes their clustering in the cell membrane, which in turn leads to further assembly of fibronectin into fibrils around the cells.56–58 In the adult disc, fibronectin proteolysis into fragments is correlated with the grade of disc degeneration, and has been shown to stimulate catabolic events that lead to the same.52