Distribution of Fibronectins in Vivo

Abstract

One of the impressive properties of fibronectins is their extremely wide distribution, which clearly suggests that they perform rather important functions. Another intriguing feature is that fibronectins occur in two distinctly different situations; first, as soluble glycoproteins in various body fluids or secreted by cells in culture and, second, as insoluble constituents of extracellular matrices and basement membranes. This obviously raises the question of the relationship between these two classes of fibronectin molecules. We will return to this question several times (see Section 3.3 and Chapters 4, 6, 7, 8, 13) but it is well to keep it in mind as we consider the expression of fibronectins in the body and in cultured cells.