Fibronectins in vascular morphogenesis

Abstract

Fibronectin is an extracellular matrix protein found only in vertebrate organisms containing endothelium-lined vasculature and is required for cardiovascular development in fish and mice. Fibronectin and its splice variants containing EIIIA and EIIIB domains are highly upregulated around newly developing vasculature during embryogenesis and in pathological conditions including atherosclerosis, cardiac hypertrophy, and tumorigenesis. However, their molecular roles in these processes are not entirely understood. We review genetic studies examining functions of fibronectin and its splice variants during embryonic cardiovascular development, and discuss potential roles of fibronectin in vascular disease and tumor angiogenesis.

Figure 1. Schematic structure of FN

FN is composed of structural repeats of three types. Type I repeats are designated in pink, type II repeats are in orange and type III repeats are in cyan (the 9^th and 10^th repeats are marked). Alternatively spliced EIIIA, EIIIB and V regions are marked. The stippled part of the V region can be included (V120 isoform) or excluded (V95 isoform) in the mouse. Red dots indicate integrin-binding sites in the 10^th type III repeat and in the V region. Integrins known to bind these sites and EIIIA are listed.