Fibronectin is one of the components of the extracellular matrix. It is a high molecular weight protein (440 kDa) capable of binding to integrins, membrane receptors with which it has similarities. Fibronectin is also able to bind to components of the extracellular matrix such as collagen, fibrin and proteoglycans.

Fibronectin is a dimer whose identical monomers are linked by disulfide bridges.

Fibronectin and other extracellular matrix proteins play an important role in cell adhesion, growth, migration and differentiation.

Fibronectin is used as an attachment factor in cell culture. It is particularly useful for culturing cells that are not able to synthesize their own matrix or when using a serum-free culture medium.