Entactin (or nidogen) is a component of the basement membrane alongside other components such as collagen type IV, proteoglycans ( heparan sulfate and glycosaminoglycans), laminin and fibronectin.
Entactin (or nidogen) is a member of the nidogen family of basement membrane glycoproteins. The protein interacts with several other components of basement membranes, and may play a role in cell interactions with the extracellular matrix.

Entactin, a 150-kD sulfated glycoprotein, is a major component of basement membranes and forms a highly stable noncovalent complex with laminin. Durkin et al. (1988) derived the complete amino acid sequence of mouse entactin from sequencing of cDNA clones.