nidogen1

Nidogen-1, also known as entactin, is a basement membrane glycoprotein that contributes to the structural organization of extracellular matrices by linking laminin and type IV collagen networks. In humans it is encoded by the NID1 gene and is found in basement membranes across a wide range of tissues.

Nidogen-1 is a modular protein with an N-terminal globular G1 domain, a central rod-like domain, and a C-terminal globular G2 domain. The G1 and G2 domains mediate binding to laminin and to collagen IV, respectively, and together with other basement membrane components help stabilize the networks that form the underlying scaffold of tissues. Nidogen-1 can also interact with additional basement membrane constituents such as perlecan and, in some contexts, with nidogen-2.

In the basement membrane, nidogen-1 functions as a crosslinker that facilitates the proper assembly and cohesion of the laminin and collagen IV networks, supporting membrane integrity and tissue architecture. Genetic studies in mice indicate partial redundancy with nidogen-2; loss of both leads to pronounced basement membrane defects and neonatal lethality, while loss of either alone yields comparatively milder phenotypes.

Clinically, altered expression of NID1 has been observed in certain diseases, and rare genetic variants have been described, but the full extent of its involvement in human pathology remains an area of ongoing research.