Laminin is a large molecular weight glycoprotein present only in basement membranes in almost every animal tissue. Each laminin is a heterotrimer assembled from alpha, beta and gamma chain subunits, secreted and incorporated into cell-associated extracellular matrices. The laminins can self-assemble, bind to other matrix macromolecules, and have unique and shared cell interactions mediated by … expand

Laminin is a large molecular weight glycoprotein present only in basement membranes in almost every animal tissue. Each laminin is a heterotrimer assembled from alpha, beta and gamma chain subunits, secreted and incorporated into cell-associated extracellular matrices. The laminins can self-assemble, bind to other matrix macromolecules, and have unique and shared cell interactions mediated by integrins, dystroglycan, and other receptors. Through these interactions, laminins critically contribute to cell differentiation, shape and movement, maintenance of tissue phenotypes, and promotion of tissue survival [ PUBMED:10842354 PUBMED:15363809 ].

The different laminin chains share a 600-residue domain I/II which oligomerises into a rod-like coiled-coil structure forming the long arm of laminins. The N-terminal short arms consist of rod-like elements (domain III and V) formed by tandem arrays of laminin-type EGF modules and several globular domains: domains IV and domain VI (laminin N-terminal). All alpha chains share a unique C-terminal G domain which consists of five laminin G modules [ PUBMED:3182802 ]. Laminin IV domain is also found in the perlecan protein, an integral component of basement membranes, which serves also as an attachment substrate for cells, but it is not found in short laminin chains (alpha4 or beta3). The function of this domain is not yet known.