Binding to cells via a high affinity receptor, laminin is thought to mediate the attachment, migration and organization of cells into tissues during embryonic development by interacting with other extracellular matrix components. Laminin is a complex glycoprotein, consisting of three different polypeptide chains (alpha, beta, gamma), which are bound to each other by disulfide bonds into a cross-shaped molecule comprising one long and three short arms with globules at each end. Alpha-4 is a subunit of laminin-8 (laminin-411), laminin-9 (laminin-421) and laminin-14 (laminin-423). Major component. Strongly expressed in peripheral nerves, cardiac muscle, fat, dermis, lung stroma, aortic endothelium, endocardium and endothelium of blood vessels in skin and brain. The alpha-helical domains I and II are thought to interact with other laminin chains to form a coiled coil structure. Domain G is globular.