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. Alpha-5 may be the major laminin alpha chain of adult epithelial and/or endothelial basal laminae. 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-5 is a subunit of laminin-10 (laminin-511), laminin-11 (laminin-521) and laminin-15 (laminin-523). Major component. In adult, high levels in heart, lung, and kidney; lower in brain, muscle and testis; very low in liver, gut and skin. Expressed in many tissues in embryonic day 11. The alpha-helical domains I and II are thought to interact with other laminin chains to form a coiled coil structure. Domains VI, IV and G are globular.