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. In adult, strong expression in heart, lung, ovary small and large intestines, placenta, liver; weak or no expression in skeletal muscle, kidney, pancreas, testis, prostate, brain. High expression in fetal lung and kidney. Expression in fetal and newborn tissues is observed in certain mesenchymal cells in tissues such as smooth muscle and dermis. 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. The disease is caused by variants affecting the gene represented in this entry. Gene LAMA4 was formerly called LAMA3.