Laminin-11

Laminins are a family of glycoproteins which are ubiquitous components of basement membranes and play key structural and functional roles. Eleven isoforms have been identified to date; each is an αβγ heterotrimer assembled from a repertoire of five α, three β and two γ chains. Studies of laminin-11 (α5β2γ1) illustrate the unique expression patterns and distinct functions that can be displayed by laminin isoforms. Laminin-11 is found in the glomerular basement membrane in kidney, in the neuromuscular synaptic cleft in skeletal muscle and in other tissues such as placenta and lung. Mice lacking laminin-11 exhibit defective glomerular filtration and developmental defects in neuromuscular synapse formation, with Schwann cells invading the synaptic cleft. Consistent with these observations, both motoneurons and Schwann cells distinguish laminin-11 from other isoforms in vitro. These results suggest that laminin-11 is a structural component of the basement membrane which influences cell behavior in physiologically relevant ways. A greater understanding of laminin-11 assembly and basement membrane incorporation could provide a logical basis for therapy in merosin-deficient congenital muscular dystrophy. Copyright (C) 1999 Elsevier Science Ltd.