Interaction of Laminin with Cell Membranes
Laminin, a major component of basement membranes, is a large (Mr =106) glycoprotein with diverse biological functions. By binding to various matrix components including type IV collagen, heparan sulfate proteoglycan and nidogen it plays a key role in the organization of the basal lamina. Furthermore laminin is involved in a variety of interactions of the basement membrane with the adjacent epithelial and mesenchymal cells. In studies on isolated cells and organoids in vitro laminin has been shown to promote cell migration and adhesion, to effect cell shape and polarity, to induce outgrowth of cell processes and neurites and to stimulate proliferation and differentiation (for recent review see 1). Laminin seems to influence predominantly epithelial cell behaviour, but also effects on mesenchymal cells have been described, for example on muscle cell differentiation. We could show that laminin if present as substrate on culture dishes selects for2 myogenic versus fibroblastic cells and stimulates myodifferentiation. These observations initiated the search for laminin-binding components on the muscle cell surface. Affinity chromatography of detergent solubilised muscle cell membranes resulted in the isolation of a 68kd protein, which upon reconstitution into liposomes binds specifically to laminin3.
KeywordsSkeletal Myoblast Laminin Receptor Muscle Cell Membrane Chicken Gizzard Smooth Muscle Cell Membrane
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