Basement membranes are extracellular matrices that coat the basal aspect of epithelial and endothelial cells and surround muscle, fat, and Schwann cells. They are self-assembled on competent cell surfaces through interactions among laminins, type IV collagens, nidogens, and proteoglycans. These matrices play crucial roles in tissue and organ morphogenesis and adult function. Mutations affecting the expression of their components can lead to developmental arrest and postnatal diseases. Basement membranes consist of a layered structure with laminins, nidogens, perlecan, and agrin forming the scaffolding and providing interactive ligands. Assembly involves binding interactions among these components, facilitated by anchorage to cell surfaces. Integrins mediate signaling through ligand binding, affecting cell adhesion, polarization, migration, and differentiation. Dystroglycan, part of the dystrophin-glycoprotein complex, acts as an anchor between the basement membrane and the cytoskeleton, and also functions as a signaling receptor. Type IV collagen forms covalently cross-linked polymers that stabilize the basement membrane. Proteoglycans like agrin, perlecan, and type XVIII collagen can tether growth factors, influencing signaling pathways. Basement membranes also serve as solid-phase agonists, transmitting mechanical and chemical signals to cells. They are essential for early embryogenesis, glomerular development, and maintaining epithelial integrity at the epidermal-dermal junction.Basement membranes are extracellular matrices that coat the basal aspect of epithelial and endothelial cells and surround muscle, fat, and Schwann cells. They are self-assembled on competent cell surfaces through interactions among laminins, type IV collagens, nidogens, and proteoglycans. These matrices play crucial roles in tissue and organ morphogenesis and adult function. Mutations affecting the expression of their components can lead to developmental arrest and postnatal diseases. Basement membranes consist of a layered structure with laminins, nidogens, perlecan, and agrin forming the scaffolding and providing interactive ligands. Assembly involves binding interactions among these components, facilitated by anchorage to cell surfaces. Integrins mediate signaling through ligand binding, affecting cell adhesion, polarization, migration, and differentiation. Dystroglycan, part of the dystrophin-glycoprotein complex, acts as an anchor between the basement membrane and the cytoskeleton, and also functions as a signaling receptor. Type IV collagen forms covalently cross-linked polymers that stabilize the basement membrane. Proteoglycans like agrin, perlecan, and type XVIII collagen can tether growth factors, influencing signaling pathways. Basement membranes also serve as solid-phase agonists, transmitting mechanical and chemical signals to cells. They are essential for early embryogenesis, glomerular development, and maintaining epithelial integrity at the epidermal-dermal junction.