Basal lamina and the organization of neuromuscular synapses.

Fast chemical synapses are comprised of presynaptic and postsynaptic specializations precisely aligned across a protein-filled synaptic cleft. At the vertebrate neuromuscular junction (NMJ), the synaptic cleft contains a structured form of extracellular matrix known as a basal lamina (BL). Synaptic BL is molecularly differentiated from the BL that covers the extrasynaptic region of the myofiber. This review summarizes current understanding of the morphology, composition, and function of the synaptic BL at the vertebrate NMJ. Considerable evidence supports the conclusion that the synaptic BL organizes and maintains pre- and postsynaptic specializations during development and regeneration, and promotes robust neurotransmission in the adult.