GENETIC-ANALYSIS OF POSTSYNAPTIC DIFFERENTIATION AT THE VERTEBRATE NEUROMUSCULAR-JUNCTION

As neuromuscular junctions form in vertebrate skeletal muscle, nicotin ic acetylcholine receptors (AChRs) become concentrated in the postsyna ptic membrane. The nerve directs this redistribution, using multiple s ignals to regulate AChRs at both transcriptional and post translationa l levels. Recent studies in vitro have led to the identification of ca ndidate nerve-derived signaling molecules (such as agrin, ARfA/neuregu lin, and calcitonin gene-related peptide) and components of their intr amuscular signaling pathways (including dystroglycan, MUSK, erbB kinas es, utrophin, and rapsyn). Studies of knock-out mice are now making it possible to test which signals and pathways are responsible for posts ynaptic differentiation in vivo.