Effect of cadherins on the development and regeneration of the neuromuscular axis.

Various cell adhesion molecules of the cadherin family characterize the neu romuscular system. During development, cadherins N and M are sequentially e xpressed by myogenic cells during the two waves of myoblast fusion. Two oth er cadherins, called 6 and 11, are also expressed during the embryonic musc ulature development. In adult muscle, cadherins N and M, whose expression i s suppressed by muscle activity, persist only at the neuromuscular junction and are reexpressed at the surface of denervated fibers. Cadherins N, M an d E are also expressed in adult peripheral nerves. Their differential local ization at Schmidt-Lanterman clefts, Ranvier nodes and neuromuscular juncti ons suggest that these molecules contribute to the stabilization of special ized intercellular contacts. In conclusion, a combination of cadherins, the expression of which is spatially and temporally regulated, participates in the differentiation and maintenance of the organization of the various cel lular and tissular components of the neuromuscular system.