Our research aims to understand processes underlying morphogenesis of neuromuscular circuits, and to uncover how alterations of these developmental processes lead to devastating neuromuscular pathologies in human. Our work integrates the study of cell fate diversity and mutual dependency of motor neurons and their target muscles. We therefore focus on the identification of signals successively exchanged by neurons and muscles during development. These include the signals acting on neuronal and muscular specification, the signals that pattern neural projections through axonal guidance and through muscle morphogenesis, and the signals that regulate homogeneous growth and match the size of neuromuscular units. We study how all these signals successfully integrate to produce locomotor activity. Recently, our results linking dysfunction of a developmental gene with a muscular dystrophy led us to start investigating the mechanisms at play during skeletal muscle homeostasis, repair, and pathologies.