Résumé
BIN1/M-Amphiphysin2 is a splice variant of Amphiphysin2 expressed in muscle that has been implicated in T-tubule biogenesis. BIN1 belongs to the BAR (Bin1-Amphiphysin-Rvs) domain family, which are known to induce membrane curvature and participate in endocytosis in certain cell types. Several BIN1 mutations are reported on centronuclear myopathies (CNMs), a heterogeneous group of inherited muscular disorders that are characterized by a compromised normal muscle function and nuclei positioning, ultimately leading to fiber atrophy and muscle weakness. The suppression of BIN1 on muscular cells has shown to impair the fusion of myoblast during muscle differentiation1, although the exact mechanism remains elusive. Here, we report that BIN1 participates in forming filopodia-like structures at myoblasts’ intercellular junctions, structures that promote adhesion and fusion of muscle cells. Furthermore, our results show that BIN1 assembles actin bundles in vitro and regulates plasma membrane tension. We identified ezrin as a new BIN1 partner and showed that ezrin association with PI(4,5)P 2-containing model membranes and the plasma membrane is favored by BIN1. Our results establish BIN1 and ezrin as central players to form long-lived filopodia-like structures, known to promote adhesion and fusion of muscle cells.