Abstract
Abstract Amphiphysin 2 (BIN1) is a membrane and actin remodeling protein mutated both in congenital and adult centronuclear myopathies. The BIN1 muscle-specific isoform finely tunes muscle regeneration in adulthood and regulates myoblast fusion. However, the underlying molecular mechanisms are unknown. Here, we report that BIN1 is required for myoblast fusion and participates in the formation of filopodia-like structures at myoblast intercellular junctions. BIN1 bundles actin in vitro and regulates the membrane-to-cortex attachment, two key processes required for myoblast fusion. We identified ezrin, a member of the ERM protein family, as a new BIN1 partner and showed that BIN1 promotes ezrin association to PI(4,5)P 2 at the cell cortex. Our results establish BIN1 and ezrin as central players at the early stages of myoblast fusion to form long-lived filopodia-like structures.