Amphiphysin is necessary for organization of the excitation–contraction coupling machinery of muscles, but not for synaptic vesicle endocytosis inDrosophila

Open Access
Publisher Website
Google Scholar
Abstract
Amphiphysins 1 and 2 are enriched in the mammalian brain and are proposed to recruit dynamin to sites of endocytosis. Shorter amphiphysin 2 splice variants are also found ubiquitously, with an enrichment in skeletal muscle. At theDrosophilalarval neuromuscular junction, amphiphysin is localized postsynaptically andamphiphysinmutants have no major defects in neurotransmission; they are also viable, but flightless. Like mammalian amphiphysin 2 in muscles,Drosophilaamphiphysin does not bind clathrin, but can tubulate lipids and is localized on T-tubules.Amphiphysinmutants have a novel phenotype, a severely disorganized T-tubule/sarcoplasmic reticulum system. We therefore propose that muscle amphiphysin is not involved in clathrin-mediated endocytosis, but in the structural organization of the membrane-bound compartments of the excitation–contraction coupling machinery of muscles.