High impact information on Amph

• Amphiphysin is necessary for organization of the excitation-contraction coupling machinery of muscles, but not for synaptic vesicle endocytosis in Drosophila [1].
• At the Drosophila larval neuromuscular junction, amphiphysin is localized postsynaptically and amphiphysin mutants have no major defects in neurotransmission; they are also viable, but flightless [1].
• Amphiphysin mutants have a novel phenotype, a severely disorganized T-tubule/sarcoplasmic reticulum system [1].
• 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 [1].
• Shorter amphiphysin 2 splice variants are also found ubiquitously, with an enrichment in skeletal muscle [1].

Biological context of Amph

• Taken together, these data are consistent with a role for Drosophila amphiphysin in endocytosis, but the details of this role may differ from that of vertebrate amphiphysins [2].
• Amphiphysin is a single-copy gene that maps to position 49B on polytene chromosomes [2].
• Messenger RNA of this amphiphysin is expressed widely during embryogenesis and has elevated expression in a number of sites including the foregut, hindgut and epidermis, but not in the central nervous system [2].
• This study challenges the notion that synaptic Amphiphysin is involved exclusively in endocytosis and suggests a novel role for this protein in postsynaptic exocytosis [3].
• Studies in cell-free systems and the lamprey giant synapse have implicated crucial roles for amphiphysin and endophilin in synaptic transmission [4].

Anatomical context of Amph

• Misexpression of Amphiphysin outside its normal membrane domain in photoreceptor neurons results in striking morphological defects [5].
• We show that Drosophila Amphiphysin is localized to actin-rich membrane domains in many cell types, including apical epithelial membranes, the intricately folded apical rhabdomere membranes of photoreceptor neurons and the postsynaptic density of glutamatergic neuromuscular junctions [5].
• Rather, amphiphysin in fly muscles appears to regulate the organization and structure of the muscle T-tubule system and possibly the subsynaptic reticulum [6].

Other interactions of Amph

• Drosophila amphiphysin functions during synaptic Fasciclin II membrane cycling [3].
• Taken together, our findings suggest that Amphiphysin is not required for viability, nor is it absolutely required for clathrin-mediated endocytosis [7].

References