title: Drosophila Swiprosin-1/EFHD2 accumulates at the prefusion complex stage during Drosophila myoblast fusion.
abstract: In the Drosophila embryo, transient cell adhesion during myoblast fusion is known to lead to the formation of fusion-restricted myogenic-adhesive structures (FuRMASs). Here, we report that within these FuRMASs, a Drosophila homologue of human and mouse swiprosins (EF-hand-domain-containing proteins) is expressed, which we named Drosophila Swiprosin-1 (Drosophila Swip-1). Drosophila Swip-1 is highly conserved and is closely related to the calcium-binding proteins swiprosin-1 and swiprosin-2 that have a role in the immune system in humans and mice. Our study shows that Drosophila Swip-1 is also expressed in corresponding cells of the Drosophila immune system. During myoblast fusion, Drosophila Swip-1 accumulates transiently in the foci of fusion-competent myoblasts (FCMs). Both the EF-hand and the coiled-coil domain of Drosophila Swip-1 are required to localise the protein to these foci. The formation of Drosophila Swip-1 foci requires successful cell adhesion between FCMs and founder cells (FCs) or growing myotubes. Moreover, Drosophila Swip-1 foci were found to increase in number in sing(22) mutants, which arrest myoblast fusion after prefusion complex formation. By contrast, Drosophila Swip-1 foci are not significantly enriched in blow(2) and kette(J4-48) mutants, which stop myogenesis beyond the prefusion complex stage but before plasma membrane merging. Therefore, we hypothesise that Drosophila Swip-1 participates in the breakdown of the prefusion complex during the progression of myoblast fusion.
authors: Philipps-Universität Marburg, Fachbereich Biologie, Entwicklungsbiologie, 35043 Marburg, Germany.
authors: Christina
authors: C
authors: Hornbruch-Freitag
authors: Barbara
authors: B
authors: Griemert
authors: Detlev
authors: D
authors: Buttgereit
authors: Renate
authors: R
authors: Renkawitz-Pohl
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002448:Cell Adhesion; D002459:Cell Fusion; D002462:Cell Membrane / Q000378:metabolism; D017124:Conserved Sequence; D022162:Cytoplasmic Vesicles / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000166:cytology* / Q000502:physiology; D005089:Exocytosis; D005260:Female; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D007107:Immune System / Q000378:metabolism; D007136:Immunoglobulins / Q000235:genetics / Q000378:metabolism; D002479:Inclusion Bodies / Q000378:metabolism; D007814:Larva / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D008648:Mesoderm / Q000378:metabolism; D008969:Molecular Sequence Data; D024510:Muscle Development; D032446:Myoblasts / Q000378:metabolism / Q000502:physiology*; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D034622:RNA Interference; D017384:Sequence Deletion; D015398:Signal Transduction
chemical_list: D029721:Drosophila Proteins; D007136:Immunoglobulins; C410904:SNS protein, Drosophila