title: WASp is required for the correct temporal morphogenesis of rhabdomere microvilli.
abstract: Microvilli are actin-based fingerlike membrane projections that form the basis of the brush border of enterocytes and the Drosophila melanogaster photoreceptor rhabdomere. Although many microvillar cytoskeletal components have been identified, the molecular basis of microvillus formation is largely undefined. Here, we report that the Wiskott-Aldrich syndrome protein (WASp) is necessary for rhabdomere microvillus morphogenesis. We show that WASp accumulates on the photoreceptor apical surface before microvillus formation, and at the time of microvillus initiation WASp colocalizes with amphiphysin and moesin. The loss of WASp delays the enrichment of F-actin on the apical photoreceptor surface, delays the appearance of the primordial microvillar projections, and subsequently leads to malformed rhabdomeres.
authors.affiliation: Division of Biology, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0649, USA. azelhof@biomail.ucsd.edu
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Zelhof
authors.forename: Robert W
authors.initials: RW
authors.lastname: Hardy
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D051186:Armadillo Domain Proteins; D015415:Biomarkers; D002462:Cell Membrane / Q000502:physiology* / Q000648:ultrastructure*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000033:anatomy & histology / Q000196:embryology* / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D008871:Microvilli / Q000502:physiology; D009024:Morphogenesis; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009469:Neuromuscular Junction / Q000378:metabolism; D017956:Photoreceptor Cells, Invertebrate / Q000002:abnormalities / Q000166:cytology / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors; D051316:Wiskott-Aldrich Syndrome Protein
chemical_list: C495305:ARM protein, Drosophila; D000199:Actins; D051186:Armadillo Domain Proteins; D015415:Biomarkers; D029721:Drosophila Proteins; D008562:Membrane Glycoproteins; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C477859:WASp protein, Drosophila; D051316:Wiskott-Aldrich Syndrome Protein; C055093:chp protein, Drosophila; C071058:moesin; C075637:amphiphysin