title: Dynein supports motility of endoplasmic reticulum in the fungus Ustilago maydis.
abstract: The endoplasmic reticulum (ER) of most vertebrate cells is spread out by kinesin-dependent transport along microtubules, whereas studies in Saccharomyces cerevisiae indicated that motility of fungal ER is an actin-based process. However, microtubules are of minor importance for organelle transport in yeast, but they are crucial for intracellular transport within numerous other fungi. Herein, we set out to elucidate the role of the tubulin cytoskeleton in ER organization and dynamics in the fungal pathogen Ustilago maydis. An ER-resident green fluorescent protein (GFP)-fusion protein localized to a peripheral network and the nuclear envelope. Tubules and patches within the network exhibited rapid dynein-driven motion along microtubules, whereas conventional kinesin did not participate in ER motility. Cortical ER organization was independent of microtubules or F-actin, but reformation of the network after experimental disruption was mediated by microtubules and dynein. In addition, a polar gradient of motile ER-GFP stained dots was detected that accumulated around the apical Golgi apparatus. Both the gradient and the Golgi apparatus were sensitive to brefeldin A or benomyl treatment, suggesting that the gradient represents microtubule-dependent vesicle trafficking between ER and Golgi. Our results demonstrate a role of cytoplasmic dynein and microtubules in motility, but not peripheral localization of the ER in U. maydis.
authors.affiliation: Max-Planck-Institut für terrestrische Mikrobiologie, Karl-von-Frisch-Strasse, D-35043 Marburg, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Wedlich-Söldner
authors.forename: Irene
authors.initials: I
authors.lastname: Schulz
authors.forename: Anne
authors.initials: A
authors.lastname: Straube
authors.forename: Gero
authors.initials: G
authors.lastname: Steinberg
mesh_terms: D020126:Brefeldin A / Q000494:pharmacology; D016764:Cell Polarity; D056445:Cytoplasmic Dyneins; D022162:Cytoplasmic Vesicles / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D004398:Dyneins / Q000235:genetics / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005456:Fluorescent Dyes / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000378:metabolism*; D009685:Nuclear Envelope / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D014588:Ustilago / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D005456:Fluorescent Dyes; D005656:Fungal Proteins; D008164:Luminescent Proteins; D020409:Molecular Motor Proteins; D011500:Protein Synthesis Inhibitors; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins; D020126:Brefeldin A; C060755:YPT1 protein, S cerevisiae; D056445:Cytoplasmic Dyneins; D004398:Dyneins; D020691:rab GTP-Binding Proteins