title: The Membrane-Associated Sec1/Munc18 KEULE is Required for Phragmoplast Microtubule Reorganization During Cytokinesis in Arabidopsis.
abstract: Cytokinesis, the partitioning of the cytoplasm following nuclear division, requires extensive coordination between membrane trafficking and cytoskeletal dynamics. In plants, the onset of cytokinesis is characterized by the assembly of a bipolar microtubule array, the phragmoplast, and of a transient membrane compartment, the cell plate. Little is known about the coordination between membrane deposition at the cell plate and the dynamics of phragmoplast microtubules. In this study, we monitor the localization dynamics of microtubule and membrane markers throughout cytokinesis. Our spatiotemporal resolution is consistent with the general view that microtubule dynamics drive membrane movements. Nonetheless, we provide evidence for active sorting at the cell plate and show that this is, at least in part, mediated by the TRAPPII tethering complex. We also characterize phragmoplast microtubule organization and cell plate formation in a suite of cytokinesis-defective mutants. Of four mutant lines with defects in phragmoplast microtubule organization, only mor1 microtubule-associated mutants exhibited aberrant cell plates. Conversely, the mutants with the strongest impairment in phragmoplast microtubule reorganization are keule alleles, which have a primary defect in membrane fusion. Our findings identify the SEC1/Munc18 protein KEULE as a central regulatory node in the coordination of membrane and microtubule dynamics during plant cytokinesis.
authors.affiliation: Botany Department, School of Life Sciences, Technische Universität München, Emil-Ramann-Street 4, 85354 Freising, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Steiner
authors.affiliation: Botany Department, School of Life Sciences, Technische Universität München, Emil-Ramann-Street 4, 85354 Freising, Germany.
authors.forename: Lin
authors.initials: L
authors.lastname: Müller
authors.affiliation: Botany Department, School of Life Sciences, Technische Universität München, Emil-Ramann-Street 4, 85354 Freising, Germany.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Rybak
authors.affiliation: Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria.
authors.forename: Vera
authors.initials: V
authors.lastname: Vodermaier
authors.affiliation: Department Biologie I, Ludwig-Maximillians Universität, 82152 Planegg-Martinsried, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Facher
authors.affiliation: Botany Department, School of Life Sciences, Technische Universität München, Emil-Ramann-Street 4, 85354 Freising, Germany.
authors.forename: Martha
authors.initials: M
authors.lastname: Thellmann
authors.affiliation: Botany Department, School of Life Sciences, Technische Universität München, Emil-Ramann-Street 4, 85354 Freising, Germany.
authors.forename: Raksha
authors.initials: R
authors.lastname: Ravikumar
authors.affiliation: Department Biologie I, Ludwig-Maximillians Universität, 82152 Planegg-Martinsried, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Wanner
authors.affiliation: Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria.
authors.forename: Marie-Theres
authors.initials: MT
authors.lastname: Hauser
authors.affiliation: Botany Department, School of Life Sciences, Technische Universität München, Emil-Ramann-Street 4, 85354 Freising, Germany. Electronic address: farhah@wzw.tum.de.
authors.forename: Farhah F
authors.initials: FF
authors.lastname: Assaad
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D048749:Cytokinesis; D008870:Microtubules / Q000378:metabolism*; D051938:Munc18 Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D021381:Protein Transport
chemical_list: D051938:Munc18 Proteins
keywords: KEULE; KNOLLE; PLEIADE/MAP65-3; cell plate; cytokinesis; phragmoplast microtubule