title: Tobacco mosaic virus movement protein functions as a structural microtubule-associated protein.
abstract: The cell-to-cell spread of Tobacco mosaic virus infection depends on virus-encoded movement protein (MP), which is believed to form a ribonucleoprotein complex with viral RNA (vRNA) and to participate in the intercellular spread of infectious particles through plasmodesmata. Previous studies in our laboratory have provided evidence that the vRNA movement process is correlated with the ability of the MP to interact with microtubules, although the exact role of this interaction during infection is not known. Here, we have used a variety of in vivo and in vitro assays to determine that the MP functions as a genuine microtubule-associated protein that binds microtubules directly and modulates microtubule stability. We demonstrate that, unlike MP in whole-cell extract, microtubule-associated MP is not ubiquitinated, which strongly argues against the hypothesis that microtubules target the MP for degradation. In addition, we found that MP interferes with kinesin motor activity in vitro, suggesting that microtubule-associated MP may interfere with kinesin-driven transport processes during infection.
authors.affiliation: Institut de Biologie Moléculaire des Plantes, Strasbourg, France.
authors.forename: Jamie
authors.initials: J
authors.lastname: Ashby
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Boutant
authors.forename: Mark
authors.initials: M
authors.lastname: Seemanpillai
authors.forename: Anna
authors.initials: A
authors.lastname: Groner
authors.forename: Adrian
authors.initials: A
authors.lastname: Sambade
authors.forename: Christophe
authors.initials: C
authors.lastname: Ritzenthaler
authors.forename: Manfred
authors.initials: M
authors.lastname: Heinlein
mesh_terms: D002478:Cells, Cultured; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D016547:Kinesins / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism; D053830:Plant Viral Movement Proteins; D011523:Protoplasts / Q000821:virology; D014026:Nicotiana / Q000821:virology; D014027:Tobacco Mosaic Virus / Q000378:metabolism / Q000472:pathogenicity*; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D008869:Microtubule-Associated Proteins; D053830:Plant Viral Movement Proteins; D014764:Viral Proteins; D049452:Green Fluorescent Proteins; D016547:Kinesins