title: The Arabidopsis mitogen-activated protein kinase 6 is associated with γ-tubulin on microtubules, phosphorylates EB1c and maintains spindle orientation under nitrosative stress.
abstract: Stress-activated plant mitogen-activated protein (MAP) kinase pathways play roles in growth adaptation to the environment by modulating cell division through cytoskeletal regulation, but the mechanisms are poorly understood. We performed protein interaction and phosphorylation experiments with cytoskeletal proteins, mass spectrometric identification of MPK6 complexes and immunofluorescence analyses of the microtubular cytoskeleton of mitotic cells using wild-type, mpk6-2 mutant and plants overexpressing the MAP kinase-inactivating phosphatase, AP2C3. We showed that MPK6 interacted with γ-tubulin and co-sedimented with plant microtubules polymerized in vitro. It was the active form of MAP kinase that was enriched with microtubules and followed similar dynamics to γ-tubulin, moving from poles to midzone during the anaphase-to-telophase transition. We found a novel substrate for MPK6, the microtubule plus end protein, EB1c. The mpk6-2 mutant was sensitive to 3-nitro-l-tyrosine (NO2 -Tyr) treatment with respect to mitotic abnormalities, and root cells overexpressing AP2C3 showed defects in chromosome segregation and spindle orientation. Our data suggest that the active form of MAP kinase interacts with γ-tubulin on specific subsets of mitotic microtubules during late mitosis. MPK6 phosphorylates EB1c, but not EB1a, and has a role in maintaining regular planes of cell division under stress conditions.
authors.affiliation: Institute of Microbiology AS CR, v.v.i., Vídeňská 1083, 142 20, Prague 4, Czech Republic.
authors.forename: Lucie
authors.initials: L
authors.lastname: Kohoutová
authors.affiliation: Institute of Microbiology AS CR, v.v.i., Vídeňská 1083, 142 20, Prague 4, Czech Republic.
authors.forename: Hana
authors.initials: H
authors.lastname: Kourová
authors.affiliation: Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Tűzoltó u. 37-47, H-1094, Budapest, Hungary.
authors.forename: Szilvia K
authors.initials: SK
authors.lastname: Nagy
authors.affiliation: Institute of Microbiology AS CR, v.v.i., Vídeňská 1083, 142 20, Prague 4, Czech Republic.
authors.forename: Jindřich
authors.initials: J
authors.lastname: Volc
authors.affiliation: Institute of Microbiology AS CR, v.v.i., Vídeňská 1083, 142 20, Prague 4, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Halada
authors.affiliation: Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Tűzoltó u. 37-47, H-1094, Budapest, Hungary.|Technical Analytical Research Group of HAS, Szent Gellért tér 4, H-1111, Budapest, Hungary.
authors.forename: Tamás
authors.initials: T
authors.lastname: Mészáros
authors.affiliation: Max F. Perutz Laboratories, University of Vienna, Vienna, Austria.|Institute of Biotechnology, University of Vilnius, Vilnius, Lithuania.
authors.forename: Irute
authors.initials: I
authors.lastname: Meskiene
authors.affiliation: School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, TW20 0EX, UK.
authors.forename: László
authors.initials: L
authors.lastname: Bögre
authors.affiliation: Institute of Microbiology AS CR, v.v.i., Vídeňská 1083, 142 20, Prague 4, Czech Republic.
authors.forename: Pavla
authors.initials: P
authors.lastname: Binarová
mesh_terms: D000705:Anaphase / Q000187:drug effects; D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002070:Butadienes / Q000494:pharmacology; D049109:Cell Proliferation / Q000187:drug effects; D020090:Chromosome Segregation / Q000187:drug effects; D048749:Cytokinesis / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D018386:Kinetochores / Q000187:drug effects / Q000378:metabolism; D018519:Meristem / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009570:Nitriles / Q000494:pharmacology; D015538:Nitrosation / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D059828:Plant Cells / Q000187:drug effects / Q000378:metabolism; D008941:Spindle Apparatus / Q000187:drug effects / Q000378:metabolism*; D013312:Stress, Physiological / Q000187:drug effects; D013692:Telophase / Q000187:drug effects; D014404:Tubulin / Q000378:metabolism*; D014443:Tyrosine / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D029681:Arabidopsis Proteins; D002070:Butadienes; C000602074:EB1c protein, Arabidopsis; D008869:Microtubule-Associated Proteins; D009570:Nitriles; D014404:Tubulin; C113580:U 0126; C002744:3-nitrotyrosine; D014443:Tyrosine; D048049:Extracellular Signal-Regulated MAP Kinases; C436293:MPK6 protein, Arabidopsis; D020928:Mitogen-Activated Protein Kinases
keywords: Arabidopsis; EB1c; MPK6; cell division; microtubules; mitogen-activated protein kinase; nitrosative stress; γ-tubulin