title: Mitogen-activated protein kinase 4 is involved in the regulation of mitotic and cytokinetic microtubule transitions in Arabidopsis thaliana.
abstract: • A mitogen-activated protein kinase kinase kinase (MAPKKK) double mutant, Arabidopsis homologue of nucleus and phragmoplast associated kinase (anp) anp2anp3, and the mitogen-activated protein kinase (MAPK) 4 mutant mpk4 of Arabidopsis thaliana show prominent cytokinetic defects. This prompted the analysis of mitotic and cytokinetic progression as a function of MAPK signalling. Mutants were compared with wild types untreated or treated with the specific MAPKK inhibitor PD98059. • This study included phenotype analysis, expression analysis of the MPK4 promoter, immunofluorescent localization of MPK4, tubulin and MAP65-1, and time-lapse microscopic visualization of the mitotic microtubule (MT) transitions in control, mutant and inhibitor-treated cells. • Mutant and inhibitor-treated cells showed defects in mitosis and cytokinesis, including aberrant spindle and phragmoplast formation and drastically delayed or abortive mitosis and cytokinesis. As a result, bi- and multinucleate cells were formed, ultimately disturbing the vegetative tissue patterning. MPK4 was localized to all stages of the expanding phragmoplast, in a pattern similar to that of its putative substrate MAP65-1. • In this study, MPK4 is shown to be involved in the regulation of mitosis/cytokinesis through modulation of the cell division plane and cytokinetic progression.
authors.affiliation: Institut für Zelluläre und Molekulare Botanik, Universität Bonn, Kirschallee 1, D53115, Bonn, Germany.
authors.forename: Martina
authors.initials: M
authors.lastname: Beck
authors.affiliation: Institut für Zelluläre und Molekulare Botanik, Universität Bonn, Kirschallee 1, D53115, Bonn, Germany.|Institute of General Botany, Faculty of Biology, University of Athens, GR15784, Greece.
authors.forename: George
authors.initials: G
authors.lastname: Komis
authors.affiliation: Institut für Zelluläre und Molekulare Botanik, Universität Bonn, Kirschallee 1, D53115, Bonn, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Ziemann
authors.affiliation: Institut für Zelluläre und Molekulare Botanik, Universität Bonn, Kirschallee 1, D53115, Bonn, Germany.
authors.forename: Diedrik
authors.initials: D
authors.lastname: Menzel
authors.affiliation: Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University, 783 01 Olomouc, Czech Republic.
authors.forename: Jozef
authors.initials: J
authors.lastname: Šamaj
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D029681:Arabidopsis Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D048749:Cytokinesis / Q000187:drug effects; D005419:Flavonoids / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D021621:Imaging, Three-Dimensional; D018519:Meristem / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008938:Mitosis / Q000187:drug effects; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D008941:Spindle Apparatus / Q000187:drug effects / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D005419:Flavonoids; C492901:MAP65-1 protein, Arabidopsis; D008869:Microtubule-Associated Proteins; D047428:Protein Kinase Inhibitors; C436292:AtMPK4 protein, Arabidopsis; D020928:Mitogen-Activated Protein Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one