title: The MAP kinase MPK4 is required for cytokinesis in Arabidopsis thaliana.
abstract: Cytokinesis in plants is achieved by the formation of the cell plate. A pathway that includes mitogen-activated protein (MAP) kinase kinase kinase and MAP kinase kinase (MAPKK) plays a key role in the control of plant cytokinesis. We show here that a MAP kinase, MPK4, is required for the formation of the cell plate in Arabidopsis thaliana. Single mutations in MPK4 caused dwarfism and characteristic defects in cytokinesis, such as immature cell plates, which became much more prominent upon introduction of a mutation in MKK6/ANQ, the MAPKK for cytokinesis, into mpk4. MKK6/ANQ strongly activated MPK4 in protoplasts, and kinase activity of MPK4 was detected in wild-type tissues that contained dividing cells but not in mkk6/anq mutants. Fluorescent protein-fused MPK4 localized to the expanding cell plates in cells of root tips. Expansion of the cell plates in mpk4 root tips appeared to be retarded. The level of MPK11 transcripts was markedly elevated in mpk4 plants, and defects in the mpk4 mpk11 double mutant with respect to growth and cytokinesis were more severe than in the corresponding single mutants. These results indicate that MPK4 is the downstream target of MKK6/ANQ in the regulation of cytokinesis in Arabidopsis and that MPK11 is also involved in cytokinesis.
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Kosetsu
authors.forename: Sachihiro
authors.initials: S
authors.lastname: Matsunaga
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Nakagami
authors.forename: Jean
authors.initials: J
authors.lastname: Colcombet
authors.forename: Michiko
authors.initials: M
authors.lastname: Sasabe
authors.forename: Takashi
authors.initials: T
authors.lastname: Soyano
authors.forename: Yuji
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Heribert
authors.initials: H
authors.lastname: Hirt
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Machida
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000166:cytology* / Q000201:enzymology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D048749:Cytokinesis / Q000502:physiology*; D048669:MAP Kinase Kinase 6 / Q000235:genetics / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010641:Phenotype; D018517:Plant Roots / Q000166:cytology / Q000201:enzymology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D014018:Tissue Distribution
chemical_list: D029681:Arabidopsis Proteins; D011993:Recombinant Fusion Proteins; C436292:AtMPK4 protein, Arabidopsis; C557478:MPK11 protein, Arabidopsis; D020928:Mitogen-Activated Protein Kinases; D048669:MAP Kinase Kinase 6; D020929:Mitogen-Activated Protein Kinase Kinases