title: Arabidopsis MPK6 is involved in cell division plane control during early root development, and localizes to the pre-prophase band, phragmoplast, trans-Golgi network and plasma membrane.
abstract: The proper spatial and temporal expression and localization of mitogen-activated protein kinases (MAPKs) is essential for developmental and cellular signalling in all eukaryotes. Here, we analysed expression, subcellular localization and function of MPK6 in roots of Arabidopsis thaliana using wild-type plants and three mpk6 knock-out mutant lines. The MPK6 promoter showed two expression maxima in the most apical part of the root meristem and in the root transition zone. This expression pattern was highly consistent with 'no root' and 'short root' phenotypes, as well as with ectopic cell divisions and aberrant cell division planes, resulting in disordered cell files in the roots of these mpk6 knock-out mutants. In dividing root cells, MPK6 was localized on the subcellular level to distinct fine spots in the pre-prophase band and phragmoplast, representing the two most important cytoskeletal structures controlling the cell division plane. By combining subcellular fractionation and microscopic in situ and in vivo co-localization methods, MPK6 was localized to the plasma membrane (PM) and the trans-Golgi network (TGN). In summary, these data suggest that MPK6 localizing to mitotic microtubules, secretory TGN vesicles and the PM is involved in cell division plane control and root development in Arabidopsis.
authors.affiliation: Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, 53115 Bonn, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Müller
authors.forename: Martina
authors.initials: M
authors.lastname: Beck
authors.forename: Ursula
authors.initials: U
authors.lastname: Mettbach
authors.forename: George
authors.initials: G
authors.lastname: Komis
authors.forename: Gerd
authors.initials: G
authors.lastname: Hause
authors.forename: Diedrik
authors.initials: D
authors.lastname: Menzel
authors.forename: Jozef
authors.initials: J
authors.lastname: Samaj
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division; D002462:Cell Membrane / Q000378:metabolism* / Q000648:ultrastructure; D003600:Cytosol / Q000378:metabolism / Q000648:ultrastructure; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D015151:Immunoblotting; D018519:Meristem / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D008861:Microsomes / Q000378:metabolism / Q000648:ultrastructure; D008870:Microtubules / Q000378:metabolism / Q000648:ultrastructure; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D011418:Prophase; D020133:Reverse Transcriptase Polymerase Chain Reaction; D021601:trans-Golgi Network / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D029681:Arabidopsis Proteins; D049452:Green Fluorescent Proteins; C436293:MPK6 protein, Arabidopsis; D020928:Mitogen-Activated Protein Kinases; D005966:Glucuronidase