NQK1/NtMEK1 is a MAPKK that acts in the NPK1 MAPKKK-mediated MAPK cascade and is required for plant cytokinesis
| Autor: | Masaki Ishikawa, Yasunori Machida, Kayoko Morikiyo, Takashi Soyano, Ryuichi Nishihama |
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| Rok vydání: | 2003 |
| Předmět: |
Cell division
MAP Kinase Signaling System Arabidopsis MAP Kinase Kinase 1 Mitosis Saccharomyces cerevisiae MAPK cascade Biology In Vitro Techniques Phragmoplast Microtubules Multinucleate Gene Expression Regulation Plant Two-Hybrid System Techniques Tobacco Genetics Animals Phosphorylation Plant Proteins Mitogen-Activated Protein Kinase Kinases Cell plate Cell cycle MAP Kinase Kinase Kinases Plants Genetically Modified Recombinant Proteins Cell biology Enzyme Activation Plants Toxic Rabbits Mitogen-Activated Protein Kinases Cytokinesis Cell Division Developmental Biology Research Paper |
| Zdroj: | Genesdevelopment. 17(8) |
| ISSN: | 0890-9369 |
| Popis: | The tobacco protein kinase NPK1 is a MAPKKK that regulates formation of the cell plate during cytokinesis. In the present study, we have identified tobacco NQK1/NtMEK1 and NRK1 as a MAPKK and a MAPK, respectively, downstream of NPK1. NQK1/NtMEK1 complements the mutation in thePBS2MAPKK gene of yeast in a manner that depends on both NPK1 and its activator, NACK1, a kinesin-like protein. Active NPK1 and NQK1/NtMEK1 phosphorylate and activate NQK1/NtMEK1 and NRK1, respectively. Both NQK1/NtMEK1 and NRK1, as well as NPK1, are activated at the late M phase of the cell cycle in tobacco cells, and they are rapidly inactivated by depolymerization of phragmoplast microtubules. These results suggest the existence of a MAPK cascade that consists of NPK1, NQK1/NtMEK1, and NRK1 and functions in a process related to the architecture of phragmoplasts at the late M phase of the cell cycle. Overexpression of kinase-negative NQK1/NtMEK1 in tobacco cells generates multinucleate cells with incomplete cross-walls.Arabidopsisplants with a mutation in theANQ1gene, an ortholog ofNQK1/NtMEK1, display a dwarf phenotype, with unusually large cells that contain multiple nuclei and cell-wall stubs in various organs. In addition,anq1homozygotes set fewer flowers and produce large and malformed pollen grains with a tetrad structure. Thus, NQK1/NtMEK1 (ANQ1) MAPKK appears to be a positive regulator of plant cytokinesis during meiosis as well as mitosis. |
| Databáze: | OpenAIRE |
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