title: Mitogen-Activated Protein Kinase Kinase 3 Is Required for Regulation during Dark-Light Transition.
abstract: Plant growth and development are coordinately orchestrated by environmental cues and phytohormones. Light acts as a key environmental factor for fundamental plant growth and physiology through photosensory phytochromes and underlying molecular mechanisms. Although phytochromes are known to possess serine/threonine protein kinase activities, whether they trigger a signal transduction pathway via an intracellular protein kinase network remains unknown. In analyses of mitogen-activated protein kinase kinase (MAPKK, also called MKK) mutants, the mkk3 mutant has shown both a hypersensitive response in plant hormone gibberellin (GA) and a less sensitive response in red light signaling. Surprisingly, light-induced MAPK activation in wild-type (WT) seedlings and constitutive MAPK phosphorylation in dark-grown mkk3 mutant seedlings have also been found, respectively. Therefore, this study suggests that MKK3 acts in negative regulation in darkness and in light-induced MAPK activation during dark-light transition.
authors.affiliation: Department of Pre-PharmMed, College of Natural Sciences, Duksung Women's University, Seoul 132-714, Korea.
authors.forename: Horim
authors.initials: H
authors.lastname: Lee
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D005875:Gibberellins / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010766:Phosphorylation; D017440:Photoperiod
chemical_list: D005875:Gibberellins; D020929:Mitogen-Activated Protein Kinase Kinases
keywords: Arabidopsis; MAP kinase kinase; MAPK cascade; gibberellin; light