title: Arabidopsis CBL-Interacting Protein Kinases Regulate Carbon/Nitrogen-Nutrient Response by Phosphorylating Ubiquitin Ligase ATL31.
abstract: In response to the ratio of available carbon (C) and nitrogen (N) nutrients, plants regulate their metabolism, growth, and development, a process called the C/N-nutrient response. However, the molecular basis of C/N-nutrient signaling remains largely unclear. In this study, we identified three CALCINEURIN B-LIKE (CBL)-INTERACTING PROTEIN KINASES (CIPKs), CIPK7, CIPK12, and CIPK14, as key regulators of the C/N-nutrient response during the post-germination growth in Arabidopsis. Single-knockout mutants of CIPK7, CIPK12, and CIPK14 showed hypersensitivity to high C/low N conditions, which was enhanced in their triple-knockout mutant, indicating that they play a negative role and at least partly function redundantly in the C/N-nutrient response. Moreover, these CIPKs were found to regulate the function of ATL31, a ubiquitin ligase involved in the C/N-nutrient response via the phosphorylation-dependent ubiquitination and proteasomal degradation of 14-3-3 proteins. CIPK7, CIPK12, and CIPK14 physically interacted with ATL31, and CIPK14, acting with CBL8, directly phosphorylated ATL31 in a Ca2+-dependent manner. Further analyses showed that these CIPKs are required for ATL31 phosphorylation and stabilization, which mediates the degradation of 14-3-3 proteins in response to C/N-nutrient conditions. These findings provide new insights into C/N-nutrient signaling mediated by protein phosphorylation.
authors.affiliation: Faculty of Science and Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Shigetaka
authors.initials: S
authors.lastname: Yasuda
authors.affiliation: Faculty of Science and Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Shoki
authors.initials: S
authors.lastname: Aoyama
authors.affiliation: Faculty of Science and Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Hasegawa
authors.affiliation: Faculty of Science and Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan. Electronic address: t-satou@sci.hokudai.ac.jp.
authors.forename: Takeo
authors.initials: T
authors.lastname: Sato
authors.affiliation: Faculty of Science and Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Yamaguchi
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D009584:Nitrogen / Q000378:metabolism; D010766:Phosphorylation; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D002244:Carbon; D009584:Nitrogen; D017346:Protein Serine-Threonine Kinases; D044767:Ubiquitin-Protein Ligases; C547213:ATL31 protein, Arabidopsis; C000605949:CIPK12 protein, Arabidopsis; C000608160:CIPK7 protein, Arabidopsis; C490996:At5g01820 protein, Arabidopsis
keywords: Arabidopsis; nutrient response; protein phosphorylation; signal transduction; ubiquitin ligase