title: GSK3-like kinases positively modulate abscisic acid signaling through phosphorylating subgroup III SnRK2s in Arabidopsis.
abstract: Arabidopsis glycogen synthase kinase 3 (GSK3)-like kinases have versatile functions in plant development and in responding to abiotic stresses. Although physiological evidence suggested a potential role of GSK3-like kinases in abscisic acid (ABA) signaling, the underlying molecular mechanism was largely unknown. Here we identified members of Snf1-related kinase 2s (SnRK2s), SnRK2.2 and SnRK2.3, that can interact with and be phosphorylated by a GSK3-like kinase, brassinosteroid insensitive 2 (BIN2). bin2-3 bil1 bil2, a loss-of-function mutant of BIN2 and its two closest homologs, BIN2 like 1 (BIL1) and BIN2 like 2 (BIL2), was hyposensitive to ABA in primary root inhibition, ABA-responsive gene expression, and phosphorylating ABA Response Element Binding Factor (ABF) 2 fragment by in-gel kinase assays, whereas bin2-1, a gain-of-function mutation of BIN2, was hypersensitive to ABA, suggesting that these GSK3-like kinases function as positive regulators in ABA signaling. Furthermore, BIN2 phosphorylated SnRK2.3 on T180, and SnRK2.3(T180A) had decreased kinase activity in both autophosphorylation and phosphorylating ABFs. Bikinin, a GSK3 kinase inhibitor, inhibited the SnRK2.3 kinase activity and its T180 phosphorylation in vivo. Our genetic analysis further demonstrated that BIN2 regulates ABA signaling downstream of the PYRABACTIN RESISTANCE1/PYR1-LIKE/REGULATORY COMPONENTS OF ABA RECEPTORS receptors and clade A protein phosphatase 2C but relies on SnRK2.2 and SnRK2.3. These findings provide significant insight into the modulation of ABA signaling by Arabidopsis GSK3-like kinases.
authors.affiliation: State Key Laboratory of Genetic Engineering and Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, People's Republic of China;
authors.forename: Zhenying
authors.initials: Z
authors.lastname: Cai
authors.affiliation: State Key Laboratory of Genetic Engineering and Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, People's Republic of China;
authors.forename: Jingjing
authors.initials: J
authors.lastname: Liu
authors.affiliation: College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China;
authors.forename: Haijiao
authors.initials: H
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Genetic Engineering and Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, People's Republic of China;
authors.forename: Cangjing
authors.initials: C
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Genetic Engineering and Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, People's Republic of China;
authors.forename: Yuxiao
authors.initials: Y
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Genetic Engineering and Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, People's Republic of China;
authors.forename: Yongchi
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Biological Sciences, Michigan Technological University, Houghton, MI 49931; and.
authors.forename: Shanjin
authors.initials: S
authors.lastname: Pan
authors.affiliation: State Key Laboratory of Genetic Engineering and Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, People's Republic of China;
authors.forename: Rui
authors.initials: R
authors.lastname: Dong
authors.affiliation: Department of Biological Sciences, Michigan Technological University, Houghton, MI 49931; and.
authors.forename: Guiliang
authors.initials: G
authors.lastname: Tang
authors.affiliation: Molecular Plant Biology Unit, Department of Biochemistry, University of Turku, FIN-20014, Turku, Finland.
authors.forename: Juan de Dios
authors.initials: Jde D
authors.lastname: Barajas-Lopez
authors.affiliation: Molecular Plant Biology Unit, Department of Biochemistry, University of Turku, FIN-20014, Turku, Finland.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Fujii
authors.affiliation: State Key Laboratory of Genetic Engineering and Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, People's Republic of China;College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China; xlwang@mail.hzau.edu.cn.
authors.forename: Xuelu
authors.initials: X
authors.lastname: Wang
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D017360:Arabidopsis / Q000378:metabolism / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D034622:RNA Interference; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology*; D053719:Tandem Mass Spectrometry
chemical_list: D029681:Arabidopsis Proteins; C492978:SnRK2 protein, Arabidopsis; D000040:Abscisic Acid; D017346:Protein Serine-Threonine Kinases; D038362:Glycogen Synthase Kinase 3
keywords: kinase activation; phosphorylation cascades; signal transduction