title: Regulators of PP2C phosphatase activity function as abscisic acid sensors.
abstract: The plant hormone abscisic acid (ABA) acts as a developmental signal and as an integrator of environmental cues such as drought and cold. Key players in ABA signal transduction include the type 2C protein phosphatases (PP2Cs) ABI1 and ABI2, which act by negatively regulating ABA responses. In this study, we identify interactors of ABI1 and ABI2 which we have named regulatory components of ABA receptor (RCARs). In Arabidopsis, RCARs belong to a family with 14 members that share structural similarity with class 10 pathogen-related proteins. RCAR1 was shown to bind ABA, to mediate ABA-dependent inactivation of ABI1 or ABI2 in vitro, and to antagonize PP2C action in planta. Other RCARs also mediated ABA-dependent regulation of ABI1 and ABI2, consistent with a combinatorial assembly of receptor complexes.
authors.affiliation: Lehrstuhl für Botanik, Technische Universität München, Am Hochanger 4, D-85354 Freising, Germany.
authors.forename: Yue
authors.initials: Y
authors.lastname: Ma
authors.forename: Izabela
authors.initials: I
authors.lastname: Szostkiewicz
authors.forename: Arthur
authors.initials: A
authors.lastname: Korte
authors.forename: Danièle
authors.initials: D
authors.lastname: Moes
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
authors.forename: Alexander
authors.initials: A
authors.lastname: Christmann
authors.forename: Erwin
authors.initials: E
authors.lastname: Grill
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism* / Q000494:pharmacology; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D018525:Germination; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000254:growth & development; D054046:Plant Stomata / Q000502:physiology; D030821:Plants, Genetically Modified; D017354:Point Mutation; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction; D013237:Stereoisomerism; D015854:Up-Regulation
chemical_list: D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; C540972:RCAR1 protein, Arabidopsis; D011993:Recombinant Fusion Proteins; D000040:Abscisic Acid; C087434:ABI1 protein, Arabidopsis; C106443:ABI2 protein, Arabidopsis; D010749:Phosphoprotein Phosphatases