title: Abscisic acid inhibits type 2C protein phosphatases via the PYR/PYL family of START proteins.
abstract: Type 2C protein phosphatases (PP2Cs) are vitally involved in abscisic acid (ABA) signaling. Here, we show that a synthetic growth inhibitor called pyrabactin functions as a selective ABA agonist. Pyrabactin acts through PYRABACTIN RESISTANCE 1 (PYR1), the founding member of a family of START proteins called PYR/PYLs, which are necessary for both pyrabactin and ABA signaling in vivo. We show that ABA binds to PYR1, which in turn binds to and inhibits PP2Cs. We conclude that PYR/PYLs are ABA receptors functioning at the apex of a negative regulatory pathway that controls ABA signaling by inhibiting PP2Cs. Our results illustrate the power of the chemical genetic approach for sidestepping genetic redundancy.
authors.affiliation: Department of Botany and Plant Sciences, University of California at Riverside, Riverside, CA 92521, USA.
authors.forename: Sang-Youl
authors.initials: SY
authors.lastname: Park
authors.forename: Pauline
authors.initials: P
authors.lastname: Fung
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Nishimura
authors.forename: Davin R
authors.initials: DR
authors.lastname: Jensen
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Fujii
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhao
authors.forename: Shelley
authors.initials: S
authors.lastname: Lumba
authors.forename: Julia
authors.initials: J
authors.lastname: Santiago
authors.forename: Americo
authors.initials: A
authors.lastname: Rodrigues
authors.forename: Tsz-Fung F
authors.initials: TF
authors.lastname: Chow
authors.forename: Simon E
authors.initials: SE
authors.lastname: Alfred
authors.forename: Dario
authors.initials: D
authors.lastname: Bonetta
authors.forename: Ruth
authors.initials: R
authors.lastname: Finkelstein
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Provart
authors.forename: Darrell
authors.initials: D
authors.lastname: Desveaux
authors.forename: Pedro L
authors.initials: PL
authors.lastname: Rodriguez
authors.forename: Peter
authors.initials: P
authors.lastname: McCourt
authors.forename: Jian-Kang
authors.initials: JK
authors.lastname: Zhu
authors.forename: Julian I
authors.initials: JI
authors.lastname: Schroeder
authors.forename: Brian F
authors.initials: BF
authors.lastname: Volkman
authors.forename: Sean R
authors.initials: SR
authors.lastname: Cutler
mesh_terms: D000040:Abscisic Acid / Q000819:agonists / Q000378:metabolism*; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*; D017343:Genes, Plant; D018525:Germination / Q000187:drug effects; D008024:Ligands; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009281:Naphthalenes / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012639:Seeds / Q000254:growth & development / Q000378:metabolism; D015398:Signal Transduction; D013449:Sulfonamides / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; D008024:Ligands; D026901:Membrane Transport Proteins; D009281:Naphthalenes; C540976:AT4G17870 protein, Arabidopsis; D011993:Recombinant Fusion Proteins; D013449:Sulfonamides; C540973:pyrabactin; D000040:Abscisic Acid; C087434:ABI1 protein, Arabidopsis; C106443:ABI2 protein, Arabidopsis; C514757:HAB1 protein, Arabidopsis; D010749:Phosphoprotein Phosphatases