Abscisic acid inhibits type 2C protein phosphatases via the PYR/PYL family of START proteins.
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.
Park
Sang-Youl
SY
Department of Botany and Plant Sciences, University of California at Riverside, Riverside, CA 92521, USA.
Fung
Pauline
P
Nishimura
Noriyuki
N
Jensen
Davin R
DR
Fujii
Hiroaki
H
Zhao
Yang
Y
Lumba
Shelley
S
Santiago
Julia
J
Rodrigues
Americo
A
Chow
Tsz-Fung F
TF
Alfred
Simon E
SE
Bonetta
Dario
D
Finkelstein
Ruth
R
Provart
Nicholas J
NJ
Desveaux
Darrell
D
Rodriguez
Pedro L
PL
McCourt
Peter
P
Zhu
Jian-Kang
JK
Schroeder
Julian I
JI
Volkman
Brian F
BF
Cutler
Sean R
SR
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
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