Abscisic acid inhibits PP2Cs via the PYR/PYL family of ABA-binding START proteins

By Sang-Youl Park, Pauline Fung, N. Nishimura, Davin R. Jensen, Hiroaki Fujii, Yang Zhao, Shelley Lumba, J. Santiago, Américo Rodrigues, T. F. Chow and 11 more. Science, 2009

2,732 citations recorded by the source corpus.

ABA Receptor Rumbled? The plant hormone abscisic acid (ABA) is critical for normal development and for mediating plant responses to stressful environmental conditions. Now, two papers present analyses of candidate ABA receptors (see the news story by Pennisi). Ma et al. (p. 1064; published online 30 April) and Park et al. (p. 1068, published online 30 April) used independent strategies to search for proteins that physically interact with ABI family phosphatase components of the ABA response signaling pathway. Both groups identified different members of the same family of proteins, which appear to interact with ABI proteins to form a heterocomplex that can act as the ABA receptor. The variety of both families suggests that the ABA receptor may not be one entity, but rather a class of closely related complexes, which may explain previous difficulties in establishing its identity. Links between two ancient multimember protein families signal responses to the plant hormone abscisic acid. 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.

Subfields: Plant Science

View Paper: https://www.semanticscholar.org/paper/74d01196394e46a20855847eb33a923402658cc7

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Citations in the corpus

PDR-type ABC transporter mediates cellular uptake of the phytohormone abscisic acid (2010, background): “The very recent discovery of a class of soluble ABA receptors is in perfect agreement with our results (12, 13).”
Genome-wide responses to drought in forest trees (2011, methodology): “More recently, using a chemical screen technique, Park et al. (2009) identified a protein, pyrabactin resistant 1 (PYR1), which is involved in ABA signalling.”
Type 2C protein phosphatases directly regulate abscisic acid-activated protein kinases in Arabidopsis (2009, background): “Based on these findings, a model was hypothesized in which RCAR/PYR and PP2C negatively regulate SnRK2 (7).”
Abscisic Acid Plays an Important Role in the Regulation of Strawberry Fruit Ripening1[W][OA] (2011, background): “…PYR1-PP2C-SnRK2 core signaling network, in which ABA promotes the interaction of PYR1 and PP2C, resulting in PP2C inhibition and SnRK2 activation, which transduces ABA signals through the phosphorylation of downstream factors such as AREB/ABF (Fujii et al., 2009; Ma et al., 2009; Park et al., 2009.”
Guard Cell Signal Transduction Network: Advances in Understanding Abscisic Acid, CO2, and Ca2+ Signaling (2010, methodology): “and ABI1 (ABA-INSENSITIVE 1) was also confirmed in tobacco (139) and in Arabidopsis (132).”
Effects of abiotic stress on plants: a systems biology perspective (2011, background): “The current model of ABA signaling includes three core components, receptors (PYR/PYL/RCAR), protein phosphatases (PP2C) and protein kinases (SnRK2/OST1) [38,39].”
Integration of Brassinosteroid Signal Transduction with the Transcription Network for Plant Growth Regulation in Arabidopsis (2010, neutral): “Some of the BRBT genes encode key components of other hormone pathways, including the ABA receptor PYR1 (Park et al., 2009), several ethylene-signaling components (CTR1, EIL1, EBF2, and ERFs) (Stepanova and Alonso, 2009); a large number of components of the auxin pathway (Chapman and Estelle, 2009);”
Comprehending crystalline β-carotene accumulation by comparing engineered cell models and the natural carotenoid-rich system of citrus (2011, neutral): “In addition to this hypothetical model, binding of PP2Cs to the ABA receptor has already been demonstrated (Park et al., 2009; for review, see Cutler et al., 2010).”