Structural and functional insights into core ABA signaling

• Published in: Current opinion in plant biology 2010-10, Vol.13 (5), p.495-502
• Main Authors: Weiner, Joshua J, Peterson, Francis C, Volkman, Brian F, Cutler, Sean R
• Format: Article
• Language: English
• Subjects: Abscisic Acid - physiology; Arabidopsis - metabolism; Arabidopsis Proteins - metabolism; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Plant; Membrane Proteins - metabolism; Membrane Transport Proteins - metabolism; Phosphoprotein Phosphatases - metabolism; Phosphorylation; Protein Phosphatase 2C; Protein-Serine-Threonine Kinases - metabolism; Signal Transduction
• ISSN: 1369-5266; 1879-0356
• DOI: 10.1016/j.pbi.2010.09.007

[Display omitted] ▶ ABA signaling is controlled by soluble ABA receptors. ▶ ABA receptors PYR1, PYL1 and PYL2 are allosteric switches controlled by ABA binding. ▶ PYR/PYL receptors inhibit PP2C phosphatases, which leads to activation of SnRK2 kinases. ▶ SnRK2s phosphorylate downstream target proteins to regulate ABA responses. ▶ The ABA signaling pathway has been reconstituted in vitro. A series of papers in the last year reported major advances in our understanding of abscisic acid (ABA) signaling: the identification of soluble ABA receptors, the elucidation of a core ABA signaling pathway and structural insights into the mechanism of ABA perception and signaling. Here we summarize these advances, which have shown in atomic resolution that the ABA receptors PYR1, PYL1 and PYL2 function as allosteric switches that inhibit type 2C protein phosphatases (PP2Cs) in response to ABA. These receptors function at the apex of a core signaling pathway that regulates ABA responses by controlling SnRK2 kinase activity and the phosphorylation of downstream target proteins such as ABFs, which control nuclear responses, and the ion channel SLAC1, which mediates electrophysiological responses to ABA.