title: Molecular basis for the selective and ABA-independent inhibition of PP2CA by PYL13.
abstract: PYR1/PYL/RCAR family proteins (PYLs) are well-characterized abscisic acid (ABA) receptors. Among the 14 PYL members in Arabidopsis thaliana, PYL13 is ABA irresponsive and its function has remained elusive. Here, we show that PYL13 selectively inhibits the phosphatase activity of PP2CA independent of ABA. The crystal structure of PYL13-PP2CA complex, which was determined at 2.4 Å resolution, elucidates the molecular basis for the specific recognition between PP2CA and PYL13. In addition to the canonical interactions between PYLs and PP2Cs, an extra interface is identified involving an element in the vicinity of a previously uncharacterized CCCH zinc-finger (ZF) motif in PP2CA. Sequence blast identified another 56 ZF-containing PP2Cs, all of which are from plants. The structure also reveals the molecular determinants for the ABA irresponsiveness of PYL13. Finally, biochemical analysis suggests that PYL13 may hetero-oligomerize with PYL10. These two PYLs antagonize each other in their respective ABA-independent inhibitions of PP2Cs. The biochemical and structural studies provide important insights into the function of PYL13 in the stress response of plant and set up a foundation for future biotechnological applications of PYL13.
authors.affiliation: 1] State Key Laboratory of Bio-membrane and Membrane Biotechnology, Tsinghua University, Beijing 100084, China [2] Center for Structural Biology, School of Medicine and School of Life Sciences, Tsinghua University, Beijing 100084, China [3] Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Wenqi
authors.initials: W
authors.lastname: Li
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Xinlei
authors.initials: X
authors.lastname: Sheng
authors.forename: Chuangye
authors.initials: C
authors.lastname: Yan
authors.forename: Rui
authors.initials: R
authors.lastname: Zhou
authors.forename: Jing
authors.initials: J
authors.lastname: Hang
authors.forename: Ping
authors.initials: P
authors.lastname: Yin
authors.forename: Nieng
authors.initials: N
authors.lastname: Yan
mesh_terms: D000040:Abscisic Acid / Q000737:chemistry / Q000378:metabolism*; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D018360:Crystallography, X-Ray; D008969:Molecular Sequence Data; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D016335:Zinc Fingers
chemical_list: D029681:Arabidopsis Proteins; D000040:Abscisic Acid; C463465:AHG3 protein, Arabidopsis; D010749:Phosphoprotein Phosphatases