| Structural highlights
Function
SLAC1_ARATH Slow, weak voltage-dependent S-type anion efflux channel involved in maintenance of anion homeostasis. Cl(-) efflux through SLAC1 causes membrane depolarization, which activates outward-rectifying K1 channels, leading to KCl and water efflux to reduce turgor further and cause stomatal closure, that reduces water loss and promotes leaf turgor. Essential for stomatal closure in response to CO(2), abscisic acid (ABA), ozone O(3), light/dark transitions, humidity change, calcium ions, hydrogen peroxide H(2)O(2), reactive oxygen species (ROS), and nitric oxide. Binds to the highly selective inward-rectifying potassium channels KAT1 and AKT2, and inhibits their activities. Functions as an essential negative regulator of inward potassium channels in guard cells. Essential for the efficient stomatal closure and opening in guard cells (PubMed:27002025). Involved in the local and/or systemic stomatal responses (e.g. stomatal closure) to light stress (PubMed:29463779).[1] [2] [3] [4] [5] [6] [7] [8] [9] [10]
Publication Abstract from PubMed
Stomata play a critical role in the regulation of gas exchange and photosynthesis in plants. Stomatal closure participates in multiple stress responses, and is regulated by a complex network including abscisic acid (ABA) signaling and ion-flux-induced turgor changes. The slow-type anion channel SLAC1 has been identified to be a central controller of stomatal closure and phosphoactivated by several kinases. Here, we report the structure of SLAC1 in Arabidopsis thaliana (AtSLAC1) in an inactivated, closed state. The cytosolic amino (N)-terminus and carboxyl (C)-terminus of AtSLAC1 are partially resolved and form a plug-like structure which packs against the transmembrane domain (TMD). Breaking the interactions between the cytosolic plug and transmembrane domain triggers channel activation. An inhibition-release model is proposed for SLAC1 activation by phosphorylation that the cytosolic plug dissociates from the transmembrane domain upon phosphorylation, and induces conformational changes to open the pore. These findings facilitate our understanding of the regulation of SLAC1 activity and stomatal aperture in plants.
Structure of the Arabidopsis guard cell anion channel SLAC1 suggests activation mechanism by phosphorylation.,Li Y, Ding Y, Qu L, Li X, Lai Q, Zhao P, Gao Y, Xiang C, Cang C, Liu X, Sun L Nat Commun. 2022 May 6;13(1):2511. doi: 10.1038/s41467-022-30253-3. PMID:35523967[11]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
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- ↑ Negi J, Matsuda O, Nagasawa T, Oba Y, Takahashi H, Kawai-Yamada M, Uchimiya H, Hashimoto M, Iba K. CO2 regulator SLAC1 and its homologues are essential for anion homeostasis in plant cells. Nature. 2008 Mar 27;452(7186):483-6. doi: 10.1038/nature06720. Epub 2008 Feb 27. PMID:18305482 doi:http://dx.doi.org/10.1038/nature06720
- ↑ Vahisalu T, Kollist H, Wang YF, Nishimura N, Chan WY, Valerio G, Lamminmaki A, Brosche M, Moldau H, Desikan R, Schroeder JI, Kangasjarvi J. SLAC1 is required for plant guard cell S-type anion channel function in stomatal signalling. Nature. 2008 Mar 27;452(7186):487-91. doi: 10.1038/nature06608. Epub 2008 Feb 27. PMID:18305484 doi:http://dx.doi.org/10.1038/nature06608
- ↑ Geiger D, Scherzer S, Mumm P, Stange A, Marten I, Bauer H, Ache P, Matschi S, Liese A, Al-Rasheid KA, Romeis T, Hedrich R. Activity of guard cell anion channel SLAC1 is controlled by drought-stress signaling kinase-phosphatase pair. Proc Natl Acad Sci U S A. 2009 Dec 15;106(50):21425-30. doi:, 10.1073/pnas.0912021106. Epub 2009 Dec 2. PMID:19955405 doi:10.1073/pnas.0912021106
- ↑ Lee SC, Lan W, Buchanan BB, Luan S. A protein kinase-phosphatase pair interacts with an ion channel to regulate ABA signaling in plant guard cells. Proc Natl Acad Sci U S A. 2009 Dec 15;106(50):21419-24. doi:, 10.1073/pnas.0910601106. Epub 2009 Dec 2. PMID:19955427 doi:http://dx.doi.org/10.1073/pnas.0910601106
- ↑ Vahisalu T, Puzorjova I, Brosche M, Valk E, Lepiku M, Moldau H, Pechter P, Wang YS, Lindgren O, Salojarvi J, Loog M, Kangasjarvi J, Kollist H. Ozone-triggered rapid stomatal response involves the production of reactive oxygen species, and is controlled by SLAC1 and OST1. Plant J. 2010 May;62(3):442-53. doi: 10.1111/j.1365-313X.2010.04159.x. Epub 2010 , Feb 1. PMID:20128877 doi:http://dx.doi.org/10.1111/j.1365-313X.2010.04159.x
- ↑ Ache P, Bauer H, Kollist H, Al-Rasheid KA, Lautner S, Hartung W, Hedrich R. Stomatal action directly feeds back on leaf turgor: new insights into the regulation of the plant water status from non-invasive pressure probe measurements. Plant J. 2010 Jun 1;62(6):1072-82. doi: 10.1111/j.1365-313X.2010.04213.x. Epub, 2010 Mar 25. PMID:20345603 doi:http://dx.doi.org/10.1111/j.1365-313X.2010.04213.x
- ↑ Zhang A, Ren HM, Tan YQ, Qi GN, Yao FY, Wu GL, Yang LW, Hussain J, Sun SJ, Wang YF. S-type Anion Channels SLAC1 and SLAH3 Function as Essential Negative Regulators of Inward K+ Channels and Stomatal Opening in Arabidopsis. Plant Cell. 2016 Apr;28(4):949-955. doi: 10.1105/tpc.16.01050. Epub 2016 Mar 21. PMID:27002025 doi:http://dx.doi.org/10.1105/tpc.16.01050
- ↑ Devireddy AR, Zandalinas SI, Gomez-Cadenas A, Blumwald E, Mittler R. Coordinating the overall stomatal response of plants: Rapid leaf-to-leaf communication during light stress. Sci Signal. 2018 Feb 20;11(518). pii: 11/518/eaam9514. doi:, 10.1126/scisignal.aam9514. PMID:29463779 doi:http://dx.doi.org/10.1126/scisignal.aam9514
- ↑ Negi J, Matsuda O, Nagasawa T, Oba Y, Takahashi H, Kawai-Yamada M, Uchimiya H, Hashimoto M, Iba K. CO2 regulator SLAC1 and its homologues are essential for anion homeostasis in plant cells. Nature. 2008 Mar 27;452(7186):483-6. doi: 10.1038/nature06720. Epub 2008 Feb 27. PMID:18305482 doi:http://dx.doi.org/10.1038/nature06720
- ↑ Li Y, Ding Y, Qu L, Li X, Lai Q, Zhao P, Gao Y, Xiang C, Cang C, Liu X, Sun L. Structure of the Arabidopsis guard cell anion channel SLAC1 suggests activation mechanism by phosphorylation. Nat Commun. 2022 May 6;13(1):2511. doi: 10.1038/s41467-022-30253-3. PMID:35523967 doi:http://dx.doi.org/10.1038/s41467-022-30253-3
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