7wnq
From Proteopedia
Cryo-EM structure of AtSLAC1 S59A mutant
Structural highlights
FunctionSLAC1_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 PubMedStomata 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. Loading citation details.. Citations No citations found References
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