Structure and Activity of SLAC1 Channels for Stomatal Signaling in Leaves

Overview

Journal Proc Natl Acad Sci U S A

Specialty Science

Date 2021 Apr 30

PMID 33926963

Citations 24

Authors

Ya-Nan Deng

Hamdy Kashtoh

Quan Wang

Guang-Xiao Zhen

Qi-Yu Li

Ling-Hui Tang

Hai-Long Gao

Chun-Rui Zhang

Li Qin

Min Su

Fei Li

Xia-He Huang

Ying-Chun Wang

Qi Xie

Oliver B Clarke

Wayne A Hendrickson

Yu-Hang Chen

Affiliations

Soon will be listed here.

Abstract

Stomata in leaves regulate gas exchange between the plant and its atmosphere. Various environmental stimuli elicit abscisic acid (ABA); ABA leads to phosphoactivation of slow anion channel 1 (SLAC1); SLAC1 activity reduces turgor pressure in aperture-defining guard cells; and stomatal closure ensues. We used electrophysiology for functional characterizations of SLAC1 (SLAC1) and cryoelectron microscopy (cryo-EM) for structural analysis of SLAC1 (SLAC1), at 2.97-Å resolution. We identified 14 phosphorylation sites in SLAC1 and showed nearly 330-fold channel-activity enhancement with 4 to 6 of these phosphorylated. Seven SLAC1-conserved arginines are poised in SLAC1 for regulatory interaction with the N-terminal extension. This SLAC1 structure has its pores closed, in a basal state, spring loaded by phenylalanyl residues in high-energy conformations. SLAC1 phosphorylation fine-tunes an equilibrium between basal and activated SLAC1 trimers, thereby controlling the degree of stomatal opening.

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