Structural basis for malate-driven, pore lipid-regulated activation of the Arabidopsis vacuolar anion channel ALMT9
In plant cells, ALMTs are key plasma and vacuolar membrane-localized anion channels regulating plant responses to the environment. Vacuolar ALMTs control anion accumulation in plant cells and, in guard cells, they regulate stomata aperture. The activation of vacuolar ALMTs depends on voltage and cytosolic malate, but the underlying molecular mechanisms remain elusive. Here we report the cryo-EM structures of ALMT9 from Arabidopsis thaliana (AtALMT9), a malate-activated vacuolar anion channel, in plugged and unplugged lipid-bound states. In all these states, membrane lipids interact with the ion conduction pathway of AtALMT9. We identify two unplugged states presenting two distinct pore width profiles. Combining structural and functional analysis we identified conserved residues involved in ion conduction and in the pore lipid interaction. Molecular dynamics simulations revealed a peculiar anion conduction mechanism in AtALMT9. We propose a voltage-dependent activation mechanism based on the competition between pore lipids and malate at the cytosolic entrance of the channel.
Authors
- Sangho Lee (ORCID: https://orcid.org/0000-0003-3886-4579)
- Yeongmok Lee (ORCID: https://orcid.org/0000-0002-7492-1043)
- Jejoong Yoo (ORCID: https://orcid.org/0000-0001-7120-8464)
- Elsa Demes (ORCID: https://orcid.org/0000-0002-8386-7763)
- Justyna Jaślan (ORCID: https://orcid.org/0000-0002-1620-912X)
- Geum‐Sook Hwang (ORCID: https://orcid.org/0000-0002-1600-1556)
- Seo Young Jang (ORCID: https://orcid.org/0000-0002-1529-2427)
- Alexis De Angeli (ORCID: https://orcid.org/0000-0003-3072-7932)
- Seoyeon Jung (ORCID: https://orcid.org/0009-0000-1471-6876)
- Jin-Kyoun Yoo
Institutions
- Centre National de la Recherche Scientifique (FR)
- Université de Montpellier (FR)
- Institut Agro Montpellier (FR)
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (FR)
- Korea Basic Science Institute (KR)
- Institut des Sciences des Plantes de Montpellier (FR)
- L'Institut Agro (FR)
- Chung-Ang University (KR)
- Sungkyunkwan University (KR)
Publication Details
- Journal
- Nature Communications
- Published
- 2025-02-20
- DOI
- https://doi.org/10.1038/s41467-025-56940-5
- Citations
- 4
- Primary Topic
- Aluminum toxicity and tolerance in plants and animals
- Type
- article
- Field-Weighted Citation Impact
- 7.00
Funders
- National Research Foundation
- Agence Nationale de la Recherche
- Korea Institute of Science and Technology Information
- Korea Basic Science Institute
- National Research Foundation of Korea
- Centre National de la Recherche Scientifique
- Institute for Information and Communications Technology Promotion
- Great Southern Development Commission, Government of Western Australia
- National Supercomputing Center, Korea Institute of Science and Technology Information