title: Complex interactions among residues within pore region determine the K+ dependence of a KAT1-type potassium channel AmKAT1.
abstract: KAT1-type channels mediate K(+) influx into guard cells that enables stomatal opening. In this study, a KAT1-type channel AmKAT1 was cloned from the xerophyte Ammopiptanthus mongolicus. In contrast to most KAT1-type channels, its activation is strongly dependent on external K(+) concentration, so it can be used as a model to explore the mechanism for the K(+) -dependent gating of KAT1-type channels. Domain swapping between AmKAT1 and KAT1 reveals that the S5-pore-S6 region controls the K(+) dependence of AmKAT1, and residue substitutions show that multiple residues within the S5-Pore linker and Pore are involved in its K(+) -dependent gating. Importantly, complex interactions occur among these residues, and it is these interactions that determine its K(+) dependence. Finally, we analyzed the potential mechanism for the K(+) dependence of AmKAT1, which could originate from the requirement of K(+) occupancy in the selectivity filter to maintain its conductive conformation. These results provide new insights into the molecular basis of the K(+) -dependent gating of KAT1-type channels.
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71, East Beijing Road, Nanjing, 210008, China.
authors.forename: Guangzhe
authors.identifier: http://orcid.org/0000-0003-3691-0789
authors.initials: G
authors.lastname: Yang
authors.affiliation: Biochimie & Physiologie Moléculaire des Plantes, UMR 5004 CNRS/386 INRA/SupAgro Montpellier/Université Montpellier 2, Campus SupAgro-INRA, 34060, Montpellier Cedex 2, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Sentenac
authors.affiliation: Biochimie & Physiologie Moléculaire des Plantes, UMR 5004 CNRS/386 INRA/SupAgro Montpellier/Université Montpellier 2, Campus SupAgro-INRA, 34060, Montpellier Cedex 2, France.
authors.forename: Anne-Aliénor
authors.initials: AA
authors.lastname: Véry
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71, East Beijing Road, Nanjing, 210008, China.
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Su
mesh_terms: D029681:Arabidopsis Proteins / Q000502:physiology*; D015640:Ion Channel Gating / Q000235:genetics* / Q000502:physiology; D054046:Plant Stomata / Q000502:physiology*; D015221:Potassium Channels / Q000502:physiology*; D024661:Potassium Channels, Inwardly Rectifying / Q000502:physiology*
chemical_list: D029681:Arabidopsis Proteins; C501210:KAT1 protein, Arabidopsis; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying
keywords: Ammopiptanthus mongolicus; K+-dependent gating; KAT1-type channel; potassium channel; protein-cation interaction