title: Allosteric coupling between proximal C-terminus and selectivity filter is facilitated by the movement of transmembrane segment 4 in TREK-2 channel.
abstract: TREK-2, a member of two-pore-domain potassium channel family, regulates cellular excitability in response to diverse stimuli. However, how such stimuli control channel function remains unclear. Here, by characterizing the responses of cytosolic proximal C-terminus deletant (ΔpCt) and transmembrane segment 4 (M4)-glycine hinge mutant (G312A) to 2-Aminoethoxydiphenyl borate (2-APB), an activator of TREK-2, we show that the transduction initiated from pCt domain is allosterically coupled with the conformation of selectivity filter (SF) via the movements of M4, without depending on the original status of SF. Moreover, ΔpCt and G312A also exhibited blunted responses to extracellular alkalization, a model to induce SF conformational transition. These results suggest that the coupling between pCt domain and SF is bidirectional, and M4 movements are involved in both processes. Further mechanistic exploration reveals that the function of Phe316, a residue close to the C-terminus of M4, is associated with such communications. However, unlike TREK-2, M4-hinge of TREK-1 only controls the transmission from pCt to SF, rather than SF conformational changes triggered by pHo changes. Together, our findings uncover the unique gating properties of TREK-2, and elucidate the mechanisms for how the extracellular and intracellular stimuli harness the pore gating allosterically.
authors.affiliation: State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
authors.forename: Ren-Gong
authors.initials: RG
authors.lastname: Zhuo
authors.affiliation: State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.|Anesthesia and Operation Center, PLA General Hospital, Beijing 100853, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Peng
authors.affiliation: State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
authors.forename: Hai-Tao
authors.initials: HT
authors.lastname: Yan
authors.affiliation: Department of Pharmacology, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China.
authors.forename: Jiang-Ping
authors.initials: JP
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
authors.forename: Jian-Quan
authors.initials: JQ
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Department of Biochemical Pharmacology, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
authors.forename: Xiao-Yun
authors.initials: XY
authors.lastname: Ma
mesh_terms: D000494:Allosteric Regulation; D000818:Animals; D005998:Glycine / Q000737:chemistry; D006801:Humans; D015640:Ion Channel Gating; D024683:Potassium Channels, Tandem Pore Domain / Q000737:chemistry / Q000378:metabolism*; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D020033:Protein Isoforms
chemical_list: C503438:KCNK10 protein, human; D024683:Potassium Channels, Tandem Pore Domain; D020033:Protein Isoforms; D005998:Glycine