title: Intersubunit Concerted Cooperative and cis-Type Mechanisms Modulate Allosteric Gating in Two-Pore-Domain Potassium Channel TREK-2.
abstract: In response to diverse stimuli, two-pore-domain potassium channel TREK-2 regulates cellular excitability, and hence plays a key role in mediating neuropathic pain, mood disorders and ischemia through. Although more and more input modalities are found to achieve their modulations via acting on the channel, the potential role of subunit interaction in these modulations remains to be explored. In the current study, the deletion (lack of proximal C-terminus, ΔpCt) or point mutation (G312A) was introduced into TREK-2 subunits to limit K(+) conductance and used to report subunit stoichiometry. The constructs were then combined with wild type (WT) subunit to produce concatenated dimers with defined composition, and the gating kinetics of these channels to 2-Aminoethoxydiphenyl borate (2-APB) and extracellular pH (pHo) were characterized. Our results show that combination of WT and ΔpCt/G312A subunits reserves similar gating properties to that of WT dimmers, suggesting that the WT subunit exerts dominant and positive effects on the mutated one, and thus the two subunits controls channel gating via a concerted cooperative manner. Further introduction of ΔpCt into the latter subunit of heterodimeric channel G312A-WT or G312A-G312A attenuated their sensitivity to 2-APB and pHo alkalization, implicating that these signals were transduced by a cis-type mechanism. Together, our findings elucidate the mechanisms for how the two subunits control the pore gating of TREK-2, in which both intersubunit concerted cooperative and cis-type manners modulate the allosteric regulations induced by 2-APB and pHo alkalization.
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, 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 ToxicologyBeijing, China; Anesthesia and Operation Center, PLA General HospitalBeijing, 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, 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, China.
authors.forename: Hai-Tao
authors.initials: HT
authors.lastname: Yan
authors.affiliation: Department of Pharmacology, School of Pharmaceutical Sciences, Southern Medical University Guangzhou, 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, 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, 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, China.
authors.forename: Xiao-Yun
authors.initials: XY
authors.lastname: Ma
keywords: 2-APB; TREK-2; allosteric regulation; concatenated dimer; intersubunit interaction; two-pore domain potassium channel