title: Positive Allosteric Modulation of Kv Channels by Sevoflurane: Insights into the Structural Basis of Inhaled Anesthetic Action.
abstract: Inhalational general anesthesia results from the poorly understood interactions of haloethers with multiple protein targets, which prominently includes ion channels in the nervous system. Previously, we reported that the commonly used inhaled anesthetic sevoflurane potentiates the activity of voltage-gated K+ (Kv) channels, specifically, several mammalian Kv1 channels and the Drosophila K-Shaw2 channel. Also, previous work suggested that the S4-S5 linker of K-Shaw2 plays a role in the inhibition of this Kv channel by n-alcohols and inhaled anesthetics. Here, we hypothesized that the S4-S5 linker is also a determinant of the potentiation of Kv1.2 and K-Shaw2 by sevoflurane. Following functional expression of these Kv channels in Xenopus oocytes, we found that converse mutations in Kv1.2 (G329T) and K-Shaw2 (T330G) dramatically enhance and inhibit the potentiation of the corresponding conductances by sevoflurane, respectively. Additionally, Kv1.2-G329T impairs voltage-dependent gating, which suggests that Kv1.2 modulation by sevoflurane is tied to gating in a state-dependent manner. Toward creating a minimal Kv1.2 structural model displaying the putative sevoflurane binding sites, we also found that the positive modulations of Kv1.2 and Kv1.2-G329T by sevoflurane and other general anesthetics are T1-independent. In contrast, the positive sevoflurane modulation of K-Shaw2 is T1-dependent. In silico docking and molecular dynamics-based free-energy calculations suggest that sevoflurane occupies distinct sites near the S4-S5 linker, the pore domain and around the external selectivity filter. We conclude that the positive allosteric modulation of the Kv channels by sevoflurane involves separable processes and multiple sites within regions intimately involved in channel gating.
authors.affiliation: Department of Neuroscience, Sidney Kimmel Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America.
authors.forename: Qiansheng
authors.initials: Q
authors.lastname: Liang
authors.affiliation: Department of Neuroscience, Sidney Kimmel Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America.
authors.forename: Warren D
authors.initials: WD
authors.lastname: Anderson
authors.affiliation: Department of Neuroscience, Sidney Kimmel Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America.
authors.forename: Shelly T
authors.initials: ST
authors.lastname: Jones
authors.affiliation: Laboratório de Biologia Teórica e Computacional, Departamento de Biologia Celular, Universidade de Brasília, Brasília, Brasil.
authors.forename: Caio S
authors.initials: CS
authors.lastname: Souza
authors.affiliation: Laboratório de Biologia Teórica e Computacional, Departamento de Biologia Celular, Universidade de Brasília, Brasília, Brasil.
authors.forename: Juliana M
authors.initials: JM
authors.lastname: Hosoume
authors.affiliation: Laboratório de Biologia Teórica e Computacional, Departamento de Biologia Celular, Universidade de Brasília, Brasília, Brasil.
authors.forename: Werner
authors.initials: W
authors.lastname: Treptow
authors.affiliation: Department of Neuroscience, Sidney Kimmel Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America.|Farber Institute for Neuroscience, Sidney Kimmel Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America.
authors.forename: Manuel
authors.initials: M
authors.lastname: Covarrubias
mesh_terms: D000494:Allosteric Regulation / Q000187:drug effects; D000495:Allosteric Site / Q000187:drug effects; D019943:Amino Acid Substitution; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D001665:Binding Sites; D004305:Dose-Response Relationship, Drug; D055724:Electrophysiological Phenomena / Q000187:drug effects; D051663:Kv1.2 Potassium Channel / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008738:Methyl Ethers / Q000494:pharmacology*; D008958:Models, Molecular; D008968:Molecular Conformation; D009154:Mutation; D009865:Oocytes; D024642:Potassium Channels, Voltage-Gated / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000077149:Sevoflurane; D014982:Xenopus laevis
chemical_list: D018685:Anesthetics, Inhalation; D051663:Kv1.2 Potassium Channel; D008738:Methyl Ethers; D024642:Potassium Channels, Voltage-Gated; D000077149:Sevoflurane