Glutamate Permeability of Chicken Best1

Jung Moo Lee; Changdev Gorakshnath Gadhe; Hyunji Kang; Ae Nim Pae; C Justin Lee

doi:10.5607/en22038

Glutamate Permeability of Chicken Best1

Exp Neurobiol. 2022 Oct 31;31(5):277-288. doi: 10.5607/en22038.

Authors

Jung Moo Lee^{1

2}, Changdev Gorakshnath Gadhe³, Hyunji Kang^{2

4}, Ae Nim Pae^{3

5}, C Justin Lee^{1

2

4}

Affiliations

¹ KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea.
² Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, Korea.
³ Brain Science Institute, Korea Institute of Science and Technology, Seoul 02792, Korea.
⁴ IBS School, University of Science and Technology, Daejeon 34113, Korea.
⁵ KIST School, University of Science and Technology, Seoul 02792, Korea.

PMID: 36351838
PMCID: PMC9659495
DOI: 10.5607/en22038

Abstract

Bestrophin-1 (Best1) is a calcium (Ca²⁺)-activated chloride (Cl^-) channel which has a phylogenetically conserved channel structure with an aperture and neck in the ion-conducting pathway. Mammalian mouse Best1 (mBest1) has been known to have a permeability for large organic anions including gluconate, glutamate, and D-serine, in addition to several small monovalent anions, such as Cl^‑, bromine (Br^-), iodine (I^-), and thiocyanate (SCN^-). However, it is still unclear whether non-mammalian Best1 has a glutamate permeability through the ion-conducting pathway. Here, we report that chicken Best1 (cBest1) is permeable to glutamate in a Ca²⁺-dependent manner. The molecular docking and molecular dynamics simulation showed a glutamate binding at the aperture and neck of cBest1 and a glutamate permeation through the ion-conducting pore, respectively. Moreover, through electrophysiological recordings, we calculated the permeability ratio of glutamate to Cl^- (P_Glutamate/P_Cl) as 0.28 based on the reversal potential shift by ion substitution from Cl^- to glutamate in the internal solution. Finally, we directly detected the Ca²⁺-dependent glutamate release through cBest1 using the ultrasensitive two-cell sniffer patch technique. Our results propose that Best1 homologs from non-mammalian (cBest1) to mammalian (mBest1) have a conserved permeability for glutamate.

Keywords: Chicken Best1; Glutamate permeability; Molecular docking simulation; Molecular dynamics simulation; Two-cell sniffer patch; Whole-cell patch-clamp recording.