Putative Pore-lining Residues and Intracellular Magnesium Influence Connexin50 Unitary Gap Junction Channel Conductance
type: CreativeWork
description: Gap junction channels (GJs) are oligomers of connexins forming channels linking neighbouring cells. GJs formed by different connexins show distinct unitary channel conductance (γj), transjunctional-voltage dependent gating (Vj-gating) properties, and magnesium modulation. We investigate here how pore-lining residues may influence these GJ properties. We mutated putative pore-lining residues in Cx50 GJ (G8E/G46E/V53E individually or in combination) to investigate γj, Vj-gating, and magnesium modulation. GJs formed by combination mutants (G8E-G46E, G46E-V53E, and G8E-G46E-V53E) were functional and showed a significantly increased γj with little change in Vj-gating, while G8E-V53E mutants failed to form functional GJs. The γjs of the mutant GJs were reduced up to 30% by inclusion of magnesium in intracellular solution. Studying the individual mutations revealed that magnesium-dependent reduction of γj are due to one or combinations of V53E and/or G46E. Increasing negatively charged glutamate residues at 53rd and/or 46th positions of Cx50 increased magnesium-sensitive ion permeation.
abstract: Gap junction channels (GJs) are oligomers of connexins forming channels linking neighbouring cells. GJs formed by different connexins show distinct unitary channel conductance (γj), transjunctional-voltage dependent gating (Vj-gating) properties, and magnesium modulation. We investigate here how pore-lining residues may influence these GJ properties. We mutated putative pore-lining residues in Cx50 GJ (G8E/G46E/V53E individually or in combination) to investigate γj, Vj-gating, and magnesium modulation. GJs formed by combination mutants (G8E-G46E, G46E-V53E, and G8E-G46E-V53E) were functional and showed a significantly increased γj with little change in Vj-gating, while G8E-V53E mutants failed to form functional GJs. The γjs of the mutant GJs were reduced up to 30% by inclusion of magnesium in intracellular solution. Studying the individual mutations revealed that magnesium-dependent reduction of γj are due to one or combinations of V53E and/or G46E. Increasing negatively charged glutamate residues at 53rd and/or 46th positions of Cx50 increased magnesium-sensitive ion permeation.
author: Sudhakar, Swathy
language: en_ca
keywords: Gap junction channel, unitary conductance, Mg2+-dependent modulation, patch clamp, electrostatics
date published: 2016-06-23
date modified: 2026-07-27T21:55:56Z
provider: Western University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: The University of Western Ontario

PropertyValue
property ID: Handle
value: https://hdl.handle.net/20.500.14721/33820