Current-direction/amplitude-dependent single channel gating kinetics of mouse pannexin 1 channel: a new concept for gating kinetics

• Type of Material: Article
• Authors: Takeshi Nomura, Kyoto Prefectural University of Medicine; Akiyuki Taruno, Kyoto Prefectural University of Medicine; Makoto Shiraishi, Kyoto Prefectural University of Medicine; Takashi Nakahari, Kyoto Prefectural University of Medicine; Toshio Inui, Kyoto Prefectural University of Medicine; Masahiro Sokabe, Nagoya University; Douglas Eaton, Emory University; Yoshinori Marunaka, Kyoto Prefectural University of Medicine
• Language: English
• Date: 2017-09-05
• Publisher: Nature Publishing Group
• Publication Version: Final Published Version
• Copyright Statement: © The Author(s) 2017
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1038/s41598-017-10921-x
• Title of Journal or Parent Work: Scientific Reports
• ISSN: 2045-2322
• Volume: 7
• Issue: 1
• Start Page: 10512
• End Page: 10512
• Grant/Funding Information: This work was supported by Grants-in-Aid from Japan Society of the Promotion of Science (JSPS KAKENHI Grant Number JP26460300 to TN, JP26713008 and JP16K15181 to AT, JP25670111 and JP15K15034 to YM), US NIH NIDDK R37 DK037963 to DCE, Salt Science (1235 to YM, 1429 and 1542 to AT), KIT-KPUM-KPU-KPhU Collaborative Research Grant (2013 and 2015) to YM, Society for Research on Umami Taste, Nestlé Nutrition Council, Japan to AT, Kyoto Prefectural Public University Corporation to AT, Kyoto-Funding for Innovation in Health-related R&D Fields to YM, Fuji Foundation for Protein Research to YM, and Cell Research Conference to YM.
• Keywords: CELL-PROLIFERATION; ATP RELEASE; PERMEATION PORE INHIBITION; RECEPTOR-CHANNEL; GAP-JUNCTION PROTEINS; POTASSIUM CHANNELS; CANCER CELL; Science & Technology - Other Topics; INDUCED NEURITE OUTGROWTH; FIND-ME SIGNAL; Multidisciplinary Sciences; Science & Technology; CONNEXIN FAMILY
• Research Categories: Biology, Cell; Biology, Molecular

Abstract

The detailed single-channel gating kinetics of mouse pannexin 1 (mPanx1) remains unknown, although mPanx1 is reported to be a voltage-activated anion-selective channel. We investigated characteristics of single-channel conductances and opening and closing rates of mPanx1 using patch-clamp techniques. The unitary current of mPanx1 shows outward rectification with single-channel conductances of ~20 pS for inward currents and ~80 pS for outward currents. The channel open time for outward currents (Cl(-) influx) increases linearly as the amplitude of single channel currents increases, while the open time for inward currents (Cl(-) efflux) is constant irrespective of changes in the current amplitude, as if the direction and amplitude of the unitary current regulates the open time. This is supported by further observations that replacement of extracellular Cl(-) with gluconate(-) diminishes the inward tail current (Cl(-) efflux) at a membrane potential of -100 mV due to the lowered outward current (gluconate(-) influx) at membrane potential of 100 mV. These results suggest that the direction and rate of charge-carrier movement regulate the open time of mPanx1, and that the previously reported voltage-dependence of Panx1 channel gating is not directly mediated by the membrane potential but rather by the direction and amplitude of currents through the channel.