2. Academic Validation
  3. Cryo-EM structure of the volume-regulated anion channel LRRC8D isoform identifies features important for substrate permeation

Cryo-EM structure of the volume-regulated anion channel LRRC8D isoform identifies features important for substrate permeation

  • Commun Biol. 2020 May 15;3(1):240. doi: 10.1038/s42003-020-0951-z.
Ryoki Nakamura # 1,  Tomohiro Numata # 2,  Go Kasuya # 3,  Takeshi Yokoyama 4,  Tomohiro Nishizawa 1,  Tsukasa Kusakizako 1,  Takafumi Kato 1,  Tatsuya Hagino 1,  Naoshi Dohmae 5,  Masato Inoue 6,  Kengo Watanabe 6,  Hidenori Ichijo 6,  Masahide Kikkawa 7,  Mikako Shirouzu 4,  Thomas J Jentsch 8,  Ryuichiro Ishitani 1,  Yasunobu Okada 9 10,  Osamu Nureki 11
Affiliations

Affiliations

  • 1 Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
  • 2 Department of Physiology, Graduate School of Medical Sciences, Fukuoka University, 7-45-1 Nanakuma, Johnan-ku, Fukuoka, Japan.
  • 3 Division of Integrative Physiology, Department of Physiology, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke-shi, Tochigi, Japan. [email protected].
  • 4 Laboratory for Protein Functional and Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa, Japan.
  • 5 Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako-shi, Saitama, Japan.
  • 6 Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
  • 7 Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
  • 8 Physiology and Pathology of Ion Transport, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin, D-13125, Berlin, Germany.
  • 9 Department of Molecular Cell Physiology, Kyoto Prefectural University of Medicine, Kyoto, Japan. [email protected].
  • 10 Department of Cell Physiology, National Institute for Physiological Sciences, Okazaki, Japan. [email protected].
  • 11 Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan. [email protected].
  • # Contributed equally.
PMID: 32415200 DOI: 10.1038/s42003-020-0951-z
Abstract

Members of the leucine-rich repeat-containing 8 (LRRC8) protein family, composed of the five LRRC8A-E isoforms, are pore-forming components of the volume-regulated anion channel (VRAC). LRRC8A and at least one of the other LRRC8 isoforms assemble into heteromers to generate VRAC transport activities. Despite the availability of the LRRC8A structures, the structural basis of how LRRC8 isoforms other than LRRC8A contribute to the functional diversity of VRAC has remained elusive. Here, we present the structure of the human LRRC8D isoform, which enables the permeation of organic substrates through VRAC. The LRRC8D homo-hexamer structure displays a two-fold symmetric arrangement, and together with a structure-based electrophysiological analysis, revealed two key features. The pore constriction on the extracellular side is wider than that in the LRRC8A structures, which may explain the increased permeability of organic substrates. Furthermore, an N-terminal helix protrudes into the pore from the intracellular side and may be critical for gating.

Figures