Integrative Approach with Electrophysiological and Theoretical Methods Reveals a New Role of S4 Positively Charged Residues in PKD2L1 Channel Voltage-Sensing

• Numata, Tomohiro

• Tsumoto, Kunichika

• Yamada, Kazunori

• Kurokawa, Tatsuki

• Hirose, Shinichi

• Nomura, Hideki

• Kawano, Mitsuhiro

• Kurachi, Yoshihisa

• Inoue, Ryuji

• Mori, Yasuo

Abstract

Numerical model-based simulations provide important insights into ion channel gating when experimental limitations exist. Here, a novel strategy combining numerical simulations with patch clamp experiments was used to investigate the net positive charges in the putative transmembrane segment 4 (S4) of the atypical, positively-shifted voltage-dependence of polycystic kidney disease 2-like 1 (PKD2L1) channel. Charge-neutralising mutations (K452Q, K455Q and K461Q) in S4 reduced gating charges, positively shifted the Boltzmann-type activation curve [i.e., open probability (Popen)-V curve] and altered the time-courses of activation/deactivation of PKD2L1, indicating that this region constitutes part of a voltage sensor. Numerical reconstruction of wild-type (WT) and mutant PKD2L1-mediated currents necessitated, besides their voltage-dependent gating parameters, a scaling factor that describes the voltage-dependence of maximal conductance, Gmax. Subsequent single-channel conductance (γ) measurements revealed that voltage-dependence of Gmax in WT can be explained by the inward-rectifying property of γ, which is greatly changed in PKD2L1 mutants. Homology modelling based on PKD2 and NaVAb structures suggest that such voltage dependence of Popen and γ in PKD2L1 could both reflect the charged state of the S4 domain. The present conjunctive experimental and theoretical approaches provide a framework to explore the undetermined mechanism(s) regulating TRP channels that possess non-classical voltage-dependent properties.

Journal

• Scientific Reports

  Scientific Reports 7 9760-, 2017-08-29

  Springer Nature

Keywords

• Ion channel signalling
• Patch clamp
• Systems analysis

Details

• CRID: 1050001335851919488
• NII Article ID: 120006364088
• ISSN: 20452322
• DOI: 10.1038/s41598-017-10357-3
• HANDLE: 2433/227883
• Web Site: https://www.nature.com/articles/s41598-017-10357-3.pdf
• Web Site: https://www.nature.com/articles/s41598-017-10357-3
• Text Lang: en
• Article Type: journal article
• Data Source:
  • IRDB
  • Crossref
  • CiNii Articles
  • KAKEN