Voltage-gating and cytosolic Ca2+ activation mechanisms of arabidopsis two-pore channel AtTPC1

Fan Ye, Lingyi Xu, Xiaoxiao Li, Weizhong Zeng, Ninghai Gan, Cheng Zhao, Wei Yang, Youxing Jiang, Jiangtao Guo

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Arabidopsis thaliana two-pore channel AtTPC1 is a voltage-gated, Ca2+-modulated, nonselective cation channel that is localized in the vacuolar membrane and responsible for generating slow vacuolar (SV) current. Under depolarizing membrane potential, cytosolic Ca2+ activates AtTPC1 by binding at the EF-hand domain, whereas luminal Ca2+ inhibits the channel by stabilizing the voltage-sensing domain II (VSDII) in the resting state. Here, we present 2.8 to 3.3 Å cryoelectron microscopy (cryo-EM) structures of AtTPC1 in two conformations, one in closed conformation with unbound EF-hand domain and resting VSDII and the other in a partially open conformation with Ca2+-bound EF-hand domain and activated VSDII. Structural comparison between the two different conformations allows us to elucidate the structural mechanisms of voltage gating, cytosolic Ca2+ activation, and their coupling in AtTPC1. This study also provides structural insight into the general voltage-gating mechanism among voltage-gated ion channels.

Original languageEnglish (US)
Article numbere2113946118
JournalProceedings of the National Academy of Sciences of the United States of America
Volume118
Issue number49
DOIs
StatePublished - Dec 7 2021

Keywords

  • Ca activation
  • Coupling
  • TPC
  • Voltage gating

ASJC Scopus subject areas

  • General

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