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Publication Abstract from PubMed

Arabidopsis thaliana two-pore channel AtTPC1 is a voltage-gated, Ca(2+)-modulated, nonselective cation channel that is localized in the vacuolar membrane and responsible for generating slow vacuolar (SV) current. Under depolarizing membrane potential, cytosolic Ca(2+) activates AtTPC1 by binding at the EF-hand domain, whereas luminal Ca(2+) inhibits the channel by stabilizing the voltage-sensing domain II (VSDII) in the resting state. Here, we present 2.8 to 3.3 A 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 Ca(2+)-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 Ca(2+) activation, and their coupling in AtTPC1. This study also provides structural insight into the general voltage-gating mechanism among voltage-gated ion channels.

Voltage-gating and cytosolic Ca(2+) activation mechanisms of Arabidopsis two-pore channel AtTPC1.,Ye F, Xu L, Li X, Zeng W, Gan N, Zhao C, Yang W, Jiang Y, Guo J Proc Natl Acad Sci U S A. 2021 Dec 7;118(49). pii: 2113946118. doi:, 10.1073/pnas.2113946118. PMID:34845029^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.