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Structure of AtTPC1 with 50 mM Ca2+
Structural highlights
FunctionTPC1_ARATH Functions as a voltage-gated inward-rectifying Ca(2+) channel (VDCC) across the vacuole membrane. Is one of the essential components of the slow vacuolar (SV) channel. Acts as the major ROS-responsive Ca(2+) channel and is the possible target of Al-dependent inhibition. Involved in the regulation of germination and stomatal movement.[1] [2] GFP_AEQVI Energy-transfer acceptor. Its role is to transduce the blue chemiluminescence of the protein aequorin into green fluorescent light by energy transfer. Fluoresces in vivo upon receiving energy from the Ca(2+)-activated photoprotein aequorin. Publication Abstract from PubMedArabidopsis 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[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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