journal contribution
posted on 2023-05-19, 19:21 authored by Jaslan, D, Mueller, TD, Becker, D, Schultz, J, Tracey Cuin, Marten, I, Dreyer, I, Schonknecht, G, Hedrich, R The two-pore cation channel TPC1 operates as a dimeric channel in animal and plant endomembranes. Each subunit consists of two homologous Shaker-like halves, with 12 transmembrane domains in total (S1–S6, S7–S12). In plants, TPC1 channels reside in the vacuolar membrane, and upon voltage stimulation, give rise to the well-known slow-activating SV currents. Here, we combined bioinformatics, structure modelling, site-directed mutagenesis, and in planta patch clamp studies to elucidate the molecular mechanisms of voltagedependent channel gating in TPC1 in its native plant background. Structure-function analysis of the Arabidopsis TPC1 channel in planta confirmed that helix S10 operates as the major voltage-sensing site, with Glu450 and Glu478 identified as possible ion-pair partners for voltage-sensing Arg537. The contribution of helix S4 to voltage sensing was found to be negligible. Several conserved negative residues on the luminal site contribute to calcium binding, stabilizing the closed channel. During evolution of plant TPC1s from two separate Shaker-like domains, the voltage-sensing function in the N-terminal Shaker-unit (S1–S4) vanished.History
Publication title
Plant BiologyVolume
18Issue
5Pagination
750-760ISSN
1435-8603Department/School
Tasmanian Institute of Agriculture (TIA)Publisher
Georg Thieme Verlag KgPlace of publication
Rudigerstr 14, Stuttgart, Germany, D-70469Rights statement
Copyright 2016 German Botanical Society and The Royal Botanical Society of the NetherlandsSocio-economic Objectives
Forest product traceability and quality assurance
