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Gating of the two-pore cation channel AtTPC1 in the plant vacuole is based on a single voltage-sensing domain

Citation

Jaslan, D and Mueller, TD and Becker, D and Schultz, J and Cuin, TA and Marten, I and Dreyer, I and Schonknecht, G and Hedrich, R, Gating of the two-pore cation channel AtTPC1 in the plant vacuole is based on a single voltage-sensing domain, Plant Biology, 18, (5) pp. 750-760. ISSN 1435-8603 (2016) [Refereed Article]

Copyright Statement

Copyright 2016 German Botanical Society and The Royal Botanical Society of the Netherlands

DOI: doi:10.1111/plb.12478

Abstract

  • 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.

    • Item Details

    Item Type:Refereed Article
    Keywords:Arabidopsis thaliana, gating, plant TPC1, two-pore ion channel, vacuole, voltage sensor
    Research Division:Biological Sciences
    Research Group:Plant biology
    Research Field:Plant physiology
    Objective Division:Plant Production and Plant Primary Products
    Objective Group:Other plant production and plant primary products
    Objective Field:Forest product traceability and quality assurance
    UTAS Author:Cuin, TA (Dr Tracey Cuin)
    ID Code:127005
    Year Published:2016
    Web of Science® Times Cited:16
    Deposited By:Agriculture and Food Systems
    Deposited On:2018-07-06
    Last Modified:2018-08-13
    Downloads:0

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