title: Arabidopsis annexin1 mediates the radical-activated plasma membrane Ca²+- and K+-permeable conductance in root cells.
abstract: Plant cell growth and stress signaling require Ca²⁺ influx through plasma membrane transport proteins that are regulated by reactive oxygen species. In root cell growth, adaptation to salinity stress, and stomatal closure, such proteins operate downstream of the plasma membrane NADPH oxidases that produce extracellular superoxide anion, a reactive oxygen species that is readily converted to extracellular hydrogen peroxide and hydroxyl radicals, OH•. In root cells, extracellular OH• activates a plasma membrane Ca²⁺-permeable conductance that permits Ca²⁺ influx. In Arabidopsis thaliana, distribution of this conductance resembles that of annexin1 (ANN1). Annexins are membrane binding proteins that can form Ca²⁺-permeable conductances in vitro. Here, the Arabidopsis loss-of-function mutant for annexin1 (Atann1) was found to lack the root hair and epidermal OH•-activated Ca²⁺- and K⁺-permeable conductance. This manifests in both impaired root cell growth and ability to elevate root cell cytosolic free Ca²⁺ in response to OH•. An OH•-activated Ca²⁺ conductance is reconstituted by recombinant ANN1 in planar lipid bilayers. ANN1 therefore presents as a novel Ca²⁺-permeable transporter providing a molecular link between reactive oxygen species and cytosolic Ca²⁺ in plants.
authors.affiliation: Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom.
authors.forename: Anuphon
authors.initials: A
authors.lastname: Laohavisit
authors.forename: Zhonglin
authors.initials: Z
authors.lastname: Shang
authors.forename: Lourdes
authors.initials: L
authors.lastname: Rubio
authors.forename: Tracey A
authors.initials: TA
authors.lastname: Cuin
authors.forename: Anne-Aliénor
authors.initials: AA
authors.lastname: Véry
authors.forename: Aihua
authors.initials: A
authors.lastname: Wang
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: Mortimer
authors.forename: Neil
authors.initials: N
authors.lastname: Macpherson
authors.forename: Katy M
authors.initials: KM
authors.lastname: Coxon
authors.forename: Nicholas H
authors.initials: NH
authors.lastname: Battey
authors.forename: Colin
authors.initials: C
authors.lastname: Brownlee
authors.forename: Ohkmae K
authors.initials: OK
authors.lastname: Park
authors.forename: Hervé
authors.initials: H
authors.lastname: Sentenac
authors.forename: Sergey
authors.initials: S
authors.lastname: Shabala
authors.forename: Alex A R
authors.initials: AA
authors.lastname: Webb
authors.forename: Julia M
authors.initials: JM
authors.lastname: Davies
mesh_terms: D017305:Annexin A1 / Q000378:metabolism*; D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D002463:Cell Membrane Permeability / Q000187:drug effects*; D004058:Diffusion / Q000187:drug effects; D017665:Hydroxyl Radical / Q000494:pharmacology*; D015640:Ion Channel Gating / Q000187:drug effects*; D008051:Lipid Bilayers / Q000378:metabolism; D059828:Plant Cells / Q000187:drug effects / Q000378:metabolism; D019441:Plant Epidermis / Q000187:drug effects / Q000378:metabolism; D018517:Plant Roots / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D011188:Potassium / Q000378:metabolism; D011523:Protoplasts / Q000187:drug effects / Q000378:metabolism; D011994:Recombinant Proteins / Q000302:isolation & purification; D051637:Shaker Superfamily of Potassium Channels / Q000378:metabolism
chemical_list: D017305:Annexin A1; D029681:Arabidopsis Proteins; D015220:Calcium Channels; D008051:Lipid Bilayers; D011994:Recombinant Proteins; D051637:Shaker Superfamily of Potassium Channels; D017665:Hydroxyl Radical; D011188:Potassium; D002118:Calcium