Two voltage-dependent calcium channels co-exist in the apical plasma membrane of Arabidopsis thaliana root hairs

Calcium (Ca²⁺)-permeable plasma membrane ion channels are critical to root hair elongation and signalling. Arabidopsis thaliana root hair plasma membrane contains a hyperpolarization-activated Ca²⁺ channel (HACC) conductance. Here, the co-residence of HACC with a depolarization-activated Ca²⁺ channe...

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Bibliographic Details
Published in:The New phytologist 2008-07, Vol.179 (2), p.378-385
Main Authors: Miedema, Henk, Demidchik, Vadim, Véry, Anne-Aliénor, Bothwell, John H.F, Brownlee, Colin, Davies, Julia M
Format: Article
Language:English
Subjects:
anion
Anions
Arabidopsis - metabolism
Arabidopsis thaliana
Calcium
Calcium - metabolism
Calcium Channels - genetics
Calcium Channels - metabolism
Calcium Channels: genetics,metabolism
Cell Membrane - metabolism
Cell membranes
channel
depolarization
Electric current
Electric potential
Electrophysiology
Gadolinium
Gene Expression Regulation, Plant - physiology
Guard cells
Life Sciences
Membrane Potentials
Phytopathology and phytopharmacy
Plant cells
Plant Roots - cytology
Plant Roots - metabolism
Plant Roots: cytology,metabolism
Plants
plasma membrane
root hair
Root hairs
Spheroplasts
Vegetal Biology
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Summary:Calcium (Ca²⁺)-permeable plasma membrane ion channels are critical to root hair elongation and signalling. Arabidopsis thaliana root hair plasma membrane contains a hyperpolarization-activated Ca²⁺ channel (HACC) conductance. Here, the co-residence of HACC with a depolarization-activated Ca²⁺ channel (DACC) conductance has been investigated. Whole-cell patch-clamping of apical plasma membrane has been used to study Ca²⁺ conductances and reveal the negative slope conductance typical of DACCs. Specific voltage protocols, Ba²⁺-permeation and inhibition by the cation channel blocker Gd³⁺ have been used to identify the DACC conductance. The Gd³⁺ sensitive DACC conductance was identified in only a minority of cells. DACC activity was quickly masked by the development of the HACC conductance. However, in the period between the disappearance of the negative slope conductance and the predominance of HACC, DACC activity could still be detected. A DACC conductance coexists with HACC in the root hair apical plasma membrane and could provide Ca²⁺ influx over a wide voltage range, consistent with a role in signalling.
ISSN:0028-646X
1469-8137
DOI:10.1111/j.1469-8137.2008.02465.x