The fou2 mutation in the major vacuolar cation channel TPC1 confers tolerance to inhibitory luminal calcium.
Details
Serval ID
serval:BIB_1F556CD8AC26
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
The fou2 mutation in the major vacuolar cation channel TPC1 confers tolerance to inhibitory luminal calcium.
Journal
The Plant journal
ISSN
1365-313X[electronic]
Publication state
Published
Issued date
2009
Peer-reviewed
Oui
Volume
58
Number
5
Pages
715-723
Language
english
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov't Publication Status: ppublish
Abstract
The SV channel encoded by the TPC1 gene represents a Ca(2+)- and voltage-dependent vacuolar cation channel. Point mutation D454N within TPC1, named fou2 for fatty acid oxygenation upregulated 2, results in increased synthesis of the stress hormone jasmonate. As wounding causes Ca2+ signals and cytosolic Ca2+ is required for SV channel function, we here studied the Ca(2+)-dependent properties of this major vacuolar cation channel with Arabidopsis thaliana mesophyll vacuoles. In patch clamp measurements, wild-type and fou2 SV channels did not exhibit differences in cytosolic Ca2+ sensitivity and Ca2+ impermeability. K+ fluxes through wild-type TPC1 were reduced or even completely faded away when vacuolar Ca2+ reached the 0.1-mm level. The fou2 protein under these conditions, however, remained active. Thus, D454N seems to be part of a luminal Ca2+ recognition site. Thereby the SV channel mutant gains tolerance towards elevated luminal Ca2+. A three-fold higher vacuolar Ca/K ratio in the fou2 mutant relative to wild-type plants seems to indicate that fou2 can accumulate higher levels of vacuolar Ca(2+) before SV channel activity vanishes and K(+) homeostasis is impaired. In response to wounding fou2 plants might thus elicit strong vacuole-derived cytosolic Ca2+ signals resulting in overproduction of jasmonate.
Keywords
Arabidopsis/genetics, Arabidopsis/metabolism, Arabidopsis Proteins/genetics, Arabidopsis Proteins/metabolism, Calcium/metabolism, Calcium Channels/genetics, Calcium Channels/metabolism, Calcium Signaling, Cytosol/metabolism, Gene Expression Regulation, Plant, Membrane Potentials, Patch-Clamp Techniques, Point Mutation, Potassium/metabolism, Vacuoles/metabolism, Vacuoles/physiology
Pubmed
Web of science
Create date
13/01/2010 14:54
Last modification date
20/08/2019 13:55