Referenced in: none

Automatically associated channels: Slo1

Title: Guard cell-specific calcium sensitivity of high density and activity SV/TPC1 channels.

Authors: Florian Rienmüller, Diana Beyhl, Silke Lautner, Jörg Fromm, Khaled A S Al-Rasheid, Peter Ache, Edward E Farmer, Irene Marten, Rainer Hedrich

Journal, date & volume: Plant Cell Physiol., 2010 Sep , 51, 1548-54

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/20630987

Abstract
The slow vacuolar (SV) channel, a Ca2+-regulated vacuolar cation conductance channel, in Arabidopsis thaliana is encoded by the single-copy gene AtTPC1. Although loss-of-function tpc1 mutants were reported to exhibit a stoma phenotype, knowledge about the underlying guard cell-specific features of SV/TPC1 channels is still lacking. Here we demonstrate that TPC1 transcripts and SV current density in guard cells were much more pronounced than in mesophyll cells. Furthermore, the SV channel in motor cells exhibited a higher cytosolic Ca2+ sensitivity than in mesophyll cells. These distinct features of the guard cell SV channel therefore probably account for the published stomatal phenotype of tpc1-2.