A TRP Homolog in Saccharomyces cerevisiae Forms an Intracellular Ca2+-Permeable Channel in the Yeast Vacuolar Membrane

The molecular identification of ion channels in internal membranes has made scant progress compared with the study of plasma membrane ion channels. We investigated a prominent voltage-dependent, cation-selective, and calcium-activated vacuolar ion conductance of 320 pS (yeast vacuolar conductance, Y...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2001-07, Vol.98 (14), p.7801-7805
Main Authors: Palmer, Chris P., Zhou, Xin-Liang, Lin, Junyu, Loukin, Stephen H., Kung, Ching, Saimi, Yoshiro
Format: Article
Language:English
Subjects:
Amino acids
Biological Sciences
Calcium
Cell membranes
Cellular biology
Genes
Genomics
Ion channels
Ions
Membranes
Proteins
Receptors
Vacuoles
Yeast
Yeasts
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Summary:The molecular identification of ion channels in internal membranes has made scant progress compared with the study of plasma membrane ion channels. We investigated a prominent voltage-dependent, cation-selective, and calcium-activated vacuolar ion conductance of 320 pS (yeast vacuolar conductance, YVC1) in Saccharomyces cerevisiae. Here we report on a gene, the deduced product of which possesses significant homology to the ion channel of the transient receptor potential (TRP) family. By using a combination of gene deletion and re-expression with direct patch clamping of the yeast vacuolar membrane, we show that this yeast TRP-like gene is necessary for the YVC1 conductance. In physiological conditions, tens of micromolar cytoplasmic Ca2+activates the YVC1 current carried by cations including Ca2+across the vacuolar membrane. Immunodetection of a tagged YVC1 gene product indicates that YVC1 is primarily localized in the vacuole and not other intracellular membranes. Thus we have identified the YVC1 vacuolar/lysosomal cation-channel gene. This report has implications for the function of TRP channels in other organisms and the possible molecular identification of vacuolar/lysosomal ion channels in other eukaryotes.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.141036198