Eukaryotic Cell
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Stolz, J.
Right arrow Articles by Vogl, C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Stolz, J.
Right arrow Articles by Vogl, C.

 Previous Article  |  Next Article 

Eukaryotic Cell, February 2005, p. 319-326, Vol. 4, No. 2
1535-9778/05/$08.00+0     doi:10.1128/EC.4.2.319-326.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Amiloride Uptake and Toxicity in Fission Yeast Are Caused by the Pyridoxine Transporter Encoded by bsu1+ (car1+)

Jürgen Stolz,* Heike J. P. Wöhrmann, and Christian Vogl

Lehrstuhl für Zellbiologie und Pflanzenphysiologie, Universität Regensburg, Regensburg, Germany

Received 11 May 2004/ Accepted 29 November 2004

Amiloride, a diuretic drug that acts by inhibition of various sodium transporters, is toxic to the fission yeast Schizosaccharomyces pombe. Previous work has established that amiloride sensitivity is caused by expression of car1+, which encodes a protein with similarity to plasma membrane drug/proton antiporters from the multidrug resistance family. Here we isolated car1+ by complementation of Saccharomyces cerevisiae mutants that are deficient in pyridoxine biosynthesis and uptake. Our data show that Car1p represents a new high-affinity, plasma membrane-localized import carrier for pyridoxine, pyridoxal, and pyridoxamine. We therefore propose the gene name bsu1+ (for vitamin B6 uptake) to replace car1+. Bsu1p displays an acidic pH optimum and is inhibited by various protonophores, demonstrating that the protein works as a proton symporter. The expression of bsu1+ is associated with amiloride sensitivity and pyridoxine uptake in both S. cerevisiae and S. pombe cells. Moreover, amiloride acts as a competitor of pyridoxine uptake, demonstrating that both compounds are substrates of Bsu1p. Taken together, our data show that S. pombe and S. cerevisiae possess unrelated plasma membrane pyridoxine transporters. The S. pombe protein may be structurally related to the unknown human pyridoxine transporter, which is also inhibited by amiloride.

* Corresponding author. Mailing address: Lehrstuhl für Zellbiologie und Pflanzenphysiologie, Universität Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany. Phone: 49-941-943-3005. Fax: 49-941-943-3352. E-mail: juergen.stolz{at}biologie.uni-regensburg.de.

Eukaryotic Cell, February 2005, p. 319-326, Vol. 4, No. 2
1535-9778/05/$08.00+0     doi:10.1128/EC.4.2.319-326.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:



HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Appl. Environ. Microbiol. Infect. Immun. J. Bacteriol.
Mol. Cell Biol. Microbiol. Mol. Biol. Rev. ALL ASM JOURNALS
Copyright © 2005 by the American Society for Microbiology.