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Vol. 25, No. 2-3, 2010
Issue release date: 2010
Section title: Original Paper
Free Access
Cell Physiol Biochem 2010;25:293–306
(DOI:10.1159/000276570)

Identification of Human Gene Products Containing Pro-Pro-x-Tyr (PY) Motifs that Enhance Glutathione and Endocytotic Marker Uptake in Yeast

Shi S.1,* · Notenboom S.1,* · Dumont M.E.2 · Ballatori N.1
Departments of 1Environmental Medicine,2and Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester,*Contributed equally to the results of this article
email Corresponding Author

Abstract

In an attempt to identify genes involved in glutathione (GSH) transport, a human mammary gland cDNA library was screened for clones capable of complementing a defect in GSH uptake in yeast cells that lack Hgt1p, the primary yeast GSH uptake transporter. Five genes capable of rescuing growth on sulfur-deficient GSH-containing medium were identified: prostate transmembrane protein, androgen induced 1 (PMEPA1); lysosomal-associated protein transmembrane 4 alpha (LAPTM4α); solute carrier family 25, member 1 (SLC25A1); lipopolysaccharide-induced TNF factor (LITAF); and cysteine/tyrosine-rich-1 (CYYR1). All of these genes encode small integral membrane proteins of unknown function, although none appear to encode prototypical GSH transporters. Nevertheless, they all increased both intracellular glutathione levels and [3H]GSH uptake rates. [3H]GSH uptake was uniformly inhibited by high concentrations of unlabeled GSH, GSSG, and ophthalmic acid. Interestingly, each protein is predicted to contain Pro-Pro-x-Tyr (PY) motifs, which are thought to be important for regulating protein cell surface expression. Uptake of the endocytotic markers lucifer yellow and FM4-64 was also enhanced by each of the five genes. Mutations of the PY motifs in LITAF largely abolished all of its effects. In summary, although the results do not reveal novel GSH transporters, they identify five PY-containing human gene products that may influence plasma membrane transport activity.

© 2010 S. Karger AG, Basel


  

Key Words

  • PY-motif
  • Yeast
  • Membrane
  • Transport
  • Endocytosis
  • Glutathione

  

Author Contacts

Ned Ballatori, Ph.D.
Box EHSC, 601 Elmwood Ave, Rochester, NY 14642 (USA)
Tel. + 1 585-275-0262, Fax: + 1 585-256-2591
E-Mail Ned_Ballatori@urmc.rochester.edu

  

Article Information

Accepted: November 19, 2009
Published online: January 12, 2010
Number of Print Pages : 14

  

Publication Details

Cellular Physiology and Biochemistry (International Journal of Experimental Cellular Physiology, Biochemistry and Pharmacology)

Vol. 25, No. 2-3, Year 2010 (Cover Date: 2010)

Journal Editor: F. Lang, Tübingen
ISSN: 1015–8987 (Print), eISSN: 1421–9778 (Online)

For additional information: http://www.karger.com/journals/cpb


Copyright / Drug Dosage / Disclaimer

Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher or, in the case of photocopying, direct payment of a specified fee to the Copyright Clearance Center.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in goverment regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.

Abstract

In an attempt to identify genes involved in glutathione (GSH) transport, a human mammary gland cDNA library was screened for clones capable of complementing a defect in GSH uptake in yeast cells that lack Hgt1p, the primary yeast GSH uptake transporter. Five genes capable of rescuing growth on sulfur-deficient GSH-containing medium were identified: prostate transmembrane protein, androgen induced 1 (PMEPA1); lysosomal-associated protein transmembrane 4 alpha (LAPTM4α); solute carrier family 25, member 1 (SLC25A1); lipopolysaccharide-induced TNF factor (LITAF); and cysteine/tyrosine-rich-1 (CYYR1). All of these genes encode small integral membrane proteins of unknown function, although none appear to encode prototypical GSH transporters. Nevertheless, they all increased both intracellular glutathione levels and [3H]GSH uptake rates. [3H]GSH uptake was uniformly inhibited by high concentrations of unlabeled GSH, GSSG, and ophthalmic acid. Interestingly, each protein is predicted to contain Pro-Pro-x-Tyr (PY) motifs, which are thought to be important for regulating protein cell surface expression. Uptake of the endocytotic markers lucifer yellow and FM4-64 was also enhanced by each of the five genes. Mutations of the PY motifs in LITAF largely abolished all of its effects. In summary, although the results do not reveal novel GSH transporters, they identify five PY-containing human gene products that may influence plasma membrane transport activity.

© 2010 S. Karger AG, Basel


  

Author Contacts

Ned Ballatori, Ph.D.
Box EHSC, 601 Elmwood Ave, Rochester, NY 14642 (USA)
Tel. + 1 585-275-0262, Fax: + 1 585-256-2591
E-Mail Ned_Ballatori@urmc.rochester.edu

  

Article Information

Accepted: November 19, 2009
Published online: January 12, 2010
Number of Print Pages : 14

  

Publication Details

Cellular Physiology and Biochemistry (International Journal of Experimental Cellular Physiology, Biochemistry and Pharmacology)

Vol. 25, No. 2-3, Year 2010 (Cover Date: 2010)

Journal Editor: F. Lang, Tübingen
ISSN: 1015–8987 (Print), eISSN: 1421–9778 (Online)

For additional information: http://www.karger.com/journals/cpb


Article / Publication Details

First-Page Preview
Abstract of Original Paper

Accepted: 11/19/2009
Published online: 1/12/2010
Issue release date: 2010

Number of Print Pages: 14
Number of Figures: 0
Number of Tables: 0

ISSN: 1015-8987 (Print)
eISSN: 1421-9778 (Online)

For additional information: http://www.karger.com/CPB


Copyright / Drug Dosage

Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher or, in the case of photocopying, direct payment of a specified fee to the Copyright Clearance Center.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in goverment regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.