QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Vol. 17, Issue 1, 90-103, January 2006

This Article Full Text Full Text (PDF) All Versions of this Article: E05-06-0515v1 17/1/90    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Reiner, S. Articles by Schneiter, R. Search for Related Content PubMed PubMed Citation Articles by Reiner, S. Articles by Schneiter, R.

A Genomewide Screen Reveals a Role of Mitochondria in Anaerobic Uptake of Sterols in Yeast

Sonja Reiner ^* , Delphine Micolod  , Günther Zellnig , and Roger Schneiter 

^* Institute of Biochemistry, Graz University of Technology, 8010 Graz, Austria; Department of Medicine, Division of Biochemistry, University of Fribourg, 1700 Fribourg, Switzerland; and Institute of Plant Sciences, Karl-Franzens University Graz, 8010 Graz, Austria

Submitted June 9, 2005; Revised September 15, 2005; Accepted October 14, 2005
Monitoring Editor: Howard Riezman

The mechanisms that govern intracellular transport of sterols in eukaryotic cells are not well understood. Saccharomyces cerevisiae is a facultative anaerobic organism that becomes auxotroph for sterols and unsaturated fatty acids in the absence of oxygen. To identify pathways that are required for uptake and transport of sterols, we performed a systematic screen of the yeast deletion mutant collection for genes that are required for growth under anaerobic conditions. Of the 4800 nonessential genes represented in the deletion collection, 37 were essential for growth under anaerobic conditions. These affect a wide range of cellular functions, including biosynthetic pathways for certain amino acids and cofactors, reprogramming of transcription and translation, mitochondrial function and biogenesis, and membrane trafficking. Thirty-three of these mutants failed to grow on lipid-supplemented media when combined with a mutation in HEM1, which mimics anaerobic conditions in the presence of oxygen. Uptake assays with radio- and fluorescently labeled cholesterol revealed that 17 of the 33 mutants strongly affect uptake and/or esterification of exogenously supplied cholesterol. Examination of the subcellular distribution of sterols in these uptake mutants by cell fractionation and fluorescence microscopy indicates that some of the mutants block incorporation of cholesterol into the plasma membrane, a presumably early step in sterol uptake. Unexpectedly, the largest class of uptake mutants is affected in mitochondrial functions, and many of the uptake mutants show electron-dense mitochondrial inclusions. These results indicate that a hitherto uncharacterized mitochondrial function is required for sterol uptake and/or transport under anaerobic conditions and are discussed in light of the fact that mitochondrial import of cholesterol is required for steroidogenesis in vertebrate cells.

Abbreviations used: ABC, ATP-binding cassette; ACAT, acyl CoA: cholesterol acyltransferase; ALA, -aminolevulinic acid; NBD-cholesterol, 25-{N-[(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-methyl]amino}-27-norcholesterol; TLC, thin-layer chromatography.

These authors contributed equally to this work.

Address correspondence to: Roger Schneiter (roger.schneiter{at}unifr.ch).

This article has been cited by other articles:

				C. A. Hodge, V. Choudhary, M. J. Wolyniak, J. J. Scarcelli, R. Schneiter, and C. N. Cole Integral membrane proteins Brr6 and Apq12 link assembly of the nuclear pore complex to lipid homeostasis in the endoplasmic reticulum J. Cell Sci., January 1, 2010; 123(1): 141 - 151. [Abstract] [Full Text] [PDF]

				M. Lin, H. Unden, N. Jacquier, R. Schneiter, U. Just, and T. Hofken The Cdc42 Effectors Ste20, Cla4, and Skm1 Down-Regulate the Expression of Genes Involved in Sterol Uptake by a Mitogen-activated Protein Kinase-independent Pathway Mol. Biol. Cell, November 15, 2009; 20(22): 4826 - 4837. [Abstract] [Full Text] [PDF]

				K. A. Houck, D. J. Dix, R. S. Judson, R. J. Kavlock, J. Yang, and E. L. Berg Profiling Bioactivity of the ToxCast Chemical Library Using BioMAP Primary Human Cell Systems J Biomol Screen, October 1, 2009; 14(9): 1054 - 1066. [Abstract] [PDF]

				B. M. Tsoi, A. G. Beckhouse, C. L. Gelling, M. J. Raftery, J. Chiu, A. M. Tsoi, L. Lauterbach, P. J. Rogers, V. J. Higgins, and I. W. Dawes Essential Role of One-carbon Metabolism and Gcn4p and Bas1p Transcriptional Regulators during Adaptation to Anaerobic Growth of Saccharomyces cerevisiae J. Biol. Chem., April 24, 2009; 284(17): 11205 - 11215. [Abstract] [Full Text] [PDF]

				D. P. Sullivan, A. Georgiev, and A. K. Menon Tritium Suicide Selection Identifies Proteins Involved in the Uptake and Intracellular Transport of Sterols in Saccharomyces cerevisiae Eukaryot. Cell, February 1, 2009; 8(2): 161 - 169. [Abstract] [Full Text] [PDF]

				W. Fei, G. Alfaro, B.-P. Muthusamy, Z. Klaassen, T. R. Graham, H. Yang, and C. T. Beh Genome-Wide Analysis of Sterol-Lipid Storage and Trafficking in Saccharomyces cerevisiae Eukaryot. Cell, February 1, 2008; 7(2): 401 - 414. [Abstract] [Full Text] [PDF]

				L.-C. Lai, A. L. Kosorukoff, P. V. Burke, and K. E. Kwast Metabolic-State-Dependent Remodeling of the Transcriptome in Response to Anoxia and Subsequent Reoxygenation in Saccharomyces cerevisiae. Eukaryot. Cell, September 1, 2006; 5(9): 1468 - 1489. [Abstract] [Full Text] [PDF]

				R. Koffel and R. Schneiter Yeh1 Constitutes the Major Steryl Ester Hydrolase under Heme-Deficient Conditions in Saccharomyces cerevisiae. Eukaryot. Cell, July 1, 2006; 5(7): 1018 - 1025. [Abstract] [Full Text] [PDF]