SUT1-promoted sterol uptake involves the ABC transporter Aus1 and the mannoprotein Dan1 whose synergistic action is sufficient for this process.
Efficient sterol influx in the yeast Saccharomyces cerevisiae is restricted to anaerobiosis or to haem deficiency resulting from mutations. Constitutive expression of SUT1, an hypoxic gene encoding a transcriptional regulator, induces sterol uptake in aerobiosis. A genome-wide approach using DNA microarray was used to identify the mediators of SUT1 effects on aerobic sterol uptake. A total of 121 ORFs (open reading frames) were significantly and differentially expressed after SUT1 overexpression, 61 down-regulated and 60 up-regulated. Among these genes, the role of the putative ABC transporter (ATP-binding-cassette transporter) Aus1, and of the cell-wall mannoprotein Dan1, was characterized better. These two genes play an essential role in aerobic sterol uptake, since their deletion compromised the SUT1 effects, but individual overexpression of either of these genes in a wild-type background was not sufficient for this process. However, constitutive co-expression of AUS1 and DAN1 in a wild-type background resulted in sterol influx in aerobiosis. These results suggest that the corresponding proteins may act synergistically in vivo to promote sterol uptake.
Alimardani
Parissa
P
Laboratoire de Génétique de la Levure, CNRS-UMR 6161, Université de Poitiers, 40 avenue du Recteur Pineau, 86022 Poitiers Cedex, France.
Régnacq
Matthieu
M
Moreau-Vauzelle
Carole
C
Ferreira
Thierry
T
Rossignol
Tristan
T
Blondin
Bruno
B
Bergès
Thierry
T
D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis / Q000378:metabolism*; D000332:Aerobiosis / Q000502:physiology; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology; D020869:Gene Expression Profiling / Q000379:methods; D015966:Gene Expression Regulation, Fungal / Q000502:physiology; D016681:Genome, Fungal; D006023:Glycoproteins; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000378:metabolism* / Q000502:physiology; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000096:biosynthesis / Q000378:metabolism* / Q000502:physiology; D013045:Species Specificity; D013261:Sterols / Q000378:metabolism*; D015534:Trans-Activators / Q000172:deficiency / Q000378:metabolism; D014158:Transcription, Genetic / Q000502:physiology
D018528:ATP-Binding Cassette Transporters; C466994:AUS1 protein, S cerevisiae; C107098:DAN1 protein, S cerevisiae; D004268:DNA-Binding Proteins; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D008869:Microtubule-Associated Proteins; C083348:ROX1 protein, S cerevisiae; D012097:Repressor Proteins; C091278:STU1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D013261:Sterols; D015534:Trans-Activators; C113958:UPC2 protein, S cerevisiae; C025363:mannoproteins