Preferences help
enabled [disable] Abstract
Number of results
2016 | 63 | 2 | 371-375
Article title

Difference in the late ergosterol biosynthesis between yeast spheroplasts and intact cells

Title variants
Languages of publication
A comparative study on post-squalene sterol synthesis in intact yeast cells and spheroplasts was carried out with strains from three genera (Saccharomyces cerevisiae, Schizosaccharomyces pombe, Pichia pastoris) as well as with engineered S. cerevisiae cells altered in regard to the late ergosterol synthesis pathway. A common outcome of incubation experiments with radioactive acetate was that in intact cells the metabolic pathway flows till its specific end product (ergosterol and its precursor, depending on the enzyme deficiency), whereas in spheroplasts the pathway was stalled some step upstream. For example, in spheroplasts from wt strains, non-cyclic triterpenes squalene and oxidosqualene accumulated as though the metabolic path was kept from producing steroid-shaped molecules different from the end product. Accumulation of non-cyclic triterpenes was observed also in spheroplasts from S. cerevisiae cells lacking 3-ketosteroid reductase activity, an enzyme belonging to the C4-demethylase complex. When production of cyclic triterpenes was compromised by loss or poor functionality of oxidosqualene cyclase (EC, the difference between intact cells and spheroplasts was still remarkable, yet limited to the different oxido/dioxidosqualene ratio. The characteristics of spheroplasts as non-proliferating cells may partially explain the observed differences in post-squalene pathway from intact cells. We cannot say if the difference in metabolic pathways in spheroplasts and intact cells is a rule. We think, however, that it is worthwhile to search for an answer, as a wider picture of the points where the metabolic pathways are stalled in spheroplasts could provide original ideas about the metabolic network in yeast.

Physical description
  • University of Torino, Department of Drug Science and Technology, Torino, Italy
  • University of Torino, Department of Drug Science and Technology, Torino, Italy
  • University of Torino, Department of Drug Science and Technology, Torino, Italy
  • University of Torino, Department of Drug Science and Technology, Torino, Italy
  • Balliano G, Dehmlow H, Oliaro-Bosso S, Scaldaferri M, Taramino S, Viola F, Caron G, Aebi J, Ackermann J (2009) Oxidosqualene cyclase from Saccharomyces cerevisiae, Trypanosoma cruzi, Pneumocystis carinii and Arabidopsis thaliana expressed in yeast: a model for the development of novel antiparasitic agents. Bioorg Med Chem Lett 19: 718-723. doi: 10.1016/j.bmcl.2008.12.040.
  • Balliano G, Viola F, Ceruti M, Cattel L (1988) Inhibition of sterol biosynthesis in Saccharomyces cerevisiae by N,N-diethylazasqualene and derivatives. Biochim Biophys Acta 959: 9-19. doi: 10.1016/0005-2760(88)90144-0.
  • Becker B, Schmitt MJ (2011) Adapting yeast as model to study ricin toxin a uptake and trafficking. Toxins 3: 834-847. doi: 10.3390/toxins3070834.
  • Beh CT, Rine J (2004) A role for yeast oxysterol-binding protein homologs in endocytosis and in the maintenance of intracellular sterol-lipid distribution. J Cell Sci 117: 2983-2996. doi: 10.1242/jcs.01157.
  • Daum G, Böhni PC, Schatz G (1982) Import of proteins into mitochondria. Cytochrome b2 and cytochrome c peroxidase are located in the intermembrane space of yeast mitochondria. J Biol Chem 257: 13028-13033.
  • Gill S, Chow R, Brown AJ (2008) Sterol regulators of cholesterol homeostasis and beyond: The oxysterol hypothesis revisited and revised. Prog Lipid Res 47: 391-404. doi: 10.1016/j.plipres.2008.04.002.
  • Milla P, Viola F, Oliaro Bosso S, Rocco F, Cattel L, Joubert BM, LeClair RJ, Matsuda SP, Balliano G (2002a) Subcellular localization of oxidosqualene cyclase from Arabidopsis thaliana, Trypanosoma cruzi, and Pneumocystis carinii expressed in yeast. Lipids 37: 1171-1176. doi: 10.1007/s11745-002-1017-9.
  • Milla P, Athenstaedt K, Viola F, Oliaro-Bosso S, Kohlwein S, Daum G, Balliano G (2002b) Yeast oxidosqualene cyclase (Erg7p) is a major component of lipid particles. J Biol Chem 277: 2406-2412. doi: 10.1074/jbc.M104195200.
  • Mo C, Milla P, Athenstaedt K, Ott R, Balliano G, Daum G, Bard M (2003) In yeast sterol biosynthesis the 3-keto reductase protein (Erg27p) is required for oxidosqualene cyclase (Erg7p) activity. Biochim Biophys Acta 1633: 68-74. doi: 10.1016/S1388-1981(03)00088-X.
  • Nelson JA, Steckbeck SR, Spencer TA (1981) Biosynthesis of 24,25-Epoxycholesterol from squalene 2,3;22,23-dioxide. J Biol Chem 256: 1067-1068.
  • Oliaro-Bosso S, Viola F, Matsuda S, Cravotto G, Tagliapietra S, Balliano G (2004) Umbelliferone aminoalkyl derivatives as inhibitors of oxidosqualene cyclases from Saccharomyces cerevisiae, Trypanosoma cruzi and Pneumocystis carinii. Lipids 39: 1007-1012. doi: 10.1007/s11745-004-1323-2.
  • Taramino S, Valachovic M, Oliaro-Bosso S, Viola F, Teske B, Bard M, Balliano G (2010a) Interactions of oxidosqualene cyclase (Erg7p) with 3-keto reductase (Erg27p) and other enzymes of sterol biosynthesis in yeast. Biochim Biophys Acta 1801: 156-162. doi: 10.1016/j.bbalip.2009.10.005.
  • Taramino S, Teske B, Oliaro-Bosso S, Bard M, Balliano G (2010b) Divergent interactions involving the oxidosqualene cyclase and the steroid-3-ketoreductase in the sterol biosynthetic pathway of mammals and yeasts. Biochim Biophys Acta 1801: 1232-1237. doi: 10.1016/j.bbalip.2010.07.006.
  • Teske B, Taramino S, Bhuiyan MS, Kumaraswami NS, Randall SK, Barbuch R, Eckstein J, Balliano G, Bard M (2008) Genetic analyses involving interactions between the ergosterol biosynthetic enzymes, lanosterol synthase (Erg7p) and 3-ketoreductase (Erg27p), in the yeast Saccharomyces cerevisiae. Biochim Biophys Acta 1781: 359-366. doi: 10.1016/j.bbalip.2008.04.017.
  • Wilcox LJ, Balderes DA, Wharton B, Tinkelenberg AH, Rao G, Sturley SL (2002) Transcriptional profiling identifies two members of the ATP-binding cassette transporter superfamily required for sterol uptake in yeast. J Biol Chem 277: 32466-32472. DOI doi: 10.1074/jbc.M204707200.
  • Wong J, Quinn CM, Gelissen IC, Brown AJ (2008) Endogenous 24(S),25-epoxycholesterol fine-tunes acute control of cellular cholesterol homeostasis. J Biol Chem 283: 700-707. doi: 10.1074/jbc.M706416200.
Document Type
Publication order reference
YADDA identifier
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.