Université de Fribourg

Characterization of yeast mutants lacking alkaline ceramidases YPC1 and YDC1

Voynova, Natalia S. ; Mallela, Shamroop K. ; Vazquez, Hector M. ; Cerantola, Vanessa ; Sonderegger, Mélanie ; Knudsen, Jens ; Ejsing, Christer S. ; Conzelmann, Andreas

In: FEMS Yeast Research, 2014, vol. 14, no. 5, p. 776–788

Humans and yeast possess alkaline ceramidases located in the early secretory pathway. Single deletions of the highly homologous yeast alkaline ceramidases YPC1 and YDC1 have very little genetic interactions or phenotypes. Here, we performed chemical-genetic screens to find deletions/conditions that would alter the growth of ypc1∆ydc1∆ double mutants. These screens...

Université de Fribourg

Yeast cells lacking all known ceramide synthases continue to make complex sphingolipids and to incorporate ceramides into glycosylphosphatidylinositol (GPI)

Vionnet, Christine ; Roubaty, Carole ; Ejsing, Christer S. ; Knudsen, Jens ; Conzelmann, Andreas

In: Journal of Biological Chemistry, 2011, vol. 286, p. 6769-6779

In yeast, the inositolphosphorylceramides mostly contain C26:0 fatty acids. Inositolphosphorylceramides were considered to be important for viability because the inositolphosphorylceramide synthase AUR1 is essential. However, lcb1Δ cells, unable to make sphingoid bases and inositolphosphorylceramides, are viable if they harbor SLC1-1, a gain of function mutation in the...

Université de Fribourg

Aureobasidin A arrests growth of yeast cells through both ceramide intoxication and deprivation of essential inositolphosphorylceramides

Cerantola, Vanessa ; Guillas, Isabelle ; Roubaty, Carole ; Vionnet, Christine ; Uldry, Danièle ; Knudsen, Jens ; Conzelmann, Andreas

In: Molecular Microbiology, 2009, vol. 71, no. 6, p. 1523 - 1537

All mature Saccharomyces cerevisiae sphingolipids comprise inositolphosphorylceramides containing C26:0 or C24:0 fatty acids and either phytosphingosine or dihydrosphingosine. Here we analysed the lipid profile of lag1Δlac1Δ mutants lacking acyl-CoA-dependent ceramide synthesis, which require the reverse ceramidase activity of overexpressed Ydc1p for sphingolipid biosynthesis and viability....

Université de Fribourg

SLC1 and SLC4 encode partially redundant acyl-Coenzyme A 1-acylglycerol-3-phosphate O-acyltransferases of budding yeast

Benghezal, Mohammed ; Roubaty, Carole ; Veepuri, Vijayanath ; Knudsen, Jens ; Conzelmann, Andreas

In: Journal of Biological Chemistry, 2007, p. jbc.M702719200

Phosphatidic acid (PA) is the intermediate, from which all glycerophospholipids are synthesized. In yeast it is generated from lyso-phosphatidic acid, which is acylated by Slc1p, a sn-2-specific, acyl-Coenzyme A-dependent 1-acylglycerol-3-phosphate O-acyltransferase. Deletion of SLC1 is not lethal and does not eliminate all microsomal 1-acylglycerol-3-phosphate O-acyltransferase activity...

Université de Fribourg

Yeast sphingolipids do not need to contain very long chain fatty acids

Cerantola, Vanessa ; Vionnet, Christine ; Aebischer, Olivier F. ; Jenny, Titus A. ; Knudsen, Jens ; Conzelmann, Andreas

In: Biochemical Journal, 2007, vol. 401, no. 1, p. 205-216

Synthesis of VLCFAs (very long chain fatty acids) and biosynthesis of DHS (dihydrosphingosine) both are of vital importance for Saccharomyces cerevisiae. The bulk of VLCFAs and DHS are used for ceramide synthesis by the Lag1p (longevity-assurance gene 1)/Lac1p (longevity-assurance gene cognate 1)/Lip1p (Lag1p/Lac1p interacting protein) ceramide synthase. LAG1 and LAC1 are...

Université de Fribourg

Acyl-CoA-binding protein, Acb1p, is required for normal vacuole function and ceramide synthesis in Saccharomyces cerevisiae

Faergeman, Nils J. ; Feddersen, Søren ; Christiansen, Janne K. ; Larsen, Morten K. ; Schneiter, Roger ; Ungermann, Christian ; Mutenda, Kudzai ; Roepstroff, Peter ; Knudsen, Jens

In: Biochemical Journal, 2004, vol. 380, p. 907-918

In the present study, we show that depletion of acyl-CoA-binding protein, Acb1p, in yeast affects ceramide levels, protein trafficking, vacuole fusion and structure. Vacuoles in Acb1p-depleted cells are multi-lobed, contain significantly less of the SNAREs (soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptors) Nyv1p, Vam3p and Vti1p, and are unable to fuse in vitro. Mass...