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

doi:10.1111/1567-1364.12169

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Characterization of yeast mutants lacking alkaline ceramidases YPC1 and YDC1

Université de Fribourg

Voynova, Natalia S. Department of Biology, University of Fribourg, Fribourg, Switzerland - Temasek Life Sciences Laboratory, National University of Singapore, Singapore City, Singapore
Mallela, Shamroop K. Department of Biology, University of Fribourg, Fribourg, Switzerland
Vazquez, Hector M. Department of Biology, University of Fribourg, Fribourg, Switzerland
Cerantola, Vanessa Department of Biology, University of Fribourg, Fribourg, Switzerland - Philip Morris Products SA, Neuchatel, Switzerland
Sonderegger, Mélanie Department of Biology, University of Fribourg, Fribourg, Switzerland
Knudsen, Jens Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
Ejsing, Christer S. Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
Conzelmann, Andreas Department of Biology, University of Fribourg, Fribourg, Switzerland

01.08.2014

Published in:

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

English 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 were essentially negative, demonstrating that ceramidase activity is not required for cell growth even under genetic stresses. A previously reported protein targeting defect of ypc1∆ could not be reproduced and reported abnormalities in sphingolipid biosynthesis detected by metabolic labeling do not alter the mass spectrometric lipid profile of ypc1∆ydc1∆ cells. Ceramides of ypc1∆ydc1∆ remained normal even in presence of aureobasidin A, an inhibitor of inositolphosphorylceramide synthase. Moreover, in caloric restriction conditions Ypc1p reduces chronological life span. A novel finding is that, when working backwards as a ceramide synthase in vivo, Ypc1p prefers C24 and C26 fatty acids as substrates, whereas it prefers C16:0, when solubilized in detergent and working in vitro. Therefore, its physiological activity may not only concern the minor ceramides containing C14 and C16. Intriguingly, so far the sole discernable benefit of conserving YPC1 for yeast resides with its ability to convey relative resistance toward H₂O₂.

Faculty

Faculté des sciences et de médecine

Department

Département de Biologie

Language