CWH43 is required for the introduction of ceramides into GPI anchors in Saccharomyces cerevisiae.
After glycosylphosphatidylinositols (GPIs) are added to GPI proteins of Saccharomyces cerevisiae, the fatty acid in sn-2 of the diacylglycerol moiety can be replaced by a C26:0 fatty acid by a deacylation-reacylation cycle catalysed by Per1p and Gup1p. Furthermore the diacylglycerol moiety of the yeast GPI anchor can also be replaced by ceramides. CWH43 of yeast is homologous to PGAP2, a gene that recently was implicated in a similar deacylation reacylation cycle of GPI proteins in mammalian cells, where PGAP2 is required for the reacylation of monoradylglycerol-type GPI anchors. Here we show that mutants lacking CWH43 are unable to synthesize ceramide-containing GPI anchors, while the replacement of C18 by C26 fatty acids on the primary diacylglycerol anchor by Per1p and Gup1p is still intact. CWH43 contains the COG3568 metal hydrolase motif, which is found in many eukaryotic and prokaryotic enzymes. The conserved His 802 residue of this motif was identified as being essential for ceramide remodelling. Ceramide remodelling is not required for the normal integration of GPI proteins into the cell wall. All remodelling reactions are dependent on prior removal of the inositol-linked fatty acid by Bst1p.
Ghugtyal
Vikram
V
University of Fribourg, Department of Medicine, Ch. Du Musée 5, CH-1700 Fribourg, Switzerland.
Vionnet
Christine
C
Roubaty
Carole
C
Conzelmann
Andreas
A
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D002473:Cell Wall / Q000378:metabolism; D002518:Ceramides / Q000378:metabolism*; D005227:Fatty Acids / Q000302:isolation & purification; D017261:Glycosylphosphatidylinositols / Q000378:metabolism*; D006639:Histidine / Q000378:metabolism; D006867:Hydrolases; D007294:Inositol / Q000378:metabolism; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism*; D014162:Transfection
C524676:CWH43 protein, S cerevisiae; D002518:Ceramides; D005227:Fatty Acids; D017261:Glycosylphosphatidylinositols; D008565:Membrane Proteins; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D007294:Inositol; D006639:Histidine; D006867:Hydrolases; C509243:Bst1 protein, S cerevisiae; D010744:Phosphoric Monoester Hydrolases