tailieunhanh - Báo cáo khoa học: PSI1 is responsible for the stearic acid enrichment that is characteristic of phosphatidylinositol in yeast

In yeast, both phosphatidylinositol and phosphatidylserine are synthesized from cytidine diphosphate-diacylglycerol. Because, as in other eukaryotes, phosphatidylinositol contains more saturated fatty acids than phosphati-dylserine (and other phospholipids), it has been hypothesized that either phosphatidylinositol is synthesized from distinct cytidine diphosphate-diacylglycerol molecules, | PSI1 is responsible for the stearic acid enrichment that is characteristic of phosphatidylinositol in yeast Marina Le Guedard1 Jean-Jacques Bessoule1 Valerie Boyer1 Sophie Ayciriex1 Gisele Velours2 Willem Kulik3 Christer S. Ejsing4 Andrej Shevchenko4 Denis Coulon1 Rene Lessire1 and Eric Testet1 1 CNRS Laboratoire de Biogenese Membranaire CNRS UMR5200 Universite de Bordeaux France 2 CNRS Institut de Biochimie et Genetique Cellulaires CNRS UMR5095 Universite de Bordeaux France 3 Academic MedicalCenter Laboratory Genetic Metabolic Diseases Emma Children s Hospitaland Department of ClinicalChemistry University of Amsterdam The Netherlands 4 Max Planck Institute of Molecular CellBiology and Genetics Dresden Germany Keywords glycerolipid acyltransferase phosphatidylinositolremodeling Saccharomyces cerevisiae stearic acid YBR042C Correspondence E. Testet CNRS Laboratoire de Biogenese Membranaire CNRS UMR5200 Universite de Bordeaux 146 rue Leo Saignat Case 92 33076 Bordeaux Cedex France Fax 33 5 56 51 83 61 Tel 33 5 57 57 11 68 E-mail Present address Department of Biochemistry and Molecular Biology University of Southern Denmark Odense Denmark Received 22 June 2009 revised 28 August 2009 accepted 4 September 2009 doi In yeast both phosphatidylinositol and phosphatidylserine are synthesized from cytidine diphosphate-diacylglycerol. Because as in other eukaryotes phosphatidylinositol contains more saturated fatty acids than phosphatidylserine and other phospholipids it has been hypothesized that either phosphatidylinositol is synthesized from distinct cytidine diphosphatediacylglycerol molecules or that after its synthesis it is modified by a hypothetical acyltransferase that incorporates saturated fatty acid into neo-synthesized molecules of phosphatidylinositol. We used database search methods to identify an acyltransferase that could catalyze such an activity. Among the various proteins that we studied we