title: The phosphatidylethanolamine level of yeast mitochondria is affected by the mitochondrial components Oxa1p and Yme1p.
abstract: The majority of phosphatidylethanolamine, an essential component of yeast mitochondria, is synthesized by phosphatidylserine decarboxylase 1 (Psd1p), a component of the inner mitochondrial membrane. Here, we report that deletion of OXA1 encoding an inner mitochondrial membrane protein translocase markedly affects the mitochondrial phosphatidylethanolamine level. In an oxa1Delta mutant, cellular and mitochondrial levels of phosphatidylethanolamine were lowered similar to a mutant with PSD1 deleted, and the rate of phosphatidylethanolamine synthesis by decarboxylation of phosphatidylserine in vivo and in vitro was decreased. This was due to a lower PSD1 transcription rate in the oxa1Delta mutant compared with wild-type and compromised assembly of Psd1p into the inner mitochondrial membrane. Lack of Mba1p, another component involved in the assembly of mitochondrial proteins into the inner mitochondrial membrane, did not affect the amount of phosphatidylethanolamine or the assembly of Psd1p. Deletion of the inner membrane protease Yme1p enhanced Psd1p stability suggesting that Yme1p contributed substantially to the proteolytic turnover of Psd1p in wild-type. In summary, our results demonstrate a link between the mitochondrial protein import machinery, assembly and stability of Psd1p, and phosphatidylethanolamine homeostasis in yeast mitochondria.
authors.affiliation: Institute of Biochemistry, Graz University of Technology, Austria.
authors.forename: Ruth
authors.initials: R
authors.lastname: Nebauer
authors.forename: Irmgard
authors.initials: I
authors.lastname: Schuiki
authors.forename: Birgit
authors.initials: B
authors.lastname: Kulterer
authors.forename: Zlatko
authors.initials: Z
authors.lastname: Trajanoski
authors.forename: Günther
authors.initials: G
authors.lastname: Daum
mesh_terms: D049069:ATP-Dependent Proteases; D000251:Adenosine Triphosphatases / Q000032:analysis / Q000378:metabolism*; D003576:Electron Transport Complex IV / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D009154:Mutation; D009687:Nuclear Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D010714:Phosphatidylethanolamines / Q000096:biosynthesis*; D010957:Plasmids; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000032:analysis / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism
chemical_list: D024101:Mitochondrial Proteins; D009687:Nuclear Proteins; C090858:OXA1 protein; D010714:Phosphatidylethanolamines; D029701:Saccharomyces cerevisiae Proteins; C483858:phosphatidylethanolamine; D003576:Electron Transport Complex IV; D049069:ATP-Dependent Proteases; C082702:YME1 protein, S cerevisiae; D000251:Adenosine Triphosphatases