tailieunhanh - Báo cáo khoa học: The phosphatidylethanolamine level of yeast mitochondria is affected by the mitochondrial components Oxa1p and Yme1p

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 OXA1encoding an inner mitochondrial membrane protein translocase markedly affects the mitochondrial phosphatidyletha-nolamine level. | ễFEBS Journal The phosphatidylethanolamine level of yeast mitochondria is affected by the mitochondrial components Oxalp and Ymelp Ruth Nebauer1 Irmgard Schuiki1 Birgit Kulterer2 Zlatko Trajanoski2 and Gunther Daum1 1 Institute of Biochemistry Graz University of Technology Austria 2 Institute for Genomics and Bioinformatics and Christian-Doppler Laboratory for Genomics and Bioinformatics Graz University of Technology Austria Keywords mitochondria Oxa1p phosphatidylethanolamine phosphatidylserine decarboxylase yeast Correspondence G. Daum Institute of Biochemistry Graz University of Technology Petersgasse 12 2 A-8010 Graz Austria Fax 43 316 873 6952 Tel 43 316 873 6462 E-mail Received 27 August 2007 revised 10 October 2007 accepted 11 October 2007 doi The majority of phosphatidylethanolamine an essential component of yeast mitochondria is synthesized by phosphatidylserine decarboxylase 1 Psdlp 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 oxalD 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 oxalD 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 .