| Structural highlights
Function
[MDM35_YEAST] Involved in mitochondrial distribution and morphology. Mediates the import of UPS1, UPS2 and UPS3, 3 atypical mitochondrial intermembrane space (IMS) proteins lacking the two major IMS-targeting signals, into the intermembrane space.[1] [2] [3] [UPS1_YEAST] Required for maintenance of normal mitochondrial morphology as well as PCP1-dependent processing of MGM1. With UPS2, controls the level of cardiolipin in mitochondria. Cardiolipin is a unique phospholipid with four fatty acid chains and is present mainly in the mitochondrial inner membrane where it stabilizes the electron transport chain supercomplex between complexes III and IV through direct interaction of their subunits.[4] [5] [6] [7]
Publication Abstract from PubMed
Eukaryotic cells are compartmentalized into membrane-bounded organelles whose functions rely on lipid trafficking to achieve membrane-specific compositions of lipids. Here we focused on the Ups1-Mdm35 system, which mediates phosphatidic acid (PA) transfer between the outer and inner mitochondrial membranes, and determined the X-ray structures of Mdm35 and Ups1-Mdm35 with and without PA. The Ups1-Mdm35 complex constitutes a single domain that has a deep pocket and flexible Omega-loop lid. Structure-based mutational analyses revealed that a basic residue at the pocket bottom and the Omega-loop lid are important for PA extraction from the membrane following Ups1 binding. Ups1 binding to the membrane is enhanced by the dissociation of Mdm35. We also show that basic residues around the pocket entrance are important for Ups1 binding to the membrane and PA extraction. These results provide a structural basis for understanding the mechanism of PA transfer between mitochondrial membranes.
Structural and mechanistic insights into phospholipid transfer by Ups1-Mdm35 in mitochondria.,Watanabe Y, Tamura Y, Kawano S, Endo T Nat Commun. 2015 Aug 3;6:7922. doi: 10.1038/ncomms8922. PMID:26235513[8]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Dimmer KS, Fritz S, Fuchs F, Messerschmitt M, Weinbach N, Neupert W, Westermann B. Genetic basis of mitochondrial function and morphology in Saccharomyces cerevisiae. Mol Biol Cell. 2002 Mar;13(3):847-53. PMID:11907266 doi:10.1091/mbc.01-12-0588
- ↑ Tamura Y, Iijima M, Sesaki H. Mdm35p imports Ups proteins into the mitochondrial intermembrane space by functional complex formation. EMBO J. 2010 Sep 1;29(17):2875-87. doi: 10.1038/emboj.2010.149. Epub 2010 Jul 9. PMID:20622808 doi:http://dx.doi.org/10.1038/emboj.2010.149
- ↑ Potting C, Wilmes C, Engmann T, Osman C, Langer T. Regulation of mitochondrial phospholipids by Ups1/PRELI-like proteins depends on proteolysis and Mdm35. EMBO J. 2010 Sep 1;29(17):2888-98. doi: 10.1038/emboj.2010.169. Epub 2010 Jul 23. PMID:20657548 doi:http://dx.doi.org/10.1038/emboj.2010.169
- ↑ Sesaki H, Dunn CD, Iijima M, Shepard KA, Yaffe MP, Machamer CE, Jensen RE. Ups1p, a conserved intermembrane space protein, regulates mitochondrial shape and alternative topogenesis of Mgm1p. J Cell Biol. 2006 Jun 5;173(5):651-8. PMID:16754953 doi:http://dx.doi.org/10.1083/jcb.200603092
- ↑ Osman C, Haag M, Potting C, Rodenfels J, Dip PV, Wieland FT, Brugger B, Westermann B, Langer T. The genetic interactome of prohibitins: coordinated control of cardiolipin and phosphatidylethanolamine by conserved regulators in mitochondria. J Cell Biol. 2009 Feb 23;184(4):583-96. doi: 10.1083/jcb.200810189. Epub 2009 Feb, 16. PMID:19221197 doi:http://dx.doi.org/10.1083/jcb.200810189
- ↑ Tamura Y, Endo T, Iijima M, Sesaki H. Ups1p and Ups2p antagonistically regulate cardiolipin metabolism in mitochondria. J Cell Biol. 2009 Jun 15;185(6):1029-45. Epub 2009 Jun 8. PMID:19506038 doi:http://dx.doi.org/jcb.200812018
- ↑ Tamura Y, Iijima M, Sesaki H. Mdm35p imports Ups proteins into the mitochondrial intermembrane space by functional complex formation. EMBO J. 2010 Sep 1;29(17):2875-87. doi: 10.1038/emboj.2010.149. Epub 2010 Jul 9. PMID:20622808 doi:http://dx.doi.org/10.1038/emboj.2010.149
- ↑ Watanabe Y, Tamura Y, Kawano S, Endo T. Structural and mechanistic insights into phospholipid transfer by Ups1-Mdm35 in mitochondria. Nat Commun. 2015 Aug 3;6:7922. doi: 10.1038/ncomms8922. PMID:26235513 doi:http://dx.doi.org/10.1038/ncomms8922
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