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Molecular investigation of mitochondrial inner membrane morphology

dc.contributor.advisorMeinecke, Michael Prof. Dr.
dc.contributor.authorTarasenko, Daryna
dc.titleMolecular investigation of mitochondrial inner membrane morphologyde
dc.contributor.refereeSchwappach, Blanche Prof. Dr.
dc.description.abstractengThe mitochondrial inner membrane (MIM) is highly curved and displays a complex but extremely organised ultrastructure. It is subdivided into two morphologically, topologically, as well as functionally, distinct compartments. The relatively flat inner boundary membrane (IBM) runs in the proximity to the mitochondrial outer membrane (MOM). The cristae membranes (CM) protrude towards the mitochondrial matrix. IBM and CM are joint by so-called cristae junctions (CJ). These narrow, tubular segments of the MIM are important not only for MIM organisation but also for overall mitochondrial and cellular physiology. The evolutionary conserved multi-subunit protein complex MICOS (mitochondrial contact sites and cristae organising system) was shown to play a profound role in CJ formation and stabilisation. MICOS deletion leads to a significant change of the MIM ultrastructure resulting in CJ loss and accumulation of CM in the form of enclosed membranous stacks. During this study, it was revealed that the MICOS core protein Mic60 displays membrane bending properties. Mic60 is able to remodel artificial membranes in vitro and induces the formation of cristae-like membrane invaginations when targeted to the bacterial cytoplasmic membrane in vivo. The membrane remodelling and lipid binding properties of the Mic60 protein are allocated to its intermembrane space domain. Experiments performed with the alphaproteobacterial homologues of Mic60 revealed that Mic60 membrane bending properties are evolutionary conserved. The alphaproteobacterial Mic60 proteins not only display membrane-remodelling effects on artificial and bacterial membranes but also, at least partially, are able to rescue the morphological defects of the MIM in mic60Δ eukaryotic cells. Thus, an unexpected role of Mic60 as a membrane-remodelling MICOS subunit was discovered. It was shown that these properties are driven by a very ancient and conserved mechanism, which, most probably, arose prior to the endosymbiotic event more than 1.5 billion years
dc.contributor.coRefereeDosch, Roland Dr.
dc.contributor.thirdRefereeJakobs, Stefan Prof. Dr.
dc.contributor.thirdRefereeKatschinski, Dörthe Prof. Dr.
dc.contributor.thirdRefereeStein, Alexander Dr.
dc.subject.engmitochondrial inner membranede
dc.subject.engcristae junctionsde
dc.subject.engMICOS complexde
dc.affiliation.instituteGöttinger Graduiertenschule für Neurowissenschaften, Biophysik und molekulare Biowissenschaften (GGNB)de
dc.subject.gokfullBiologie (PPN619462639)de

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