Biophysical Society Thematic Meeting| Padova 2019

Quantitative Aspects of Membrane Fusion and Fission

Friday Speaker Abstracts

STRUCTURAL INSIGHTS INTO MITOCHONDRIAL INNER MEMBRANE REMODELING Katja Faelber 1 ; Lea Dietrich 2 ; Jeffrey Noel 1 ; Werner Kühlbrandt 2 ; Oliver Daumke 1,3 ; 1 Max Delbrück Center for Molecular Medicine, Crystallography, Berlin, Germany 2 Max Planck Institute of Biophysics, Structural Biology, Frankfurt/Main, Hessen, Germany 3 Freie Universität Berlin, Institute of Biochemistry, Berlin, Germany Mitochondrial Genome Maintenance Protein1 (Mgm1) is a dynamin-like GTPase in fungi that remodels the mitochondrial inner membrane (IM). Mgm1 is involved in membrane fusion and in the stabilization of the cristae architecture. Since the underlying molecular mechanisms were unknown, we solved the 3.6 Åcrystal structure of Mgm1 and determined the assembly mechanism of Mgm1 on membranes by cryo electron tomography.Whereas the overall domain composition of the Mgm1 structure is similar to other dynamin superfamily members, the assembly model is remarkable different to that of dynamin. Biochemical assays and molecular dynamic simulations confirm our structural data.Based on our new structures we propose molecular models how the assembly of Mgm1 on positive or negative membrane curvature remodels the IM of mitochondria.

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