Research Report 2010 - MDC

acbFigure 1a: EHD2 is tubulatingphosphatidyl-serine (PS)liposomes and oligomerisesin ring-like oligomers asanalysed by negative-stainelectron microscopy.Micrographs of PS liposomesin the absence (top)or presence (bottom) ofEHD2 and 1 mM ATP-γ-S.Figure 1b: Ribbon-typepresentation of the EHD2dimer. The structure ofEHD2 was determined byX-ray crystallography. Thetwo-fold axis is indicted bya dashed line.Figure 1c: Top and side viewof the proposed EHD2oligomer with the lipidbindingsites of EHD2 pointingtowards the liposomesurface. The EH-domainsare omitted for clarity.with ATP binding and hydrolysis. Furthermore, wewould like to obtain structural information of membrane-boundoligomerised EHD2 using electron-paramagneticresonance studies. Finally, we are interestedto study the physiological function of EHD2 using cellularstudies.2. Structure and function of the GIMAP familyThe GIMAP GTPases comprise seven members inhumans which are predominantly expressed in cells ofthe immune system. Some of the members localise tothe mitochondrial membrane and are proposed to regulateapoptosis by regulating the entry of cytochrome cfrom the mitochondria into the cytosol. We will clarifythe exact function of this protein family at the mitochondriaand the interaction with membranes usingstructural, biochemical and cell-biological methods.These results will have implications for several types ofleukaemia in which GIMAP members are overexpressed.3. Structural insights into the antiviral effector MxA.Mx (myxovirus-resistance) proteins are interferoninducedkey effector molecules in the innate immunesystem mediating cellular resistance against a widerange of pathogens including influenza virus. The proteinsbelong to the dynamin superfamily and havebeen shown to tubulate liposomes and oligomerise inrings around the tubulated liposomes. We are interestedto understand the structural details of oligomerisationand to decipher the exact mode of antiviral actionusing a structural approach.Selected PublicationsDaumke O, Lundmark R, Vallis Y, Martens S, Butler PJ, McMahon HM.(2007) Architectural and mechanistic insights into an EHD ATPase involvedin membrane remodelling. Nature 449, 923-927.Henne WM, Kent HM, Ford MG, Hegde BG, Daumke O, Butler PJ, Mittal R,Langen R, Evans PR, McMahon HT. (2007) Structure and analysis of FCHo2F-BAR domain: A dimerizing and membrane recruitment module thateffects membrane curvature. Structure 15, 839-852.Kupzig S, Deaconescu D, Bouyoucef D, Walker SA, Liu Q, Polte CL, DaumkeO, Ishizaki T, Lockyer PJ, Wittinghofer A, Cullen PJ. (2006) GAP1 familymembers constitute bifunctional RAS and RAP GTPase-activating proteins.J Biol Chem 281, 9891-9900.Chakrabarti PP, Daumke O, Suveyzdis Y, Kötting C, Gerwert K, WittinghoferA. (2006) Insight into catalysis of a unique GTPase reaction by a combinedbiochemical and FTIR approach. J Mol Biol 367, 983-985.Daumke O, Weyand M, Chakrabarti PP, Vetter I, Wittinghofer A. (2004). TheGTPase-activating protein Rap1GAP uses a catalytic asparagine. Nature429, 197-201.Cancer Research 113