Objective Fusion of two biological membranes is essential to life. It is required during organism development, for trafficking of material between cellular compartments, for transfer of information across synapses, and for entry of viruses into cells. Fusion must be carefully controlled and the core fusion components are typically found within a complex regulatory machine. There have been decades of research on the structure and function of individual components, on the dynamics and biophysics of fusion, and on phenotypes resulting from mutating or inhibiting component proteins. These have led to a model for fusion in which regulated refolding or assembly of proteins draws two membranes closer together until they fuse. Despite this breadth of study, we know very little about how the components of the fusion machinery function in context: How are they arranged on the membrane around the site of fusion? How do they respond structurally to regulation? How does the fully assembled machinery rearrange to reshape the membrane and drive fusion? These gaps in knowledge can be attributed to a shortage of structural biology methods able to derive structural data on proteins assembled within complex, heterogeneous or dynamic environments such as a fusion site. Here I propose to apply a combination of state-of-the-art cryo-electron tomography, image processing and correlative fluorescence and electron microscopy methods to obtain detailed structural information on assembled fusion machineries and of fusion intermediates both in vitro and in vivo. I will study how influenza virus fuses with a target membrane, complemented by studies on fusion of HIV-1 and of synaptic vesicles. By determining how viral and synaptic fusion complexes reposition and restructure prior to fusion, how they arrange around the fusion site, how they reshape the membrane to induce fusion, and how these processes can be regulated and inhibited, I will derive a mechanistic model of membrane fusion in situ. Fields of science natural sciencesbiological sciencesmicrobiologyvirologymedical and health scienceshealth sciencesinfectious diseasesRNA virusesebolanatural sciencesbiological sciencesbiochemistrybiomoleculesproteinsnatural sciencesphysical sciencesopticsmicroscopyelectron microscopynatural sciencesbiological sciencesmolecular biologystructural biology Programme(s) H2020-EU.1.1. - EXCELLENT SCIENCE - European Research Council (ERC) Main Programme Topic(s) ERC-CoG-2014 - ERC Consolidator Grant Call for proposal ERC-2014-CoG See other projects for this call Funding Scheme ERC-COG - Consolidator Grant Host institution UNITED KINGDOM RESEARCH AND INNOVATION Net EU contribution € 1 785 961,00 Address POLARIS HOUSE NORTH STAR AVENUE SN2 1FL Swindon United Kingdom See on map Region South West (England) Gloucestershire, Wiltshire and Bristol/Bath area Swindon Activity type Research Organisations Links Contact the organisation Opens in new window Website Opens in new window Participation in EU R&I programmes Opens in new window HORIZON collaboration network Opens in new window Total cost € 1 785 961,00 Beneficiaries (2) Sort alphabetically Sort by Net EU contribution Expand all Collapse all UNITED KINGDOM RESEARCH AND INNOVATION United Kingdom Net EU contribution € 1 785 961,00 Address POLARIS HOUSE NORTH STAR AVENUE SN2 1FL Swindon See on map Region South West (England) Gloucestershire, Wiltshire and Bristol/Bath area Swindon Activity type Research Organisations Links Contact the organisation Opens in new window Website Opens in new window Participation in EU R&I programmes Opens in new window HORIZON collaboration network Opens in new window Total cost € 1 785 961,00 EUROPEAN MOLECULAR BIOLOGY LABORATORY Participation ended Germany Net EU contribution € 180 000,00 Address Meyerhofstrasse 1 69117 Heidelberg See on map Region Baden-Württemberg Karlsruhe Heidelberg, Stadtkreis Activity type Research Organisations Links Contact the organisation Opens in new window Website Opens in new window Participation in EU R&I programmes Opens in new window HORIZON collaboration network Opens in new window Total cost € 180 000,00