Membrane fusion, mediated by viral spike glycoproteins, is a key process in the infection cycle of all enveloped human and animal viruses. The overall goal of the proposed research is to understand the structural biology of viral membrane fusion. Although numerous crystal structures of the ectodomains of several enveloped virus spike glycoproteins have been determined over the years, we are only beginning to understand the structural transformations that take place when these proteins interact with membranes and how they drive membranes to fuse. In the previous grant period we have made substantial progress towards elucidating the structures of the fusion domains of influenza virus, human immunodeficiency virus, and Ebola virus in membrane environments. We have further been able to determine structural changes in these fusion domains that are conducive to membrane fusion. Most notably, membrane-bound influenza and Ebola virus fusion domains undergo large conformational changes in response to pH, i.e. there fusion trigger in the endosome. We also found that the conformation of the HIV fusion domain responds critically to cholesterol in the target membrane and that numerous critical mutants in these viral fusion domains affect their fusion function in a fashion that can be predicted by their altered structures. Based on these achievements, we now propose to test (1) the hypothesis that a deeper insertion of the Ebola virus fusion loop through a """"""""clenching of a fist"""""""" motion is responsible for Ebola GP2-mediated membrane fusion, (2) the hypothesis that cholesterol and possibly cholesterol-rich lipid domains plays a key role in human immunodeficiency and other virus entry, and (3) the hypothesis that a common membrane perturbation mechanism involving lipid order and bilayer curvature changes underlies membrane fusion promoted by influenza, HIV and Ebola viruses.

Public Health Relevance

Viral infections cause many difficult to cure diseases. One approach to combat viral infections is to find better viral entry inhibitors. This basic science project aims at a better fundamental understanding of how viruses such as influenza, HIV, and Ebola enter cells by membrane fusion. Knowledge gained from this research will help to eventually design new strategies to interrupt the infection cycle of these viruses at the stage of cell entry by membrane fusion. !

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
2R01AI030557-21
Application #
8461054
Study Section
Special Emphasis Panel (ZRG1-BCMB-H (02))
Program Officer
Repik, Patricia M
Project Start
1991-09-01
Project End
2017-08-31
Budget Start
2012-09-28
Budget End
2013-08-31
Support Year
21
Fiscal Year
2012
Total Cost
$519,918
Indirect Cost
$188,952
Name
University of Virginia
Department
Physiology
Type
Schools of Medicine
DUNS #
065391526
City
Charlottesville
State
VA
Country
United States
Zip Code
22904
Yang, Sung-Tae; Lim, Sung In; Kiessling, Volker et al. (2016) Site-specific fluorescent labeling to visualize membrane translocation of a myristoyl switch protein. Sci Rep 6:32866
Lee, Jinwoo; Gregory, Sonia M; Nelson, Elizabeth A et al. (2016) The Roles of Histidines and Charged Residues as Potential Triggers of a Conformational Change in the Fusion Loop of Ebola Virus Glycoprotein. PLoS One 11:e0152527
Yang, Sung-Tae; Kiessling, Volker; Tamm, Lukas K (2016) Line tension at lipid phase boundaries as driving force for HIV fusion peptide-mediated fusion. Nat Commun 7:11401
Yang, Sung-Tae; Kreutzberger, Alex J B; Lee, Jinwoo et al. (2016) The role of cholesterol in membrane fusion. Chem Phys Lipids 199:136-43
Yang, Sung-Tae; Kiessling, Volker; Simmons, James A et al. (2015) HIV gp41-mediated membrane fusion occurs at edges of cholesterol-rich lipid domains. Nat Chem Biol 11:424-31
Gregory, Sonia M; Larsson, Per; Nelson, Elizabeth A et al. (2014) Ebolavirus entry requires a compact hydrophobic fist at the tip of the fusion loop. J Virol 88:6636-49
Moissoglu, Konstadinos; Kiessling, Volker; Wan, Chen et al. (2014) Regulation of Rac1 translocation and activation by membrane domains and their boundaries. J Cell Sci 127:2565-76
Tamm, Lukas K; Lee, Jinwoo; Liang, Binyong (2014) Capturing glimpses of an elusive HIV gp41 prehairpin fusion intermediate. Structure 22:1225-6
Tamm, Lukas K (2013) Lateral membrane diffusion corralled. Biophys J 104:1399-400
Wang, Da-Neng; Stieglitz, Heather; Marden, Jennifer et al. (2013) Benjamin Franklin, Philadelphia's favorite son, was a membrane biophysicist. Biophys J 104:287-91

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