Presentation

Members

Permanent
• Winfried Weissenhorn, Professor, University Grenoble Alpes
• Remy Sadoul, Professor, University Grenoble Alpes
• Cécile Boscheron, Scientist, CEA
• Delphine Guilligay, Engineer (IE), CNRS
• Christine Chatellard, Research Engineer (IR), University Grenoble Alpes
• Nolwenn Miguet, Technician and graduate student, University Grenoble Alpes

Non-permanent
• Christophe Caillat, Post-doc
• Guidenn Sulbaran Machado, Post-doc
• Kimi Azad, Post-doc
• Haiyan Wang, PhD student

Research topics

The focus of our research is to obtain insight into the structural and functional role of proteins and complexes that control and catalyze entry and budding processes of enveloped viruses such as HIV-1. We employ a combination of molecular biology, protein chemistry, X-ray crystallography and electron microscopy (collaboration) to address these questions.

Enveloped virus budding
Enveloped viruses express structural proteins that together with a distinct set of cellular proteins mediate virus assembly at cellular membranes and the release of infectious virions. We study cellular complexes such as ESCRT proteins and their regulators to understand the molecular mechanism of virus release by membrane fission.

Model for ESCRT-III driven HIV-1 budding
ESCRT-III is recruited once Gag assembly has been completed and Tsg101 and Alix are present at the budding site. First, CHMP4B is recruited and polymerizes within the membrane neck structure (green polymer), which may induce a first constriction of the neck. CHMP4B filaments then form the platform to recruit CHMP2B (red) alone or CHMP3-CHMP2A filaments (red) that can form dome-like structures. These polymers have a high affinity for membrane, which can induce membrane neck constriction and together with the action of VPS4 fission. VPS4-driven disassembly of ESCRT-III filaments and fission are likely concomitant processes.

HIV-1 entry
The HIV-1 envelope glycoprotein is composed of a receptor binding subunit, gp120 that is non-covalently linked to the membrane anchored fusion protein, gp41. Triggered by cellular receptor binding, the trimeric envelope complex mediates fusion of viral and cellular membranes through the rearrangement of the fusion protein subunit into a six helical bundle core structure. Our interest is to understand the structural transitions that gp41 undergoes from a native conformation to a fusion intermediate conformation and the final post fusion structure. Because gp41 contains highly conserved epitopes within its membrane proximal region (MPR), we aim to understand their conformation that is recognized by broadly neutralizing antibodies in order to exploit the structural knowledge for vaccine development.

Innate immune factors
The early step of infection triggers the expression of interferon-induced genes that act during an early defense mechanism. We study the structure and regulation of tetherin that physically links enveloped viruses including HIV-1 to the plasma membrane and targets them for lysosomal degradation in the absence of the viral antagonist. Likewise other restriction factors target budding and entry processes of a number of enveloped viruses and we study their structure to gain insight into their function.

Keywords

HIV-1, Env, ESCRT, membrane fission, budding, X-ray crystallography.

Selected publications

• Pinto,D., Fenwick, C., Caillat, C., Silacci, C., Guseva, S., Dehez, F., Chipot, C., Barbieri, S., Minola, A., Jarrossay, D., Tomaras, G.D., Shen, X., Riva, A., Tarkowski, M., Schwartz, O., Bruel, T., Dufloo, J., Seaman, M.S., Montefiori, D.C., Lanzavecchia, A., Corti, D., Pantaleo, G. and Weissenhorn, W. (2019) Structural Basis for Broad HIV-1 Neutralization by the MPER-Specific Human Broadly Neutralizing Antibody LN01. Cell Host & Microbe, 26(5):623-637.e8. doi : 10.1016/j.chom.2019.09.016.

• Maity S, Caillat C, Miguet N, Sulbaran G, Effantin G, Schoehn G, Roos WH, & Weissenhorn W (2019) VPS4 triggers constriction and cleavage of ESCRT-III helical filaments.Sci Adv 5(4) : eaau7198

• Ventimiglia, L.N., Cuesta-Geijo, M. A., Martinelli, N., Caballe, A., Macheboeuf, P., Miguet, M., Parnham, I. M., Olmos, Y., Carlton, J. G., Weissenhorn W. and Martin-Serrano, J. (2018) CC2D1B coordinates ESCRT-III activity during the mitotic reformation of the nuclear envelope. Dev Cell 47, 547-563.

• De Franceschi N, Alqabandi M, Miguet N, Caillat C, Mangenot S, Weissenhorn W and Bassereau P. (2018) The ESCRT protein CHMP2B acts as a diffusion barrier on reconstituted membrane necks. J Cell Sci. 132(4).

• Crespo-Yàñez X, Aguilar-Gurrieri C, Jacomin AC, Journet A, Mortier M, Taillebourg E, Soleilhac E, Weissenhorn W and Fauvarque MO. (2018) CHMP1B is a target of USP8/UBPY regulated by ubiquitin during endocytosis. PLoS Genet. 14(6):e1007456.

• Effantin, G., Estrozi, L., Ashman, N., Renesto, P., Stanke, N., Lindemann, D., Schoehn, G., and Weissenhorn, W. (2016) Cryo-electron microscopy Structure of the native Prototype Foamy Virus Glycoprotein and virus Architecture. PLoS Pathogens 12(7):e1005721.

• C. Caillat, P. Macheboeuf, Y. Wu, A.A. McCarthy, E. Boeri-Erba, G. Effantin, H.G. Gottlinger, W. Weissenhorn and P. Renesto (2015) Asymmetric ring structure of Vps4 required for ESCRT-III disassembly. Nat Commun 6:8781.

• V. Buzon, G. Natrajan, D. Schibli, F. Campelo, M. M. Kozlov, and W. Weissenhorn (2010) Crystal structure of HIV-1 gp41 including both fusion peptide and membrane proximal external regions. PLoS Pathogens, 6(5) e1000880

• A. Hinz, N.Miguet, G. Natrajan, Y. Usami, H. Yamanaka, P. Renesto, B. Hartlieb, A. A. McCarthy, J.-P. Simorre, H. Gottlinger and W. Weissenhorn (2010) Structural basis of HIV-1 tethering to membranes by the Bst2/tetherin ectodomain. Cell Host Microbe, 7, 314-323.

• Lata S, Schoehn G, Jain A, Pires R, Piehler J, Gottlinger HG, Weissenhorn W. (2008) Helical structures of ESCRT-III are disassembled by VPS4. Science 321, 1354-1357.

• T. Muziol, E. Pineda-Molina, G. Schoehn, R. Ravelli, A. Zamborlini, Y. Usami, H. Göttlinger, and W. Weissenhorn (2006) Structural basis for budding by the ESCRT-III factor CHMP3. Dev. Cell, 10, 821-830.

The complete publication list is available here.

The complete list of PhD thesis can be found here