Our overall approach is to kinetically resolve steps in the pathway of viral envelope glycoprotein-mediated membrane fusion and to uncover physical parameters underlying those steps using a variety of biochemical, biophysical, virological, and molecular and cell biological techniques in vitro studies with infectious virus and HIV envelope proteins expressed in cells. We are using peptide-based entry inhibitors linked to specific lipids to probe details of the fusion reaction. We have recently shown that conjugation of sphinganine (a precursor of dehydrospingomyelin) confers a striking specificity to the inhibitory potential of a short HIV-based peptide suggesting that sphingopeptides act as double edged swords with both lipid and peptide playing a role in the inhibition of HIV entry. We have developed novel methodologies to study fusion based on photo-induced chemical reactions in the membrane using hydrophobic probes such as Iodonaphtylazide. We are applying this methodology both in the analytical mode (identification of domains of viral proteins and of receptors involved in fusion) and the functional mode (affecting viral protein-induced fusion). Using photo-reactive hydrophobic probes we have found ways to inactivate viral envelope glycoproteins while leaving their overall structures intact. These studies have important implications for anti-viral therapies and vaccine development.

National Institute of Health (NIH)
National Cancer Institute (NCI)
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National Cancer Institute Division of Basic Sciences
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Klug, Yoel A; Ashkenazi, Avraham; Viard, Mathias et al. (2014) Early and late HIV-1 membrane fusion events are impaired by sphinganine lipidated peptides that target the fusion site. Biochem J 461:213-22
Reingewertz, Tali H; Britan-Rosich, Elena; Rotem-Bamberger, Shahar et al. (2013) Mapping the Vif-A3G interaction using peptide arrays: a basis for anti-HIV lead peptides. Bioorg Med Chem 21:3523-32
Blumenthal, Robert; Durell, Stewart; Viard, Mathias (2012) HIV entry and envelope glycoprotein-mediated fusion. J Biol Chem 287:40841-9
Ashkenazi, Avraham; Viard, Mathias; Unger, Linor et al. (2012) Sphingopeptides: dihydrosphingosine-based fusion inhibitors against wild-type and enfuvirtide-resistant HIV-1. FASEB J 26:4628-36
Reuven, Eliran Moshe; Dadon, Yakir; Viard, Mathias et al. (2012) HIV-1 gp41 transmembrane domain interacts with the fusion peptide: implication in lipid mixing and inhibition of virus-cell fusion. Biochemistry 51:2867-78
Belanger, Julie M; Raviv, Yossef; Viard, Mathias et al. (2012) Orthogonal inactivation of influenza and the creation of detergent resistant viral aggregates: towards a novel vaccine strategy. Virol J 9:72
Yavlovich, Amichai; Viard, Mathias; Zhou, Ming et al. (2012) Ectopic ATP synthase facilitates transfer of HIV-1 from antigen-presenting cells to CD4(+) target cells. Blood 120:1246-53
Belanger, Julie M; Raviv, Yossef; Viard, Mathias et al. (2011) Effects of UVA irradiation, aryl azides, and reactive oxygen species on the orthogonal inactivation of the human immunodeficiency virus (HIV-1). Virology 417:221-8
Ashkenazi, Avraham; Viard, Mathias; Wexler-Cohen, Yael et al. (2011) Viral envelope protein folding and membrane hemifusion are enhanced by the conserved loop region of HIV-1 gp41. FASEB J 25:2156-66
Rosa Borges, Andrew; Wieczorek, Lindsay; Johnson, Benitra et al. (2010) Multivalent dendrimeric compounds containing carbohydrates expressed on immune cells inhibit infection by primary isolates of HIV-1. Virology 408:80-8

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