Characterization of the mechanisms of HIV-1 Vpr(52-96) internalization in cells

Vanille J. Greiner, Volodymyr Shvadchak, Joëlle Fritz, Youri Arntz, Pascal Didier, Benoît Frisch, Christian Boudier, Yves Mély, Hugues De Rocquigny*

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

10 Citations (Scopus)


Addition of Vpr C-terminus to various cell types provokes cell apoptosis. This property was recently shown useful to develop inhibitors of cell proliferation. In that context, we investigated the cellular uptake of rhodamine- and fluorescein-labeled Vpr(52-96) peptides to understand the mechanism of Vpr C-terminus entry into cells. Dynamic light scattering data indicated that this peptide spontaneously formed polydispersed aggregates in cell culture medium. The fluorescently labeled Vpr(52-96) peptide was efficiently internalized, appearing either as large fluorescent patches in the cytoplasm or in a more diffuse form throughout the cell. Using isothermal titration calorimetry, we demonstrated that Vpr(52-96) can tightly associate with heparin, a glycosaminoglycan analog of heparan sulphate, suggesting a central role of the ubiquitous cell surface-associated heparan sulphate proteoglycans for the internalization of Vpr C-terminus. Fluorescently-labeled transferrin and methyl-β-cyclodextrin showed that the Vpr C-terminus was mediated through clathrin- and caveolae/raft-dependent endocytosis. We found that Vpr C-terminus uptake was partly blocked at 4 °C suggesting the importance of membrane fluidity for Vpr C-terminus entry. In fact, atomic force microscopy and liposome leakage further indicated that the Vpr peptide can destabilize and disrupt model membrane bilayers, suggesting that this mechanism may contribute to the passive entry of the peptide. Finally, using fluorescence lifetime imaging, we found that the Vpr(52-96) peptide was stable in cells for at least 48 h, probably as a consequence of the poor accessibility of the peptide to proteolytic enzymes in aggregates.

Original languageEnglish
Pages (from-to)1647-1658
Number of pages12
Issue number10
Publication statusPublished - Oct 2011
Externally publishedYes


  • Confocal microscopy
  • FLIM
  • Fluorescence
  • HIV
  • Vpr


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