Filovirus Entry: A Novelty in the Viral Fusion World

Hunt, Catherine L.; Lennemann, Nicholas J.; Maury, Wendy

Unlike some other class I viral glycoproteins, no evidence exists that EBOV GP 1 undergoes conformational changes upon binding to a cell surface receptor. Presumably receptor/virus interactions lead directly to virus internalization into endosomes; however, this has not been demonstrated directly to date. Characterization of the endosomal vesicles mediating EBOV uptake is limited. Saaed et al. have demonstrated that the Early Endosome Antigen 1 (EEA1) colocalizes with EBOV virus particles in endosomes early during infection of Vero cells [62] , whereas Nanbo et al. have shown association of EBOV particles lacking VP30 associated with the sorting nexin 5 (SNX5) within 10 minutes of transduction [63] . Early and late endosomal proteins, Rab5 and Rab 7, respectively, have also been shown to be required for productive infection [62, 63] . Several GTPases previously implicated in endocytosis, RhoB, Rac1 and CDC42, are also important for EBOV GP-dependent transduction, providing additional insights into trafficking pathways used by these viruses [63, 76] .