Internalization and Fusion Mechanism of Vesicular Stomatitis Virus and Related Rhabdoviruses

Abstract

Members of the Rhabdoviridae infect a wide variety of animals and plants, and are the causative agents of many important diseases. Rhabdoviruses enter host cells following internalization into endosomes, with the glycoprotein (G protein) mediating both receptor binding to host cells and fusion with the cellular membrane. The recently solved crystal structure of vesicular stomatitis virus G has allowed considerable insight into the mechanism of rhabdovirus entry, in particular the low pH-dependent conformational changes that lead to fusion activation. Rhabdovirus entry shows several distinct features compared with other enveloped viruses; first, the entry process appears to consist of two distinct fusion events, initial fusion into vesicles within endosomes followed by back-fusion into the cytosol; second, the conformational changes in the G protein that lead to fusion activation are reversible; and third, the G protein is structurally distinct from other viral fusion proteins and is not proteolytically cleaved. The internalization and fusion mechanisms of rhabdoviruses are discussed in this article, with a focus on viral systems where the G protein has been studied extensively: vesicular stomatitis virus and rabies virus, as well as viral hemorrhagic septicemia virus.

CD46 Null Packaging Cell Line Improves Measles Lentiviral Vector Production and Gene Delivery to Hematopoietic Stem and Progenitor Cells

“…We first compared the subcellular trafficking of H/F LV produced in WT HEK293T cells with VSV-G LV in activated UCB-derived CD34 + HSPCs through staining for EEA1 and by co-localization of LV p24 protein by confocal microscopy (Figure 5A). VSV-G was shown to co-localize with EEA1 + endosomes 15 min after LV addition and decrease after 1 hr, consistent with VSV-G LV’s reported dependence on endosomal maturation for core escape (Figure 5B) 34 . By contrast, WT H/F LV p24 showed minimal co-localization with EEA1 + signal at both time points, supporting a non-endosome-mediated entry mechanism.

Figure 5H/F LVs Demonstrate Distinct Cellular Trafficking Patterns and Improved Transduction Ability in Cytokine-Stimulated CD34 + HSPCs(A) Experimental workflow of transduction of UCB-derived CD34 + HSPCs by VSV-G or H/F LV.

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His-tagged norovirus-like particles: A versatile platform for cellular delivery and surface display

“…As shown in Figure 6, the delivery of Alexa488 into HEK293T cells was only observed when cells were exposed to VLPs displaying both Alexa488 and VSV-G conjugates. By contrast, there was no detectable fluorescence signal This experimental set-up can be considered challenging, as the VSV-G peptide transduces cells as a trimer [39] and there was no control over the exact location of conjugation as to enter three adjacent peptides near each other. This configuration therefore differs from the traditional method of pseudotyping, in which the VSV-G is inherently integrated into the VLP or virus envelope through co-transfection of expression vectors.…”

Inhibitors of thiol-mediated uptake

“…receptor. [12][13][14][26][27][28][29][30] The unusual, formally anti-cooperative (Hill coefficients < 1) DRCs further supported thiol-mediated uptake as complex multitarget systems. Despite the complexity of these systems, results did not much depend on assay conditions.…”

“…The covalently bound substrate then enters the cell either by fusion, endocytosis, or direct translocation across the plasma membrane into the cytosol. Thiol-disulde exchange has been conrmed to play an essential role in the cellular entry of some viruses 1, [11][12][13][14] and toxins. 2 Indeed, diphtheria toxin and HIV were among the rst to be recognized to enter cells via thiol-mediated uptake.…”