Bunyavirus Late Penetration and Autophagy
Cell Biology
Final Report Abstract
Bunyaviruses are important pathogenic arthropod-borne viruses (arboviruses), causing severe diseases in humans and domestic animals. Outbreaks are no longer limited to tropical and developing countries. Global trade, deforestation, and global warming are reasons for the expansion of arthropod vectors, and the viruses they carry. The mosquito-borne bunyavirus Rift Valley fever (RVFV) spread from sub- Saharan parts of Africa over the entire continent and to the Arabic peninsula during the last two decades. As it already happened for other arboviruses (e.g., dengue virus), RVFV is now at risk of introduction into Southern Europe. Bunyaviruses represent a risk to public health and agricultural productivity and must be taken seriously as potential emerging and reemerging pathogens. For humans, neither specific antiviral treatments nor vaccines are currently approved. Ideally, treating phlebovirus infection in humans would target early virus-host cell interactions, preventing the release of the virus genome into the cytosol. Yet, the details of the entry pathways exploited by phleboviruses are mostly elusive, awaiting to be uncovered. In this project, we used Uukuniemi virus (UUKV), which is a validated BSL-2 surrogate for phleboviruses of higher biosafety classification such as RVFV. Many open questions and conceptual uncertainties remain regarding bunyavirus entry. While UUKV can be confidently considered as a late-penetrating virus, infectious entry does not require Rab7, the only small Rab GTPase documented thus far as critical for the maturation of classical late endosomes. We previously analyzed small interfering RNAs against the whole human genome for their ability to block entry and infection by Uukuniemi (UUKV) and identified six Rab molecules with a potential role in UUKV infection. Within this project, we could confirm that two Rab molecules out of the six have a role in UUKV infection, i.e., Rab1b and Rab11a, and pursued investigation in the role of these two Rabs in UUKV cellular life cycle. Rab1b works in a coordinate manner with the guanine nucleotide exchange factor (GBF1) to govern vesicular trafficking in the ER-Golgi network. Rab11a regulates recycling endosome trafficking and is involved in the initiation of autophagy. Addressing single steps of the virus entry process and further stages of the viral infection, we found that Rab11 and GBF1 specifically promote UUKV entry and egress, respectively. Overall, the results gained here point towards the importance of Rab1b/GBF1 for the release of a broad range of RNA viruses while our data on Rab11a provide new insights into the role of this small GTPase in late endosomal intracellular trafficking in general.
Publications
- (2018). Deciphering virus entry with fluorescently labeled viral particles. Methods Mol Biol, 1836:159-83
Hoffmann A, Mazelier M, Léger P, and Lozach PY
(See online at https://doi.org/10.1007/978-1-4939-8678-1_8) - (2019). Cell biology of phlebovirus entry. Virologie, 23(3):176-87
Uckeley ZM, Koch J, Tischler N, Léger P, and Lozach PY
- (2019). Quantitative proteomics of Uukuniemi virus-host cell interactions reveals GBF1 as proviral host factor for phleboviruses. Mol Cell Proteomics, 18(12):2401-17
Uckeley ZM, Moeller R, Kühn LI, Nilsson E, Robens C, Lasswitz L, Lindqvist R, Lenman A, Passos V, Voß Y, Sommerauer C, Kampmann M, Goffinet C, Meissner F, Överby AK, Lozach PY, and Gerold G
(See online at https://doi.org/10.1074/mcp.ra119.001631) - (2020). Cell Biology of viral infections. Cells, 9(11):2431
Lozach PY
(See online at https://doi.org/10.3390/cells9112431) - (2020). Novel Toscana virus reverse genetics system establishes NSs as an antagonist of type I interferon responses. Viruses, 12(4):400
Woelfl F, Léger P, Oreshkova N, Pahmeier F, Windhaber S, Koch J, Stanifer M, Roman Sosa G, Uckeley ZM, Rey FA, Boulant S, Kortekaas J, Wichgers Schreur PJ, and Lozach PY
(See online at https://doi.org/10.3390/v12040400) - (2020). NSs amyloid formation is associated with the virulence of Rift Valley fever virus in mice. Nat Com, 11(1):3281
Léger P, Nachman E, Richter K, Tamietti C, Koch J, Burk R, Kummer S, Xin Q, Stanifer M, Bouloy M, Boulant S, Kräusslich HG, Montagutelli X, Flamand M, Nussbaum-Krammer C, and Lozach PY
(See online at https://doi.org/10.1038/s41467-020-17101-y) - (2021). Rift Valley fever virus and the amazing NSs protein. Med Sci, 37:601-8
Léger P and Lozach PY
(See online at https://doi.org/10.1051/medsci/2021090) - (2021). TMPRSS2 expression dictates the entry route used by SARS-CoV-2 to infect host cells. Embo J, e107821
Koch J, Uckeley ZM, Doldan P, Stanifer M, Boulant S, and Lozach PY
(See online at https://doi.org/10.15252/embj.2021107821)
