@article{10639,
  abstract     = {With more than 80 members worldwide, the Orthobunyavirus genus in the Peribunyaviridae family is a large genus of enveloped RNA viruses, many of which are emerging pathogens in humans and livestock. How orthobunyaviruses (OBVs) penetrate and infect mammalian host cells remains poorly characterized. Here, we investigated the entry mechanisms of the OBV Germiston (GERV). Viral particles were visualized by cryo-electron microscopy and appeared roughly spherical with an average diameter of 98 nm. Labeling of the virus with fluorescent dyes did not adversely affect its infectivity and allowed the monitoring of single particles in fixed and live cells. Using this approach, we found that endocytic internalization of bound viruses was asynchronous and occurred within 30-40 min. The virus entered Rab5a+ early endosomes and, subsequently, late endosomal vacuoles containing Rab7a but not LAMP-1. Infectious entry did not require proteolytic cleavage, and endosomal acidification was sufficient and necessary for viral fusion. Acid-activated penetration began 15-25 min after initiation of virus internalization and relied on maturation of early endosomes to late endosomes. The optimal pH for viral membrane fusion was slightly below 6.0, and penetration was hampered when the potassium influx was abolished. Overall, our study provides real-time visualization of GERV entry into host cells and demonstrates the importance of late endosomal maturation in facilitating OBV penetration.},
  author       = {Windhaber, Stefan and Xin, Qilin and Uckeley, Zina M. and Koch, Jana and Obr, Martin and Garnier, Céline and Luengo-Guyonnot, Catherine and Duboeuf, Maëva and Schur, Florian KM and Lozach, Pierre-Yves},
  issn         = {1098-5514},
  journal      = {Journal of Virology},
  keywords     = {virology, insect science, immunology, microbiology},
  number       = {5},
  publisher    = {American Society for Microbiology},
  title        = {{The Orthobunyavirus Germiston enters host cells from late endosomes}},
  doi          = {10.1128/jvi.02146-21},
  volume       = {96},
  year         = {2022},
}

@article{10103,
  abstract     = {The small cellular molecule inositol hexakisphosphate (IP6) has been known for ~20 years to promote the in vitro assembly of HIV-1 into immature virus-like particles. However, the molecular details underlying this effect have been determined only recently, with the identification of the IP6 binding site in the immature Gag lattice. IP6 also promotes formation of the mature capsid protein (CA) lattice via a second IP6 binding site, and enhances core stability, creating a favorable environment for reverse transcription. IP6 also enhances assembly of other retroviruses, from both the Lentivirus and the Alpharetrovirus genera. These findings suggest that IP6 may have a conserved function throughout the family Retroviridae. Here, we discuss the different steps in the viral life cycle that are influenced by IP6, and describe in detail how IP6 interacts with the immature and mature lattices of different retroviruses.},
  author       = {Obr, Martin and Schur, Florian KM and Dick, Robert A.},
  issn         = {1999-4915},
  journal      = {Viruses},
  keywords     = {virology, infectious diseases},
  number       = {9},
  publisher    = {MDPI},
  title        = {{A structural perspective of the role of IP6 in immature and mature retroviral assembly}},
  doi          = {10.3390/v13091853},
  volume       = {13},
  year         = {2021},
}