Viral membrane fusion

Membrane fusion is essential for cellular entry of enveloped viruses. Here, authors use time-resolved cryo-electron tomography and subtomogram averaging to capture 3D organization and population evolution of intermediates during membrane fusion of CHIKV, a medically important alphavirus.

The mechanism of flavivirus activation for membrane fusion is not yet understood. Here, Vaney et al. describe how the viral pr protein, derived from an HSP40/DnaJ chaperonin, interacts with a pH sensing loop in the envelope protein E for fusogenic activation.

Major facilitator superfamily protein MFSD2A takes essential omega-3 fatty acids into the brain, and is the receptor of SYNC2 membrane fusogen in placenta. A cryo-EM structure of the human MFSD2A–SYNC2 complex reveals key aspects of MFSD2A transport and receptor mechanisms.

Here, Claireaux et al. show that people who naturally control HIV infection express lower levels of the viral co-receptor CCR5 in specific CD4⁺ T cells, and that this results from mutations or receptor internalization by CD4⁺ T cell-produced chemokines.

Adeno-associated viruses can be secreted in a pre-lytic manner as free or extracellular vesicle (EV)-associated particles. Here, Elmore et al. show that the recently identified membrane-associated accessory protein (MAAP) functions as an AAV egress factor via association to EVs.

Cryo-electron microscopy and cryo-electron tomography reveal conformational changes of the bluetongue virus capsid protein VP5 that lead to membrane perforation and virus release into the cytosol.