biostudies-literatureMcLaren MMedical Research CouncilRCUK | Biotechnology and Biological Sciences Research CouncilEC | Horizon 2020 Framework ProgrammeMinisterio de Economía y CompetitividadWellcome TrustBiotechnology and Biological Sciences Research Council1834-1845https://www.ebi.ac.uk/biostudies/studies/S-EPMC10522483biostudies-literatureUnknown8(10)Translational control is an essential process for the cell to adapt to varying physiological or environmental conditions. To survive adverse conditions such as low nutrient levels, translation can be shut down almost entirely by inhibiting ribosomal function. Here we investigated eukaryotic hibernating ribosomes from the microsporidian parasite Spraguea lophii in situ by a combination of electron cryo-tomography and single-particle electron cryo-microscopy. We show that microsporidian spores contain hibernating ribosomes that are locked in a dimeric (100S) state, which is formed by a unique dimerization mechanism involving the beak region. The ribosomes within the dimer are fully assembled, suggesting that they are ready to be activated once the host cell is invaded. This study provides stNature microbiologyCryoEM reveals that ribosomes in microsporidian spores are locked in a dimeric hibernating state.PMC10522483803894BB/R008639/1212439/Z/18/Z202904/Z/16/ZBB/R000484/1206181/Z/17/ZCTQ201782222-RIsupov MNWalter ADaum BGold VAMMcLaren MGambelli LGil-Diez PConnell SRConners RWilliams BfalseCryoEM reveals that ribosomes in microsporidian spores are locked in a dimeric hibernating state.Translational control is an essential process for the cell to adapt to varying physiological or environmental conditions. To survive adverse conditions such as low nutrient levels, translation can be shut down almost entirely by inhibiting ribosomal function. Here we investigated eukaryotic hibernating ribosomes from the microsporidian parasite Spraguea lophii in situ by a combination of electron cryo-tomography and single-particle electron cryo-microscopy. We show that microsporidian spores contain hibernating ribosomes that are locked in a dimeric (100S) state, which is formed by a unique dimerization mechanism involving the beak region. The ribosomes within the dimer are fully assembled, suggesting that they are ready to be activated once the host cell is invaded. This study provides st2023-01-01T00:00:00Z2023 Oct2026-04-12T23:03:37.148Z2025-02-19T04:08:07.379ZS-EPMC105224833770990210.1038/s41564-023-01469-w