Proteasomes (prosomes) inhibit the translation of tobacco mosaic virus RNA by preventing the formation of initiation complexes.

Proteasomes (prosomes) are large multiprotein complexes. They are involved in protein degradation of ubiquitin-conjugated proteins and in the generation of MHC class I peptides. We gave further evidence that they interfere with in vitro protein synthesis. Proteasomes inhibit the translation of Tobacco mosaic virus RNA. Analysis of cell-free systems by sucrose gradient centrifugation revealed that they prevent the formation of 80S initiation complexes but not the early phase of initiation.