"Quantitative mass spectrometry of affinity purified ribosomes uncovers ribosome interactome specialization during viral infection”

Viruses are obligate intracellular parasites that rely on the host cell for their replication. While some viruses can encode proteins involved in the replication of their own genetic material, all known viruses depend exclusively on the host translation machinery for the synthesis of viral proteins. Translational control is thus a key stage of host-virus interactions, being regulated by the cell to restrict virus replication, and hijacked by many viruses to maximize their protein output.
Ribosomes are at the heart of the translation process and could therefore represent an important target for viruses to take control over host protein synthesis machinery. To test this hypothesis, we decided to study the potential changes in ribosome composition that might take place during the course of infection. To this aim, we introduced tandem-affinity tags to endogenous loci coding for ribosomal proteins and optimized a purification protocol that allowed to characterize the complete proteome of ribosomes in a quantitative manner. Applying this approach to cells infected with Sindbis virus (a positive-strand RNA virus from the alphavirus genus) we have been able to identify significant changes in ribosome composition taking place during viral replication. Our results expand the list of ribosome-interacting proteins and uncover new factors involved in virus replication.