Viral Infections Drive Functional Remodeling of Ribosome-Associated Proteins

Viruses hijack host ribosomes to synthesize their proteins and have evolved various strategies to manipulate translation, including the association of numerous non-ribosomal proteins, known as ribosome-associated proteins (RAPs), with the core ribosome. However, current methods of capturing RAPs that associate transiently and/or in small amounts with ribosomes are suboptimal. To address this issue, we developed an enhanced ribosome affinity purification (eRAP) method that enables the capture of over 500 previously unreported RAPs. Using eRAP, we investigated whether the composition of ribosomes changes during infection by two very different viruses: herpes simplex virus 1 (HSV-1) and Sindbis virus (SINV). Our results revealed that viral infection does not substantially alter the composition of core ribosomes but does drive extensive remodeling of RAPs in a virus-specific manner. Functional analyses with SINV showed that several of these RAPs are critical for viral propagation. Additionally, we discovered that the RAP ASCC3 plays a novel role in promoting the expression of secretory proteins, including viral glycoproteins. This occurs independently of ASCC3s canonical function of rescuing ribosome collisions. Together, our findings establish the ribosome as a dynamic regulatory hub that undergoes remodeling to achieve virus-specific translational output, highlighting the functional significance of ribosomal heterogeneity.