Proteomic and mechanistic dissection of the poxvirus-customized ribosome

Stephen DiGiuseppe, Madeline G. Rollins, Helen Astar, Natalia Khalatyan, Jeffrey N. Savas, Derek Walsh

Research output: Contribution to journalArticlepeer-review

Abstract

Ribosomes are often viewed as protein synthesis machines that lack intrinsic regulatory capacity. However, studies have established that ribosomes can functionally diversify through changes in the composition of, or post-translational modifications to ribosomal subunit proteins (RPs). We recently found that poxviruses phosphorylate unique sites in the RP, receptor for activated C kinase 1 (RACK1) to enhance viral protein synthesis. Here, we developed approaches for large-scale proteomic analysis of ribosomes isolated from cells infected with different viruses. Beyond RACK1, we identified additional phosphorylation events within RPS2 and RPS28 that arise during poxvirus infection, but not other viruses tested. The modified sites lie within unstructured loop domains that position around the mRNA entry and exit channel, respectively, and site-substitution mutants revealed that each modified residue contributed differently to poxvirus replication. Our findings reveal the broader extent to which poxviruses customize host ribosomes and provide new insights into how ribosomes can functionally diversify.

Original languageEnglish (US)
JournalJournal of cell science
Volume134
Issue number5
DOIs
StatePublished - Jul 9 2020

Keywords

  • Phosphorylation
  • Post-translational modification
  • Poxvirus
  • RPS
  • Ribosome

ASJC Scopus subject areas

  • Cell Biology

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