Human cytomegalovirus (HCMV) is an important pathogen with multiple immune evasion strategies, including virally facilitated degradation of host antiviral restriction factors. Here, we describe a multiplexed approach to discover proteins with innate immune function on the basis of active degradation by the proteasome or lysosome during early-phase HCMV infection. Using three orthogonal proteomic/transcriptomic screens to quantify protein degradation, with high confidence we identified 35 proteins enriched in antiviral restriction factors. A final screen employed a comprehensive panel of viral mutants to predict viral genes that target >250 human proteins. This approach revealed that helicase-like transcription factor (HLTF), a DNA helicase important in DNA repair, potently inhibits early viral gene expression but is rapidly degraded during infection. The functionally unknown HCMV protein UL145 facilitates HLTF degradation by recruiting the Cullin4 E3 ligase complex. Our approach and data will enable further identifications of innate pathways targeted by HCMV and other viruses.

• Keywords
• host-pathogen interaction, immune evasion, innate immunity, lysosome, proteasome, protein degradation, pulsed SILAC, quantitative proteomics, restriction factor, tandem mass tag,
• MeSH
• Cytomegalovirus Infections genetics   immunology   virology   MeSH
• Cytomegalovirus genetics   immunology   physiology   MeSH
• DNA-Binding Proteins chemistry   genetics   immunology   MeSH
• Immune Evasion MeSH
• Humans MeSH
• Proteins chemistry   genetics   immunology   MeSH
• Proteomics MeSH
• Protein Stability MeSH
• Transcription Factors chemistry   genetics   immunology   MeSH
• Viral Proteins chemistry   genetics   immunology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• DNA-Binding Proteins MeSH
• HLTF protein, human MeSH Browser
• Proteins MeSH
• Transcription Factors MeSH
• Viral Proteins MeSH