Cytosolic sensors can trigger type I interferon responses after the detection of duplex DNA viruses and subsequent activation of the cyclic GMP-AMP synthase (cGAS)–adaptor STING pathways, but several tumor viruses can evade this pathway. In Science, Lau et al. identify two viral proteins, adenovirus E1A and human papillomavirus E7, that inhibit the activation of STING. Transduction of transformed cells with either E1A or E7 is sufficient to blunt type I interferon production; however, knockdown of either viral protein in established transformed cell lines 'rescues' this response. Both E1A and E7 have a peptide motif consisting of Leu-X-Cys-X-Glu (where 'X' is any amino acid) that is required for the inhibition of STING. Whether this interaction is direct or requires other factors remains uncertain. What is clear, however, is that DNA viruses have evolved strategies to combat antiviral responses elictied by the STING pathway.

Science (24 September 2015) doi:10.1126/science.aab3291