Research ArticleStructural Biology

Single Amino Acid Substitutions Confer the Antiviral Activity of the TRAF3 Adaptor Protein onto TRAF5

Science Signaling  13 Nov 2012:
Vol. 5, Issue 250, pp. ra81
DOI: 10.1126/scisignal.2003152

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TRAF5 Becomes Antiviral

The adaptor protein TRAF3 promotes antiviral responses by binding to Cardif, a component of a viral response pathway that triggers the production of interferon. Zhang et al. determined the crystal structure of the TRAF domain of TRAF3 bound to the TRAF3-binding peptide of Cardif, as well as that of the TRAF domain of TRAF5, which does not bind to Cardif and cannot substitute for TRAF3 in antiviral responses. The authors identified two amino acids in TRAF3 that participated in binding to Cardif. Substitution of the corresponding residues in TRAF5 with those in TRAF3 produced TRAF5 mutants that bound to Cardif and partially substituted for TRAF3 in antiviral responses. TRAF3 interacts with many proteins that participate in multiple signaling pathways that promote inflammation, and these results raise the possibility of selectively interfering with a subset of its interactions without interfering with its ability to mediate antiviral responses.