Weapons of STAT destruction. Interferon evasion by paramyxovirus V protein.

The signal transducer and activator of transcription (STAT) family of proteins function to activate gene transcription downstream of myriad cytokine and growth factor signals. The prototype STAT proteins, STAT1 and STAT2, are required for innate and adaptive antimicrobial immune responses that result from interferon signal transduction. While many viruses have evolved the ability to avoid these antiviral cytokines, the Paramyxoviruses are distinct in their abilities to interfere directly with STAT proteins. Individual paramyxovirus species differ greatly in their precise mechanism of STAT signaling evasion, but a virus-encoded protein called V plays a central role in this process. The theme of V-dependent interferon evasion and its variations provide significant insights into virus-host interactions and viral immune evasion that can help define targets for antiviral drug design. Exposure of the viral weapons of STAT destruction may also be instructive for application to STAT-directed therapeutics for diseases characterized by STAT hyperactivity.