TRIM25 and its emerging RNA-binding roles in antiviral defense.

The innate immune system is the body's first line of defense against viruses, with pattern recognition receptors (PRRs) recognizing molecules unique to viruses and triggering the expression of interferons and other anti-viral cytokines, leading to the formation of an anti-viral state. The tripartite motif containing 25 (TRIM25) is an E3 ubiquitin ligase thought to be a key component in the activation of signaling by the PRR retinoic acid-inducible gene I protein (RIG-I). TRIM25 has recently been identified as an RNA-binding protein, raising the question of whether its RNA-binding activity is important for its role in innate immunity. Here, we review TRIM25's mechanisms and pathways in noninfected and infected cells. We also introduce models that explain how TRIM25 binding to RNA could modulate its functions and play part in the antiviral response. These findings have opened new lines of investigations into functional and molecular roles of TRIM25 and other E3 ubiquitin ligases in cell biology and control of pathogenic infections. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition.