TRIM25 RING-finger E3 ubiquitin ligase is essential for RIG-I-mediated antiviral activity

Abstract

Retinoic-acid-inducible gene-I (RIG-I; also called DDX58) is a cytosolic viral RNA receptor that interacts with MAVS (also called VISA, IPS-1 or Cardif) to induce type I interferon-mediated host protective innate immunity against viral infection. Furthermore, members of the tripartite motif (TRIM) protein family, which contain a cluster of a RING-finger domain, a B box/coiled-coil domain and a SPRY domain, are involved in various cellular processes, including cell proliferation and antiviral activity. Here we report that the amino-terminal caspase recruitment domains (CARDs) of RIG-I undergo robust ubiquitination induced by TRIM25 in mammalian cells. The carboxy-terminal SPRY domain of TRIM25 interacts with the N-terminal CARDs of RIG-I; this interaction effectively delivers the Lys 63-linked ubiquitin moiety to the N-terminal CARDs of RIG-I, resulting in a marked increase in RIG-I downstream signalling activity. The Lys 172 residue of RIG-I is critical for efficient TRIM25-mediated ubiquitination and for MAVS binding, as well as the ability of RIG-I to induce antiviral signal transduction. Furthermore, gene targeting demonstrates that TRIM25 is essential not only for RIG-I ubiquitination but also for RIG-I-mediated interferon- production and antiviral activity in response to RNA virus infection. Thus, we demonstrate that TRIM25 E3 ubiquitin ligase induces the Lys 63-linked ubiquitination of RIG-I, which is crucial for the cytosolic RIG-I signalling pathway to elicit host antiviral innate immunity.

DEAD/H BOX 3 (DDX3) helicase binds the RIG‐I adaptor IPS‐1 to up‐regulate IFN‐β‐inducing potential

“…Proteins involved in type I IFN induction are found ubiquitinated for their functional regulation. It has been reported that TRIM25 [19] and Riplet/RNF135 [20] act as ubiquitin ligases to activate RIG-I for IFN-b induction in their different sites of RIG-I ubiquitination. Another ubiquitin ligase RNF125 polyubiquitinates RIG-I through Lys48, leading to degradation of RIG-I [21].…”

TRIM59 interacts with ECSIT and negatively regulates NF-κB and IRF-3/7-mediated signal pathways

“…TRIM5 inhibits infection of HIV-1 and other retroviruses upon entry into the cell by engaging the viral capsid and inducing premature uncoating [21]. Moreover, it has been reported that interferon signaling and NF-B signaling are regulated by TRIM proteins including TRIM8, TRIM21, TRIM25, TRIM27, TRIM30 and TRIM56 [5,[22][23][24][25][26][27]. Recently, it has been reported that TRIM56 interacts with STING and targets it for lysine 63-linked ubiquitination, followed by induction of STING dimerization and activation of the IFN-promoter [27].…”

“…TRIM proteins are involved in a various biological processes [3,4]. TRIM25, also known as estrogen-responsive finger protein (EFP), induces type I IFN production and NF-B activity through the conjugation of a lysine 63-linked polyubiquitin chain to RIG-I [5]. Another study showed that TRIM25 also has an E3 ligase activity for ISG15 conjugation [6].…”

Functional role of TRIM E3 ligase oligomerization and regulation of catalytic activity

“…TRIM25 plays a crucial role in the anti‐viral response by ubiquitinating the N‐terminal caspase activation and recruitment domains (CARDs) of the cytosolic pattern recognition receptor RIG‐I. This event is critical to promote interaction with the adaptor protein MAVS and the subsequent activation of a signalling pathway leading to type 1 interferon production (Gack et al , 2007). TRIM32 has a broader cellular role and has been shown to regulate neuronal development, the stability of sarcomeric architecture and has more recently been reported to restrict influenza A virus (Shieh et al , 2011; Zhang et al , 2012; Fu et al , 2015).…”