TRAF3-interacting protein 2 (Act1) (TRAF3IP2)

TRAF3-interacting protein 2 (TRAF3IP2), commonly known as Act1, is a critical adapter protein and E3 ubiquitin ligase that serves as a central node in the interleukin-17 (IL-17) signaling pathway [1, 2]. It contains a conserved SEFIR domain that facilitates its direct interaction with the IL-17 receptor (IL-17R) complex upon ligand binding, a step that is indispensable for IL-17-mediated inflammatory responses [2, 5]. This recruitment is essential for the subsequent engagement of TRAF6 and the activation of downstream NF-kappa-B, MAPK, and C/EBP signaling cascades [1, 4]. These pathways drive the expression of pro-inflammatory cytokines and chemokines that are vital for host defense against fungal and bacterial pathogens but also contribute to chronic inflammatory diseases [2]. Genetic variations in the TRAF3IP2 gene, such as the rs33980500 polymorphism, are strongly associated with susceptibility to autoimmune conditions including psoriasis, psoriatic arthritis, and ankylosing spondylitis [3]. Because Act1 is a mandatory intracellular mediator for multiple members of the IL-17 receptor family, it represents a high-value therapeutic target for treating Th17-mediated autoimmune disorders [4]. Current drug development efforts focus on small-molecule inhibitors and peptide mimetics that disrupt the Act1-IL-17R interaction or inhibit its enzymatic activity [4, 5]. Sources: [1] UniProt (Q9H1Y0); [2] Nat Immunol. 2007;8(10):1083-91; [3] N Engl J Med. 2010;363(24):2311-21; [4] Cytokine. 2011;55(3):317-21; [5] Nat Rev Immunol. 2009;9(8):556-67.

Other names

Act1CIKSConnection to IKK and SAPK/JNKNF-kappa-B activator 1TRAF3IP2

Inhibition of the interaction between the IL-17 receptor and Act1 via SEFIR domain disruption, or inhibition of Act1's E3 ubiquitin ligase activity, thereby preventing the recruitment of TRAF6 and subsequent activation of pro-inflammatory NF-kappa-B and MAPK signaling pathways [2, 4].