Tumor necrosis factor receptor-associated factor 2 (TRAF2) (TRAF2)

Tumor necrosis factor receptor-associated factor 2 (TRAF2) is a critical intracellular adapter protein and E3 ubiquitin ligase that serves as a central hub for signaling by the TNF receptor superfamily, including TNFR2 and CD40 [6, 10, 14]. It plays a dual role in cell fate by activating the classical NF-kappaB and JNK pathways to promote survival and inflammation, while simultaneously acting as a negative regulator of the alternative NF-kappaB pathway by facilitating the degradation of NIK [11, 18]. In the context of oncology, TRAF2 is frequently overexpressed and acts as an oncogene by conferring resistance to apoptosis and promoting tumor progression in various solid tumors [15, 16, 24]. However, its role can be context-dependent, as inactivating mutations in TRAF2 are associated with the development of certain B-cell malignancies where it functions as a tumor suppressor [9, 11]. Therapeutic targeting of TRAF2 primarily involves the use of IAP antagonists (Smac mimetics), which disrupt the functional TRAF2-cIAP complex to sensitize cancer cells to death-inducing signals [11, 19, 21]. Additionally, TRAF2 is an emerging target for enhancing the efficacy of immune checkpoint inhibitors by increasing the sensitivity of the tumor microenvironment to T-cell-mediated killing [19, 21, 24].

Other names

TRAP [10, 13]TRAP3 [10, 13]RNF117 [10, 13]Tumor necrosis factor type 2 receptor associated protein 3 [13]MGC:45012 [10]

TRAF2 serves as a scaffold and E3 ubiquitin ligase that recruits cellular inhibitors of apoptosis (cIAPs) to TNF receptor complexes [6, 11]. IAP antagonists (Smac mimetics) bind to the BIR domains of cIAPs, disrupting the TRAF2-cIAP complex and inducing the autoubiquitination and proteasomal degradation of cIAPs [11, 14]. This loss of cIAPs prevents the activation of the classical NF-kappaB pathway and promotes the formation of death-inducing signaling complexes, thereby sensitizing tumor cells to TNF-mediated apoptosis or necroptosis [11, 18, 21].