Tumor necrosis factor-related apoptosis-inducing ligand death receptors (TRAIL-R1 and TRAIL-R2) (TRAIL-R1/2)

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) death receptors, specifically TRAIL-R1 (DR4) and TRAIL-R2 (DR5), are transmembrane proteins that play a critical role in the extrinsic pathway of programmed cell death [2, 12]. These receptors are members of the tumor necrosis factor receptor (TNFR) superfamily and are distinguished by an intracellular death domain required for apoptotic signaling [2, 16]. Upon binding to the TRAIL ligand, the receptors trimerize and recruit the adaptor protein FADD and initiator caspases to form the death-inducing signaling complex (DISC) [7, 16, 20]. A unique feature of the TRAIL system is its ability to selectively trigger apoptosis in malignant cells while sparing most healthy tissues, which often express decoy receptors that lack functional death domains [3, 12, 20]. This selectivity has made TRAIL death receptors a major focus for cancer drug development, leading to the creation of recombinant TRAIL variants and agonistic monoclonal antibodies [3, 4, 19]. However, clinical success has been limited by factors such as short drug half-lives, poor receptor clustering, and intrinsic tumor resistance mediated by anti-apoptotic proteins like c-FLIP [4, 7, 19]. Modern therapeutic strategies involve next-generation agonists with enhanced potency and combination therapies designed to sensitize resistant tumors to TRAIL-mediated killing [1, 4, 6].

Other names

Death receptor 4 (DR4)Death receptor 5 (DR5)TRAIL-R1TRAIL-R2Tumor necrosis factor receptor superfamily member 10A (TNFRSF10A)Tumor necrosis factor receptor superfamily member 10B (TNFRSF10B)APO2CD261CD262KILLERTRICK2

Agonism of TRAIL-R1 and TRAIL-R2 induces receptor trimerization and assembly of the death-inducing signaling complex (DISC), leading to the activation of the extrinsic apoptotic cascade via Caspase-8 and Caspase-10.