Human Tumor Necrosis Factor Receptor Superfamily Member 9 (TNFRSF9) Protein

Background

TNFRSF9, also known as 4-1BB or CD137, is a member of the tumor necrosis factor receptor (TNFR) superfamily and plays a key role in immune regulation. This receptor is expressed primarily on activated T cells, as well as on natural killer (NK) cells, dendritic cells, and some other immune cell types, particularly after stimulation. It serves as a co-stimulatory receptor, enhancing T-cell proliferation, survival, and effector function, making it pivotal in immune responses and antitumor immunity. TNFRSF9 has gained attention as a therapeutic target in cancer immunotherapy due to its role in enhancing immune cell activation and persistence. Upon binding with its ligand, TNFSF9 (also known as 4-1BB ligand or 4-1BBL), TNFRSF9 undergoes trimerization, which is essential for transmitting downstream signaling. This receptor’s functions extend beyond tumor immunity; it is also involved in chronic inflammation and autoimmune diseases, and as such, modulation of TNFRSF9 signaling has therapeutic implications across several pathologies.