4-1BB Inhibitor

CD137 signaling involves the collaboration between the canonical and noncanonical nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), mitogen activated protein kinase (MAPK), and phosphatidylinositol 3-kinase (PI3K)/AKT/protein kinase B signaling pathways. Similar to other TNFR receptors, CD137 signaling is mediated through the scaffold proteins, TNF receptor associated factors (TRAF) 1, 2 and 3. TRAF-1 is required for the maximum activation of canonical NF-κB signaling after CD137 stimulation, and prevents non-canonical NF-κB signaling by inhibiting NF-κB inducing kinase (NIK) after TCR stimulation. TRAF-1 and leukocyte-specific protein 1 (LSP1) interactions induce MAPK signaling resulting in the activation of extracellular regulated kinase (ERK). TRAF-2 is required for CD137 stimulation of the non-canonical NF-κB pathway, and TRAF-3 regulates TRAF-2 signaling. TRAF-3 is ubiquitinated after CD137 signaling by cellular inhibitor of apoptosis protein 1 (cIAP1) resulting in degradation. In addition to TRAF binding sites, the cytoplasmic tail of CD137 contains a site for lymphocyte-specific protein kinase (Lck), a protein tyrosine kinase involved in TCR signaling, providing an additional docking site to amplify TCR signaling.
https://www.bocsci.com/tag/4-1bb-also-known-as-cd137-8.html