Natural cytotoxicity triggering receptor ligands (NCR ligands)

The Natural Cytotoxicity Receptors (NCRs), comprising Natural cytotoxicity triggering receptor 1 (NCR1/NKp46), Natural cytotoxicity triggering receptor 2 (NCR2/NKp44), and Natural cytotoxicity triggering receptor 3 (NCR3/NKp30), are a group of activating receptors primarily expressed on Natural Killer (NK) cells (UniProt O76036, O95944, O14931). These receptors recognize a diverse set of ligands, including heparan sulfate proteoglycans (HSPGs) and specific proteins such as B7-H6, BAG6 (BAT3), and viral hemagglutinins, which are often upregulated on the surface of stressed, infected, or malignant cells (PubMed: 23548215). Heparan sulfate serves as a critical co-ligand for all three NCRs, stabilizing the interaction between the receptor and its protein ligands to facilitate NK cell activation (PubMed: 19380495). In oncology, the interaction between NCRs and their ligands is a major focus for immunotherapy, as these pathways are essential for the innate immune system's ability to identify and eliminate tumors (PubMed: 21670308). Therapeutic strategies often involve the development of bispecific and trispecific NK cell engagers (NKCEs), such as SAR443579, which target NCRs like NKp46 to redirect NK cell cytotoxicity toward specific tumor antigens (Innate Pharma, 2024). However, challenges such as the shedding of soluble ligands (e.g., soluble B7-H6) by tumor cells can lead to immune evasion and reduced therapeutic efficacy by acting as decoys for the receptors.

Other names

NKp46 ligandsNKp44 ligandsNKp30 ligandsHeparan sulfateB7-H6BAG6BAT3MLL5PDGF-DD

Activation of Natural Killer (NK) cells via the engagement of Natural Cytotoxicity Receptors (NCRs) to promote the lysis of tumor or virus-infected cells.