Natural cytotoxicity receptor (NCR) (NCR)

Natural cytotoxicity receptors (NCRs), including NKp46 (NCR1), NKp44 (NCR2), and NKp30 (NCR3), are a family of germline-encoded activating receptors primarily expressed on Natural Killer (NK) cells (UniProt P72041, O95944, O14931). These receptors play a pivotal role in the innate immune system by recognizing specific ligands that are upregulated on the surface of tumor cells or virally infected cells due to cellular stress or oncogenic transformation (PubMed: 23548215). Key ligands include B7-H6, which binds to NKp30, and various stress-induced molecules like MLL5 or viral proteins that trigger NK cell degranulation and cytokine release (PubMed: 19448622). In therapeutic development, the NCR-ligand axis is targeted using multi-specific NK cell engagers (NKCEs) that bridge NCRs on NK cells to tumor-associated antigens, thereby inducing potent and selective tumor cell lysis (PubMed: 31142854). These agents, such as SAR443579, are designed to enhance anti-tumor immunity while potentially offering a safer profile than T-cell-based therapies by avoiding systemic hyper-inflammation (ClinicalTrials.gov: NCT05086315). However, challenges remain, including the shedding of soluble ligands by tumors, which can neutralize receptor activity and facilitate immune evasion (PubMed: 20944004).

Other names

NKp46NKp44NKp30NCR1NCR2NCR3CD335CD336CD337Natural killer cell p46-related proteinNatural killer cell p44-related proteinNatural killer cell p30-related proteinNatural cytotoxicity receptors – tumor/stress ligands

Engagement of Natural cytotoxicity receptors (NCRs) on Natural Killer (NK) cells to trigger intracellular signaling via ITAM-containing adapter proteins (e.g., CD3z, FceRIg), leading to NK cell activation, degranulation of perforin and granzymes, and secretion of proinflammatory cytokines to induce target cell lysis.