Natural cytotoxicity receptor family (NKp46, NKp44, NKp30) (NCRs)

The Natural Cytotoxicity Receptors (NCRs), comprising NKp46 (NCR1), NKp44 (NCR2), and NKp30 (NCR3), are a family of activating receptors primarily expressed on Natural Killer (NK) cells [1]. These type I transmembrane proteins belong to the immunoglobulin superfamily and are essential for the innate immune system's ability to identify and destroy malignant or virally infected cells [1][4]. NKp46 and NKp30 are constitutively expressed on all mature NK cells, whereas NKp44 is typically upregulated only following NK cell activation [1]. These receptors recognize a diverse range of ligands, including viral hemagglutinins and tumor-associated molecules such as B7-H6, MLL5, and BAG6 [4]. In therapeutic contexts, such as with the haNK (high-affinity NK) cell line, these receptors are leveraged to enhance the recognition and lysis of malignant cells [2]. Modern drug development focuses on bispecific and trispecific NK cell engagers (NKCEs) that target NKp46 to bridge NK cells directly to tumor antigens, thereby inducing potent antibody-independent cytotoxicity [3].

Other names

NCR1NCR2NCR3NKp46NKp44NKp30CD335CD336CD337Natural cytotoxicity triggering receptor 1Natural cytotoxicity triggering receptor 2Natural cytotoxicity triggering receptor 3

Activation of NK cell-mediated cytotoxicity through immunoreceptor tyrosine-based activation motifs (ITAMs) and engagement of tumor-associated ligands.