NRK1 Recombinant Rabbit mAb (S-4979-71)

NRK1 (nicotinamide riboside kinase 1, gene name NMRK1/C9orf95) is a key enzyme in the cytoplasmic NAD⁺ salvage synthesis pathway. It consists of 199 amino acids, and its crystal structure reveals that the active site lies in a groove between a central parallel β-sheet core and the LID and NMP-binding domains, with Asp56 and Arg129 recognizing the ribose hydroxyl groups and Asp36 acting as the catalytic base. NRK1 catalyzes the phosphorylation of nicotinamide riboside (NR) to generate nicotinamide mononucleotide (NMN), representing an important route of NAD⁺ biosynthesis that is independent of the Preiss-Handler pathway; it can also phosphorylate NR analogues such as the antitumor drug tiazofurin. Recent studies have revealed that NRK1 plays important regulatory functions in immunometabolism: upon CD4⁺ T cell activation, NRK1 expression is upregulated, and by locally elevating cytosolic NAD⁺/H levels it enhances glycolytic efficiency and drives NADPH production, thereby maintaining reduced glutathione and reducing reactive oxygen species accumulation, which in turn promotes NFAT nuclear translocation and suppresses excessive inflammatory responses, while also promoting effector T cell survival by regulating Bcl-2 family proteins. In fungal and viral infection models, T cell-intrinsic NRK1 function is essential for maintaining effector CD4⁺ T cell numbers and pathogen clearance.