N-acetylglucosamine-1-phosphodiester alpha-N-acetylglucosaminidase (NAGPA)

N-acetylglucosamine-1-phosphodiester alpha-N-acetylglucosaminidase (NAGPA), commonly referred to as the "uncovering enzyme," is a lysosomal glycosidase predominantly localized in the trans-Golgi network. It catalyzes the second key step in the generation of the mannose-6-phosphate (M6P) recognition marker critical for lysosomal enzyme targeting, by removing a terminal N-acetylglucosamine residue from phosphomannosyl diesters on newly synthesized acid hydrolases[1][3][7]. This reaction enables the exposed M6P to be recognized by M6P receptors, ensuring proper trafficking of lytic enzymes to lysosomes. NAGPA is synthesized as an inactive proenzyme, requiring proteolytic activation. Structurally, it features conserved domains critical for its enzymatic function and specificity in substrate recognition. Mutations in the NAGPA gene are associated with non-syndromic persistent stuttering, thought to arise from impaired enzyme folding and decreased activity, leading to defects in lysosomal enzyme targeting and cellular protein homeostasis[1][4][7]. Currently, there are no approved drugs directly targeting NAGPA, and therapeutic manipulation of its function would require careful risk assessment due to its fundamental cellular role.

Other names

Mannose 6-phosphate-uncovering enzymeUncovering enzymeUCEPhosphodiester alpha-GlcNAcaseLysosomal alpha-N-acetylglucosaminidaseAlpha-N-acetylglucosaminyl phosphodiesteraseAPAA

Not applicable (no direct therapeutic inhibitor or agonist in clinical use) Drugs that would target this pathway would likely modulate N-acetylglucosamine removal and thus alter lysosomal targeting