N-acetylglucosamine-1-phosphotransferase (GlcNAc-1-phosphotransferase) (GlcNAc-1-phosphotransferase)

N-acetylglucosamine-1-phosphotransferase is a Golgi-resident enzyme complex responsible for the initial step in the formation of the mannose 6-phosphate (M6P) recognition marker on lysosomal acid hydrolases [1, 15]. This hexameric complex, composed of alpha, beta, and gamma subunits, catalyzes the transfer of N-acetylglucosamine-1-phosphate from UDP-GlcNAc to specific mannose residues on newly synthesized enzymes [2, 13]. The M6P tag is essential for the recognition of these enzymes by M6P receptors, which facilitate their transport from the trans-Golgi network to the lysosomal system [9, 17]. Deficiencies in this enzyme, caused by mutations in the GNPTAB or GNPTG genes, result in Mucolipidosis II (I-cell disease) and Mucolipidosis III (pseudo-Hurler polydystrophy) [1, 4]. These disorders are characterized by the failure to target enzymes to lysosomes, leading to their hypersecretion into the blood and severe multi-systemic clinical manifestations [10, 13]. While there are currently no approved small molecule drugs that target this enzyme for inhibition, it remains a significant focus for gene therapy and enzyme replacement strategies aimed at restoring lysosomal function [13, 17]. Additionally, certain mutations in the subunits of this enzyme have been linked to persistent stuttering, highlighting its role in neurological pathways [15].

Other names

UDP-N-acetylglucosamine-1-phosphotransferasePhosphotransferaseGNPTABGNPTGGlcNAc-PTaseUDP-N-acetylglucosamine-lysosomal-enzyme N-acetylglucosaminephosphotransferaseGlcNAc-phosphotransferase

Catalyzes the transfer of N-acetylglucosamine-1-phosphate from UDP-GlcNAc to mannose residues on lysosomal hydrolases [1, 2, 15].