N-acetylglucosamine-1-phosphate transferase subunit gamma (GNPTG)

N-acetylglucosamine-1-phosphate transferase subunit gamma (GNPTG) is the non-catalytic gamma subunit of the hexameric N-acetylglucosamine-1-phosphotransferase complex, which is essential for targeting lysosomal hydrolases to the lysosome through the synthesis of mannose 6-phosphate (M6P) recognition markers. GNPTG acts as an accessory protein with a mannose-6-phosphate receptor homology (MRH) domain that assists substrate glycan binding and presentation to the GNPTAB catalytic subunits, influencing enzymatic specificity and efficiency. Genetic defects in GNPTG cause mucolipidosis type IIIC (mucolipidosis III gamma), a lysosomal storage disorder characterized by mislocalization of lysosomal enzymes[1][3][4]. The gamma subunit is not sufficient for catalysis but is required for the proper function of the complex on certain lysosomal hydrolase substrates and enhances the addition of multiple phospho-GlcNAc groups to pathway glycans[1].

Other names

GNPTGC16orf27GNPTAGLP2537RJD9N-acetylglucosamine-1-phosphotransferase gamma subunitN-acetylglucosamine-1-phosphate transferase gamma subunitGlcNAc-1-phosphotransferase subunit gammaUDP-N-acetylglucosamine-1-phosphotransferase subunit gamma