7DXI

Structure of Drosophila melanogaster GlcNAc-1-phosphotransferase

Summary for 7DXI

• Entry DOI: 10.2210/pdb7dxi/pdb
• EMDB information: 30910
• Descriptor: FI02838p, CALCIUM ION (2 entities in total)
• Functional Keywords: gnptab, glcnac-1-phosphotransferase, sugar binding protein, transferase
• Biological source: Drosophila melanogaster (Fruit fly)
• Total number of polymer chains: 2
• Total formula weight: 135931.16

Authors

Du, S.,Xiao, J.,Guopeng, W. (deposition date: 2021-01-19, release date: 2022-02-02, Last modification date: 2025-06-25)

Primary citation

Du, S.,Wang, G.,Zhang, Z.,Ma, C.,Gao, N.,Xiao, J.
Structural insights into how GlcNAc-1-phosphotransferase directs lysosomal protein transport.
J.Biol.Chem., 298:101702-101702, 2022

PubMed Abstract: GlcNAc-1-phosphotransferase catalyzes the initial step in the formation of the mannose-6-phosphate tag that labels ∼60 lysosomal proteins for transport. Mutations in GlcNAc-1-phosphotransferase are known to cause lysosomal storage disorders such as mucolipidoses. However, the molecular mechanism of GlcNAc-1-phosphotransferase activity remains unclear. Mammalian GlcNAc-1-phosphotransferases are α2β2γ2 hexamers in which the core catalytic α- and β-subunits are derived from the GNPTAB (N-acetylglucosamine-1-phosphate transferase subunits alpha and beta) gene. Here, we present the cryo-electron microscopy structure of the Drosophila melanogaster GNPTAB homolog, DmGNPTAB. We identified four conserved regions located far apart in the sequence that fold into the catalytic domain, which exhibits structural similarity to that of the UDP-glucose glycoprotein glucosyltransferase. Comparison with UDP-glucose glycoprotein glucosyltransferase also revealed a putative donor substrate-binding site, and the functional requirements of critical residues in human GNPTAB were validated using GNPTAB-knockout cells. Finally, we show that DmGNPTAB forms a homodimer that is evolutionarily conserved and that perturbing the dimer interface undermines the maturation and activity of human GNPTAB. These results provide important insights into GlcNAc-1-phosphotransferase function and related diseases.

PubMed: 35148990
DOI: 10.1016/j.jbc.2022.101702

Experimental method

ELECTRON MICROSCOPY (3.53 Å)