ZFIN ID: ZDB-PUB-130708-62
The DMAP interaction domain of UDP-GlcNAc:lysosomal enzyme N-acetylglucosamine-1-phosphotransferase is a substrate recognition module
Qian, Y., Flanagan-Steet, H., van Meel, E., Steet, R., and Kornfeld, S.A.
Date: 2013
Source: Proceedings of the National Academy of Sciences of the United States of America   110(25): 10246-10251 (Journal)
Registered Authors: Flanagan-Steet, Heather, Steet, Richard
Keywords: none
MeSH Terms:
  • Abnormalities, Multiple/enzymology
  • Abnormalities, Multiple/metabolism*
  • Acetylglucosamine/metabolism
  • Animals
  • Female
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Hydrolases/metabolism
  • Lysosomes/enzymology*
  • Male
  • Mannosephosphates/metabolism
  • Mice
  • Mucolipidoses/enzymology
  • Mucolipidoses/metabolism*
  • Mutagenesis, Site-Directed
  • Mutation, Missense
  • Phosphorylation/physiology
  • Protein Structure, Tertiary/physiology
  • Protein Subunits/chemistry
  • Protein Subunits/genetics
  • Protein Subunits/metabolism
  • Ribonucleoproteins, Small Nuclear/chemistry
  • Ribonucleoproteins, Small Nuclear/genetics
  • Ribonucleoproteins, Small Nuclear/metabolism
  • Substrate Specificity
  • Transferases (Other Substituted Phosphate Groups)/chemistry
  • Transferases (Other Substituted Phosphate Groups)/genetics
  • Transferases (Other Substituted Phosphate Groups)/metabolism*
  • Zebrafish
  • Zebrafish Proteins/chemistry
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
PubMed: 23733939 Full text @ Proc. Natl. Acad. Sci. USA
UDP-GlcNAc:lysosomal enzyme N-acetylglucosamine-1-phosphotransferase (GlcNAc-1-phosphotransferase) is an α2β2γ2 heterohexamer that mediates the initial step in the formation of the mannose 6-phosphate recognition signal on lysosomal acid hydrolases. We previously reported that the specificity of the reaction is determined by the ability of the α/β subunits to recognize a conformation-dependent protein determinant present on the acid hydrolases. We now present evidence that the DNA methyltransferase-associated protein (DMAP) interaction domain of the α subunit functions in this recognition process. First, GST-DMAP pulled down several acid hydrolases, but not nonlysosomal glycoproteins. Second, recombinant GlcNAc-1-phosphotransferase containing a missense mutation in the DMAP interaction domain (Lys732Asn) identified in a patient with mucolipidosis II exhibited full activity toward the simple sugar α-methyl D-mannoside but impaired phosphorylation of acid hydrolases. Finally, unlike the WT enzyme, expression of the K732N mutant in a zebrafish model of mucolipidosis II failed to correct the phenotypic abnormalities. These results indicate that the DMAP interaction domain of the α subunit functions in the selective recognition of acid hydrolase substrates and provides an explanation for the impaired phosphorylation of acid hydrolases in a patient with mucolipidosis II.