The DMAP interaction domain of UDP-GlcNAc: Lysosomal enzyme N-acetylglucosamine-1-phosphotransferase is a substrate recognition module

Yi Qian, Heather Flanagan-Steet, Eline Van Meel, Richard Steet, Stuart A. Kornfeld

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

UDP-GlcNAc:lysosomal enzyme/V-acetylglucosamine-1-phospho-transferase (GlcNAc-1-phosphotransferase) is an α2β2γ 2 heterohex-amer 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.

Original languageEnglish
Pages (from-to)10246-10251
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume110
Issue number25
DOIs
StatePublished - Jun 18 2013

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