|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.
|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|
|PubMed:||23733939 Full text @ Proc. Natl. Acad. Sci. USA|
Qian, Y., Flanagan-Steet, H., van Meel, E., Steet, R., and Kornfeld, S.A. (2013) The DMAP interaction domain of UDP-GlcNAc:lysosomal enzyme N-acetylglucosamine-1-phosphotransferase is a substrate recognition module. Proceedings of the National Academy of Sciences of the United States of America. 110(25):10246-10251.
ABSTRACTUDP-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.