Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9127305 | Gene | 2005 | 10 Pages |
Abstract
In a screen of signal peptide-containing proteins from a mouse hypothetical protein library, we identified the mouse UDP-GlcNAc:lysosomal enzyme N-acetylglucosamine-1-phosphotransferase-γ chain (GlcNAc-1-phosphotransferase-γ) (GenBank accession no. AAR19081, HYP36 in this study). The mouse GlcNAc-1-phosphotransferase-γ was localized in the Golgi complex in cells and was expressed ubiquitously in mouse tissues, as shown by fluorescence microscope analysis and a semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) assay, respectively. Domain analysis showed that the mouse GlcNAc-1-phosphotransferase-γ had a conserved mannose-6-phosphate (M-6-P)-binding domain. Interestingly, we found that overexpression of the mouse GlcNAc-1-phosphotransferase-γ in fibroblast cell line NIH-3T3 induced accumulation of macromolecules, formation of large cytoplasmic vacuoles and decrease of lysosomal enzymes in cells. This phenotype was reminiscent of inclusion cells (I-cells) that were reported in mucolipidosis diseases caused by abnormal sorting of lysosomal proteins. Transient ectopic expression of GlcNAc-1-phosphotransferase-γ in endoplasmic reticulum (ER) induced lowered lysosomal enzyme activity in cells. These results suggested on one hand that GlcNAc-1-phosphotransferase-γ is an essential subunit of the GlcNAc-1-phosphotransferase, and on the other hand, the molecule might not only recognize the substrates of GlcNAc-1-phosphotransferase, but also the lysosomal proteins with M-6-P residuals.
Keywords
PBSM-6-Portho-nitrophenyl-β-d-galactopyranosideGlcNAc-1-phosphotransferaseRFPONPGFCSRT-PCReGFPcDNADNA complementary to RNALysosomal enzymesBase pair(s)Curlfetal calf serumendoplasmic reticulummannose-6-phosphatePhosphate-buffered salineProtein sortingreverse transcription–polymerase chain reactionenhanced green fluorescence proteinRed fluorescence proteinGene therapykilobase(s)
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Authors
Qiang Sun, Jiang Li, Chunmei Wang, Xiaofeng Huang, Hongyan Huang, Dewei Du, Yingmin Liang, Hua Han,