N-Glycosylation plays a role in protein folding of human UGT1A9
| Autor: | Miki Nakajima, Tsuyoshi Yokoi, Ryoichi Fujiwara, Hiroyuki Yamanaka, Haruko Sakai, Toshihisa Koga |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: |
Glycan
animal structures Glycosylation Biology N-Glycosylation Biochemistry chemistry.chemical_compound N-linked glycosylation Enzyme Stability Humans Asparagine Enzyme activity Protein folding Glucuronosyltransferase Cells Cultured Pharmacology UGT1A9 Endoplasmic reticulum Tunicamycin Indolizines carbohydrates (lipids) Membrane protein chemistry UDP-Glucuronosyltransferase 1A9 biology.protein Unfolded protein response lipids (amino acids peptides and proteins) Electrophoresis Polyacrylamide Gel |
| Zdroj: | Biochemical Pharmacology. 79(8):1165-1172 |
| ISSN: | 0006-2952 |
| Popis: | 金沢大学医薬保健研究域薬学系 UDP-glucuronosyltransferases (UGTs) catalyze the glucuronidation of a variety of xeno/endobiotics. UGTs are type I membrane proteins of the endoplasmic reticulum (ER) with a glycosylated luminal domain. In the present study, we investigated the role of N-glycosylation in the function of human UGT1A9. Mutation analysis at the potential N-glycosylation sites at residues 71, 292, and 344 (from asparagine to glutamine) revealed that all of them were glycosylated, but the extent of glycosylation and/or size of the glycan differed. In comparison with the wild-type, these mutants showed decreased enzyme activities in parallel with the extent of the band shift in Western blot analysis. To evaluate the role of glycosylation in the enzyme activity, we produced unglycosylated UGT1A9 by treating HEK293 cells transiently transfected with expression plasmid with tunicamycin. The unglycosylated UGT1A9 was almost inactive, which was not an indirect effect of ER stress. To the contrary, the deglycosylated UGT1A9, which was produced by the treatment with Endo H under the non-denaturing condition, showed the same enzyme kinetics as the control. These results suggest that the glycosylation that occurs during translation is important for the folding of UGT1A9. The thermal stability analysis of the mutated and deglycosylated UGT1A9 proteins supported the findings. In conclusion, we found that the N-glycosylation has an important role in the folding of UGT1A9. © 2009 Elsevier Inc. All rights reserved. |
| Databáze: | OpenAIRE |
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