Transport, enzymatic activity, and stability of mutant sulfamidase (SGSH) identified in patients with mucopolysaccharidosis type III A.

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Etat: Supprimée
Version: de l'auteur⸱e
ID Serval
serval:BIB_1493F7B9C2CC
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Transport, enzymatic activity, and stability of mutant sulfamidase (SGSH) identified in patients with mucopolysaccharidosis type III A.
Périodique
Human Mutation
Auteur⸱e⸱s
Muschol N., Storch S., Ballhausen D., Beesley C., Westermann J.C., Gal A., Ullrich K., Hopwood J.J., Winchester B., Braulke T.
ISSN
1098-1004 (Electronic)
ISSN-L
1059-7794
Statut éditorial
Publié
Date de publication
2004
Peer-reviewed
Oui
Volume
23
Numéro
6
Pages
559-566
Langue
anglais
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov'tPublication Status: ppublish
Résumé
Mucopolysaccharidosis type IIIA (MPSIIIA) is an autosomal recessive lysosomal storage disease caused by mutations in the N-sulfoglucosamine sulfohydrolase gene (SGSH; encoding sulfamidase, also sulphamidase) leading to the lysosomal accumulation and urinary excretion of heparan sulfate. Considerable variation in the onset and severity of the clinical phenotype is observed. We report here on expression studies of four novel mutations: c.318C>A (p.Ser106Arg), c.488T>C (p.Leu163Pro), c.571G>A (p.Gly191Arg), and c.1207_1209delTAC (p.Tyr403del), and five previously known mutations: c.220C>T (p.Arg74Cys), c.697C>T (p.Arg233X), c.1297C>T (p.Arg433Trp), c.1026dupC (p.Leu343fsX158), and c.1135delG (p.Val379fsX33) identified in MPSIIIA patients. Transient expression of mutant sulfamidases in BHK or CHO cells revealed that all the mutants were enzymatically inactive with the exception of c.318C>A (p.Ser106Arg), which showed 3.3% activity of the expressed wild-type enzyme. Western blot analysis demonstrated that the amounts of expressed mutant sulfamidases were significantly reduced compared with cells expressing wild type. No polypeptides were immunodetectable in extracts of cells transfected with the cDNA carrying the c.697C>T (p.Arg233X) nonsense mutation. In vitro translation and pulse-chase experiments showed that rapid degradation rather than a decrease in synthesis is responsible for the low, steady-state level of the mutant proteins in cells. The amounts of secreted mutant precursor forms, the cellular stability, the proteolytic processing, and data from double-label immunofluorescence microscopy suggest that the degradation of the majority of newly synthesized c.220C>T (p.Arg74Cys), c.571G>A (p.Gly191Arg), c.1297C>T (p.Arg433Trp), c.1026dupC (p.Leu343fsX158), and c.1135delG (p.Val379fsX33) mutant proteins probably occurs in the ER, whereas c.488T>C (p.Leu163Pro) mutant protein showed instability in the lysosomes.
Mots-clé
Animals, CHO Cells, Cell Line, Cricetinae, Endoplasmic Reticulum/metabolism, Enzyme Stability, Humans, Hydrolases/genetics, Hydrolases/metabolism, Lysosomes/metabolism, Molecular Sequence Data, Mucopolysaccharidosis III/enzymology, Mucopolysaccharidosis III/genetics, Mutation, Precipitin Tests, Protein Biosynthesis, Protein Transport, Recombinant Proteins/genetics
Pubmed
Web of science
Création de la notice
29/03/2010 12:21
Dernière modification de la notice
20/08/2019 12:43
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