Inhibition of N-linked glycosylation prevents inclusion formation by the dystonia-related mutant form of torsinA.
Most cases of early-onset torsion dystonia are associated with a mutation in the DYT1 gene that results in the loss of a glutamic acid residue in the carboxy terminus of the encoded protein, torsinA. When overexpressed in cultured cells, wild-type torsinA distributes diffusely throughout the endoplasmic reticulum (ER), while the dystonia-related mutant, torsinADeltaE, accumulates within multilamellar membrane inclusions. Here we show that inclusion formation requires the addition of an N-linked oligosaccharide to one of two asparagine residues within the ATP-binding domain of the mutant protein. In the absence of this modification, overexpressed torsinADeltaE was localized diffusely throughout the cell in a reticular pattern resembling that of wild-type torsinA. In contrast, the localization of wild-type torsinA did not appear to vary with its glycosylation state. These results thus indicate that torsinADeltaE must achieve a specific conformation to induce formation of intracellular membrane inclusions.
Bragg
D Cristopher
DC
Departments of Neurology and Radiology Massachusetts General Hospital, Charlestown, MA 02129, USA. bragg@helix.mgh.harvard.edu
Kaufman
Caroline A
CA
Kock
Norman
N
Breakefield
Xandra O
XO
D000595:Amino Acid Sequence / Q000502:physiology; D000818:Animals; D001216:Asparagine / Q000378:metabolism; D001921:Brain / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D002522:Chlorocebus aethiops; D004422:Dystonia Musculorum Deformans / Q000235:genetics / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006031:Glycosylation / Q000187:drug effects; D006801:Humans; D002479:Inclusion Bodies / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D007425:Intracellular Membranes / Q000378:metabolism* / Q000473:pathology; D018832:Molecular Chaperones / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D009844:Oligosaccharides / Q000378:metabolism; D011487:Protein Conformation; D017434:Protein Structure, Tertiary / Q000235:genetics; D014415:Tunicamycin / Q000494:pharmacology; D014709:Vero Cells
D018832:Molecular Chaperones; D009844:Oligosaccharides; C108175:TOR1A protein, human; D014415:Tunicamycin; D001216:Asparagine