title: Lumenal localization in the endoplasmic reticulum of the C-terminal tail of an AE1 mutant responsible for hereditary spherocytosis in cattle.
abstract: An R664X nonsense mutant AE1 is responsible for dominant hereditary spherocytosis in cattle and is degraded by the proteasomal endoplasmic reticulum-associated degradation. The present study demonstrated that R664X AE1 translated in vitro had the trypsin-sensitve site identical to that of the wild-type AE1. The P661S/R664X mutant containing a possible N-glycosylation site at Asn660 showed an increase in size by 3 kDa both in the cell-free translation system and in transfected HEK293 cells. Moreover, steady state levels of R664X and P661S/R664X in HEK293 cells were markedly increased in the presence of a proteasome inhibitior. These findings indicate that the truncated C-terminal region of R664X AE1 has lumenal localization in the endoplasmic reticulum and is not accessible to proteasomal machineries in the cytosol.
authors.affiliation: Laboratory of Molecular Medicine, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Ito
authors.forename: Yayoi
authors.initials: Y
authors.lastname: Otsuka
authors.forename: Ichiro
authors.initials: I
authors.lastname: Koshino
authors.forename: Mutsumi
authors.initials: M
authors.lastname: Inaba
mesh_terms: D000818:Animals; D001457:Anion Exchange Protein 1, Erythrocyte / Q000235:genetics / Q000378:metabolism*; D002417:Cattle; D002418:Cattle Diseases / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D017354:Point Mutation; D013103:Spherocytosis, Hereditary / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*
chemical_list: D001457:Anion Exchange Protein 1, Erythrocyte