Japanese Journal of Veterinary Research;Volume 54, Number 4

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Lumenal localization in the endoplasmic reticulum of the C-terminal tail of an AE1mutant responsible for hereditary spherocytosis in cattle

Ito, Daisuke;Otsuka, Yayoi;Koshino, Ichiro;Inaba, Mutsumi

Permalink : http://hdl.handle.net/2115/20029
JaLCDOI : 10.14943/jjvr.54.4.191
KEYWORDS : AE1;endoplasmic reticulum;proteasome

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 R664XAE1 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 cellfree 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.

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