Ricin A chain utilises the endoplasmic reticulum‐associated protein degradation pathway to enter the cytosol of yeast

FEBS Letters

Wolf, Dieter H.²  Römisch, Karin³  Roberts, Lynne M.¹  Lord, J.Michael¹  Davey, John¹  Simpson, Jeremy C.¹ 

[1] Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK;Institut für Biochemie der Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany;Cambridge Institute for Medical Research and Department of Clinical Biochemistry, University of Cambridge, Hills Road, Cambridge CB2 2XY, UK

关键词: Ricin A chain;    Endoplasmic reticulum;    Proteasomal degradation;    Sec61p;    RTA;    ricin toxin A chain;    RTB;    ricin toxin B chain;    ER;    endoplasmic reticulum;    ERAD;    endoplasmic reticulum-associated protein degradation;   

DOI  :  10.1016/S0014-5793(99)01222-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Cytotoxic proteins such as ricin A chain (RTA) have target substrates in the cytosol and therefore have to reach this cellular compartment in order to act. RTA is thought to translocate into the cytosol from the lumen of the endoplasmic reticulum (ER), although how it traverses the ER membrane has not been established. Using yeast mutants defective in various aspects of the ER-associated protein degradation (ERAD) pathway, we show that RTA introduced into the yeast ER subverts this pathway to enter the cytosol via the Sec61p translocon. A significant proportion of the exported RTA avoided proteasomal degradation. These data are consistent with the contention that the RTA component from ricin endocytosed by mammalian cells may likewise exploit ERAD to translocate into the cytosol.

【 授权许可】

Unknown