The alpha chain of the T cell antigen receptor is degraded in the cytosol

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Item Type:	Article
Title:	The alpha chain of the T cell antigen receptor is degraded in the cytosol
Creators Name:	Huppa, J.B. and Ploegh, H.L.
Abstract:	To reach the cell surface, the T cell receptor for antigen (TCR)-CD3 complex must assemble in the endoplasmic reticulum (ER), where single subunits are retained and degraded. However, the exact location of breakdown and the mechanism and proteases involved in destruction of free subunits have remained elusive. We show that degradation of the TCR alpha chain is impaired in the presence of lactacystin and carboxybenzyl-leucyl-leucyl-leucinal, two inhibitors for proteasomal proteolysis. We identified breakdown intermediates that were either soluble, cytosolic, and devoid of N-linked glycans, or membrane-associated and partially deglycosylated by cytosolic N-glycanase. Protease protection experiments showed a cytosolic disposition of these membrane-associated intermediates. Combined, these results argue for a cytosolic degradation route of the TCR alpha chain involving dislocation from the ER, followed by cytosolic deglycosylation and proteolysis by the proteasome.
Keywords:	Acetylcysteine, Anti-Bacterial Agents, COS Cells, Cell Compartmentation, Cysteine Proteinase Inhibitors, Cytosol, Detergents, Endoplasmic Reticulum, Glycosylation, Lactams, Protein Conformation, Protein Folding, alpha-beta T-Cell Antigen Receptors, Trypsin / Metabolism, Animals
Source:	Immunity
ISSN:	1074-7613
Publisher:	Cell Press
Volume:	7
Number:	1
Page Range:	113-22
Date:	1 July 1997
Official Publication:	https://doi.org/10.1016/S1074-7613(00)80514-2
PubMed:	View item in PubMed

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