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The C‐terminal T peptide of acetylcholinesterase enhances degradation of unassembled active subunits through the ERAD pathway
Author(s) -
Belbeoc'h Stéphanie,
Massoulié Jean,
Bon Suzanne
Publication year - 2003
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdg360
Subject(s) - biology , endoplasmic reticulum associated protein degradation , endoplasmic reticulum , peptide , secretion , biochemistry , microbiology and biotechnology , unfolded protein response
The catalytic domain of acetylcholinesterase AChE T subunits is followed by a C‐terminal T peptide which mediates their association with the proline‐rich attachment domain (PRAD) of anchoring proteins. Addition of the T peptide induced intracellular degradation and concomitantly reduced to variable degrees the secretion of AChE species differing in their oligomerization capacity and of human alkaline phosphatase. The T peptide forms an amphiphilic α‐helix, containing a series of conserved aromatic residues. Replacement of two, four or five aromatic residues gradually suppressed degradation and increased secretion. Co‐expression with a PRAD‐ containing protein induced the assembly of PRAD‐linked tetramers in the endoplasmic reticulum (ER) and allowed partial secretion of a dimerization‐ defective mutant; by masking the aromatic side chains, hetero‐oligomerization rescued this enzyme from degradation. Degradation was due to ERAD, since it was not blocked by brefeldin A but was sensitive to proteasome inhibitors. Kifunensine reduced degradation, suggesting a cooperativity between the glycosylated catalytic domain and the non‐glycosylated T peptide. This system appears particularly well suited to analyze the mechanisms which determine the degradation of correctly folded multidomain proteins in the ER.