N-linked sugar-regulated protein folding and quality control in the ER.
Semin Cell Dev Biol
; 41: 79-89, 2015 May.
Article
em En
| MEDLINE
| ID: mdl-25534658
ABSTRACT
Asparagine-linked glycans (N-glycans) are displayed on the majority of proteins synthesized in the endoplasmic reticulum (ER). Removal of the outermost glucose residue recruits the lectin chaperone malectin possibly involved in a first triage of defective polypeptides. Removal of a second glucose promotes engagement of folding and quality control machineries built around the ER lectin chaperones calnexin (CNX) and calreticulin (CRT) and including oxidoreductases and peptidyl-prolyl isomerases. Deprivation of the last glucose residue dictates the release of N-glycosylated polypeptides from the lectin chaperones. Correctly folded proteins are authorized to leave the ER. Non-native polypeptides are recognized by the ER quality control key player UDP-glucose glycoprotein glucosyltransferase 1 (UGT1), re-glucosylated and re-addressed to the CNX/CRT chaperone binding cycle to provide additional opportunity for the protein to fold in the ER. Failure to attain the native structure determines the selection of the misfolded polypeptides for proteasome-mediated degradation.
Palavras-chave
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Polissacarídeos
/
Glicoproteínas
/
Dobramento de Proteína
/
Retículo Endoplasmático
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Semin Cell Dev Biol
Assunto da revista:
EMBRIOLOGIA
Ano de publicação:
2015
Tipo de documento:
Article
País de afiliação:
Estados Unidos