The hydrophobic core of the Sec61 translocon defines the hydrophobicity threshold for membrane integration.
Mol Biol Cell
; 21(10): 1662-70, 2010 May 15.
Article
en En
| MEDLINE
| ID: mdl-20357000
ABSTRACT
The Sec61 translocon mediates the translocation of proteins across the endoplasmic reticulum membrane and the lateral integration of transmembrane segments into the lipid bilayer. The structure of the idle translocon is closed by a lumenal plug domain and a hydrophobic constriction ring. To test the function of the apolar constriction, we have mutated all six ring residues of yeast Sec61p to more hydrophilic, bulky, or even charged amino acids (alanines, glycines, serines, tryptophans, lysines, or aspartates). The translocon was found to be surprisingly tolerant even to the charge mutations in the constriction ring, because growth and translocation efficiency were not drastically affected. Most interestingly, ring mutants were found to affect the integration of hydrophobic sequences into the lipid bilayer, indicating that the translocon does not simply catalyze the partitioning of potential transmembrane segments between an aqueous environment and the lipid bilayer but that it also plays an active role in setting the hydrophobicity threshold for membrane integration.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Retículo Endoplásmico
Límite:
Animals
Idioma:
En
Revista:
Mol Biol Cell
Asunto de la revista:
BIOLOGIA MOLECULAR
Año:
2010
Tipo del documento:
Article
País de afiliación:
Suiza