A conserved GXXXG motif in APH-1 is critical for assembly and activity of the gamma-secretase complex.
J Biol Chem
; 279(6): 4144-52, 2004 Feb 06.
Article
en En
| MEDLINE
| ID: mdl-14627705
ABSTRACT
The multipass membrane protein APH-1, found in the gamma-secretase complex together with presenilin, nicastrin, and PEN-2, is essential for Notch signaling in Caenorhabditis elegans embryos and is required for intramembrane proteolysis of Notch and beta-amyloid precursor protein in mammalian and Drosophila cells. In C. elegans, a mutation of the conserved transmembrane Gly123 in APH-1 (mutant or28) leads to a notch/glp-1 loss-of-function phenotype. In this study, we show that the corresponding mutation in mammalian APH-1aL (G122D) disrupts the physical interaction of APH-1aL with hypoglycosylated immature nicastrin and the presenilin holoprotein as well as with mature nicastrin, presenilin, and PEN-2. The G122D mutation also reduced gamma-secretase activity in intramembrane proteolysis of membrane-tethered Notch. Moreover, we found that the conserved transmembrane Gly122, Gly126, and Gly130 in the fourth transmembrane region of mammalian APH-1aL are part of the membrane helix-helix interaction GXXXG motif and are essential for the stable association of APH-1aL with presenilin, nicastrin, and PEN-2. These findings suggest that APH-1 plays a GXXXG-dependent scaffolding role in both the initial assembly and subsequent maturation and maintenance of the active gamma-secretase complex.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Endopeptidasas
/
Proteínas de la Membrana
Tipo de estudio:
Prognostic_studies
Límite:
Animals
/
Humans
Idioma:
En
Revista:
J Biol Chem
Año:
2004
Tipo del documento:
Article
País de afiliación:
Estados Unidos