Rescue of expression and function of long QT syndrome-causing mutant hERG channels by enhancing channel stability in the plasma membrane.
J Biol Chem
; 300(8): 107526, 2024 Aug.
Article
en En
| MEDLINE
| ID: mdl-38960041
ABSTRACT
The human ether-a-go-go-related gene (hERG) encodes the Kv11.1 (or hERG) channel that conducts the rapidly activating delayed rectifier potassium current (IKr). Naturally occurring mutations in hERG impair the channel function and cause long QT syndrome type 2. Many missense hERG mutations lead to a lack of channel expression on the cell surface, representing a major mechanism for the loss-of-function of mutant channels. While it is generally thought that a trafficking defect underlies the lack of channel expression on the cell surface, in the present study, we demonstrate that the trafficking defective mutant hERG G601S can reach the plasma membrane but is unstable and quickly degrades, which is akin to WT hERG channels under low K+ conditions. We previously showed that serine (S) residue at 624 in the innermost position of the selectivity filter of hERG is involved in hERG membrane stability such that substitution of serine 624 with threonine (S624T) enhances hERG stability and renders hERG insensitive to low K+ culture. Here, we report that the intragenic addition of S624T substitution to trafficking defective hERG mutants G601S, N470D, and P596R led to a complete rescue of the function of these otherwise loss-of-function mutant channels to a level similar to the WT channel, representing the most effective rescue means for the function of mutant hERG channels. These findings not only provide novel insights into hERG mutation-mediated channel dysfunction but also point to the critical role of S624 in hERG stability on the plasma membrane.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Síndrome de QT Prolongado
/
Membrana Celular
/
Canal de Potasio ERG1
Límite:
Animals
/
Humans
Idioma:
En
Revista:
J Biol Chem
/
J. biol. chem
/
Journal of biological chemistry
Año:
2024
Tipo del documento:
Article
País de afiliación:
Canadá