SHARPIN stabilizes ß-catenin through a linear ubiquitination-independent manner to support gastric tumorigenesis.
Gastric Cancer
; 24(2): 402-416, 2021 Mar.
Article
en En
| MEDLINE
| ID: mdl-33159601
ABSTRACT
BACKGROUND:
Aberrant activation of Wnt/ß-catenin signaling by dysregulated post-translational protein modifications, especially ubiquitination is causally linked to cancer development and progression. Although Lys48-linked ubiquitination is known to regulate Wnt/ß-catenin signaling, it remains largely obscure how other types of ubiquitination, such as linear ubiquitination governs its signaling activity.METHODS:
The expression and regulatory mechanism of linear ubiquitin chain assembly complex (LUBAC) on Wnt/ß-catenin signaling was examined by immunoprecipitation, western blot and immunohistochemical staining. The ubiquitination status of ß-catenin was detected by ubiquitination assay. The impacts of SHARPIN, a core component of LUBAC on malignant behaviors of gastric cancer cells were determined by various functional assays in vitro and in vivo.RESULTS:
Unlike a canonical role in promoting linear ubiquitination, SHARPIN specifically interacts with ß-catenin to maintain its protein stability. Mechanistically, SHARPIN competes with the E3 ubiquitin ligase ß-Trcp1 for ß-catenin binding, thereby decreasing ß-catenin ubiquitination levels to abolish its proteasomal degradation. Importantly, SHARPIN is required for invasiveness and malignant growth of gastric cancer cells in vitro and in vivo, a function that is largely dependent on its binding partner ß-catenin. In line with these findings, elevated expression of SHARPIN in gastric cancer tissues is associated with disease malignancy and correlates with ß-catenin expression levels.CONCLUSIONS:
Our findings reveal a novel molecular link connecting linear ubiquitination machinery and Wnt/ß-catenin signaling via SHARPIN-mediated stabilization of ß-catenin. Targeting the linear ubiquitination-independent function of SHARPIN could be exploited to inhibit the hyperactive ß-catenin signaling in a subset of human gastric cancers.Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Neoplasias Gástricas
/
Ubiquitinas
/
Beta Catenina
/
Ubiquitinación
/
Carcinogénesis
Límite:
Humans
Idioma:
En
Revista:
Gastric Cancer
Asunto de la revista:
GASTROENTEROLOGIA
/
NEOPLASIAS
Año:
2021
Tipo del documento:
Article