Matriptase-mediated cleavage of EpCAM destabilizes claudins and dysregulates intestinal epithelial homeostasis.
J Clin Invest
; 127(2): 623-634, 2017 Feb 01.
Article
en En
| MEDLINE
| ID: mdl-28094766
Congenital tufting enteropathy (CTE) is a severe autosomal recessive human diarrheal disorder with characteristic intestinal epithelial dysplasia. CTE can be caused by mutations in genes encoding EpCAM, a putative adhesion molecule, and HAI-2, a cell surface protease inhibitor. A similar phenotype occurs in mice whose intestinal epithelial cells (IECs) fail to express the tight junction-associated protein claudin-7. EpCAM stabilizes claudin-7 in IECs, and HAI-2 regulates the cell surface serine protease matriptase, a known modifier of intestinal epithelial physiology. Therefore, we hypothesized that HAI-2, matriptase, EpCAM, and claudin-7 were functionally linked. Herein we have demonstrated that active matriptase cleaves EpCAM after Arg80 and that loss of HAI-2 in IECs led to unrestrained matriptase activity and efficient cleavage of EpCAM. Cleavage of EpCAM decreased its ability to associate with claudin-7 and targeted it for internalization and lysosomal degradation in conjunction with claudin-7. CTE-associated HAI-2 mutant proteins exhibited reduced ability to inhibit matriptase and also failed to efficiently stabilize claudin-7 in IECs. These results identify EpCAM as a substrate of matriptase and link HAI-2, matriptase, EpCAM, and claudin-7 in a functionally important pathway that causes disease when it is dysregulated.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Serina Endopeptidasas
/
Claudinas
/
Molécula de Adhesión Celular Epitelial
/
Mucosa Intestinal
/
Proteínas de la Membrana
Tipo de estudio:
Prognostic_studies
Límite:
Animals
/
Humans
Idioma:
En
Revista:
J Clin Invest
Año:
2017
Tipo del documento:
Article
Pais de publicación:
Estados Unidos