Activation of epithelial sodium channels by mouse channel activating proteases (mCAP) expressed in Xenopus oocytes requires catalytic activity of mCAP3 and mCAP2 but not mCAP1

Détails

ID Serval
serval:BIB_DBD91E3FEDD9
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Activation of epithelial sodium channels by mouse channel activating proteases (mCAP) expressed in Xenopus oocytes requires catalytic activity of mCAP3 and mCAP2 but not mCAP1
Périodique
Journal of the American Society of Nephrology
Auteur(s)
Andreasen  D., Vuagniaux  G., Fowler-Jaeger  N., Hummler  E., Rossier  B. C.
ISSN
1046-6673
Statut éditorial
Publié
Date de publication
04/2006
Peer-reviewed
Oui
Volume
17
Numéro
4
Pages
968-76
Notes
In Vitro Journal Article Research Support, Non-U.S. Gov't --- Old month value: Apr
Résumé
Mouse channel activating proteases 1, 2, and 3 (mCAP1, mCAP2, and mCAP3) were described recently as regulators of the epithelial sodium channel (ENaC). The mCAP are membrane-bound serine proteases that are synthesized as inactive proenzymes. To mature into active proteases, they undergo intramolecular cleavage by auto- and/or heterocatalytic processing. Specific antibodies against each mCAP were developed to distinguish between proenzyme and active protease by Western blot analysis. Various point mutations were introduced in the catalytic or protein-protein interacting domains of mCAP and wild-type and mutant enzymes were expressed in the Xenopus oocyte expression system to test for ability to activate ENaC. In mCAP3, an intact catalytic triad was necessary for activation of ENaC but not for intramolecular cleavage of the protease. This suggests a heterocatalytic mechanism. Mutating the catalytic triad of mCAP2 not only abolished ENaC activation completely but also impeded cleavage of the protease. Processing of mCAP2 therefore seems to be autocatalytic. Furthermore, mutations in conserved residues of mCAP2 located in two protein-protein interacting domains significantly modulated ENaC activation. Surprisingly, mCAP1 catalytically inactive mutants were still able to fully activate ENaC, and no evidence of mCAP1 intramolecular cleavage was seen. The presence of an intact glycosylphosphatidylinositol anchor, however, was required. It is concluded that auto- and heterocatalytic requirements are specific for each CAP and that endogenous partners are a necessity for activation of ENaC by mCAP in the Xenopus oocyte expression system.
Mots-clé
Animals Antibodies Catalytic Domain/genetics Epithelial Sodium Channel Female Membrane Proteins/genetics/immunology/*metabolism Mice Mutagenesis, Site-Directed Oocytes/metabolism Recombinant Fusion Proteins/genetics/immunology/metabolism Serine Endopeptidases/genetics/immunology/*metabolism Serpins/genetics/immunology/*metabolism Sodium Channels/*metabolism Xenopus laevis
Pubmed
Web of science
Open Access
Oui
Création de la notice
24/01/2008 14:00
Dernière modification de la notice
20/08/2019 17:00
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