2007 JASN IMPACT FACTOR 7.111	HOME   AUTHOR INFO   EDITORIAL BOARD   SUBSCRIBE   FEEDBACK   ALERTS   HELP
advanced	CURRENT ISSUE	ARCHIVES	JASN Express	ONLINE SUBMISSION

This Article Full Text Full Text (PDF) All Versions of this Article: ASN.2005060637v1 17/4/968    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Andreasen, D. Articles by Rossier, B. C. Search for Related Content PubMed PubMed Citation Articles by Andreasen, D. Articles by Rossier, B. C.

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

Département de Pharmacologie et de Toxicologie, Université de Lausanne, Lausanne, Switzerland

Address correspondence to: Dr. Bernard C. Rossier, Institut de Pharmacologie et de Toxicologie, Université de Lausanne, Rue du Bugnon 27, Lausanne, CH-1005 Switzerland. Phone: +41-21-692-5360; Fax: +41-21-692-5355; E-mail: bernard.rossier{at}unil.ch

Received for publication June 20, 2005. Accepted for publication January 24, 2006.

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.

This article has been cited by other articles:

				K. W. Rickert, P. Kelley, N. J. Byrne, R. E. Diehl, D. L. Hall, A. M. Montalvo, J. C. Reid, J. M. Shipman, B. W. Thomas, S. K. Munshi, et al. Structure of Human Prostasin, a Target for the Regulation of Hypertension J. Biol. Chem., December 12, 2008; 283(50): 34864 - 34872. [Abstract] [Full Text] [PDF]

				A. P. Albert, A. M. Woollhead, O. J. Mace, and D. L. Baines AICAR decreases the activity of two distinct amiloride-sensitive Na+-permeable channels in H441 human lung epithelial cell monolayers Am J Physiol Lung Cell Mol Physiol, November 1, 2008; 295(5): L837 - L848. [Abstract] [Full Text] [PDF]

				A. Garcia-Caballero, Y. Dang, H. He, and M. J. Stutts ENaC Proteolytic Regulation by Channel-activating Protease 2 J. Gen. Physiol., October 27, 2008; 132(5): 521 - 535. [Abstract] [Full Text] [PDF]

				A. Diakov, K. Bera, M. Mokrushina, B. Krueger, and C. Korbmacher Cleavage in the {gamma}-subunit of the epithelial sodium channel (ENaC) plays an important role in the proteolytic activation of near-silent channels J. Physiol., October 1, 2008; 586(19): 4587 - 4608. [Abstract] [Full Text] [PDF]

				M. D. Carattino, R. P. Hughey, and T. R. Kleyman Proteolytic Processing of the Epithelial Sodium Channel {gamma} Subunit Has a Dominant Role in Channel Activation J. Biol. Chem., September 12, 2008; 283(37): 25290 - 25295. [Abstract] [Full Text] [PDF]

				M. M. Myerburg, E. E. McKenna, C. J. Luke, R. A. Frizzell, T. R. Kleyman, and J. M. Pilewski Prostasin expression is regulated by airway surface liquid volume and is increased in cystic fibrosis Am J Physiol Lung Cell Mol Physiol, May 1, 2008; 294(5): L932 - L941. [Abstract] [Full Text] [PDF]

				A. Adebamiro, Y. Cheng, U. S. Rao, H. Danahay, and R. J. Bridges A Segment of {gamma} ENaC Mediates Elastase Activation of Na+ Transport J. Gen. Physiol., November 26, 2007; 130(6): 611 - 629. [Abstract] [Full Text] [PDF]

				A. Bengrine, J. Li, L. L. Hamm, and M. S. Awayda Indirect Activation of the Epithelial Na+ Channel by Trypsin J. Biol. Chem., September 14, 2007; 282(37): 26884 - 26896. [Abstract] [Full Text] [PDF]

				J. B. Bruns, M. D. Carattino, S. Sheng, A. B. Maarouf, O. A. Weisz, J. M. Pilewski, R. P. Hughey, and T. R. Kleyman Epithelial Na+ Channels Are Fully Activated by Furin- and Prostasin-dependent Release of an Inhibitory Peptide from the {gamma}-Subunit J. Biol. Chem., March 2, 2007; 282(9): 6153 - 6160. [Abstract] [Full Text] [PDF]

				H.-Y. Lin, H. Zhang, Q. Yang, H.-X. Wang, H.-M. Wang, K. X. Chai, L.-M. Chen, and C. Zhu Expression of Prostasin and Protease Nexin-1 in Rhesus Monkey (Macaca mulatta) Endometrium and Placenta During Early Pregnancy J. Histochem. Cytochem., October 1, 2006; 54(10): 1139 - 1147. [Abstract] [Full Text] [PDF]

Copyright © 2008 by the American Society of Nephrology. Online ISSN: 1533-3450 Print ISSN: 1046-6673