| Deubiquitylating Enzyme USP2 counteracts Nedd4-2-mediated Down-regulation of KCNQ1 Potassium Channels. | |
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MedLine Citation:
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PMID: 22024150 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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BACKGROUND: KCNQ1 (K(V)7.1), together with its KCNE β-subunits, plays a pivotal role in both the repolarisation of cardiac tissue and in water and salt transport across epithelial membranes. Nedd4/Nedd4-like (neuronal precursor cell-expressed developmentally down-regulated 4) ubiquitin-protein ligases interact with the KCNQ1 potassium channel through a PY motif located in the C-terminus of KCNQ1. This interaction induces ubiquitylation of KCNQ1, resulting in a reduced surface density of the channel. It was reported recently that the epithelial sodium channel ENaC is regulated by the reverse process - deubiquitylation, mediated by USP2 (ubiquitin-specific protease 2). OBJECTIVE: In this report we investigated whether deubiquitylation may regulate KCNQ1 channel complexes. METHODS: In this study we used electrophysiology, biochemistry and confocal microscopy. RESULTS: Electrophysiological investigations of KCNQ1/KCNE1 proteins co-expressed with USP2-45 or USP2-69 isoforms and Nedd4-2 in Xenopus laevis oocytes and mammalian cells revealed that both USP2 isoforms counter the Nedd4-2-specific down-regulation of I(Ks). Biochemical studies showed that total and surface-expressed KCNQ1 protein was more abundant when co-expressed with USP2 and Nedd4-2 as compared to Nedd4-2 alone. Western blotting revealed partial protection against covalent attachment of ubiquitin moieties on KCNQ1 when USP2 was co-expressed with Nedd4-2. Co-immunoprecipitation assays suggested that USP2 can bind to KCNQ1 independently of the PY motif. Immunocytochemistry confirmed that USP2 restores the membrane localization of KCNQ1. CONCLUSION: These results demonstrate that USP2 can be a potent regulator of KCNQ1 surface density. USP2, which is well expressed in many tissues, may thereby be important in controlling the KCNQ1 channel dynamics in vivo. |
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Authors:
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Katarzyna Krzystanek; Hanne Borger Rasmussen; Morten Grunnet; Olivier Staub; Søren-Peter Olesen; Hugues Abriel; Thomas Jespersen |
Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-10-21 |
Journal Detail:
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Title: Heart rhythm : the official journal of the Heart Rhythm Society Volume: - ISSN: 1556-3871 ISO Abbreviation: - Publication Date: 2011 Oct |
Date Detail:
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Created Date: 2011-10-25 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 101200317 Medline TA: Heart Rhythm Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Copyright Information:
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Copyright © 2011. Published by Elsevier Inc. |
Affiliation:
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The Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark; Department of Clinical Research, University of Bern, Murtenstrasse 35, 3010 Bern, Switzerland. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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