title: AUF1 is upregulated by angiotensin II to destabilize cardiac Kv4.3 channel mRNA.
abstract: Expression of cardiac myocyte Kv4 channels (Kv4.3 for human, Kv4.2 and Kv4.3 for rodents) is downregulated with hypertrophy in vivo leading to a decrease in the transient outward current (Ito). This effect is recapitulated in vitro with rat neonatal cardiac myocytes treated with angiotensin II (Ang II), which acts via AT(1) receptors, NADPH oxidase and p38 MAP kinase to destabilize the 3' untranslated region (3'UTR) of the Kv4.3 channel messenger RNA (mRNA). Here deletion analysis and mutagenesis identify an AU-rich element (ARE) in the Kv4.3 3'UTR that is required for Ang II-induced destabilization. Overexpression of AUF1 (ARE/poly-(U)-binding/degradation factor 1), an RNA destabilizing protein, mimics and occludes the Ang II effect, while RNA interference targeted against AUF1 blocks the Ang II effect on the Kv4.3 3'UTR. Ang II upregulates AUF1 by activating AT(1) receptors, NADPH oxidase and p38 MAP kinase. Finally, pull-down assays establish that Ang II increases AUF1 binding to the ARE required for destabilization, while binding of the mRNA stabilizing protein HuR is unaffected. Hence, Ang II acts via AT(1) receptors, NADPH oxidase and p38 MAP kinase to upregulate AUF1, which in turn binds to an ARE in the Kv4.3 3'UTR to destabilize the channel mRNA.
authors.affiliation: Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors.forename: Chaoming
authors.initials: C
authors.lastname: Zhou
authors.forename: Chandra Z
authors.initials: CZ
authors.lastname: Vignere
authors.forename: Edwin S
authors.initials: ES
authors.lastname: Levitan
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics / Q000378:metabolism*; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001483:Base Sequence / Q000235:genetics; D002478:Cells, Cultured; D000081035:Heterogeneous Nuclear Ribonucleoprotein D0; D034502:Heterogeneous-Nuclear Ribonucleoprotein D / Q000235:genetics / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism*; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D020871:RNA Stability / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D044140:Receptor, Angiotensin, Type 1 / Q000819:agonists / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion / Q000235:genetics; D051672:Shal Potassium Channels / Q000096:biosynthesis* / Q000235:genetics; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: D020413:3' Untranslated Regions; C000630986:HNRNPD protein, human; D000081035:Heterogeneous Nuclear Ribonucleoprotein D0; D034502:Heterogeneous-Nuclear Ribonucleoprotein D; C000630988:Hnrnpd protein, rat; D044140:Receptor, Angiotensin, Type 1; D051672:Shal Potassium Channels; D000804:Angiotensin II; D019255:NADPH Oxidases; D048051:p38 Mitogen-Activated Protein Kinases
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