title: RNA editing in the central cavity as a mechanism to regulate surface expression of the voltage-gated potassium channel Kv1.1.
abstract: Voltage-gated potassium (Kv) 1.1 channels undergo a specific enzymatic RNA deamination, generating a channel with a single amino acid exchange located in the inner pore cavity (Kv1.1(I400V)). We studied I400V-edited Kv1.1 channels in more detail and found that Kv1.1(I400V) gave rise to much smaller whole-cell currents than Kv1.1. To elucidate the mechanism behind this current reduction, we conducted electrophysiological recordings on single-channel level and did not find any differences. Next we examined channel surface expression in Xenopus oocytes and HeLa cells using a chemiluminescence assay and found the edited channels to be less readily expressed at the surface membrane. This reduction in surface expression was verified by fluorescence imaging experiments. Western blot analysis for comparison of protein abundances and glycosylation patterns did not show any difference between Kv1.1 and Kv1.1(I400V), further indicating that changed trafficking of Kv1.1(I400V) is causing the current reduction. Block of endocytosis by dynasore or AP180C did not abolish the differences in current amplitudes between Kv1.1 and Kv1.1(I400V), suggesting that backward trafficking is not affected. Therefore, our data suggest that I400V RNA editing of Kv1.1 leads to a reduced current size by a decreased forward trafficking of the channel to the surface membrane. This effect is specific for Kv1.1 because coexpression of Kv1.4 channel subunits with Kv1.1(I400V) abolishes these trafficking effects. Taken together, we identified RNA editing as a novel mechanism to regulate homomeric Kv1.1 channel trafficking. Fine-tuning of Kv1.1 surface expression by RNA editing might contribute to the complexity of neuronal Kv channel regulation.
authors.affiliation: Institut für Physiologie und Pathophysiologie, Fachbereich Medizin, and Philipps-Universität Marburg, 35037 Marburg, Germany.
authors.forename: Anne K
authors.initials: AK
authors.lastname: Streit
authors.affiliation: Institut für Physiologie und Pathophysiologie, Fachbereich Medizin, and Philipps-Universität Marburg, 35037 Marburg, Germany.
authors.forename: Lina A
authors.initials: LA
authors.lastname: Matschke
authors.affiliation: Institut für Pharmakologie und Klinische Pharmazie, Fachbereich Pharmazie, Philipps-Universität Marburg, 35037 Marburg, Germany.
authors.forename: Amalia M
authors.initials: AM
authors.lastname: Dolga
authors.affiliation: Institut für Physiologie und Pathophysiologie, Fachbereich Medizin, and Philipps-Universität Marburg, 35037 Marburg, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Rinné
authors.affiliation: Institut für Physiologie und Pathophysiologie, Fachbereich Medizin, and Philipps-Universität Marburg, 35037 Marburg, Germany. Electronic address: decher@staff.uni-marburg.de.
authors.forename: Niels
authors.initials: N
authors.lastname: Decher
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D005786:Gene Expression Regulation / Q000502:physiology*; D006031:Glycosylation; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D051662:Kv1.1 Potassium Channel / Q000096:biosynthesis* / Q000235:genetics; D020125:Mutation, Missense; D021381:Protein Transport / Q000502:physiology; D017393:RNA Editing / Q000502:physiology*; D014982:Xenopus laevis
chemical_list: D051662:Kv1.1 Potassium Channel
keywords: Electrophysiology; Ion Channel; Neurophysiology; Patch Clamp Electrophysiology; Physiology; Plasma Membrane; Potassium Channel; RNA Editing; Trafficking; Xenopus
references.citation: Neuron. 1998 Apr;20(4):809-19
references.pmid: 9581771
references.citation: Neuron. 2008 May 8;58(3):387-400
references.pmid: 18466749
references.citation: Sci Transl Med. 2012 Nov 21;4(161):161ra152
references.pmid: 23147003
references.citation: FEBS Lett. 1988 Dec 19;242(1):199-206
references.pmid: 2462513
references.citation: Epilepsia. 2011 Mar;52(3):645-8
references.pmid: 21371023
references.citation: Curr Opin Cell Biol. 2007 Aug;19(4):474-82
references.pmid: 17624753
references.citation: Nat Struct Mol Biol. 2004 Oct;11(10):950-6
references.pmid: 15361858
references.citation: Mol Biol Cell. 2014 Jun 15;25(12):1877-91
references.pmid: 24743596
references.citation: Science. 2001 Jan 12;291(5502):316-9
references.pmid: 11209084
references.citation: Nat Genet. 1994 Oct;8(2):136-40
references.pmid: 7842011
references.citation: J Biol Chem. 2003 Jul 11;278(28):25558-67
references.pmid: 12730233
references.citation: Eur J Neurosci. 1995 Nov 1;7(11):2189-205
references.pmid: 8563969
references.citation: Neuron. 1990 Jan;4(1):39-51
references.pmid: 2310574
references.citation: J Biol Chem. 2000 Sep 22;275(38):29685-93
references.pmid: 10896669
references.citation: Proc Natl Acad Sci U S A. 2007 Nov 13;104(46):18103-8
references.pmid: 17991770
references.citation: Pflugers Arch. 2014 Aug;466(8):1559-70
references.pmid: 24196565
references.citation: J Neurophysiol. 2008 Oct;100(4):2125-36
references.pmid: 18684900
references.citation: Biochem J. 2005 May 15;388(Pt 1):355-62
references.pmid: 15636584
references.citation: EMBO J. 2010 Jul 7;29(13):2101-13
references.pmid: 20461057
references.citation: Sci Rep. 2013 Oct 23;3:3025
references.pmid: 24149575
references.citation: J Neurosci Res. 1995 May 1;41(1):15-26
references.pmid: 7674375
references.citation: Neurotherapeutics. 2007 Apr;4(2):258-66
references.pmid: 17395136
references.citation: Annu Rev Physiol. 2002;64:19-46
references.pmid: 11826262
references.citation: Science. 2001 Feb 9;291(5506):1051-5
references.pmid: 11161218
references.citation: J Neurochem. 2010 Feb;112(4):913-23
references.pmid: 19968754
references.citation: Science. 2003 Aug 8;301(5634):832-6
references.pmid: 12907802