title: Kif5b is an essential forward trafficking motor for the Kv1.5 cardiac potassium channel.
abstract: We have investigated the role of the kinesin I isoform Kif5b in the trafficking of a cardiac voltage-gated potassium channel, Kv1.5. In Kv1.5-expressing HEK293 cells and H9c2 cardiomyoblasts, current densities were increased from control levels of 389 +/- 50.0 and 317 +/- 50.3 pA pF(1), respectively, to 614 +/- 74.3 and 580 +/- 90.9 pA pF(1) in cells overexpressing the Kif5b motor. Overexpression of the Kif5b motor increased Kv1.5 expression additively with several manipulations that reduce channel internalization, suggesting that it is involved in the delivery of the channel to the cell surface. In contrast, expression of a Kif5b dominant negative (Kif5bDN) construct increased Kv1.5 expression non-additively with these manipulations. Thus, the dominant negative acts by indirectly inhibiting endocytosis. The increase in Kv1.5 currents induced by wild-type Kif5b was dependent on Golgi function; a 6 h treatment with Brefeldin A reduced Kv1.5 currents to control levels in Kif5b-overexpressing cells but had little effect on the increase associated with Kif5bDN expression. Finally, expression of the Kif5bDN prior to induction of Kv1.5 in a tetracycline inducible system blocked surface expression of the channel in both HEK293 cells and H9c2 cardiomyoblasts. Thus, Kif5b is essential to anterograde trafficking of a cardiac voltage-gated potassium channel.
authors.affiliation: Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3.
authors.forename: Alireza Dehghani
authors.initials: AD
authors.lastname: Zadeh
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Cheng
authors.forename: Hongjian
authors.initials: H
authors.lastname: Xu
authors.forename: Nathan
authors.initials: N
authors.lastname: Wong
authors.forename: Zhuren
authors.initials: Z
authors.lastname: Wang
authors.forename: Charitha
authors.initials: C
authors.lastname: Goonasekara
authors.forename: David F
authors.initials: DF
authors.lastname: Steele
authors.forename: David
authors.initials: D
authors.lastname: Fedida
mesh_terms: D020126:Brefeldin A / Q000494:pharmacology; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D015870:Gene Expression; D006056:Golgi Apparatus / Q000187:drug effects / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D016547:Kinesins / Q000235:genetics / Q000378:metabolism*; D051666:Kv1.5 Potassium Channel / Q000235:genetics / Q000378:metabolism*; D008564:Membrane Potentials; D008870:Microtubules / Q000378:metabolism; D032386:Myoblasts, Cardiac / Q000187:drug effects / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D014162:Transfection
chemical_list: C496981:KCNA5 protein, human; C488101:KIF5B protein, human; D051666:Kv1.5 Potassium Channel; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D020126:Brefeldin A; D016547:Kinesins
references.citation: Nature. 2002 May 2;417(6884):83-7
references.pmid: 11986669
references.citation: J Biol Chem. 2001 Oct 19;276(42):39419-27
references.pmid: 11487588
references.citation: Circ Res. 2005 Aug 19;97(4):363-71
references.pmid: 16051887
references.citation: Mol Biol Cell. 2004 Sep;15(9):4073-88
references.pmid: 15215309
references.citation: J Biol Chem. 2007 Oct 5;282(40):29612-20
references.pmid: 17673464
references.citation: Eur J Neurosci. 2007 Jan;25(1):136-46
references.pmid: 17241275
references.citation: J Physiol. 2008 Oct 15;586(20):4793-813
references.pmid: 18755741
references.citation: Am J Physiol Heart Circ Physiol. 2009 Jan;296(1):H71-83
references.pmid: 18978193
references.citation: J Biol Chem. 2000 Apr 21;275(16):11597-602
references.pmid: 10766775
references.citation: J Heart Lung Transplant. 2004 Aug;23(8):954-63
references.pmid: 15312825
references.citation: Mol Biol Cell. 1999 Dec;10(12):4107-20
references.pmid: 10588646
references.citation: Mol Biol Cell. 1999 Nov;10(11):3717-28
references.pmid: 10564267
references.citation: Physiol Rev. 2008 Jul;88(3):1089-118
references.pmid: 18626067
references.citation: FEBS Lett. 2002 Nov 20;531(3):529-37
references.pmid: 12435606
references.citation: FEBS Lett. 2003 Jul 17;547(1-3):205-11
references.pmid: 12860415
references.citation: Biochem Biophys Res Commun. 2006 Mar 31;342(1):1-8
references.pmid: 16466689
references.citation: Circ Res. 2003 Oct 17;93(8):744-51
references.pmid: 14500335
references.citation: Circ Res. 2007 Mar 16;100(5):686-92
references.pmid: 17293474
references.citation: J Cell Sci. 1993 Nov;106 ( Pt 3):955-66
references.pmid: 7905879
references.citation: J Cell Biol. 1992 Mar;116(5):1071-80
references.pmid: 1740466
references.citation: J Biol Chem. 2006 Jan 6;281(1):365-73
references.pmid: 16257958
references.citation: Proc Natl Acad Sci U S A. 2001 Nov 20;98(24):14055-9
references.pmid: 11698661
references.citation: J Biol Chem. 2003 May 2;278(18):16262-70
references.pmid: 12601004
references.citation: J Physiol. 2007 Jul 1;582(Pt 1):17-26
references.pmid: 17412767
references.citation: Biochem J. 2003 Nov 1;375(Pt 3):761-8
references.pmid: 12901718
references.citation: Science. 2000 Jun 9;288(5472):1796-802
references.pmid: 10846156