Abstract
Voltage-gated K+ channels are important modulators of the cardiac action potential. However, the correlation of endogenous myocyte currents with K+ channels cloned from human heart is complicated by the possibility that heterotetrameric alpha-subunit combinations and function-altering beta subunits exist in native tissue. Therefore, a variety of subunit interactions may generate cardiac K+ channel diversity. We report here the cloning of a voltage-gated K+ channel beta subunit, hKv beta 3, from adult human left ventricle that shows 84% and 74% amino acid sequence identity with the previously cloned rat Kv beta 1 and Kv beta 2 subunits, respectively. Together these three Kv beta subunits share > 82% identity in the carboxyl-terminal 329 aa and show low identity in the amino-terminal 79 aa. RNA analysis indicated that hKv beta 3 message is 2-fold more abundant in human ventricle than in atrium and is expressed in both healthy and diseased human hearts. Coinjection of hKv beta 3 with a human cardiac delayed rectifier, hKv1.5, in Xenopus oocytes increased inactivation, induced an 18-mV hyperpolarizing shift in the activation curve, and slowed deactivation (tau = 8.0 msec vs. 35.4 msec at -50 mV). hKv beta 3 was localized to human chromosome 3 by using a human/rodent cell hybrid mapping panel. These data confirm the presence of functionally important K+ channel beta subunits in human heart and indicate that beta-subunit composition must be accounted for when comparing cloned channels with endogenous cardiac currents.
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- Balser J. R., Bennett P. B., Roden D. M. Time-dependent outward current in guinea pig ventricular myocytes. Gating kinetics of the delayed rectifier. J Gen Physiol. 1990 Oct;96(4):835–863. doi: 10.1085/jgp.96.4.835. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Benndorf K., Markwardt F., Nilius B. Two types of transient outward currents in cardiac ventricular cells of mice. Pflugers Arch. 1987 Aug;409(6):641–643. doi: 10.1007/BF00584667. [DOI] [PubMed] [Google Scholar]
- Bennett P. B., Jr, Makita N., George A. L., Jr A molecular basis for gating mode transitions in human skeletal muscle Na+ channels. FEBS Lett. 1993 Jul 12;326(1-3):21–24. doi: 10.1016/0014-5793(93)81752-l. [DOI] [PubMed] [Google Scholar]
- Boyd A. E., 3rd Sulfonylurea receptors, ion channels, and fruit flies. Diabetes. 1988 Jul;37(7):847–850. doi: 10.2337/diab.37.7.847. [DOI] [PubMed] [Google Scholar]
- Boyle W. A., Nerbonne J. M. A novel type of depolarization-activated K+ current in isolated adult rat atrial myocytes. Am J Physiol. 1991 Apr;260(4 Pt 2):H1236–H1247. doi: 10.1152/ajpheart.1991.260.4.H1236. [DOI] [PubMed] [Google Scholar]
- Bradbury A. F., Smyth D. G. Peptide amidation. Trends Biochem Sci. 1991 Mar;16(3):112–115. doi: 10.1016/0968-0004(91)90044-v. [DOI] [PubMed] [Google Scholar]
- Browne D. L., Gancher S. T., Nutt J. G., Brunt E. R., Smith E. A., Kramer P., Litt M. Episodic ataxia/myokymia syndrome is associated with point mutations in the human potassium channel gene, KCNA1. Nat Genet. 1994 Oct;8(2):136–140. doi: 10.1038/ng1094-136. [DOI] [PubMed] [Google Scholar]
- Cuttitta F. Peptide amidation: signature of bioactivity. Anat Rec. 1993 May;236(1):87-93, 172-3; discussion 93-5. doi: 10.1002/ar.1092360112. [DOI] [PubMed] [Google Scholar]
- De Waard M., Pragnell M., Campbell K. P. Ca2+ channel regulation by a conserved beta subunit domain. Neuron. 1994 Aug;13(2):495–503. doi: 10.1016/0896-6273(94)90363-8. [DOI] [PubMed] [Google Scholar]
- Dixon J. E., McKinnon D. Quantitative analysis of potassium channel mRNA expression in atrial and ventricular muscle of rats. Circ Res. 1994 Aug;75(2):252–260. doi: 10.1161/01.res.75.2.252. [DOI] [PubMed] [Google Scholar]
- Escande D., Coulombe A., Faivre J. F., Deroubaix E., Coraboeuf E. Two types of transient outward currents in adult human atrial cells. Am J Physiol. 1987 Jan;252(1 Pt 2):H142–H148. doi: 10.1152/ajpheart.1987.252.1.H142. [DOI] [PubMed] [Google Scholar]
- Han K. K., Martinage A. Post-translational chemical modification(s) of proteins. Int J Biochem. 1992;24(1):19–28. doi: 10.1016/0020-711x(92)90225-p. [DOI] [PubMed] [Google Scholar]
- Heidbüchel H., Vereecke J., Carmeliet E. Three different potassium channels in human atrium. Contribution to the basal potassium conductance. Circ Res. 1990 May;66(5):1277–1286. doi: 10.1161/01.res.66.5.1277. [DOI] [PubMed] [Google Scholar]
- Hume J. R., Uehara A. Ionic basis of the different action potential configurations of single guinea-pig atrial and ventricular myocytes. J Physiol. 1985 Nov;368:525–544. doi: 10.1113/jphysiol.1985.sp015874. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Isom L. L., De Jongh K. S., Patton D. E., Reber B. F., Offord J., Charbonneau H., Walsh K., Goldin A. L., Catterall W. A. Primary structure and functional expression of the beta 1 subunit of the rat brain sodium channel. Science. 1992 May 8;256(5058):839–842. doi: 10.1126/science.1375395. [DOI] [PubMed] [Google Scholar]
- Jiang C., Atkinson D., Towbin J. A., Splawski I., Lehmann M. H., Li H., Timothy K., Taggart R. T., Schwartz P. J., Vincent G. M. Two long QT syndrome loci map to chromosomes 3 and 7 with evidence for further heterogeneity. Nat Genet. 1994 Oct;8(2):141–147. doi: 10.1038/ng1094-141. [DOI] [PubMed] [Google Scholar]
- Klocke R., Roberds S. L., Tamkun M. M., Gronemeier M., Augustin A., Albrecht B., Pongs O., Jockusch H. Chromosomal mapping in the mouse of eight K(+)-channel genes representing the four Shaker-like subfamilies Shaker, Shab, Shaw, and Shal. Genomics. 1993 Dec;18(3):568–574. doi: 10.1016/s0888-7543(05)80358-1. [DOI] [PubMed] [Google Scholar]
- Majumder K., De Biasi M., Wang Z., Wible B. A. Molecular cloning and functional expression of a novel potassium channel beta-subunit from human atrium. FEBS Lett. 1995 Mar 13;361(1):13–16. doi: 10.1016/0014-5793(95)00120-x. [DOI] [PubMed] [Google Scholar]
- Makita N., Bennett P. B., Jr, George A. L., Jr Voltage-gated Na+ channel beta 1 subunit mRNA expressed in adult human skeletal muscle, heart, and brain is encoded by a single gene. J Biol Chem. 1994 Mar 11;269(10):7571–7578. [PubMed] [Google Scholar]
- Messner D. J., Catterall W. A. The sodium channel from rat brain. Separation and characterization of subunits. J Biol Chem. 1985 Sep 5;260(19):10597–10604. [PubMed] [Google Scholar]
- Morales M. J., Castellino R. C., Crews A. L., Rasmusson R. L., Strauss H. C. A novel beta subunit increases rate of inactivation of specific voltage-gated potassium channel alpha subunits. J Biol Chem. 1995 Mar 17;270(11):6272–6277. doi: 10.1074/jbc.270.11.6272. [DOI] [PubMed] [Google Scholar]
- Po S., Roberds S., Snyders D. J., Tamkun M. M., Bennett P. B. Heteromultimeric assembly of human potassium channels. Molecular basis of a transient outward current? Circ Res. 1993 Jun;72(6):1326–1336. doi: 10.1161/01.res.72.6.1326. [DOI] [PubMed] [Google Scholar]
- Po S., Snyders D. J., Baker R., Tamkun M. M., Bennett P. B. Functional expression of an inactivating potassium channel cloned from human heart. Circ Res. 1992 Sep;71(3):732–736. doi: 10.1161/01.res.71.3.732. [DOI] [PubMed] [Google Scholar]
- Ptácek L. J., George A. L., Jr, Barchi R. L., Griggs R. C., Riggs J. E., Robertson M., Leppert M. F. Mutations in an S4 segment of the adult skeletal muscle sodium channel cause paramyotonia congenita. Neuron. 1992 May;8(5):891–897. doi: 10.1016/0896-6273(92)90203-p. [DOI] [PubMed] [Google Scholar]
- Quast U., Cook N. S. In vitro and in vivo comparison of two K+ channel openers, diazoxide and cromakalim, and their inhibition by glibenclamide. J Pharmacol Exp Ther. 1989 Jul;250(1):261–271. [PubMed] [Google Scholar]
- Rettig J., Heinemann S. H., Wunder F., Lorra C., Parcej D. N., Dolly J. O., Pongs O. Inactivation properties of voltage-gated K+ channels altered by presence of beta-subunit. Nature. 1994 May 26;369(6478):289–294. doi: 10.1038/369289a0. [DOI] [PubMed] [Google Scholar]
- Roberds S. L., Tamkun M. M. Cloning and tissue-specific expression of five voltage-gated potassium channel cDNAs expressed in rat heart. Proc Natl Acad Sci U S A. 1991 Mar 1;88(5):1798–1802. doi: 10.1073/pnas.88.5.1798. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ruppersberg J. P., Frank R., Pongs O., Stocker M. Cloned neuronal IK(A) channels reopen during recovery from inactivation. Nature. 1991 Oct 17;353(6345):657–660. doi: 10.1038/353657a0. [DOI] [PubMed] [Google Scholar]
- Ruppersberg J. P., Stocker M., Pongs O., Heinemann S. H., Frank R., Koenen M. Regulation of fast inactivation of cloned mammalian IK(A) channels by cysteine oxidation. Nature. 1991 Aug 22;352(6337):711–714. doi: 10.1038/352711a0. [DOI] [PubMed] [Google Scholar]
- Sakmann B., Trube G. Conductance properties of single inwardly rectifying potassium channels in ventricular cells from guinea-pig heart. J Physiol. 1984 Feb;347:641–657. doi: 10.1113/jphysiol.1984.sp015088. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sanguinetti M. C., Jurkiewicz N. K. Delayed rectifier outward K+ current is composed of two currents in guinea pig atrial cells. Am J Physiol. 1991 Feb;260(2 Pt 2):H393–H399. doi: 10.1152/ajpheart.1991.260.2.H393. [DOI] [PubMed] [Google Scholar]
- Sanguinetti M. C., Jurkiewicz N. K. Two components of cardiac delayed rectifier K+ current. Differential sensitivity to block by class III antiarrhythmic agents. J Gen Physiol. 1990 Jul;96(1):195–215. doi: 10.1085/jgp.96.1.195. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Scott V. E., Rettig J., Parcej D. N., Keen J. N., Findlay J. B., Pongs O., Dolly J. O. Primary structure of a beta subunit of alpha-dendrotoxin-sensitive K+ channels from bovine brain. Proc Natl Acad Sci U S A. 1994 Mar 1;91(5):1637–1641. doi: 10.1073/pnas.91.5.1637. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Snyders D. J., Tamkun M. M., Bennett P. B. A rapidly activating and slowly inactivating potassium channel cloned from human heart. Functional analysis after stable mammalian cell culture expression. J Gen Physiol. 1993 Apr;101(4):513–543. doi: 10.1085/jgp.101.4.513. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sutkowski E. M., Catterall W. A. Beta 1 subunits of sodium channels. Studies with subunit-specific antibodies. J Biol Chem. 1990 Jul 25;265(21):12393–12399. [PubMed] [Google Scholar]
- Tamkun M. M., Knoth K. M., Walbridge J. A., Kroemer H., Roden D. M., Glover D. M. Molecular cloning and characterization of two voltage-gated K+ channel cDNAs from human ventricle. FASEB J. 1991 Mar 1;5(3):331–337. doi: 10.1096/fasebj.5.3.2001794. [DOI] [PubMed] [Google Scholar]
- Tseng G. N., Hoffman B. F. Two components of transient outward current in canine ventricular myocytes. Circ Res. 1989 Apr;64(4):633–647. doi: 10.1161/01.res.64.4.633. [DOI] [PubMed] [Google Scholar]
- Wang Z., Fermini B., Nattel S. Sustained depolarization-induced outward current in human atrial myocytes. Evidence for a novel delayed rectifier K+ current similar to Kv1.5 cloned channel currents. Circ Res. 1993 Dec;73(6):1061–1076. doi: 10.1161/01.res.73.6.1061. [DOI] [PubMed] [Google Scholar]
- Wettwer E., Amos G. J., Posival H., Ravens U. Transient outward current in human ventricular myocytes of subepicardial and subendocardial origin. Circ Res. 1994 Sep;75(3):473–482. doi: 10.1161/01.res.75.3.473. [DOI] [PubMed] [Google Scholar]
- White M. M., Chen L. Q., Kleinfield R., Kallen R. G., Barchi R. L. SkM2, a Na+ channel cDNA clone from denervated skeletal muscle, encodes a tetrodotoxin-insensitive Na+ channel. Mol Pharmacol. 1991 May;39(5):604–608. [PubMed] [Google Scholar]
- Yue D. T., Marban E. A novel cardiac potassium channel that is active and conductive at depolarized potentials. Pflugers Arch. 1988 Dec;413(2):127–133. doi: 10.1007/BF00582522. [DOI] [PubMed] [Google Scholar]