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Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1991 Jan 1;88(1):53–57. doi: 10.1073/pnas.88.1.53

Sequence and functional expression in Xenopus oocytes of a human insulinoma and islet potassium channel.

L H Philipson 1, R E Hice 1, K Schaefer 1, J LaMendola 1, G I Bell 1, D J Nelson 1, D F Steiner 1
PMCID: PMC50746  PMID: 1986382

Abstract

Regulation of insulin secretion involves the coordinated control of ion channels in the beta-cell membrane. We have isolated and characterized cDNA and genomic clones encoding a voltage-dependent K+ channel isoform expressed in human islets and in a human insulinoma. This K+ channel isoform, designated hPCN1, with a deduced amino acid sequence of 613 residues (Mr = 67,097), is related to the Shaker family of Drosophila K+ channels. hPCN1 is homologous to two other human K+ channel isoforms we have isolated, hPCN2 and hPCN3, with 55% and 65% amino acid sequence identity, respectively. The electrophysiological characteristics of hPCN1 were determined after microinjection of synthetic RNA into Xenopus oocytes. Two-microelectrode voltage-clamp recordings of oocytes injected with hPCN1 RNA revealed a voltage-dependent outward K+ current that inactivated slowly with time. Outward currents were inhibited by 4-aminopyridine with a Ki less than 0.10 mM and were relatively insensitive to tetraethylammonium ion or Ba2+. A delayed rectifier K+ channel such as hPCN1 could restore the resting membrane potential of beta cells after depolarization and thereby contribute to the regulation of insulin secretion.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Ashcroft F. M. Adenosine 5'-triphosphate-sensitive potassium channels. Annu Rev Neurosci. 1988;11:97–118. doi: 10.1146/annurev.ne.11.030188.000525. [DOI] [PubMed] [Google Scholar]
  2. Asplund K., Freinkel N. Phosphate metabolism and glucose-initiated efflux of phosphate ions in islets of fetal pancreas. Diabetes. 1978 Jun;27(6):611–619. doi: 10.2337/diab.27.6.611. [DOI] [PubMed] [Google Scholar]
  3. Baumann A., Krah-Jentgens I., Müller R., Müller-Holtkamp F., Seidel R., Kecskemethy N., Casal J., Ferrus A., Pongs O. Molecular organization of the maternal effect region of the Shaker complex of Drosophila: characterization of an I(A) channel transcript with homology to vertebrate Na channel. EMBO J. 1987 Nov;6(11):3419–3429. doi: 10.1002/j.1460-2075.1987.tb02665.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Betsholtz C., Baumann A., Kenna S., Ashcroft F. M., Ashcroft S. J., Berggren P. O., Grupe A., Pongs O., Rorsman P., Sandblom J. Expression of voltage-gated K+ channels in insulin-producing cells. Analysis by polymerase chain reaction. FEBS Lett. 1990 Apr 9;263(1):121–126. doi: 10.1016/0014-5793(90)80719-y. [DOI] [PubMed] [Google Scholar]
  5. Blackshear P. J., Nairn A. C., Kuo J. F. Protein kinases 1988: a current perspective. FASEB J. 1988 Nov;2(14):2957–2969. doi: 10.1096/fasebj.2.14.2972578. [DOI] [PubMed] [Google Scholar]
  6. Bokvist K., Rorsman P., Smith P. A. Block of ATP-regulated and Ca2(+)-activated K+ channels in mouse pancreatic beta-cells by external tetraethylammonium and quinine. J Physiol. 1990 Apr;423:327–342. doi: 10.1113/jphysiol.1990.sp018025. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Bokvist K., Rorsman P., Smith P. A. Effects of external tetraethylammonium ions and quinine on delayed rectifying K+ channels in mouse pancreatic beta-cells. J Physiol. 1990 Apr;423:311–325. doi: 10.1113/jphysiol.1990.sp018024. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. 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]
  9. Butler A., Wei A. G., Baker K., Salkoff L. A family of putative potassium channel genes in Drosophila. Science. 1989 Feb 17;243(4893):943–947. doi: 10.1126/science.2493160. [DOI] [PubMed] [Google Scholar]
  10. Chandy K. G., Williams C. B., Spencer R. H., Aguilar B. A., Ghanshani S., Tempel B. L., Gutman G. A. A family of three mouse potassium channel genes with intronless coding regions. Science. 1990 Feb 23;247(4945):973–975. doi: 10.1126/science.2305265. [DOI] [PubMed] [Google Scholar]
  11. Christie M. J., North R. A., Osborne P. B., Douglass J., Adelman J. P. Heteropolymeric potassium channels expressed in Xenopus oocytes from cloned subunits. Neuron. 1990 Mar;4(3):405–411. doi: 10.1016/0896-6273(90)90052-h. [DOI] [PubMed] [Google Scholar]
  12. Espinosa de los Monteros, Driscoll S. G., Steinke J. Insulin release from isolated human fetal pancreatic islets. Science. 1970 May 29;168(3935):1111–1112. doi: 10.1126/science.168.3935.1111. [DOI] [PubMed] [Google Scholar]
  13. Flatt P. R. Defective regulation of insulin secretion in diabetes and insulinoma. Biochem Soc Trans. 1990 Feb;18(1):124–127. doi: 10.1042/bst0180124. [DOI] [PubMed] [Google Scholar]
  14. Frech G. C., VanDongen A. M., Schuster G., Brown A. M., Joho R. H. A novel potassium channel with delayed rectifier properties isolated from rat brain by expression cloning. Nature. 1989 Aug 24;340(6235):642–645. doi: 10.1038/340642a0. [DOI] [PubMed] [Google Scholar]
  15. Frohman M. A., Dush M. K., Martin G. R. Rapid production of full-length cDNAs from rare transcripts: amplification using a single gene-specific oligonucleotide primer. Proc Natl Acad Sci U S A. 1988 Dec;85(23):8998–9002. doi: 10.1073/pnas.85.23.8998. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Giles W. R., Shibata E. F. Voltage clamp of bull-frog cardiac pace-maker cells: a quantitative analysis of potassium currents. J Physiol. 1985 Nov;368:265–292. doi: 10.1113/jphysiol.1985.sp015857. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. HODGKIN A. L., HUXLEY A. F. The components of membrane conductance in the giant axon of Loligo. J Physiol. 1952 Apr;116(4):473–496. doi: 10.1113/jphysiol.1952.sp004718. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Hitchcock M. J., Ginns E. I., Marcus-Sekura C. J. Microinjection into Xenopus oocytes: equipment. Methods Enzymol. 1987;152:276–284. doi: 10.1016/0076-6879(87)52031-6. [DOI] [PubMed] [Google Scholar]
  19. House C., Kemp B. E. Protein kinase C contains a pseudosubstrate prototope in its regulatory domain. Science. 1987 Dec 18;238(4834):1726–1728. doi: 10.1126/science.3686012. [DOI] [PubMed] [Google Scholar]
  20. Isacoff E. Y., Jan Y. N., Jan L. Y. Evidence for the formation of heteromultimeric potassium channels in Xenopus oocytes. Nature. 1990 Jun 7;345(6275):530–534. doi: 10.1038/345530a0. [DOI] [PubMed] [Google Scholar]
  21. Kamb A., Iverson L. E., Tanouye M. A. Molecular characterization of Shaker, a Drosophila gene that encodes a potassium channel. Cell. 1987 Jul 31;50(3):405–413. doi: 10.1016/0092-8674(87)90494-6. [DOI] [PubMed] [Google Scholar]
  22. Kamb A., Weir M., Rudy B., Varmus H., Kenyon C. Identification of genes from pattern formation, tyrosine kinase, and potassium channel families by DNA amplification. Proc Natl Acad Sci U S A. 1989 Jun;86(12):4372–4376. doi: 10.1073/pnas.86.12.4372. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Kayano T., Fukumoto H., Eddy R. L., Fan Y. S., Byers M. G., Shows T. B., Bell G. I. Evidence for a family of human glucose transporter-like proteins. Sequence and gene localization of a protein expressed in fetal skeletal muscle and other tissues. J Biol Chem. 1988 Oct 25;263(30):15245–15248. [PubMed] [Google Scholar]
  24. Kozak M. The scanning model for translation: an update. J Cell Biol. 1989 Feb;108(2):229–241. doi: 10.1083/jcb.108.2.229. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Krieg P. A., Melton D. A. An enhancer responsible for activating transcription at the midblastula transition in Xenopus development. Proc Natl Acad Sci U S A. 1987 Apr;84(8):2331–2335. doi: 10.1073/pnas.84.8.2331. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Lawn R. M., Fritsch E. F., Parker R. C., Blake G., Maniatis T. The isolation and characterization of linked delta- and beta-globin genes from a cloned library of human DNA. Cell. 1978 Dec;15(4):1157–1174. doi: 10.1016/0092-8674(78)90043-0. [DOI] [PubMed] [Google Scholar]
  27. Leucine-zipper motif update. Nature. 1989 Jul 13;340(6229):103–104. doi: 10.1038/340103a0. [DOI] [PubMed] [Google Scholar]
  28. McCormack T., Vega-Saenz de Miera E. C., Rudy B. Molecular cloning of a member of a third class of Shaker-family K+ channel genes in mammals. Proc Natl Acad Sci U S A. 1990 Jul;87(13):5227–5231. doi: 10.1073/pnas.87.13.5227. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Papazian D. M., Schwarz T. L., Tempel B. L., Jan Y. N., Jan L. Y. Cloning of genomic and complementary DNA from Shaker, a putative potassium channel gene from Drosophila. Science. 1987 Aug 14;237(4816):749–753. doi: 10.1126/science.2441470. [DOI] [PubMed] [Google Scholar]
  30. Petersen O. H., Findlay I. Electrophysiology of the pancreas. Physiol Rev. 1987 Jul;67(3):1054–1116. doi: 10.1152/physrev.1987.67.3.1054. [DOI] [PubMed] [Google Scholar]
  31. Provencher S. W. A Fourier method for the analysis of exponential decay curves. Biophys J. 1976 Jan;16(1):27–41. doi: 10.1016/S0006-3495(76)85660-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Rorsman P., Arkhammar P., Bokvist K., Hellerström C., Nilsson T., Welsh M., Welsh N., Berggren P. O. Failure of glucose to elicit a normal secretory response in fetal pancreatic beta cells results from glucose insensitivity of the ATP-regulated K+ channels. Proc Natl Acad Sci U S A. 1989 Jun;86(12):4505–4509. doi: 10.1073/pnas.86.12.4505. [DOI] [PMC free article] [PubMed] [Google Scholar]
  33. Ruppersberg J. P., Schröter K. H., Sakmann B., Stocker M., Sewing S., Pongs O. Heteromultimeric channels formed by rat brain potassium-channel proteins. Nature. 1990 Jun 7;345(6275):535–537. doi: 10.1038/345535a0. [DOI] [PubMed] [Google Scholar]
  34. Saiki R. K., Scharf S., Faloona F., Mullis K. B., Horn G. T., Erlich H. A., Arnheim N. Enzymatic amplification of beta-globin genomic sequences and restriction site analysis for diagnosis of sickle cell anemia. Science. 1985 Dec 20;230(4732):1350–1354. doi: 10.1126/science.2999980. [DOI] [PubMed] [Google Scholar]
  35. Sanke T., Bell G. I., Sample C., Rubenstein A. H., Steiner D. F. An islet amyloid peptide is derived from an 89-amino acid precursor by proteolytic processing. J Biol Chem. 1988 Nov 25;263(33):17243–17246. [PubMed] [Google Scholar]
  36. Satin L. S., Hopkins W. F., Fatherazi S., Cook D. L. Expression of a rapid, low-voltage threshold K current in insulin-secreting cells is dependent on intracellular calcium buffering. J Membr Biol. 1989 Dec;112(3):213–222. doi: 10.1007/BF01870952. [DOI] [PubMed] [Google Scholar]
  37. Schwarz T. L., Tempel B. L., Papazian D. M., Jan Y. N., Jan L. Y. Multiple potassium-channel components are produced by alternative splicing at the Shaker locus in Drosophila. Nature. 1988 Jan 14;331(6152):137–142. doi: 10.1038/331137a0. [DOI] [PubMed] [Google Scholar]
  38. Smith P. A., Bokvist K., Arkhammar P., Berggren P. O., Rorsman P. Delayed rectifying and calcium-activated K+ channels and their significance for action potential repolarization in mouse pancreatic beta-cells. J Gen Physiol. 1990 Jun;95(6):1041–1059. doi: 10.1085/jgp.95.6.1041. [DOI] [PMC free article] [PubMed] [Google Scholar]
  39. Stühmer W., Ruppersberg J. P., Schröter K. H., Sakmann B., Stocker M., Giese K. P., Perschke A., Baumann A., Pongs O. Molecular basis of functional diversity of voltage-gated potassium channels in mammalian brain. EMBO J. 1989 Nov;8(11):3235–3244. doi: 10.1002/j.1460-2075.1989.tb08483.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  40. Swanson R., Marshall J., Smith J. S., Williams J. B., Boyle M. B., Folander K., Luneau C. J., Antanavage J., Oliva C., Buhrow S. A. Cloning and expression of cDNA and genomic clones encoding three delayed rectifier potassium channels in rat brain. Neuron. 1990 Jun;4(6):929–939. doi: 10.1016/0896-6273(90)90146-7. [DOI] [PubMed] [Google Scholar]
  41. Tempel B. L., Jan Y. N., Jan L. Y. Cloning of a probable potassium channel gene from mouse brain. Nature. 1988 Apr 28;332(6167):837–839. doi: 10.1038/332837a0. [DOI] [PubMed] [Google Scholar]
  42. Wei A., Covarrubias M., Butler A., Baker K., Pak M., Salkoff L. K+ current diversity is produced by an extended gene family conserved in Drosophila and mouse. Science. 1990 May 4;248(4955):599–603. doi: 10.1126/science.2333511. [DOI] [PubMed] [Google Scholar]

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