Abstract
YKC1 (TOK1, DUK1, YORK) encodes the outwardly rectifying K+ channel of the yeast plasma membrane. Non-targeted mutations of YKC1 were isolated by their ability to completely block proliferation when expressed in yeast. All such mutations examined occurred near the cytoplasmic ends of the transmembrane segments following either of the duplicated P loops, which we termed the 'post-P loop' (PP) regions. These PP mutations specifically caused marked defects in the 'C1' states, a set of interrelated closed states that Ykc1 enters and exits at rates of tens to hundreds of milliseconds. These results indicate that the Ykc1 PP region plays a role in determining closed state conformations and that non-targeted mutagenesis and microbial selection can be a valuable tool for probing structure-function relationships of ion channels.
Full Text
The Full Text of this article is available as a PDF (478.0 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Armstrong C. M. Interaction of tetraethylammonium ion derivatives with the potassium channels of giant axons. J Gen Physiol. 1971 Oct;58(4):413–437. doi: 10.1085/jgp.58.4.413. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bertl A., Anderson J. A., Slayman C. L., Gaber R. F. Use of Saccharomyces cerevisiae for patch-clamp analysis of heterologous membrane proteins: characterization of Kat1, an inward-rectifying K+ channel from Arabidopsis thaliana, and comparison with endogeneous yeast channels and carriers. Proc Natl Acad Sci U S A. 1995 Mar 28;92(7):2701–2705. doi: 10.1073/pnas.92.7.2701. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bertl A., Slayman C. L., Gradmann D. Gating and conductance in an outward-rectifying K+ channel from the plasma membrane of Saccharomyces cerevisiae. J Membr Biol. 1993 Mar;132(3):183–199. doi: 10.1007/BF00235737. [DOI] [PubMed] [Google Scholar]
- Czempinski K., Zimmermann S., Ehrhardt T., Müller-Röber B. New structure and function in plant K+ channels: KCO1, an outward rectifier with a steep Ca2+ dependency. EMBO J. 1997 May 15;16(10):2565–2575. doi: 10.1093/emboj/16.10.2565. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fink M., Duprat F., Lesage F., Reyes R., Romey G., Heurteaux C., Lazdunski M. Cloning, functional expression and brain localization of a novel unconventional outward rectifier K+ channel. EMBO J. 1996 Dec 16;15(24):6854–6862. [PMC free article] [PubMed] [Google Scholar]
- Goldin A. L. Maintenance of Xenopus laevis and oocyte injection. Methods Enzymol. 1992;207:266–279. doi: 10.1016/0076-6879(92)07017-i. [DOI] [PubMed] [Google Scholar]
- Goldin A. L., Sumikawa K. Preparation of RNA for injection into Xenopus oocytes. Methods Enzymol. 1992;207:279–297. doi: 10.1016/0076-6879(92)07018-j. [DOI] [PubMed] [Google Scholar]
- Goldstein S. A., Price L. A., Rosenthal D. N., Pausch M. H. ORK1, a potassium-selective leak channel with two pore domains cloned from Drosophila melanogaster by expression in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A. 1996 Nov 12;93(23):13256–13261. doi: 10.1073/pnas.93.23.13256. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gordon S. E., Zagotta W. N. A histidine residue associated with the gate of the cyclic nucleotide-activated channels in rod photoreceptors. Neuron. 1995 Jan;14(1):177–183. doi: 10.1016/0896-6273(95)90252-x. [DOI] [PubMed] [Google Scholar]
- Grey M., Brendel M. A ten-minute protocol for transforming Saccharomyces cerevisiae by electroporation. Curr Genet. 1992 Oct;22(4):335–336. doi: 10.1007/BF00317931. [DOI] [PubMed] [Google Scholar]
- Gustin M. C., Martinac B., Saimi Y., Culbertson M. R., Kung C. Ion channels in yeast. Science. 1986 Sep 12;233(4769):1195–1197. doi: 10.1126/science.2426783. [DOI] [PubMed] [Google Scholar]
- Gustin M. C., Zhou X. L., Martinac B., Kung C. A mechanosensitive ion channel in the yeast plasma membrane. Science. 1988 Nov 4;242(4879):762–765. doi: 10.1126/science.2460920. [DOI] [PubMed] [Google Scholar]
- Ketchum K. A., Joiner W. J., Sellers A. J., Kaczmarek L. K., Goldstein S. A. A new family of outwardly rectifying potassium channel proteins with two pore domains in tandem. Nature. 1995 Aug 24;376(6542):690–695. doi: 10.1038/376690a0. [DOI] [PubMed] [Google Scholar]
- Lee H. C., Toung Y. P., Tu Y. S., Tu C. P. A molecular genetic approach for the identification of essential residues in human glutathione S-transferase function in Escherichia coli. J Biol Chem. 1995 Jan 6;270(1):99–109. doi: 10.1074/jbc.270.1.99. [DOI] [PubMed] [Google Scholar]
- Lesage F., Guillemare E., Fink M., Duprat F., Lazdunski M., Romey G., Barhanin J. A pH-sensitive yeast outward rectifier K+ channel with two pore domains and novel gating properties. J Biol Chem. 1996 Feb 23;271(8):4183–4187. doi: 10.1074/jbc.271.8.4183. [DOI] [PubMed] [Google Scholar]
- Lesage F., Lauritzen I., Duprat F., Reyes R., Fink M., Heurteaux C., Lazdunski M. The structure, function and distribution of the mouse TWIK-1 K+ channel. FEBS Lett. 1997 Jan 27;402(1):28–32. doi: 10.1016/s0014-5793(96)01491-3. [DOI] [PubMed] [Google Scholar]
- Liman E. R., Tytgat J., Hess P. Subunit stoichiometry of a mammalian K+ channel determined by construction of multimeric cDNAs. Neuron. 1992 Nov;9(5):861–871. doi: 10.1016/0896-6273(92)90239-a. [DOI] [PubMed] [Google Scholar]
- McPhee J. C., Ragsdale D. S., Scheuer T., Catterall W. A. A critical role for transmembrane segment IVS6 of the sodium channel alpha subunit in fast inactivation. J Biol Chem. 1995 May 19;270(20):12025–12034. doi: 10.1074/jbc.270.20.12025. [DOI] [PubMed] [Google Scholar]
- Miosga T., Witzel A., Zimmermann F. K. Sequence and function analysis of a 9.46 kb fragment of Saccharomyces cerevisiae chromosome X. Yeast. 1994 Jul;10(7):965–973. doi: 10.1002/yea.320100712. [DOI] [PubMed] [Google Scholar]
- Reid J. D., Lukas W., Shafaatian R., Bertl A., Scheurmann-Kettner C., Guy H. R., North R. A. The S. cerevisiae outwardly-rectifying potassium channel (DUK1) identifies a new family of channels with duplicated pore domains. Receptors Channels. 1996;4(1):51–62. [PubMed] [Google Scholar]
- Schreibmayer W., Lester H. A., Dascal N. Voltage clamping of Xenopus laevis oocytes utilizing agarose-cushion electrodes. Pflugers Arch. 1994 Mar;426(5):453–458. doi: 10.1007/BF00388310. [DOI] [PubMed] [Google Scholar]
- Sikorski R. S., Boeke J. D. In vitro mutagenesis and plasmid shuffling: from cloned gene to mutant yeast. Methods Enzymol. 1991;194:302–318. doi: 10.1016/0076-6879(91)94023-6. [DOI] [PubMed] [Google Scholar]
- Stanfield P. R. Tetraethylammonium ions and the potassium permeability of excitable cells. Rev Physiol Biochem Pharmacol. 1983;97:1–67. doi: 10.1007/BFb0035345. [DOI] [PubMed] [Google Scholar]
- Zhou X. L., Vaillant B., Loukin S. H., Kung C., Saimi Y. YKC1 encodes the depolarization-activated K+ channel in the plasma membrane of yeast. FEBS Lett. 1995 Oct 9;373(2):170–176. doi: 10.1016/0014-5793(95)01035-d. [DOI] [PubMed] [Google Scholar]