Abstract
Gating of cystic fibrosis transmembrane conductance regulator (CFTR) channels requires intermolecular or interdomain interactions, but the exact nature and physiological significance of those interactions remains uncertain. Subconductance states of the channel may result from alterations in interactions among domains, and studying mutant channels enriched for a single conductance type may elucidate those interactions. Analysis of CFTR channels in inside-out patches revealed that mutation of cysteine residues in NBD1 and NBD2 affects the frequency of channel opening to the full-size versus a 3-pS subconductance. Mutating cysteines in NBD1 resulted in channels that open almost exclusively to the 3-pS subconductance, while mutations of cysteines in NBD2 decreased the frequency of subconductance openings. Wild-type channels open to both size conductances and make fast transitions between them within a single open burst. Full-size and subconductance openings of both mutant and wild-type channels are similarly activated by ATP and phosphorylation. However, the different size conductances open very differently in the presence of a nonhydrolyzable ATP analog, with subconductance openings significantly shortened by ATPgammaS, while full-size channels are locked open. In wild-type channels, reducing conditions increase the frequency and decrease the open time of subconductance channels, while oxidizing conditions decrease the frequency of subconductance openings. In contrast, in the cysteine mutants studied, altering redox potential has little effect on gating of the subconductance.
Full Text
The Full Text of this article is available as a PDF (1.1 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Ames G. F., Lecar H. ATP-dependent bacterial transporters and cystic fibrosis: analogy between channels and transporters. FASEB J. 1992 Jun;6(9):2660–2666. doi: 10.1096/fasebj.6.9.1377140. [DOI] [PubMed] [Google Scholar]
- Anderson M. P., Berger H. A., Rich D. P., Gregory R. J., Smith A. E., Welsh M. J. Nucleoside triphosphates are required to open the CFTR chloride channel. Cell. 1991 Nov 15;67(4):775–784. doi: 10.1016/0092-8674(91)90072-7. [DOI] [PubMed] [Google Scholar]
- Anderson M. P., Gregory R. J., Thompson S., Souza D. W., Paul S., Mulligan R. C., Smith A. E., Welsh M. J. Demonstration that CFTR is a chloride channel by alteration of its anion selectivity. Science. 1991 Jul 12;253(5016):202–205. doi: 10.1126/science.1712984. [DOI] [PubMed] [Google Scholar]
- Arnelle D. R., Stamler J. S. NO+, NO, and NO- donation by S-nitrosothiols: implications for regulation of physiological functions by S-nitrosylation and acceleration of disulfide formation. Arch Biochem Biophys. 1995 Apr 20;318(2):279–285. doi: 10.1006/abbi.1995.1231. [DOI] [PubMed] [Google Scholar]
- Baukrowitz T., Hwang T. C., Nairn A. C., Gadsby D. C. Coupling of CFTR Cl- channel gating to an ATP hydrolysis cycle. Neuron. 1994 Mar;12(3):473–482. doi: 10.1016/0896-6273(94)90206-2. [DOI] [PubMed] [Google Scholar]
- Bear C. E., Li C. H., Kartner N., Bridges R. J., Jensen T. J., Ramjeesingh M., Riordan J. R. Purification and functional reconstitution of the cystic fibrosis transmembrane conductance regulator (CFTR). Cell. 1992 Feb 21;68(4):809–818. doi: 10.1016/0092-8674(92)90155-6. [DOI] [PubMed] [Google Scholar]
- Cheng S. H., Gregory R. J., Marshall J., Paul S., Souza D. W., White G. A., O'Riordan C. R., Smith A. E. Defective intracellular transport and processing of CFTR is the molecular basis of most cystic fibrosis. Cell. 1990 Nov 16;63(4):827–834. doi: 10.1016/0092-8674(90)90148-8. [DOI] [PubMed] [Google Scholar]
- Cheng S. H., Rich D. P., Marshall J., Gregory R. J., Welsh M. J., Smith A. E. Phosphorylation of the R domain by cAMP-dependent protein kinase regulates the CFTR chloride channel. Cell. 1991 Sep 6;66(5):1027–1036. doi: 10.1016/0092-8674(91)90446-6. [DOI] [PubMed] [Google Scholar]
- Cotten J. F., Welsh M. J. Covalent modification of the regulatory domain irreversibly stimulates cystic fibrosis transmembrane conductance regulator. J Biol Chem. 1997 Oct 10;272(41):25617–25622. doi: 10.1074/jbc.272.41.25617. [DOI] [PubMed] [Google Scholar]
- Egan M., Flotte T., Afione S., Solow R., Zeitlin P. L., Carter B. J., Guggino W. B. Defective regulation of outwardly rectifying Cl- channels by protein kinase A corrected by insertion of CFTR. Nature. 1992 Aug 13;358(6387):581–584. doi: 10.1038/358581a0. [DOI] [PubMed] [Google Scholar]
- Feng Y., Forgac M. Inhibition of vacuolar H(+)-ATPase by disulfide bond formation between cysteine 254 and cysteine 532 in subunit A. J Biol Chem. 1994 May 6;269(18):13224–13230. [PubMed] [Google Scholar]
- Gadsby D. C., Nairn A. C. Control of CFTR channel gating by phosphorylation and nucleotide hydrolysis. Physiol Rev. 1999 Jan;79(1 Suppl):S77–S107. doi: 10.1152/physrev.1999.79.1.S77. [DOI] [PubMed] [Google Scholar]
- Gadsby D. C., Nairn A. C. Regulation of CFTR channel gating. Trends Biochem Sci. 1994 Nov;19(11):513–518. doi: 10.1016/0968-0004(94)90141-4. [DOI] [PubMed] [Google Scholar]
- Graham F. L., van der Eb A. J. Transformation of rat cells by DNA of human adenovirus 5. Virology. 1973 Aug;54(2):536–539. doi: 10.1016/0042-6822(73)90163-3. [DOI] [PubMed] [Google Scholar]
- Gulbis J. M., Mann S., MacKinnon R. Structure of a voltage-dependent K+ channel beta subunit. Cell. 1999 Jun 25;97(7):943–952. doi: 10.1016/s0092-8674(00)80805-3. [DOI] [PubMed] [Google Scholar]
- Gulbis J. M., Zhou M., Mann S., MacKinnon R. Structure of the cytoplasmic beta subunit-T1 assembly of voltage-dependent K+ channels. Science. 2000 Jul 7;289(5476):123–127. doi: 10.1126/science.289.5476.123. [DOI] [PubMed] [Google Scholar]
- Gunderson K. L., Kopito R. R. Conformational states of CFTR associated with channel gating: the role ATP binding and hydrolysis. Cell. 1995 Jul 28;82(2):231–239. doi: 10.1016/0092-8674(95)90310-0. [DOI] [PubMed] [Google Scholar]
- Gunderson K. L., Kopito R. R. Effects of pyrophosphate and nucleotide analogs suggest a role for ATP hydrolysis in cystic fibrosis transmembrane regulator channel gating. J Biol Chem. 1994 Jul 29;269(30):19349–19353. [PubMed] [Google Scholar]
- Harrington M. A., Gunderson K. L., Kopito R. R. Redox reagents and divalent cations alter the kinetics of cystic fibrosis transmembrane conductance regulator channel gating. J Biol Chem. 1999 Sep 24;274(39):27536–27544. doi: 10.1074/jbc.274.39.27536. [DOI] [PubMed] [Google Scholar]
- Haws C., Krouse M. E., Xia Y., Gruenert D. C., Wine J. J. CFTR channels in immortalized human airway cells. Am J Physiol. 1992 Dec;263(6 Pt 1):L692–L707. doi: 10.1152/ajplung.1992.263.6.L692. [DOI] [PubMed] [Google Scholar]
- Ho S. N., Hunt H. D., Horton R. M., Pullen J. K., Pease L. R. Site-directed mutagenesis by overlap extension using the polymerase chain reaction. Gene. 1989 Apr 15;77(1):51–59. doi: 10.1016/0378-1119(89)90358-2. [DOI] [PubMed] [Google Scholar]
- Hwang T. C., Nagel G., Nairn A. C., Gadsby D. C. Regulation of the gating of cystic fibrosis transmembrane conductance regulator C1 channels by phosphorylation and ATP hydrolysis. Proc Natl Acad Sci U S A. 1994 May 24;91(11):4698–4702. doi: 10.1073/pnas.91.11.4698. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ikuma M., Welsh M. J. Regulation of CFTR Cl- channel gating by ATP binding and hydrolysis. Proc Natl Acad Sci U S A. 2000 Jul 18;97(15):8675–8680. doi: 10.1073/pnas.140220597. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ishihara H., Welsh M. J. Block by MOPS reveals a conformation change in the CFTR pore produced by ATP hydrolysis. Am J Physiol. 1997 Oct;273(4 Pt 1):C1278–C1289. doi: 10.1152/ajpcell.1997.273.4.C1278. [DOI] [PubMed] [Google Scholar]
- Kembi F., Harrington M. A. Interdomain but not intermolecular interactions observed in CFTR channels. Biochem Biophys Res Commun. 2001 Nov 9;288(4):819–826. doi: 10.1006/bbrc.2001.5848. [DOI] [PubMed] [Google Scholar]
- Köttgen M., Busch A. E., Hug M. J., Greger R., Kunzelmann K. N-Acetyl-L-cysteine and its derivatives activate a Cl- conductance in epithelial cells. Pflugers Arch. 1996 Feb;431(4):549–555. doi: 10.1007/BF02191902. [DOI] [PubMed] [Google Scholar]
- Li C., Ramjeesingh M., Wang W., Garami E., Hewryk M., Lee D., Rommens J. M., Galley K., Bear C. E. ATPase activity of the cystic fibrosis transmembrane conductance regulator. J Biol Chem. 1996 Nov 8;271(45):28463–28468. doi: 10.1074/jbc.271.45.28463. [DOI] [PubMed] [Google Scholar]
- Loo T. W., Clarke D. M. Membrane topology of a cysteine-less mutant of human P-glycoprotein. J Biol Chem. 1995 Jan 13;270(2):843–848. doi: 10.1074/jbc.270.2.843. [DOI] [PubMed] [Google Scholar]
- McDonough S., Davidson N., Lester H. A., McCarty N. A. Novel pore-lining residues in CFTR that govern permeation and open-channel block. Neuron. 1994 Sep;13(3):623–634. doi: 10.1016/0896-6273(94)90030-2. [DOI] [PubMed] [Google Scholar]
- Rich D. P., Gregory R. J., Anderson M. P., Manavalan P., Smith A. E., Welsh M. J. Effect of deleting the R domain on CFTR-generated chloride channels. Science. 1991 Jul 12;253(5016):205–207. doi: 10.1126/science.1712985. [DOI] [PubMed] [Google Scholar]
- Sarkar G., Sommer S. S. The "megaprimer" method of site-directed mutagenesis. Biotechniques. 1990 Apr;8(4):404–407. [PubMed] [Google Scholar]
- Stutts M. J., Gabriel S. E., Price E. M., Sarkadi B., Olsen J. C., Boucher R. C. Pyridine nucleotide redox potential modulates cystic fibrosis transmembrane conductance regulator Cl- conductance. J Biol Chem. 1994 Mar 25;269(12):8667–8674. [PubMed] [Google Scholar]
- Tabcharani J. A., Chang X. B., Riordan J. R., Hanrahan J. W. Phosphorylation-regulated Cl- channel in CHO cells stably expressing the cystic fibrosis gene. Nature. 1991 Aug 15;352(6336):628–631. doi: 10.1038/352628a0. [DOI] [PubMed] [Google Scholar]
- Tao T., Xie J., Drumm M. L., Zhao J., Davis P. B., Ma J. Slow conversions among subconductance states of cystic fibrosis transmembrane conductance regulator chloride channel. Biophys J. 1996 Feb;70(2):743–753. doi: 10.1016/S0006-3495(96)79614-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wang S., Yue H., Derin R. B., Guggino W. B., Li M. Accessory protein facilitated CFTR-CFTR interaction, a molecular mechanism to potentiate the chloride channel activity. Cell. 2000 Sep 29;103(1):169–179. doi: 10.1016/s0092-8674(00)00096-9. [DOI] [PubMed] [Google Scholar]
- Ward C. L., Kopito R. R. Intracellular turnover of cystic fibrosis transmembrane conductance regulator. Inefficient processing and rapid degradation of wild-type and mutant proteins. J Biol Chem. 1994 Oct 14;269(41):25710–25718. [PubMed] [Google Scholar]
- Xie J., Drumm M. L., Ma J., Davis P. B. Intracellular loop between transmembrane segments IV and V of cystic fibrosis transmembrane conductance regulator is involved in regulation of chloride channel conductance state. J Biol Chem. 1995 Nov 24;270(47):28084–28091. doi: 10.1074/jbc.270.47.28084. [DOI] [PubMed] [Google Scholar]
- Yue H., Devidas S., Guggino W. B. The two halves of CFTR form a dual-pore ion channel. J Biol Chem. 2000 Apr 7;275(14):10030–10034. doi: 10.1074/jbc.275.14.10030. [DOI] [PubMed] [Google Scholar]
- Zeltwanger S., Wang F., Wang G. T., Gillis K. D., Hwang T. C. Gating of cystic fibrosis transmembrane conductance regulator chloride channels by adenosine triphosphate hydrolysis. Quantitative analysis of a cyclic gating scheme. J Gen Physiol. 1999 Apr;113(4):541–554. doi: 10.1085/jgp.113.4.541. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Zerhusen B., Zhao J., Xie J., Davis P. B., Ma J. A single conductance pore for chloride ions formed by two cystic fibrosis transmembrane conductance regulator molecules. J Biol Chem. 1999 Mar 19;274(12):7627–7630. doi: 10.1074/jbc.274.12.7627. [DOI] [PubMed] [Google Scholar]
- al-Shawi M. K., Urbatsch I. L., Senior A. E. Covalent inhibitors of P-glycoprotein ATPase activity. J Biol Chem. 1994 Mar 25;269(12):8986–8992. [PubMed] [Google Scholar]
