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Strong cooperativity between subunits in voltage-gated proton channels

Abstract

Voltage-activated proton (Hv) channels are essential components in the innate immune response. Hv channels are dimeric proteins with one proton permeation pathway per subunit. It is unknown how Hv channels are activated by voltage and whether there is any cooperation between subunits during voltage activation. Using cysteine accessibility measurements and voltage-clamp fluorometry, we show data consistent with the possibility that the fourth transmembrane segment S4 functions as the voltage sensor in Ciona intestinalis Hv channels. Unexpectedly, in a dimeric Hv channel, the S4 in both subunits must move to activate the two proton permeation pathways. In contrast, if Hv subunits are prevented from dimerizing, the movement of a single S4 is sufficient to activate the proton permeation pathway in a subunit. These results indicate strong cooperativity between subunits in dimeric Hv channels.

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Figure 1: State-dependent modification of S4 residues by external MTSET.
Figure 2: State-dependent modification of S4 residues by internal MTSET.
Figure 3: Kinetics of S4 movement.
Figure 4: Kinetics in monomeric ΔNΔC Ci-Hv channels.
Figure 5: Estimates of the effective gating charge in WT Hv channels.
Figure 6: Channel opening in monomeric and dimeric Hv channels.

References

  1. Decoursey, T.E. Voltage-gated proton channels and other proton transfer pathways. Physiol. Rev. 83, 475–579 (2003).

    CAS  Article  Google Scholar 

  2. Okamura, Y. Biodiversity of voltage sensor domain proteins. Pflugers Arch. 454, 361–371 (2007).

    CAS  Article  Google Scholar 

  3. Ramsey, I.S., Moran, M.M., Chong, J.A. & Clapham, D.E. A voltage-gated proton-selective channel lacking the pore domain. Nature 440, 1213–1216 (2006).

    CAS  Article  Google Scholar 

  4. Sasaki, M., Takagi, M. & Okamura, Y. A voltage sensor–domain protein is a voltage-gated proton channel. Science 312, 589–592 (2006).

    CAS  Article  Google Scholar 

  5. Hille, B. Ion Channels of Excitable Membranes (Sinauer Associates, Sunderland, Massachusetts, USA, 2001).

  6. Jiang, Y. et al. X-ray structure of a voltage-dependent K+ channel. Nature 423, 33–41 (2003).

    CAS  Article  Google Scholar 

  7. Long, S.B., Campbell, E.B. & Mackinnon, R. Crystal structure of a mammalian voltage-dependent Shaker family K+ channel. Science 309, 897–903 (2005).

    CAS  Article  Google Scholar 

  8. Long, S.B., Tao, X., Campbell, E.B. & MacKinnon, R. Atomic structure of a voltage-dependent K+ channel in a lipid membrane–like environment. Nature 450, 376–382 (2007).

    CAS  Article  Google Scholar 

  9. Koch, H.P. et al. Multimeric nature of voltage-gated proton channels. Proc. Natl. Acad. Sci. USA 105, 9111–9116 (2008).

    CAS  Article  Google Scholar 

  10. Tombola, F., Ulbrich, M.H. & Isacoff, E.Y. The voltage-gated proton channel Hv1 has two pores, each controlled by one voltage sensor. Neuron 58, 546–556 (2008).

    CAS  Article  Google Scholar 

  11. Lee, S.Y., Letts, J.A. & Mackinnon, R. Dimeric subunit stoichiometry of the human voltage-dependent proton channel Hv1. Proc. Natl. Acad. Sci. USA 105, 7692–7695 (2008).

    CAS  Article  Google Scholar 

  12. Aggarwal, S.K. & MacKinnon, R. Contribution of the S4 segment to gating charge in the Shaker K+ channel. Neuron 16, 1169–1177 (1996).

    CAS  Article  Google Scholar 

  13. Larsson, H.P., Baker, O.S., Dhillon, D.S. & Isacoff, E.Y. Transmembrane movement of the shaker K+ channel S4. Neuron 16, 387–397 (1996).

    CAS  Article  Google Scholar 

  14. Mannuzzu, L.M., Moronne, M.M. & Isacoff, E.Y. Direct physical measure of conformational rearrangement underlying potassium channel gating. Science 271, 213–216 (1996).

    CAS  Article  Google Scholar 

  15. Seoh, S.A., Sigg, D., Papazian, D.M. & Bezanilla, F. Voltage-sensing residues in the S2 and S4 segments of the Shaker K+ channel. Neuron 16, 1159–1167 (1996).

    CAS  Article  Google Scholar 

  16. Yusaf, S.P., Wray, D. & Sivaprasadarao, A. Measurement of the movement of the S4 segment during the activation of a voltage-gated potassium channel. Pflugers Arch. 433, 91–97 (1996).

    CAS  Article  Google Scholar 

  17. Schoppa, N.E., McCormack, K., Tanouye, M.A. & Sigworth, F.J. The size of gating charge in wild-type and mutant Shaker potassium channels. Science 255, 1712–1715 (1992).

    CAS  Article  Google Scholar 

  18. Zagotta, W.N., Hoshi, T., Dittman, J. & Aldrich, R.W. Shaker potassium channel gating. II: Transitions in the activation pathway. J. Gen. Physiol. 103, 279–319 (1994).

    CAS  Article  Google Scholar 

  19. Gonzalez, C., Rosenman, E., Bezanilla, F., Alvarez, O. & Latorre, R. Modulation of the Shaker K+ channel gating kinetics by the S3–S4 linker. J. Gen. Physiol. 115, 193–208 (2000).

    CAS  Article  Google Scholar 

  20. Baker, O.S., Larsson, H.P., Mannuzzu, L.M. & Isacoff, E.Y. Three transmembrane conformations and sequence-dependent displacement of the S4 domain in Shaker K+ channel gating. Neuron 20, 1283–1294 (1998).

    CAS  Article  Google Scholar 

  21. Mannuzzu, L.M. & Isacoff, E.Y. Independence and cooperativity in rearrangements of a potassium channel voltage sensor revealed by single subunit fluorescence. J. Gen. Physiol. 115, 257–268 (2000).

    CAS  Article  Google Scholar 

  22. Pathak, M., Kurtz, L., Tombola, F. & Isacoff, E. The cooperative voltage sensor motion that gates a potassium channel. J. Gen. Physiol. 125, 57–69 (2005).

    CAS  Article  Google Scholar 

  23. Schoppa, N.E. & Sigworth, F.J. Activation of Shaker potassium channels. III. An activation gating model for wild-type and V2 mutant channels. J. Gen. Physiol. 111, 313–342 (1998).

    CAS  Article  Google Scholar 

  24. Zagotta, W.N., Hoshi, T. & Aldrich, R.W. Shaker potassium channel gating. III: Evaluation of kinetic models for activation. J. Gen. Physiol. 103, 321–362 (1994).

    CAS  Article  Google Scholar 

  25. Chapman, M.L., VanDongen, H.M. & VanDongen, A.M. Activation-dependent subconductance levels in the drk1 K+ channel suggest a subunit basis for ion permeation and gating. Biophys. J. 72, 708–719 (1997).

    CAS  Article  Google Scholar 

  26. Zheng, J. & Sigworth, F.J. Selectivity changes during activation of mutant Shaker potassium channels. J. Gen. Physiol. 110, 101–117 (1997).

    CAS  Article  Google Scholar 

  27. DeCoursey, T.E. & Cherny, V.V. Deuterium isotope effects on permeation and gating of proton channels in rat alveolar epithelium. J. Gen. Physiol. 109, 415–434 (1997).

    CAS  Article  Google Scholar 

  28. Mannikko, R., Elinder, F. & Larsson, H.P. Voltage-sensing mechanism is conserved among ion channels gated by opposite voltages. Nature 419, 837–841 (2002).

    CAS  Article  Google Scholar 

  29. Yang, N., George, A.L. Jr. & Horn, R. Molecular basis of charge movement in voltage-gated sodium channels. Neuron 16, 113–122 (1996).

    Article  Google Scholar 

  30. Pathak, M.M. et al. Closing in on the resting state of the Shaker K+ channel. Neuron 56, 124–140 (2007).

    CAS  Article  Google Scholar 

  31. Campos, F.V., Chanda, B., Roux, B. & Bezanilla, F. Two atomic constraints unambiguously position the S4 segment relative to S1 and S2 segments in the closed state of Shaker K+ channel. Proc. Natl. Acad. Sci. USA 104, 7904–7909 (2007).

    CAS  Article  Google Scholar 

  32. Bezanilla, F. The voltage sensor in voltage-dependent ion channels. Physiol. Rev. 80, 555–592 (2000).

    CAS  Article  Google Scholar 

  33. Bruening-Wright, A., Elinder, F. & Larsson, H.P. Kinetic relationship between the voltage sensor and the activation gate in spHCN channels. J. Gen. Physiol. 130, 71–81 (2007).

    CAS  Article  Google Scholar 

  34. Cha, A. & Bezanilla, F. Characterizing voltage-dependent conformational changes in the Shaker K+ channel with fluorescence. Neuron 19, 1127–1140 (1997).

    CAS  Article  Google Scholar 

  35. Cha, A., Snyder, G.E., Selvin, P.R. & Bezanilla, F. Atomic scale movement of the voltage-sensing region in a potassium channel measured via spectroscopy. Nature 402, 809–813 (1999).

    CAS  Article  Google Scholar 

  36. Gonzalez, C., Morera, F.J., Rosenmann, E., Alvarez, O. & Latorre, R. S3b amino acid residues do not shuttle across the bilayer in voltage-dependent Shaker K+ channels. Proc. Natl. Acad. Sci. USA 102, 5020–5025 (2005).

    CAS  Article  Google Scholar 

  37. Sigg, D. & Bezanilla, F. Total charge movement per channel. The relation between gating charge displacement and the voltage sensitivity of activation. J. Gen. Physiol. 109, 27–39 (1997).

    CAS  Article  Google Scholar 

  38. Cherny, V.V., Markin, V.S. & DeCoursey, T.E. The voltage-activated hydrogen ion conductance in rat alveolar epithelial cells is determined by the pH gradient. J. Gen. Physiol. 105, 861–896 (1995).

    CAS  Article  Google Scholar 

  39. Almers, W. Gating currents and charge movements in excitable membranes. Rev. Physiol. Biochem. Pharmacol. 82, 96–190 (1978).

    CAS  Article  Google Scholar 

  40. Larsson, H.P., Tzingounis, A.V., Koch, H.P. & Kavanaugh, M.P. Fluorometric measurements of conformational changes in glutamate transporters. Proc. Natl. Acad. Sci.USA 101, 3951–3956 (2004).

    CAS  Article  Google Scholar 

  41. Koch, H.P., Hubbard, J.M. & Larsson, H.P. Voltage-independent sodium-binding events reported by the 4B–4C loop in the human glutamate transporter EAAT3. J. Biol. Chem. 282, 24547–24553 (2007).

    CAS  Article  Google Scholar 

  42. Koch, H.P. & Larsson, H.P. Small-scale molecular motions accomplish glutamate uptake in human glutamate transporters. J. Neurosci. 25, 1730–1736 (2005).

    CAS  Article  Google Scholar 

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Acknowledgements

We thank K. Magleby, S. Rebolledo and F. Elinder for constructive criticism. This work was supported by the US National Institutes of Health NS051169 (H.P.L.).

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C.G., B.M.D., H.P.K. and H.P.L. designed research, performed research, analyzed data, and wrote the paper.

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Correspondence to H Peter Larsson.

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Gonzalez, C., Koch, H., Drum, B. et al. Strong cooperativity between subunits in voltage-gated proton channels. Nat Struct Mol Biol 17, 51–56 (2010). https://doi.org/10.1038/nsmb.1739

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