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Multiple regulatory sites in large-conductance calcium-activated potassium channels

Nature volume 418, pages 880–884 (2002)Cite this article

Abstract

Large conductance, Ca2+- and voltage-activated K+ channels (BK) respond to two distinct physiological signals—membrane voltage and cytosolic Ca2+ (refs 1, 2). Channel opening is regulated by changes in Ca2+ concentration spanning 0.5 µM to 50 mM (refs 2–5), a range of Ca2+ sensitivity unusual among Ca2+-regulated proteins. Although voltage regulation arises from mechanisms shared with other voltage-gated channels6,7,8, the mechanisms of Ca2+ regulation remain largely unknown. One potential Ca2+-regulatory site, termed the ‘Ca2+ bowl’, has been located to the large cytosolic carboxy terminus9,10,11. Here we show that a second region of the C terminus, the RCK domain (regulator of conductance for K+ (ref. 12)), contains residues that define two additional regulatory effects of divalent cations. One site, together with the Ca2+ bowl, accounts for all physiological regulation of BK channels by Ca2+; the other site contributes to effects of millimolar divalent cations that may mediate physiological regulation by cytosolic Mg2+ (refs 5, 13). Independent regulation by multiple sites explains the large concentration range over which BK channels are regulated by Ca2+. This allows BK channels to serve a variety of physiological roles contingent on the Ca2+ concentration to which the channels are exposed14,15.

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Figure 1: Schematic representation of the Slo1 α-subunit.
Figure 2: The Ca2+ bowl and D362A/D367A account for all physiologically relevant Ca2+-dependent regulation of BK channels.
Figure 3: The RCK domain also mediates effects of high concentrations of Ca2+ and Mg2+.
Figure 4: Mutation of all three regulatory elements produces Ca2+-dependent suppression of BK current.

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References

  1. Barrett, J. N., Magleby, K. L. & Pallotta, B. S. Properties of single calcium-activated potassium channels in cultured rat muscle. J. Physiol. (Lond.) 331, 211–230 (1982)

    Article  CAS  Google Scholar 

  2. Moczydlowski, E. & Latorre, R. Gating kinetics of Ca2+-activated K+ channels from rat muscle incorporated into planar lipid bilayers. Evidence for two voltage-dependent Ca2+ binding reactions. J. Gen. Physiol. 82, 511–542 (1983)

    Article  CAS  Google Scholar 

  3. Cox, D. H., Cui, J. & Aldrich, R. W. Allosteric gating of a large conductance Ca-activated K+ channel. J. Gen. Physiol. 110, 257–281 (1997)

    Article  CAS  Google Scholar 

  4. Cox, D. & Aldrich, R. Role of the β1 subunit in large-conductance Ca2+-activated K+ channel gating energetics. Mechanisms of enhanced Ca2+ sensitivity. J. Gen. Physiol. 116, 411–432 (2000)

    Article  CAS  Google Scholar 

  5. Zhang, X., Solaro, C. & Lingle, C. Allosteric regulation of BK channel gating by Ca2+ and Mg2+ through a non-selective, low affinity divalent cation site. J. Gen. Physiol. 118, 607–635 (2001)

    Article  CAS  Google Scholar 

  6. Cui, J., Cox, D. H. & Aldrich, R. W. Intrinsic voltage dependence and Ca2+ regulation of mslo large conductance Ca-activated K+ channels. J. Gen. Physiol. 109, 647–673 (1997)

    Article  CAS  Google Scholar 

  7. Cui, J. & Aldrich, R. W. Allosteric linkage between voltage and Ca2+-dependent activation of BK-type mslo1 K+ channels. Biochemistry 39, 15612–15619 (2000)

    Article  CAS  Google Scholar 

  8. Horrigan, F. T., Cui, J. & Aldrich, R. W. Allosteric voltage gating of potassium channels I. Mslo ionic currents in the absence of Ca2+. J. Gen. Physiol. 114, 277–304 (2002)

    Article  Google Scholar 

  9. Schreiber, M. & Salkoff, L. A novel calcium-sensing domain in the BK channel. Biophys. J. 73, 1355–1363 (1997)

    Article  CAS  Google Scholar 

  10. Schreiber, M., Yuan, A. & Salkoff, L. Transplantable sites confer calcium sensitivity to BK channels. Nature Neurosci. 2, 416–421 (1999)

    Article  CAS  Google Scholar 

  11. Bian, S., Favre, I. & Moczydlowski, E. Ca2+-binding activity of a COOH-terminal fragment of the Drosophila BK channel involved in Ca2+-dependent activation. Proc. Natl Acad. Sci. USA 98, 4776–4781 (2001)

    Article  ADS  CAS  Google Scholar 

  12. Jiang, Y., Pico, A., Cadene, M., Chait, B. T. & MacKinnon, R. Structure of the RCK domain from the E. coli K+ channel and demonstration of its presence in the human BK channel. Neuron 29, 593–601 (2001)

    Article  CAS  Google Scholar 

  13. Shi, J. & Cui, J. Intracellular Mg2+ enhances the function of BK-type Ca2+-activated K+ channels. J. Gen. Physiol. 118, 589–606 (2001)

    Article  ADS  CAS  Google Scholar 

  14. Shao, L. R., Halvorsrud, R., Borg-Graham, L. & Storm, J. F. The role of BK-type Ca2+-dependent K+ channels in spike broadening during repetitive firing in rat hippocampal pyramidal cells. J. Physiol. 521(1), 135–146 (1999)

    Article  CAS  Google Scholar 

  15. Jones, E. M., Gray-Keller, M. & Fettiplace, R. The role of Ca2+-activated K+ channel spliced variants in the tonotopic organization of the turtle cochlea. J. Physiol. 518, 653–665 (1999)

    Article  CAS  Google Scholar 

  16. Adelman, J. P. et al. Calcium-activated potassium channels expressed from cloned complementary DNAs. Neuron 9, 209–216 (1992)

    Article  CAS  Google Scholar 

  17. Butler, A., Tsunoda, S., McCobb, D. P., Wei, A. & Salkoff, L. mSlo, a complex mouse gene encoding “maxi” calcium-activated potassium channels. Science 261, 221–224 (1993)

    Article  ADS  CAS  Google Scholar 

  18. Shen, K. Z. et al. Tetraethylammonium block of Slowpoke calcium-activated potassium channels expressed in Xenopus oocytes: evidence for tetrameric channel formation. Pflugers Arch. 426, 440–445 (1994)

    Article  CAS  Google Scholar 

  19. Meera, P., Wallner, M., Song, M. & Toro, L. Large conductance voltage- and calcium-dependent K+ channel, a distinct member of voltage-dependent ion channels with seven N-terminal transmembrane segments (S0-S6), an extracellular N terminus, and an intracellular (S9-S10) C terminus. Proc. Natl Acad. Sci. USA 94, 14066–14071 (1997)

    Article  ADS  CAS  Google Scholar 

  20. Wei, A., Solaro, C., Lingle, C. & Salkoff, L. Calcium sensitivity of BK-type KCa channels determined by a separable domain. Neuron 13, 671–681 (1994)

    Article  CAS  Google Scholar 

  21. Jiang, Y. et al. Crystal structure and mechanism of a calcium-gated potassium channel. Nature 417, 515–522 (2002)

    Article  ADS  CAS  Google Scholar 

  22. Bellamacina, C. R. The nicotinamide dinucleotide binding motif: a comparison of nucleotide binding proteins. FASEB J. 10, 1257–1269 (1996)

    Article  CAS  Google Scholar 

  23. Schreiber, M. et al. Slo3, a novel pH-sensitive K+ channel from mammalian spermatocytes. J. Biol. Chem. 273, 3509–3516 (1998)

    Article  CAS  Google Scholar 

  24. Moss, B. L. & Magleby, K. L. Gating and conductance properties of BK channels are modulated by the S9-S10 tail domain of the alpha subunit. A study of mSlo1 and mSlo3 wild-type and chimeric channels. J. Gen. Physiol. 118, 711–734 (2001)

    Article  CAS  Google Scholar 

  25. Golowasch, J., Kirkwood, A. & Miller, C. Allosteric effects of Mg2+ on the gating of Ca2+-activated K+ channels from mammalian skeletal muscle. J. Exp. Biol. 124, 5–13 (1986)

    CAS  PubMed  Google Scholar 

  26. Oberhauser, A., Alvarez, O. & Latorre, R. Activation by divalent cations of a Ca2+-activated K+ channel from skeletal muscle membrane. J. Gen. Physiol. 92, 67–86 (1988)

    Article  CAS  Google Scholar 

  27. Ferguson, W. B. Competitive Mg2+ block of a large-conductance, Ca2+-activated K+ channel in rat skeletal muscle. Ca2+, Sr2+, and Ni2+ also block. J. Gen. Physiol. 98, 163–181 (1991)

    Article  CAS  Google Scholar 

  28. Rothberg, B. S. & Magleby, K. L. Gating kinetics of single large-conductance Ca2+-activated K+ channels in high Ca2+ suggest a two-tiered allosteric gating mechanism. J. Gen. Physiol. 114, 93–124 (1999)

    Article  CAS  Google Scholar 

  29. Xia, X. M., Ding, J. P. & Lingle, C. J. Molecular basis for the inactivation of Ca2+- and voltage-dependent BK channels in adrenal chromaffin cells and rat insulinoma tumour cells. J. Neurosci. 19, 5255–5264 (1999)

    Article  CAS  Google Scholar 

  30. Lingle, C., Zeng, X.-H., Ding, J.-P. & Xia, X.-M. Inactivation of BK channels mediated by the N-terminus of the β3b auxiliary subunit involves a two-step mechanism: possible separation of binding and blockade. J. Gen. Physiol. 117, 583–605 (2001)

    Article  CAS  Google Scholar 

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Acknowledgements

We thank the members of our laboratory for encouragement and assistance during this work and L. Lavack for preparation and care of oocytes. We thank J. H. Steinbach, J. Nerbonne and L. Salkoff for discussions and comments on the manuscript. We also thank the Department of Anesthesiology, Washington University School of Medicine, for material support.

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  1. Department of Anesthesiology, Washington University School of Medicine, Box 8054, St. Louis, Missouri, 63110, USA

    Xiao-Ming Xia, Xuhui Zeng & Christopher J. Lingle

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Correspondence to Christopher J. Lingle.

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Xia, XM., Zeng, X. & Lingle, C. Multiple regulatory sites in large-conductance calcium-activated potassium channels. Nature 418, 880–884 (2002). https://doi.org/10.1038/nature00956

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