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Properties of the Ca2+-activated K+ channel in one-step inside-out vesicles from human red cell membranes

Nature volume 296, pages 742744 (22 April 1982) | Download Citation

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Abstract

The presence of a calcium-activated potassium channel in some mammalian red cell membranes makes them useful experimental models in which to study the properties of similar mechanisms believed to be involved in the control of membrane potential and conductance, at rest and during activity, in many other cells. However, vesicles prepared from human red cell membranes by the method of Steck et al.1, whether inside-out (IOVs) or right-side out (ROVs), either failed to show any Ca2+-activated component of K+(Rb+) fluxes2 or showed only a very reduced calcium sensitivity and K+/Na+ selectivity3. This is surprising because there is good functional preservation of other transport mechanisms, such as the anion carrier4, Ca2+ pump5 and Na+ pump6. Our failure to confirm reports7 that the calcium response could be restored in ‘silent’ IOVs by addition of protein concentrates from red cell lysates prompted the search for and discovery of vesiculation procedures which produced ion-tight IOVs in a single step, with minimum loss of membrane components and transport properties8–11. We report here (1) the conditions which favour preservation or loss of the Ca2+-activated component of the 86Rb efflux from one-step IOVs, (2) an approximate estimate of the number of Ca2+-activated K+ channels per red cell, and (3) that individual Ca2+-activated K+ channels respond in an all or nothing fashion to Ca2+ activation and differ in their threshold sensitivity to ionized calcium.

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References

  1. 1.

    , , & Science 168, 255–257 (1970).

  2. 2.

    & Biochim. biophys. Acta 508, 236–245 (1978).

  3. 3.

    & Biochim. biophys. Acta 554, 180–194 (1979).

  4. 4.

    , & Alfred Benzon Symp. 14, 329–340 (1980).

  5. 5.

    & Biochim. biophys. Acta 510, 373–377 (1978).

  6. 6.

    & Nature 285, 338–339 (1980).

  7. 7.

    , & Alfred Benzon Symp. 14, 220–231 (1980).

  8. 8.

    , & J. Physiol., Lond. 307, 36–37P (1980).

  9. 9.

    & J. Physiol., Lond. 308, 8–9P (1980).

  10. 10.

    , & Proc. 5th int. Conf. Red Cell Metabolism and Function (ed. Brewer, G. J.) (Liss, New York, in the press).

  11. 11.

    & in Techniques in Lipid & Membrane Biochemistry (eds Kornberg, H. L. et al.) (Elsevier, Amsterdam, in the press).

  12. 12.

    & Proc. natn. Acad. Sci. U.S.A. 66, 936–943 (1970).

  13. 13.

    & J. Physiol., Lond. 251, 671–682 (1975).

  14. 14.

    & J. Membrane Biol. 6, 315–328 (1971).

  15. 15.

    & FEBS Lett. 107, 209–212 (1979).

  16. 16.

    J. Physiol., Lond. 249, 27–50 (1975).

  17. 17.

    J. Physiol., Lond. 256, 227–244 (1976).

  18. 18.

    , & Biochim. biophys. Acta 556, 118–130 (1979).

  19. 19.

    & Nature 263, 336–338 (1976).

  20. 20.

    & Biochim. biophys. Acta 249, 601–605 (1971).

  21. 21.

    & in Comparative Physiology (eds Bolis, L., Schmidt-Nielsen, K. & Maddrell, S. H. P.) 543–581 (North-Holland, Amsterdam, 1973).

  22. 22.

    in Comparative Biochemistry and Physiology of Transport (eds Bolis, L., Bloch, K., Luria, S. E. & Lynen, F.) 310–316 (North-Holland, Amsterdam, 1974).

  23. 23.

    , , & in Comparative Biochemistry and Physiology of Transport (eds Bolis, L., Bloch, K., Luria, S. E. & Lynen, F.) 305–309 (North-Holland, Amsterdam, 1974).

  24. 24.

    & J. Membrane Biol. 54, 119–131 (1980).

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Author information

Author notes

    • Shmuel Muallem

    Premanent address: Department of Biochemistry, The Weitzmann Institute, Rehovot, Israel.

Affiliations

  1. Physiological Laboratory, University of Cambridge, Cambridge CB2 3EG, UK

    • Virgilio L. Lew
    • , Shmuel Muallem
    •  & Carol A. Seymour

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https://doi.org/10.1038/296742a0

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