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. 1996 Jul;71(1):156–162. doi: 10.1016/S0006-3495(96)79212-3

Ca2+ current activation rate correlates with alpha 1 subunit density.

B A Adams 1, T Tanabe 1, K G Beam 1
PMCID: PMC1233467  PMID: 8804599

Abstract

We report here that L-type Ca2+ channels activate rapidly in myotubes expressing current at high density and slowly in myotubes expressing current at low density. Partial block of the current in individual cells does not slow activation, indicating that Ca2+ influx does not link activation rate to current density. Activation rate is positively correlated with the density of gating charge (Qmax) associated with the L-type Ca2+ channels. The range of values for Qmax, and the relationship between activation rate and Qmax, are similar for myotubes expressing native or recombinant L-type Ca2+ channels, whereas peak Ca2+ current density is approximately 3-fold higher for native channels. Taken together, these results suggest that Ca2+ channel density can govern activation kinetics. Our findings have important important implications for studies of ion channel function because they suggest that biophysical properties can be significantly influenced by channel density, both in heterologous expression systems and in native tissues.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Adams B. A., Beam K. G. A novel calcium current in dysgenic skeletal muscle. J Gen Physiol. 1989 Sep;94(3):429–444. doi: 10.1085/jgp.94.3.429. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Adams B. A., Tanabe T., Mikami A., Numa S., Beam K. G. Intramembrane charge movement restored in dysgenic skeletal muscle by injection of dihydropyridine receptor cDNAs. Nature. 1990 Aug 9;346(6284):569–572. doi: 10.1038/346569a0. [DOI] [PubMed] [Google Scholar]
  3. Artalejo C. R., Ariano M. A., Perlman R. L., Fox A. P. Activation of facilitation calcium channels in chromaffin cells by D1 dopamine receptors through a cAMP/protein kinase A-dependent mechanism. Nature. 1990 Nov 15;348(6298):239–242. doi: 10.1038/348239a0. [DOI] [PubMed] [Google Scholar]
  4. Beam K. G., Knudson C. M., Powell J. A. A lethal mutation in mice eliminates the slow calcium current in skeletal muscle cells. Nature. 1986 Mar 13;320(6058):168–170. doi: 10.1038/320168a0. [DOI] [PubMed] [Google Scholar]
  5. Bean B. P., Rios E. Nonlinear charge movement in mammalian cardiac ventricular cells. Components from Na and Ca channel gating. J Gen Physiol. 1989 Jul;94(1):65–93. doi: 10.1085/jgp.94.1.65. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Bean B. Taking the beta test. Nature. 1994 Mar 3;368(6466):15–16. doi: 10.1038/368015a0. [DOI] [PubMed] [Google Scholar]
  7. Blumenthal E. M., Kaczmarek L. K. The minK potassium channel exists in functional and nonfunctional forms when expressed in the plasma membrane of Xenopus oocytes. J Neurosci. 1994 May;14(5 Pt 2):3097–3105. doi: 10.1523/JNEUROSCI.14-05-03097.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Brust P. F., Simerson S., McCue A. F., Deal C. R., Schoonmaker S., Williams M. E., Veliçelebi G., Johnson E. C., Harpold M. M., Ellis S. B. Human neuronal voltage-dependent calcium channels: studies on subunit structure and role in channel assembly. Neuropharmacology. 1993 Nov;32(11):1089–1102. doi: 10.1016/0028-3908(93)90004-m. [DOI] [PubMed] [Google Scholar]
  9. Cui J., Kline R. P., Pennefather P., Cohen I. S. Gating of IsK expressed in Xenopus oocytes depends on the amount of mRNA injected. J Gen Physiol. 1994 Jul;104(1):87–105. doi: 10.1085/jgp.104.1.87. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Delbono O. Calcium current activation and charge movement in denervated mammalian skeletal muscle fibres. J Physiol. 1992;451:187–203. doi: 10.1113/jphysiol.1992.sp019160. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Dirksen R. T., Beam K. G. Single calcium channel behavior in native skeletal muscle. J Gen Physiol. 1995 Feb;105(2):227–247. doi: 10.1085/jgp.105.2.227. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Donaldson P. L., Beam K. G. Calcium currents in a fast-twitch skeletal muscle of the rat. J Gen Physiol. 1983 Oct;82(4):449–468. doi: 10.1085/jgp.82.4.449. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Feldmeyer D., Melzer W., Pohl B., Zöllner P. Fast gating kinetics of the slow Ca2+ current in cut skeletal muscle fibres of the frog. J Physiol. 1990 Jun;425:347–367. doi: 10.1113/jphysiol.1990.sp018107. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Gurnett C. A., De Waard M., Campbell K. P. Dual function of the voltage-dependent Ca2+ channel alpha 2 delta subunit in current stimulation and subunit interaction. Neuron. 1996 Feb;16(2):431–440. doi: 10.1016/s0896-6273(00)80061-6. [DOI] [PubMed] [Google Scholar]
  15. Hamill O. P., Marty A., Neher E., Sakmann B., Sigworth F. J. Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches. Pflugers Arch. 1981 Aug;391(2):85–100. doi: 10.1007/BF00656997. [DOI] [PubMed] [Google Scholar]
  16. Hille B. Modulation of ion-channel function by G-protein-coupled receptors. Trends Neurosci. 1994 Dec;17(12):531–536. doi: 10.1016/0166-2236(94)90157-0. [DOI] [PubMed] [Google Scholar]
  17. Hofmann F., Biel M., Flockerzi V. Molecular basis for Ca2+ channel diversity. Annu Rev Neurosci. 1994;17:399–418. doi: 10.1146/annurev.ne.17.030194.002151. [DOI] [PubMed] [Google Scholar]
  18. Hoshi T., Rothlein J., Smith S. J. Facilitation of Ca2+-channel currents in bovine adrenal chromaffin cells. Proc Natl Acad Sci U S A. 1984 Sep;81(18):5871–5875. doi: 10.1073/pnas.81.18.5871. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Hullin R., Singer-Lahat D., Freichel M., Biel M., Dascal N., Hofmann F., Flockerzi V. Calcium channel beta subunit heterogeneity: functional expression of cloned cDNA from heart, aorta and brain. EMBO J. 1992 Mar;11(3):885–890. doi: 10.1002/j.1460-2075.1992.tb05126.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Lacerda A. E., Kim H. S., Ruth P., Perez-Reyes E., Flockerzi V., Hofmann F., Birnbaumer L., Brown A. M. Normalization of current kinetics by interaction between the alpha 1 and beta subunits of the skeletal muscle dihydropyridine-sensitive Ca2+ channel. Nature. 1991 Aug 8;352(6335):527–530. doi: 10.1038/352527a0. [DOI] [PubMed] [Google Scholar]
  21. Mori Y., Friedrich T., Kim M. S., Mikami A., Nakai J., Ruth P., Bosse E., Hofmann F., Flockerzi V., Furuichi T. Primary structure and functional expression from complementary DNA of a brain calcium channel. Nature. 1991 Apr 4;350(6317):398–402. doi: 10.1038/350398a0. [DOI] [PubMed] [Google Scholar]
  22. Nakai J., Adams B. A., Imoto K., Beam K. G. Critical roles of the S3 segment and S3-S4 linker of repeat I in activation of L-type calcium channels. Proc Natl Acad Sci U S A. 1994 Feb 1;91(3):1014–1018. doi: 10.1073/pnas.91.3.1014. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Neely A., Wei X., Olcese R., Birnbaumer L., Stefani E. Potentiation by the beta subunit of the ratio of the ionic current to the charge movement in the cardiac calcium channel. Science. 1993 Oct 22;262(5133):575–578. doi: 10.1126/science.8211185. [DOI] [PubMed] [Google Scholar]
  24. Perez-Reyes E., Castellano A., Kim H. S., Bertrand P., Baggstrom E., Lacerda A. E., Wei X. Y., Birnbaumer L. Cloning and expression of a cardiac/brain beta subunit of the L-type calcium channel. J Biol Chem. 1992 Jan 25;267(3):1792–1797. [PubMed] [Google Scholar]
  25. Perez-Reyes E., Kim H. S., Lacerda A. E., Horne W., Wei X. Y., Rampe D., Campbell K. P., Brown A. M., Birnbaumer L. Induction of calcium currents by the expression of the alpha 1-subunit of the dihydropyridine receptor from skeletal muscle. Nature. 1989 Jul 20;340(6230):233–236. doi: 10.1038/340233a0. [DOI] [PubMed] [Google Scholar]
  26. Pietrobon D., Hess P. Novel mechanism of voltage-dependent gating in L-type calcium channels. Nature. 1990 Aug 16;346(6285):651–655. doi: 10.1038/346651a0. [DOI] [PubMed] [Google Scholar]
  27. Pérez-García M. T., Kamp T. J., Marbán E. Functional properties of cardiac L-type calcium channels transiently expressed in HEK293 cells. Roles of alpha 1 and beta subunits. J Gen Physiol. 1995 Feb;105(2):289–305. doi: 10.1085/jgp.105.2.289. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Rios E., Brum G. Involvement of dihydropyridine receptors in excitation-contraction coupling in skeletal muscle. Nature. 1987 Feb 19;325(6106):717–720. doi: 10.1038/325717a0. [DOI] [PubMed] [Google Scholar]
  29. Sanchez J. A., Stefani E. Inward calcium current in twitch muscle fibres of the frog. J Physiol. 1978 Oct;283:197–209. doi: 10.1113/jphysiol.1978.sp012496. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Sculptoreanu A., Scheuer T., Catterall W. A. Voltage-dependent potentiation of L-type Ca2+ channels due to phosphorylation by cAMP-dependent protein kinase. Nature. 1993 Jul 15;364(6434):240–243. doi: 10.1038/364240a0. [DOI] [PubMed] [Google Scholar]
  31. Singer D., Biel M., Lotan I., Flockerzi V., Hofmann F., Dascal N. The roles of the subunits in the function of the calcium channel. Science. 1991 Sep 27;253(5027):1553–1557. doi: 10.1126/science.1716787. [DOI] [PubMed] [Google Scholar]
  32. Snutch T. P., Reiner P. B. Ca2+ channels: diversity of form and function. Curr Opin Neurobiol. 1992 Jun;2(3):247–253. doi: 10.1016/0959-4388(92)90111-w. [DOI] [PubMed] [Google Scholar]
  33. Swandulla D., Armstrong C. M. Calcium channel block by cadmium in chicken sensory neurons. Proc Natl Acad Sci U S A. 1989 Mar;86(5):1736–1740. doi: 10.1073/pnas.86.5.1736. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Tanabe T., Adams B. A., Numa S., Beam K. G. Repeat I of the dihydropyridine receptor is critical in determining calcium channel activation kinetics. Nature. 1991 Aug 29;352(6338):800–803. doi: 10.1038/352800a0. [DOI] [PubMed] [Google Scholar]
  35. Tanabe T., Beam K. G., Adams B. A., Niidome T., Numa S. Regions of the skeletal muscle dihydropyridine receptor critical for excitation-contraction coupling. Nature. 1990 Aug 9;346(6284):567–569. doi: 10.1038/346567a0. [DOI] [PubMed] [Google Scholar]
  36. Tanabe T., Beam K. G., Powell J. A., Numa S. Restoration of excitation-contraction coupling and slow calcium current in dysgenic muscle by dihydropyridine receptor complementary DNA. Nature. 1988 Nov 10;336(6195):134–139. doi: 10.1038/336134a0. [DOI] [PubMed] [Google Scholar]
  37. Tanabe T., Takeshima H., Mikami A., Flockerzi V., Takahashi H., Kangawa K., Kojima M., Matsuo H., Hirose T., Numa S. Primary structure of the receptor for calcium channel blockers from skeletal muscle. Nature. 1987 Jul 23;328(6128):313–318. doi: 10.1038/328313a0. [DOI] [PubMed] [Google Scholar]
  38. Varadi G., Lory P., Schultz D., Varadi M., Schwartz A. Acceleration of activation and inactivation by the beta subunit of the skeletal muscle calcium channel. Nature. 1991 Jul 11;352(6331):159–162. doi: 10.1038/352159a0. [DOI] [PubMed] [Google Scholar]
  39. Véry A. A., Bosseux C., Gaymard F., Sentenac H., Thibaud J. B. Level of expression in Xenopus oocytes affects some characteristics of a plant inward-rectifying voltage-gated K+ channel. Pflugers Arch. 1994 Oct;428(3-4):422–424. doi: 10.1007/BF00724528. [DOI] [PubMed] [Google Scholar]
  40. Wei X. Y., Perez-Reyes E., Lacerda A. E., Schuster G., Brown A. M., Birnbaumer L. Heterologous regulation of the cardiac Ca2+ channel alpha 1 subunit by skeletal muscle beta and gamma subunits. Implications for the structure of cardiac L-type Ca2+ channels. J Biol Chem. 1991 Nov 15;266(32):21943–21947. [PubMed] [Google Scholar]

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