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. 1999 Dec;77(6):2999–3009. doi: 10.1016/S0006-3495(99)77131-6

Effects of channel cytoplasmic regions on the activation mechanisms of cardiac versus skeletal muscle Na(+) channels.

E S Bennett 1
PMCID: PMC1300571  PMID: 10585922

Abstract

Functional comparison of skeletal muscle (rSkM1) and cardiac (hH1) voltage-gated sodium channel isoforms expressed in Chinese hamster ovary cells showed rSkM1 half-activation (V(a)) and inactivation (V(i)) voltages 7 and 10 mV more depolarized than hH1 V(a) and V(i), respectively. Internal papain perfusion removed fast inactivation from each isoform and caused a 20-mV hyperpolarizing shift in hH1 V(a), with an insignificant change in rSkM1 V(a). Activation voltage of the inactivation-deficient hH1 mutant, hH1Q3, was nearly identical to wild-type hH1 V(a), both before and after papain treatment, with hH1Q3 V(a) also shifted by nearly 20 mV after internal papain perfusion. These data indicate that while papain removes both hH1 and rSkM1 inactivation, it has a second effect only on hH1 that causes a shift in activation voltage. Internal treatment with an antibody directed against the III-IV linker essentially mimicked papain treatment by removing some inactivation from each isoform and causing a 12-mV shift in hH1 V(a), while rSkM1 V(a) remained constant. This suggests that some channel segment within, near, or interacting with the III-IV linker is involved in establishing hH1 activation voltage. Together the data show that rSkM1 and hH1 activation mechanisms are different and are the first to suggest a role for a cytoplasmic structure in the voltage-dependent activation of cardiac sodium channels.

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Selected References

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

  1. Armstrong C. M., Bezanilla F. Inactivation of the sodium channel. II. Gating current experiments. J Gen Physiol. 1977 Nov;70(5):567–590. doi: 10.1085/jgp.70.5.567. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Armstrong C. M., Bezanilla F., Rojas E. Destruction of sodium conductance inactivation in squid axons perfused with pronase. J Gen Physiol. 1973 Oct;62(4):375–391. doi: 10.1085/jgp.62.4.375. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Bennett E., Urcan M. S., Tinkle S. S., Koszowski A. G., Levinson S. R. Contribution of sialic acid to the voltage dependence of sodium channel gating. A possible electrostatic mechanism. J Gen Physiol. 1997 Mar;109(3):327–343. doi: 10.1085/jgp.109.3.327. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Catterall W. A. Structure and function of voltage-gated ion channels. Annu Rev Biochem. 1995;64:493–531. doi: 10.1146/annurev.bi.64.070195.002425. [DOI] [PubMed] [Google Scholar]
  5. Cha A., Ruben P. C., George A. L., Jr, Fujimoto E., Bezanilla F. Voltage sensors in domains III and IV, but not I and II, are immobilized by Na+ channel fast inactivation. Neuron. 1999 Jan;22(1):73–87. doi: 10.1016/s0896-6273(00)80680-7. [DOI] [PubMed] [Google Scholar]
  6. Chahine M., Deschene I., Chen L. Q., Kallen R. G. Electrophysiological characteristics of cloned skeletal and cardiac muscle sodium channels. Am J Physiol. 1996 Aug;271(2 Pt 2):H498–H506. doi: 10.1152/ajpheart.1996.271.2.H498. [DOI] [PubMed] [Google Scholar]
  7. Chen L. Q., Chahine M., Kallen R. G., Barchi R. L., Horn R. Chimeric study of sodium channels from rat skeletal and cardiac muscle. FEBS Lett. 1992 Sep 14;309(3):253–257. doi: 10.1016/0014-5793(92)80783-d. [DOI] [PubMed] [Google Scholar]
  8. Chen L. Q., Santarelli V., Horn R., Kallen R. G. A unique role for the S4 segment of domain 4 in the inactivation of sodium channels. J Gen Physiol. 1996 Dec;108(6):549–556. doi: 10.1085/jgp.108.6.549. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Eaton D. C., Brodwick M. S., Oxford G. S., Rudy B. Arginine-specific reagents remove sodium channel inactivation. Nature. 1978 Feb 2;271(5644):473–476. doi: 10.1038/271473a0. [DOI] [PubMed] [Google Scholar]
  10. Gellens M. E., George A. L., Jr, Chen L. Q., Chahine M., Horn R., Barchi R. L., Kallen R. G. Primary structure and functional expression of the human cardiac tetrodotoxin-insensitive voltage-dependent sodium channel. Proc Natl Acad Sci U S A. 1992 Jan 15;89(2):554–558. doi: 10.1073/pnas.89.2.554. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Gonoi T., Hille B. Gating of Na channels. Inactivation modifiers discriminate among models. J Gen Physiol. 1987 Feb;89(2):253–274. doi: 10.1085/jgp.89.2.253. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Hartmann H. A., Tiedeman A. A., Chen S. F., Brown A. M., Kirsch G. E. Effects of III-IV linker mutations on human heart Na+ channel inactivation gating. Circ Res. 1994 Jul;75(1):114–122. doi: 10.1161/01.res.75.1.114. [DOI] [PubMed] [Google Scholar]
  13. Horn R., Brodwick M. S., Eaton D. C. Effect of protein cross-linking reagents on membrane currents of squid axon. Am J Physiol. 1980 Mar;238(3):C127–C132. doi: 10.1152/ajpcell.1980.238.3.C127. [DOI] [PubMed] [Google Scholar]
  14. Jan L. Y., Jan Y. N. Cloned potassium channels from eukaryotes and prokaryotes. Annu Rev Neurosci. 1997;20:91–123. doi: 10.1146/annurev.neuro.20.1.91. [DOI] [PubMed] [Google Scholar]
  15. Ji S., George A. L., Jr, Horn R., Barchi R. L. Paramyotonia congenita mutations reveal different roles for segments S3 and S4 of domain D4 in hSkM1 sodium channel gating. J Gen Physiol. 1996 Feb;107(2):183–194. doi: 10.1085/jgp.107.2.183. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Kallen R. G., Cohen S. A., Barchi R. L. Structure, function and expression of voltage-dependent sodium channels. Mol Neurobiol. 1993 Fall-Winter;7(3-4):383–428. doi: 10.1007/BF02769184. [DOI] [PubMed] [Google Scholar]
  17. Kirsch G. E., Skattebøl A., Possani L. D., Brown A. M. Modification of Na channel gating by an alpha scorpion toxin from Tityus serrulatus. J Gen Physiol. 1989 Jan;93(1):67–83. doi: 10.1085/jgp.93.1.67. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Oxford G. S. Some kinetic and steady-state properties of sodium channels after removal of inactivation. J Gen Physiol. 1981 Jan;77(1):1–22. doi: 10.1085/jgp.77.1.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Oxford G. S., Wu C. H., Narahashi T. Removal of sodium channel inactivation in squid giant axons by n-bromoacetamide. J Gen Physiol. 1978 Mar;71(3):227–247. doi: 10.1085/jgp.71.3.227. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Patlak J. Molecular kinetics of voltage-dependent Na+ channels. Physiol Rev. 1991 Oct;71(4):1047–1080. doi: 10.1152/physrev.1991.71.4.1047. [DOI] [PubMed] [Google Scholar]
  21. Richmond J. E., Featherstone D. E., Hartmann H. A., Ruben P. C. Slow inactivation in human cardiac sodium channels. Biophys J. 1998 Jun;74(6):2945–2952. doi: 10.1016/S0006-3495(98)78001-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Scheuer T., Auld V. J., Boyd S., Offord J., Dunn R., Catterall W. A. Functional properties of rat brain sodium channels expressed in a somatic cell line. Science. 1990 Feb 16;247(4944):854–858. doi: 10.1126/science.2154850. [DOI] [PubMed] [Google Scholar]
  23. Stimers J. R., Bezanilla F., Taylor R. E. Sodium channel activation in the squid giant axon. Steady state properties. J Gen Physiol. 1985 Jan;85(1):65–82. doi: 10.1085/jgp.85.1.65. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Stühmer W., Conti F., Suzuki H., Wang X. D., Noda M., Yahagi N., Kubo H., Numa S. Structural parts involved in activation and inactivation of the sodium channel. Nature. 1989 Jun 22;339(6226):597–603. doi: 10.1038/339597a0. [DOI] [PubMed] [Google Scholar]
  25. Trimmer J. S., Cooperman S. S., Agnew W. S., Mandel G. Regulation of muscle sodium channel transcripts during development and in response to denervation. Dev Biol. 1990 Dec;142(2):360–367. doi: 10.1016/0012-1606(90)90356-n. [DOI] [PubMed] [Google Scholar]
  26. Trimmer J. S., Cooperman S. S., Tomiko S. A., Zhou J. Y., Crean S. M., Boyle M. B., Kallen R. G., Sheng Z. H., Barchi R. L., Sigworth F. J. Primary structure and functional expression of a mammalian skeletal muscle sodium channel. Neuron. 1989 Jul;3(1):33–49. doi: 10.1016/0896-6273(89)90113-x. [DOI] [PubMed] [Google Scholar]
  27. Ukomadu C., Zhou J., Sigworth F. J., Agnew W. S. muI Na+ channels expressed transiently in human embryonic kidney cells: biochemical and biophysical properties. Neuron. 1992 Apr;8(4):663–676. doi: 10.1016/0896-6273(92)90088-u. [DOI] [PubMed] [Google Scholar]
  28. Vassilev P. M., Scheuer T., Catterall W. A. Identification of an intracellular peptide segment involved in sodium channel inactivation. Science. 1988 Sep 23;241(4873):1658–1661. doi: 10.1126/science.241.4873.1658. [DOI] [PubMed] [Google Scholar]
  29. Vassilev P., Scheuer T., Catterall W. A. Inhibition of inactivation of single sodium channels by a site-directed antibody. Proc Natl Acad Sci U S A. 1989 Oct;86(20):8147–8151. doi: 10.1073/pnas.86.20.8147. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Wang D. W., George A. L., Jr, Bennett P. B. Comparison of heterologously expressed human cardiac and skeletal muscle sodium channels. Biophys J. 1996 Jan;70(1):238–245. doi: 10.1016/S0006-3495(96)79566-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. West J. W., Scheuer T., Maechler L., Catterall W. A. Efficient expression of rat brain type IIA Na+ channel alpha subunits in a somatic cell line. Neuron. 1992 Jan;8(1):59–70. doi: 10.1016/0896-6273(92)90108-p. [DOI] [PubMed] [Google Scholar]
  32. Yang J. S., Sladky J. T., Kallen R. G., Barchi R. L. TTX-sensitive and TTX-insensitive sodium channel mRNA transcripts are independently regulated in adult skeletal muscle after denervation. Neuron. 1991 Sep;7(3):421–427. doi: 10.1016/0896-6273(91)90294-a. [DOI] [PubMed] [Google Scholar]

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