Skip to main content
NCBI home page
Cellular and Molecular Neurobiology logoLink to Cellular and Molecular Neurobiology
. 2004 Jun;24(3):317–330. doi: 10.1023/B:CEMN.0000022765.52109.26

Intramembrane Charge Movement Associated with Endogenous K+ Channel Activity in HEK-293 Cells

Guillermo Avila 1, Alejandro Sandoval 2, Ricardo Felix 2
PMCID: PMC11529952  PMID: 15206817

Abstract

1. The use of molecular biology in combination with electrophysiology in the HEK-293 cell line has given fascinating insights into neuronal ion channel function. Nevertheless, to fully understand the properties of channels exogenously expressed in these cells, a detailed evaluation of endogenous channels is indispensable.

2. Previous studies have shown the expression of endogenous voltage-gated K+, Ca2+, and Cl− channels and this predicts that changes in membrane potential will cause intramembrane charge movement, though this gating charge translocation remain undefined. Here, we confirm this prediction by performing patch-clamp experiments to record ionic and gating currents. Our data show that HEK-293 cells express at least two types of K+-selective endogenous channels which sustain the majority of the ionic current, and exclude a significant contribution from Ca2+ and Cl− channels to the whole-cell current.

3. Gating currents were unambiguously resolved after ionic current blockade enabling this first report of intramembrane charge movement in HEK-293 cells arising entirely from endogenous K+ channel activity, and providing valuable information concerning the activation mechanism of voltage-gated K+ channels in these cells.

Keywords: K+ channels, Ca2+ channels, gating currents, HEK-293 cells

REFERENCES

  1. Armstrong, C. M., and Bezanilla, F. (1973). Currents related to the movement of the gating particles of the sodium channels. Nature242:459-461. [DOI] [PubMed] [Google Scholar]
  2. Avila, G., and Dirksen, R. T. (2000). Functional impact of the ryanodine receptor on the skeletal muscle L-type Ca2 channel. J. Gen. Physiol. 115:467-480. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Bangalore, R., Mehrke, G., Gingrich, K., Hofmann, F., and Kass, R. S. (1996). Influence of L-type Ca2 channel α2δ-subunit on ionic and gating current in transiently transfected HEK 293 cells. Am. J. Physiol.270:H1521-H1528. [DOI] [PubMed] [Google Scholar]
  4. Berjukow, S., Doring, F., Froschmayr, M., Grabner, M., Glossmann, H., and Hering, S. (1996). Endogenous calcium channels in human embryonic kidney (HEK293) cells. Br. J. Pharmacol. 118:748-754. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Bezanilla, F., Perozo, E., and Stefani, E. (1994). Gating of Shaker K+ channels. II. The components of gating currents and a model of channel activation. Biophys. J.66:1011-1021. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Gamper, N., Fillon, S., Huber, S. M., Feng, Y., Kobayashi, T., Cohen, P., and Lang, F. (2002). IGF-1 up-regulates K+ channels via P13-kinase, PDK1 and SGK1. Pflugers Arch.443:625-634. [DOI] [PubMed] [Google Scholar]
  7. Jiang, B., Sun, X., Cao, K., and Wang, R. (2002). Endogenous Kv channels in human embryonic kidney (HEK-293) cells. Mol. Cell. Biochem. 238:69-79. [DOI] [PubMed] [Google Scholar]
  8. Jones, L. P., Patil, P. G., Snutch, T. P., and Yue, D. T. (1997). G-protein modulation of N-type calcium channel gating current in human embryonic kidney cells (HEK 293). J. Physiol.498:601-610. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Josephson, I. R. (1997). Kinetic components of the gating currents of human cardiac L-type Ca2 channels. Pflugers Arch.433:321-329. [DOI] [PubMed] [Google Scholar]
  10. Kushmerick, C., Romano-Silva, M. A., Gomez, M. V., and Prado, M. A. (2001). Changes in Ca2 channel expression upon differentiation of SN56 cholinergic cells. Brain Res.916:199-210. [DOI] [PubMed] [Google Scholar]
  11. Larsson, H. P. (2002). The search is on for the voltage sensor-to-gate coupling. J. Gen. Physiol.120:475-481. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Marty, A., and Neher, E. (1995). Tight-seal whole-cell recording. In Sakmann, B., and Neher, E. (eds.), Single-Channel Recording, Plenum, New York, pp. 31-52. [Google Scholar]
  13. Meza, U., Avila, G., Felix, R., Gomora, J. C., and Cota, G. (1994). Long-term regulation of calcium channels in clonal pituitary cells by epidermal growth factor, insulin, and glucocorticoids. J. Gen. Physiol. 104:1019-1038. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Perozo, E., Santacruz-Toloza, L., Stefani, E., Bezanilla, F., and Papazian, D. (1994). S4 mutations alter gating currents of Shaker K+ channels. Biophys. J.66:345-354. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Petersen, K. R., and Nerbonne, J. M. (1999). Expression environment determines K+ current properties: Kv1 and Kv4 alpha-subunit-induced K+ currents in mammalian cell lines and cardiac myocytes. Pflugers Arch.437:381-392. [DOI] [PubMed] [Google Scholar]
  16. Scott, R. H., Sutton, K. G., Griffin, A., Stapleton, S. R., and Currie, K. P. (1995). Aspects of calcium-activated chloride currents: A neuronal perspective. Pharmacol. Ther.66:535-565. [DOI] [PubMed] [Google Scholar]
  17. Shaw, G., Morse, S., Ararat, M., and Graham, F. L. (2002). Preferential transformation of human neuronal cells by human adenoviruses and the origin of HEK 293 cells. FASEB J. 16:869-871. [DOI] [PubMed] [Google Scholar]
  18. Stefani, E., Ottolia, M., Noceti, F., Olcese, R., Wallner, M., Latorre, R., and Toro, L. (1997). Voltage-controlled gating in a large conductance Ca2-sensitive K+ channel (hslo). Proc. Natl. Acad. Sci. U.S.A.94:5427-5431. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Uebele, V. N., England, S. K., Chaudhary, A., Tamkun, M. M., and Snyders, D. J. (1996). Functional differences in Kv1.5 currents expressed in mammalian cell lines are due to the presence of endogenous Kv beta 2.1 subunits. J. Biol. Chem.271:2406-2412. [DOI] [PubMed] [Google Scholar]
  20. Yu, S. P., and Kerchner, G. A. (1998). Endogenous voltage-gated potassium channels in human embryonic kidney (HEK293) cells. J. Neurosci. Res.52:612-627. [DOI] [PubMed] [Google Scholar]
  21. Zhu, G., Zhang, Y., Xu, H., and Jiang, C. (1998). Identification of endogenous outward currents in the human embryonic kidney (HEK 293) cell line. J. Neurosci. Methods81:73-83. [DOI] [PubMed] [Google Scholar]

Articles from Cellular and Molecular Neurobiology are provided here courtesy of Springer

RESOURCES