Pflügers Archiv

, Volume 430, Issue 3, pp 340–347

On the regulation of the expressed L-type calcium channel by cAMP-dependent phosphorylation

  • Xiangang Zong
  • Jürgen Schreieck
  • Gerhard Mehrke
  • Andera Welling
  • Angela Schuster
  • Eva Bosse
  • Veit Flockerzi
  • Franz Hofmann
Original Article Molecular and Cellular Physiology

DOI: 10.1007/BF00373908

Cite this article as:
Zong, X., Schreieck, J., Mehrke, G. et al. Pflügers Arch (1995) 430: 340. doi:10.1007/BF00373908

Abstract

The Ca2+ channel subunits α1C-a and α1C-b were stably expressed in Chinese hamster ovary (CHO) and human embryonic kidney (HEK) 293 cells. The peak Ba2+ current (IBa) of these cells was not affected significantly by internal dialysis with 0.1 mM cAMP-dependent protein kinase inhibitor peptide (mPKI), 25 μM cAMP-dependent protein kinase catalytic subunit (PKA), or a combination of 25 μM PKA and 1 μM okadaic acid. The activity of the α1C-b channel subunit expressed stably in HEK 293 cells was depressed by 1 μM H 89 and was not increased by superfusion with 5 μM forskolin plus 20 μM isobutylmethylxanthine (IBMX). The α1C-a·β2·α2/δ complex was transiently expressed in HEK 293 cells; it was inhibited by internal dialysis of the cells with 1 μM H 89, but was not affected by internal dialysis with mPKI, PKA or microcystin. Internal dialysis of cells expressing the α1C-a·β2·α2/δ channel with 10 μM PKA did not induce facilitation after a 150-ms prepulse to +50 mV. The Ca2+ current (ICa) of cardiac myocytes increased threefold during internal dialysis with 5 μM PKA or 25 μM microcystin and during external superfusion with 0.1 μM isoproterenol or 5 μM forskolin plus 50 μM IBMX. These results indicate that the L-type Ca2+ channel expressed is not modulated by cAMP-dependent phosphorylation to the same extent as in native cardiac myocytes.

Key words

L-Type calcium channelscAMP-dependent regulation of calcium channelsTransient and stable expression of calcium channelsCHO cellsHEK 293 cells

Copyright information

© Springer-Verlag 1995

Authors and Affiliations

  • Xiangang Zong
    • 1
  • Jürgen Schreieck
    • 1
  • Gerhard Mehrke
    • 1
  • Andera Welling
    • 1
  • Angela Schuster
    • 1
  • Eva Bosse
    • 1
  • Veit Flockerzi
    • 1
  • Franz Hofmann
    • 1
  1. 1.Institut für Pharmakologie und Toxikologie der TUMMunichGermany
  2. 2.Pharmakologisches Institut, Abteilung Molekulare Pharmakologie, Medizinische FakultätUniversität HeidelbergHeidelbergGermany