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

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)...

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Main Authors: Zong, Xiangang (Author) , Schreieck, Jürgen (Author) , Mehrke, Gerhard (Author) , Welling, Andrea (Author) , Schuster, Angela (Author) , Bossert, Eva-Maria (Author) , Flockerzi, Veit (Author) , Hofmann, Franz (Author)
Format: Article (Journal)
Language:English
Published: July 1995
In: Pflügers Archiv
Year: 1995, Volume: 430, Issue: 3, Pages: 340-347
ISSN:1432-2013
DOI:10.1007/BF00373908
Online Access:Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1007/BF00373908
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Author Notes:Xiangang Zong, Jürgen Schreieck, Gerhard Mehrke, Andera Welling, Angela Schuster, Eva Bosse, Veit Flockerzi, Franz Hofmann
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Summary: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.
Item Description:Gesehen am 18.02.2025
Physical Description:Online Resource
ISSN:1432-2013
DOI:10.1007/BF00373908

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