Abstract
In contrast to vascular smooth muscle (VSM). cAMP-depehdent phosphorylation increases L-type voltage dependent Ca2+-channel (L-VDCC) activity in heart. To investigate whether this difference depends on the tissue-specific α1-subunit of the L-VDCC or its regulation by other subunits, we used a Xenopus laevis oocyte expression system. Injection of cAMP into oocytes expressing cardiac α1 or VSM α1 alone had no effect on L-VDCC activity. However, cAMP increased L-VDCC activity 2-fold in oocytes co-expressing cardiac α1 or VSM α1 with the skeletal muscle ß-subunit. These results suggest that the presence of the ß-subunit is required for cAMP-mediated increase of L-VDCC activity and that the characteristics of tissue-specific ß-subunits may explain differential regulation of L-VDCC activity.
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Klöckner, U., Itagaki, K., Bodi, I. et al. β-Subunit expression is required for cAMP-dependent increase of cloned cardiac and vascular calcium channel currents. Pflügers Arch 420, 413–415 (1992). https://doi.org/10.1007/BF00374479
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DOI: https://doi.org/10.1007/BF00374479