Regulation of a heart potassium channel by protein kinase A and C.
The enzymes adenosine 3',5'-monophosphate (cAMP)-dependent protein kinase (protein kinase A) and protein kinase C regulate the activity of a diverse group of cellular proteins including membrane ion channel proteins. When protein kinase A was stimulated in cardiac ventricular myocytes with the membrane-soluble cAMP analog 8-chlorphenylthio cAMP (8-CPT cAMP), the amplitude of the delayed-rectifier potassium current (IK) doubled when recorded at 32 degrees C but was not affected at 22 degrees C. In contrast, modulation of the calcium current (ICa) by 8-CPT cAMP was independent of temperature with similar increases in ICa occurring at both temperatures. Stimulation of protein kinase C by phorbol 12,13-dibutyrate also enhanced IK in a temperature-dependent manner but failed to increase ICa at either temperature. Thus, cardiac delayed-rectifier potassium but not calcium channels are regulated by two distinct protein kinases in a similar temperature-dependent fashion.
Walsh
K B
KB
Department of Physiology, University of Rochester, School of Medicine and Dentistry, NY 14642.
Kass
R S
RS
D000818:Animals; D000242:Cyclic AMP / Q000031:analogs & derivatives* / Q000494:pharmacology; D006168:Guinea Pigs; D006321:Heart / Q000502:physiology*; D006706:Homeostasis; D066298:In Vitro Techniques; D007700:Kinetics; D008564:Membrane Potentials; D015221:Potassium Channels / Q000502:physiology*; D011493:Protein Kinase C / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism*; D013816:Thermodynamics; D013873:Thionucleotides / Q000494:pharmacology*; D016276:Ventricular Function
D015221:Potassium Channels; D013873:Thionucleotides; C015929:8-((4-chlorophenyl)thio)cyclic-3',5'-AMP; D000242:Cyclic AMP; D011494:Protein Kinases; D011493:Protein Kinase C