Evidence that Ca2+/calmodulin-dependent protein phosphorylation is involved in the opening process of potassium channels in identified snail neurons.
The effect of Ca2+/calmodulin-dependent protein phosphorylation on K+ channels was examined in snail neurons, using several pharmacological agents, the voltage clamp method and the pressure injection technique. H-7, a general protein kinase inhibitor, reduced the delayed outward K+ current (IKD) which was suppressed by tetraethylammonium. Ca2+/calmodulin-dependent protein kinase II, when injected into neurons which had been treated with H-7, transiently restored the reduced IKD nearly to the pre-H-7 level. However, this restoration was blocked by W-7, a calmodulin inhibitor. In contrast, the catalytic subunit of cAMP-dependent protein kinase or protein kinase C injected into the H-7-treated neurons had little effect on the current. These findings suggest that Ca2+/calmodulin-dependent protein phosphorylation is involved in the opening process of K+ channels.
Onozuka
M
M
Department of Anatomy, Gifu University School of Medicine, Japan.
Furuichi
H
H
Imai
S
S
Fukami
Y
Y
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000818:Animals; D002118:Calcium / Q000502:physiology*; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000502:physiology*; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology*; D007546:Isoquinolines / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D010766:Phosphorylation / Q000187:drug effects; D010879:Piperazines / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases / Q000502:physiology*; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D012908:Snails; D013449:Sulfonamides / Q000494:pharmacology; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology
D002147:Calmodulin; D007546:Isoquinolines; D010879:Piperazines; D015221:Potassium Channels; D047428:Protein Kinase Inhibitors; D013449:Sulfonamides; D013757:Tetraethylammonium Compounds; C017967:W 7; D019789:Tetraethylammonium; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D011494:Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002118:Calcium