Biomaterial Database

G protein regulation of cardiac muscarinic potassium channel. 1995

Y Kurachi

Department of Pharmacology II, Faculty of Medicine, Osaka University, Japan.

Several ion channels can be regulated by G proteins in a "membrane-delimited" manner. The cardiac muscarinic K+ (KACh) channel, which is responsible for the acetylcholine (ACh) or adenosine-induced deceleration of heart beat and atrioventricular conduction, is the prototype of this type of receptor-dependent regulation of ion channels. Because similar transduction mechanisms are utilized by various membrane receptors, such as somatostatin, 5-hydroxytryptamine-1, alpha 2-adrenergic, mu-and delta-opioid, D2-dopamine, and gamma-aminobutyric acid B receptors, in neuronal, hormone-secreting, renal, or smooth muscle cells, the G protein (GK)-KACh channel system illustrates the principles underlying one of the most important cell signaling mechanisms (B. Hille. Neuron 9: 187-195, 1992). It seems that both alpha- and beta gamma-subunits of GK may be involved in the regulation of the KACh channel of mammalian atrial muscle. A general consensus of opinion has emerged, after some years of controversy, to support the notion that physiological activation of the channel by GK is the responsibility of the beta gamma-subunits. Recent evidence suggests that the KACh channel interacts with the alpha-subunit in the terminating process of activation.

UI	MeSH Term	Description	Entries
D009116	Muscarine	A toxic alkaloid found in Amanita muscaria (fly fungus) and other fungi of the Inocybe species. It is the first parasympathomimetic substance ever studied and causes profound parasympathetic activation that may end in convulsions and death. The specific antidote is atropine.
D009206	Myocardium	The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.	Muscle, Cardiac,Muscle, Heart,Cardiac Muscle,Myocardia,Cardiac Muscles,Heart Muscle,Heart Muscles,Muscles, Cardiac,Muscles, Heart
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D004789	Enzyme Activation	Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.	Activation, Enzyme,Activations, Enzyme,Enzyme Activations
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000368	Aged	A person 65 years of age or older. For a person older than 79 years, AGED, 80 AND OVER is available.	Elderly
D000369	Aged, 80 and over	Persons 80 years of age and older.	Oldest Old
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D015221	Potassium Channels	Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits.	Ion Channels, Potassium,Ion Channel, Potassium,Potassium Channel,Potassium Ion Channels,Channel, Potassium,Channel, Potassium Ion,Channels, Potassium,Channels, Potassium Ion,Potassium Ion Channel
D019204	GTP-Binding Proteins	Regulatory proteins that act as molecular switches. They control a wide range of biological processes including: receptor signaling, intracellular signal transduction pathways, and protein synthesis. Their activity is regulated by factors that control their ability to bind to and hydrolyze GTP to GDP. EC 3.6.1.-.	G-Proteins,GTP-Regulatory Proteins,Guanine Nucleotide Regulatory Proteins,G-Protein,GTP-Binding Protein,GTP-Regulatory Protein,Guanine Nucleotide Coupling Protein,G Protein,G Proteins,GTP Binding Protein,GTP Binding Proteins,GTP Regulatory Protein,GTP Regulatory Proteins,Protein, GTP-Binding,Protein, GTP-Regulatory,Proteins, GTP-Binding,Proteins, GTP-Regulatory