Kir3.1 | GIRK1 | Potassium Voltage-Gated Channel Subfamily J Member 3
Family:
Inward-rectifier potassium ion channel
Subgroups:
Seven families channels demonstrate robust inward rectification: Kir1.1; Kir2.1 - Kir2.4; Kir3.1 - Kir3.4, Kir4.1 - Kir4.2; Kir5.1, Kir6.1 - Kir6.2; Kir7.1
Topology:
The channel protein contains two membrane spanning alpha helices denoted as M1 and M2. Four identical subunits form a functional homotetramer, heterotetramers can combine with members of the same subfamily
Kir3.1 Background Information
Kir3.1, also colled GIRK1, is a inward rectifier potassium channel which is a mamber of the subfamily of G protein-coupled inwardly-rectifying potassium channels (GIRKs). In the heart, it forms heteromers with Kir3.4 (GIRK4). When activated by parasympathetic signals such as acetylcholine through M2 muscarinic receptors, it causes an outward current of potassium, which slows down the heart rate. Kir3.1 and Kir3.4 are as well called muscarinic potassium channels and mediate the current IKAChthe heart.
Gene:
KCNJ3
Human Protein:
UniProt P48549
Tissue:
Heart, brain, prostate
Function/ Application:
ACh-activated K+ current in the heart (IKACh)
Pathology:
QT syndrome type 13, hyperaldosteronism type 3, adenocarcinomas, diabetes mellitus, Andersen Syndrome, Leber Congenital Amaurosis 16drome, ataxia, Parkinson's disease
Interaction:
Associates with Kir3.2 (GIRK2), Kir3.3 (GIRK3), Kir3.4 (GIRK4) to form a G-protein activated heteromultimer pore-forming unit. It is not functional as homomer. It interacts with PRKACG, GNAI3, GNB3, GNB1, Adrenoceptor beta 2
Modulator:
Tertiapin-Q, Glyburide, Halothane, Flupirtine
Assays:
Patch clamp
Recommended Reviews:
Kubo et al. (2005) International Union of Pharmacology. LIV. Nomenclature and Molecular Relationships of Inwardly Rectifying Potassium Channels. Pharmacol Rev 57(4):509-526