Kir3.1 | Potassium Voltage-Gated Channel Subfamily J Member 3

Family:
Inward-rectifier potassium ion channel

Subgroups:
Seven families channels demonstrate robust inward rectification: K_ir1.1; K_ir2.1 - K_ir2.4; K_ir3.1 - K_ir3.4, K_ir4.1 - K_ir4.2; K_ir5.1, K_ir6.1 - K_ir6.2; K_ir7.1

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

K_ir3.1, 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 K_ir3.4 (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. K_ir3.1 and K_ir3.4 are as well called muscarinic potassium channels and mediate the current I_KAChthe heart.

Gene:
KCNJ3

Human Protein:
UniProt P48549

Tissue:
Heart, brain, prostate

Function/ Application:
ACh-activated K⁺ current in the heart (I_KACh)

Pathology:
QT syndrome type 13, hyperaldosteronism type 3, adenocarcinomas, diabetes mellitus, Andersen Syndrome, Leber Congenital Amaurosis 16drome, ataxia, Parkinson's disease

Interaction:
Associates with K_ir3.2 (GIRK2), K_ir3.3 (GIRK3), K_ir3.4 (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