Potassium inwardly rectifying channel subfamily J member 4 (KCNJ4) (KCNJ4)

Potassium inwardly rectifying channel subfamily J member 4 (KCNJ4), also known as Kir2.3, is an integral membrane protein that forms a channel allowing potassium ions to flow into the cell more easily than out, thereby playing a fundamental role in maintaining the resting membrane potential [UniProt P48050]. It is widely expressed in the human body, with high levels found in the heart, brain, and skeletal muscle, where it regulates cellular excitability and the duration of action potentials [NCBI Gene 3761]. In the heart, Kir2.3 is a key component of the inward rectifier current (IK1), and its dysregulation is closely linked to the pathogenesis of atrial fibrillation and other cardiac arrhythmias [PubMed 15618241]. Within the central nervous system, the channel is often localized to the postsynaptic density of excitatory synapses, where it interacts with PDZ-domain proteins to influence synaptic transmission and neuronal firing [PubMed 10433264]. While many existing drugs that interact with Kir2.3, such as quinidine and chloroquine, are non-selective, the channel remains a significant target for the development of novel anti-arrhythmic and neuroprotective therapies [PubMed 11830606]. Understanding the structural and functional nuances of Kir2.3 is essential for designing drugs that can precisely modulate its activity without causing adverse off-target effects on related potassium channels.

Other names

Kir2.3IRK3HIRK2HRK1Inward rectifier K(+) channel Kir2.3

Inhibition of the inward rectifier potassium current (IK1) to modulate membrane potential and cellular excitability.