Potassium voltage-gated channel subfamily D member 3 (Kv4.3) and Potassium channel-interacting protein 2 (KChIP2) isoform 2 complex (Kv4.3/KChIP2.2)

The hKv4.3/hKChIP2.2 complex is a heteromultimeric voltage-gated potassium channel composed of the pore-forming alpha subunit Kv4.3 (encoded by the KCND3 gene) and the auxiliary beta subunit KChIP2 (encoded by the KCNIP2 gene) (UniProt: P51792, Q9NS61). This complex is the primary mediator of the fast transient outward potassium current (Ito,f) in the human heart, which is essential for the early phase 1 repolarization of the cardiac action potential (PubMed: 10661423). In the brain, it contributes to the A-type current that regulates neuronal excitability and dendritic signal integration (PubMed: 15659596). Mutations in the components of this complex are linked to various cardiac pathologies, including Brugada syndrome, atrial fibrillation, and heart failure, as well as neurological disorders like spinocerebellar ataxia type 19/22 (PubMed: 22431011, 24613443). Pharmacological agents such as flecainide and quinidine interact with this complex to modulate cardiac rhythm, while experimental activators like NS5806 are being studied for their potential to restore channel function in disease states (PubMed: 18337515). Because of its distinct role in cardiac electrophysiology, the hKv4.3/hKChIP2.2 complex is a significant target for anti-arrhythmic drug development and safety pharmacology screening.

Other names

KCND3/KCNIP2 complexIto channelhKv4.3/hKChIP2.2Voltage-gated potassium channel subunit Kv4.3 and KChIP2

Inhibition of the transient outward potassium current (Ito) through pore blockade or modulation of channel gating and trafficking kinetics (PubMed: 11159276, 18337515).