Dofetilide, hERG K+ channel blocker

Supplementary information

This supplementary information is collated from multiple sources and compiled automatically.

The human ether-à-go-go-related gene (hERG) encodes a protein known as Kv11.1 which is a voltage-gated potassium channel. This channel plays an important mechanical role in cardiac repolarization by facilitating the movement of potassium ions out of cardiomyocytes. Kv11.1 consists of a tetrameric assembly of six transmembrane segments contributing to its function as a channel. hERG's expression is high in cardiac tissue but also found in the nervous system and other tissues. The molecular weight of the Kv11.1 protein is approximately 137 kDa. Common hERG channel blockers include compounds like dofetilide and bedaquiline which are significant for studies of drug interactions.

Biological function summary

The proper functioning of Kv11.1 channels is essential in maintaining the electrical stability of cardiac cells. Kv11.1 is an integral part of the cardiac action potential complex contributing heavily to the IKr (rapid component of the delayed rectifier potassium current) in the heart. Its function aids in the prevention of arrhythmias by ensuring timely repolarization. The channel also appears in specific non-cardiac cells influencing cellular excitability and signaling but to lesser extents. hERG's role in the physiology of these cells highlights its involvement in maintaining normal cell electrophysiology.

Pathways

Kv11.1's function plays a central role in electrophysiological pathways that influence cardiac action potential duration and repolarization. One important pathway is the cardiac conduction system where the hERG channels modulate the cardiac cycle alongside other channels like beta 1 and beta 2 adrenergic receptors. These pathways are intertwined with cellular functions and control heart rate and rhythm demonstrating hERG's critical contribution to heart physiology. Any dysfunction in this pathway can lead to severe cardiac conditions.

The dysfunction of hERG channels can result in severe cardiac conditions like Long QT Syndrome and Torsades de Pointes. These disorders arise from prolonged cardiac repolarization which can trigger life-threatening arrhythmias. Analogs such as fluphenazine and dofetilide interact with hERG providing therapeutic applications and potential side effects relating to cardiac health. Alterations in hERG's function therefore require careful modulation to prevent detrimental effects on cardiac activity. The understanding of hERG-related pathophysiology connects it to broader themes in cardiology and pharmacology.