Multiple Modes of A-Type Potassium Current Regulation

Shi-Qing Cai, Wenchao Li, Federico Sesti
2007 Current pharmaceutical design  
Voltage-dependent potassium (K + ) channels (Kv) regulate cell excitability by controlling the movement of K + ions across the membrane in response to changes in the cell voltage. The Kv family, which includes A-type channels, constitute the largest group of K + channel genes within the superfamily of Na + , Ca 2+ and K + voltage-gated channels. The name "A-type" stems from the typical profile of these currents that results form the opposing effects of fast activation and inactivation. In
more » ... al cells, A-type currents (IA), determine the interval between two consecutive action potentials during repetitive firing. In cardiac muscle, A-type currents (Ito), control the initial repolarization of the myocardium. Structurally, A-type channels are tetramers of -subunits each containing six putative transmembrane domains including a voltage-sensor. A-type channels can be modulated by means of protein-protein interactions with so-called -subunits that control inactivation voltage sensitivity and other properties, and by post-transcriptional modifications such as phosphorylation or oxidation. Recently a new mode of A-type regulation has been discovered in the form of a class of hybrid -subunits that posses their own enzymatic activity. Here, we review the biophysical and physiological properties of these multiple modes of A-type channel regulation.
doi:10.2174/138161207782341286 pmid:18045167 fatcat:z5zrm7623zfhpmb7ztawws6k44