Multiple modes of A-type potassium current regulation

作者：Cai Shi Qing; Li Wenchao; Sesti Federico^*

来源：Current Pharmaceutical Design, 2007, 13(31): 3178-3184.

DOI：10.2174/138161207782341286

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+, Ca2+ 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 neuronal cells, A-type currents ( IA), determine the interval between two consecutive action potentials during repetitive firing. In cardiac muscle, A-type currents (I-to), control the initial repolarization of the myocardium. Structurally, A-type channels are tetramers of alpha-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 beta-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 beta-subunits that posses their own enzymatic activity. Here, we review the biophysical and physiological properties of these multiple modes of A-type channel regulation.

• 出版日期2007