Current Pharmaceutical Design

William A. Banks  
Building 1, Room 810A
1600 S. Columbian Way
Seattle, WA 98108


Multiple Modes of A-Type Potassium Current Regulation

Author(s): Shi-Qing Cai, Wenchao Li, Federico Sesti.


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 (Ito), control the initial repolarization of the myocardium. Structurally, A-type channels are tetramers of α-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 β-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 β-subunits that posses their own enzymatic activity. Here, we review the biophysical and physiological properties of these multiple modes of A-type channel regulation.

Keywords: NADP binding pocket, KChIPs, KCNE genes, peptidase-like proteins, enzymatic modulation

Order Reprints Order Eprints Rights & PermissionsPrintExport

Article Details

Year: 2007
Page: [3178 - 3184]
Pages: 7
DOI: 10.2174/138161207782341286
Price: $58