Referenced in: none

Automatically associated channels: Kv1.2 , Kv1.4 , Kv1.5 , Kv11.1 , Kv3.1 , Kv4.3 , Kv7.1

Title: Endocytic regulation of voltage-dependent potassium channels in the heart.

Authors: Kuniaki Ishii, Ikuo Norota, Yutaro Obara

Journal, date & volume: J. Pharmacol. Sci., 2012 Dec 18 , 120, 264-9

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/23165803

Abstract
Understanding the regulation of cardiac ion channels is critical for the prevention of arrhythmia caused by abnormal excitability. Ion channels can be regulated by a change in function (qualitative) and a change in number (quantitative). Functional changes have been extensively investigated for many ion channels including cardiac voltage-dependent potassium channels. By contrast, the regulation of ion channel numbers has not been widely examined, particularly with respect to acute modulation of ion channels. This article briefly summarizes stimulus-induced endocytic regulation of major voltage-dependent potassium channels in the heart. The stimuli known to cause their endocytosis include receptor activation, drugs, and low extracellular [K(+)], following which the potassium channels undergo either clathrin-mediated or caveolin-mediated endocytosis. Receptor-mediated endocytic regulation has been demonstrated for Kv1.2, Kv1.5, KCNQ1 (Kv7.1), and Kv4.3, while drug-induced endocytosis has been demonstrated for Kv1.5 and hERG. Low [K(+)](o)-induced endocytosis might be unique for hERG channels, whose electrophysiological characteristics are known to be under strong influence of [K(+)](o). Although the precise mechanisms have not been elucidated, it is obvious that major cardiac voltage-dependent potassium channels are modulated by endocytosis, which leads to changes in cardiac excitability.