Physiological properties of hERG 1a/1b heteromeric currents and a hERG 1b-specific mutation associated with Long-QT syndrome.

ABSTRACT: Cardiac I Kr is a critical repolarizing current in the heart and a target for inherited and acquired long-QT syndrome (LQTS). Biochemical and functional studies have demonstrated that I Kr channels are heteromers composed of both hERG 1a and 1b subunits, yet our current understanding of I Kr functional properties derives primarily from studies of homooligomers of the original hERG 1a isolate. Here, we examine currents produced by hERG 1a and 1a/1b channels expressed in HEK-293 cells at near-physiological temperatures. We find that heteromeric hERG 1a/1b currents are much larger than hERG 1a currents and conduct 80% more charge during an action potential. This surprising difference corresponds to a 2-fold increase in the apparent rates of activation and recovery from inactivation, thus redu

SUBMITTER: Sale H 

PROVIDER: S-EPMC2761010 | biostudies-literature | 2008 Sep

REPOSITORIES: biostudies-literature