Referenced in: none

Automatically associated channels: Kv11.1

Title: Cardiac IKr channels minimally comprise hERG 1a and 1b subunits.

Authors: Eugenia M C Jones, Elon C Roti Roti, Jinling Wang, Samantha A Delfosse, Gail A Robertson

Journal, date & volume: J. Biol. Chem., 2004 Oct 22 , 279, 44690-4

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/15304481

Abstract
Previous studies suggest native cardiac IKr channels are composed of alpha subunits encoded solely by the 1a transcript of the ERG1 gene. Using isoform-specific ERG1 antibodies, we have new evidence that subunits encoded by an alternate transcript, ERG1b, are also expressed in rat, canine, and human heart. The ERG1a and -1b subunits associate in vivo where they localize to the T tubules of ventricular myocytes. These data indicate native ventricular IKr channels are heteromers containing two alpha subunit types, ERG1a and -1b. The hERG1b-specific exon thus represents a novel target to screen for mutations causing type 2 long QT syndrome. These findings also suggest phenotypic analyses of existing type 2 long QT syndrome mutations, especially those exclusive to the hERG1a amino terminus, should be carried out in systems expressing both subunits.