Format

Send to

Choose Destination
Proc Natl Acad Sci U S A. 2010 Nov 2;107(44):18862-7. doi: 10.1073/pnas.1010354107. Epub 2010 Oct 20.

Stoichiometry of the KCNQ1 - KCNE1 ion channel complex.

Author information

1
Division of Biophysics and Neurobiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan.

Abstract

The KCNQ1 voltage-gated potassium channel and its auxiliary subunit KCNE1 play a crucial role in the regulation of the heartbeat. The stoichiometry of KCNQ1 and KCNE1 complex has been debated, with some results suggesting that the four KCNQ1 subunits that form the channel associate with two KCNE1 subunits (a 42 stoichiometry), while others have suggested that the stoichiometry may not be fixed. We applied a single molecule fluorescence bleaching method to count subunits in many individual complexes and found that the stoichiometry of the KCNQ1 - KCNE1 complex is flexible, with up to four KCNE1 subunits associating with the four KCNQ1 subunits of the channel (a 44 stoichiometry). The proportion of the various stoichiometries was found to depend on the relative expression densities of KCNQ1 and KCNE1. Strikingly, both the voltage-dependence and kinetics of gating were found to depend on the relative densities of KCNQ1 and KCNE1, suggesting the heart rhythm may be regulated by the relative expression of the auxiliary subunit and the resulting stoichiometry of the channel complex.

Comment in

PMID:
20962273
PMCID:
PMC2973890
DOI:
10.1073/pnas.1010354107
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center