Monitoring Structural Reorganization of Calmodulin in Complex with the C-Terminus of KCNQ Channels

  1. Gomis-Perez, Carolina
  2. Nunez-Viadero, Eider 1
  3. Bernardo-Seisdedos, Ganeko
  4. Malo, Covadonga
  5. Areso, Pilar 1
  6. Villarroel, Alvaro 1
  1. 1 Universidad del País Vasco/Euskal Herriko Unibertsitatea
    info

    Universidad del País Vasco/Euskal Herriko Unibertsitatea

    Lejona, España

    ROR https://ror.org/000xsnr85

Journal:
Biophysical Journal

ISSN: 0006-3495

Year of publication: 2017

Volume: 112

Issue: 3

Pages: 109a

Type: Article

DOI: 10.1016/J.BPJ.2016.11.620 GOOGLE SCHOLAR lock_openOpen access editor

More publications in: Biophysical Journal

Abstract

Calmodulin (CaM) is an essential component of the non-inactivating voltage-dependent potassium channels conformed by Kv7 subunits, and mediates current suppression upon intracellular calcium elevation. Despite recent atomic-level information on CaM complexed to Kv7 domains, the structural consequences upon calcium binding remains elusive. To obtain insights on the structural changes caused by calcium, we have monitored FRET between the AB module tagged with the blue protein mTFP1 and CaM tagged with the yellow protein Venus using purified recombinant proteins. In addition, FRET has been monitored in CaM/AB complexes in which the AB module was tagged with both fluorescent proteins. Significant changes in energy transfer were observed in the presence of calcium, being more prominent for Kv7.1 than for Kv7.2 subunits. Thus, these data suggest that calcium causes structural changes to different extent on each Kv7 isoform.