β1-subunit-induced structural rearrangements of the Ca2+- and voltage-activated K+ (BK) channel

Proc Natl Acad Sci U S A. 2016 Jun 7;113(23):E3231-9. doi: 10.1073/pnas.1606381113. Epub 2016 May 23.

Abstract

Large-conductance Ca(2+)- and voltage-activated K(+) (BK) channels are involved in a large variety of physiological processes. Regulatory β-subunits are one of the mechanisms responsible for creating BK channel diversity fundamental to the adequate function of many tissues. However, little is known about the structure of its voltage sensor domain. Here, we present the external architectural details of BK channels using lanthanide-based resonance energy transfer (LRET). We used a genetically encoded lanthanide-binding tag (LBT) to bind terbium as a LRET donor and a fluorophore-labeled iberiotoxin as the LRET acceptor for measurements of distances within the BK channel structure in a living cell. By introducing LBTs in the extracellular region of the α- or β1-subunit, we determined (i) a basic extracellular map of the BK channel, (ii) β1-subunit-induced rearrangements of the voltage sensor in α-subunits, and (iii) the relative position of the β1-subunit within the α/β1-subunit complex.

Keywords: BK channels; lanthanide resonance energy transfer; β1-subunit.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Energy Transfer
  • Female
  • Large-Conductance Calcium-Activated Potassium Channel alpha Subunits / chemistry
  • Large-Conductance Calcium-Activated Potassium Channel alpha Subunits / genetics
  • Large-Conductance Calcium-Activated Potassium Channel alpha Subunits / physiology
  • Large-Conductance Calcium-Activated Potassium Channel beta Subunits / chemistry*
  • Large-Conductance Calcium-Activated Potassium Channel beta Subunits / genetics
  • Large-Conductance Calcium-Activated Potassium Channel beta Subunits / physiology
  • Models, Molecular
  • Oocytes
  • Protein Conformation
  • Protein Domains
  • Xenopus laevis

Substances

  • Large-Conductance Calcium-Activated Potassium Channel alpha Subunits
  • Large-Conductance Calcium-Activated Potassium Channel beta Subunits