Optical waveguide lightmode spectroscopic techniques for investigating membrane-bound ion channel activities

PLoS One. 2013 Dec 10;8(12):e81398. doi: 10.1371/journal.pone.0081398. eCollection 2013.

Abstract

Optical waveguide lightmode spectroscopic (OWLS) techniques were probed for monitoring ion permeation through channels incorporated into artificial lipid environment. A novel sensor set-up was developed by depositing liposomes or cell-derived membrane fragments onto hydrophilic polytetrafluoroethylene (PTFE) membrane. The fibrous material of PTFE membrane could entrap lipoid vesicles and the water-filled pores provided environment for the hydrophilic domains of lipid-embedded proteins. The sensor surface was kept clean from the lipid holder PTFE membrane by a water- and ion-permeable polyethylene terephthalate (PET) mesh. The sensor set-up was tested with egg yolk lecithin liposomes containing gramicidin ion channels and with cell-derived membrane fragments enriched in GABA-gated anion channels. The method allowed monitoring the move of Na(+) and organic cations through gramicidin channels and detecting the Cl(-)-channel functions of the (α5β2γ2) GABAA receptor in the presence or absence of GABA and the competitive GABA-blocker bicuculline.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Membrane / metabolism*
  • Gramicidin / metabolism
  • HEK293 Cells
  • Humans
  • Ion Channels / metabolism*
  • Lasers*
  • Liposomes / metabolism
  • Movement
  • Optical Devices*
  • Protein Binding
  • Receptors, GABA-A / metabolism

Substances

  • Ion Channels
  • Liposomes
  • Receptors, GABA-A
  • Gramicidin

Grants and funding

This work was supported by the EU FP7 ASMENA Project (Grant No.: CP-FP-214666-2) and the grant of Hungarian Scientific Research Fund (OTKA K 106191). N.K. and P.G. were partially supported by TÁMOP-4.2.1/B-09/1/KMR-2010-0001 and OMFB-00380/2007. The funders (EU FP7 ASMENA Project, Hungarian Scientific Research Fund (OTKA), TÁMOP-4.2.1/B-09 and OMFB-00380) had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.