Quantifying membrane permeability of amphotericin B ion channels in single living cells

Tzu Sen Yang, Keng Liang Ou, Pei Wen Peng, Bing Chun Liou, Wei Ting Wang, Yuan Chen Huang, Chung Min Tsai, Ching-Hua Su

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Recently, the structure-function relationships between amphotericin B (AmB) and ergosterol have been solved using synthetic techniques that require a mycosamine-mediated direct binding interaction between AmB and ergosterol to form AmB ion channels. However, studies to directly probe the AmB-induced membrane permeability changes have not been conducted. In the present work, we investigate the following fundamental question: does AmB induce concentration- and time-dependent permeability changes across ergosterol-containing membranes? Herein, we employ fluorescent dyes of known average diameter to quantify the diameters of AmB ion channels. In addition, we take a single-particle tracking approach to define the intracellular microrheology in the absence and presence of AmB ion channels. Present results show that increasing AmB concentration tends to increase the preferential accumulation of AmB ion channels in the presence of the excess membrane-embedded ergosterol. We found that AmB induces time-dependent membrane permeability; increases approaching 50% in both the velocity fluctuations and diffusion coefficients of vesicles occur on the same time scale as the efflux of potassium ions (≅ 30 min). Furthermore, we propose a two-dimensional, semi-regular tessellation model to geometrically assess the pore size of the AmB ion channels in response to the AmB dose. This approach offers one possibility for the design of AmB ion channels with tunable aqueous pore size, which could provide an opportunity to replace damaged membrane water channels of the aquaporin family in future applications.

Original languageEnglish
Pages (from-to)1794-1801
Number of pages8
JournalBiochimica et Biophysica Acta - Biomembranes
Volume1828
Issue number8
DOIs
Publication statusPublished - 2013

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Keywords

  • Amphotericin B
  • Amphotericin B ion channel
  • Intracellular microrheology
  • Membrane permeability
  • Taiwanofungus camphorates

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Biophysics

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