In vitro Assay to Evaluate Cation Transport of Ionophores

Huriye D Uzun; Melissa Vázquez-Hernández; Julia E Bandow; Thomas Günther Pomorski

doi:10.21769/BioProtoc.4552

In vitro Assay to Evaluate Cation Transport of Ionophores

Bio Protoc. 2022 Nov 20;12(22):e4552. doi: 10.21769/BioProtoc.4552.

Authors

Huriye D Uzun^{1

2}, Melissa Vázquez-Hernández³, Julia E Bandow³, Thomas Günther Pomorski^{1

2}

Affiliations

¹ Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany.
² Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark.
³ Applied Microbiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany.

Abstract

Ion homeostasis is a fundamental regulator of cellular processes and depends upon lipid membranes, which function as ion permeability barriers. Ionophores facilitate ion transport across cell membranes and offer a way to manipulate cellular ion composition. Here, we describe a calcein quenching assay based on large unilamellar vesicles that we used to evaluate divalent cation transport of the ionophore 4-Br-A23187. This assay can be used to study metal transport by ionophores and membrane proteins, under well-defined conditions. This protocol was validated in: Proteomics (2022), DOI: 10.1002/pmic.202200061 Graphical abstract.

Keywords: Calcein; Cobalt; Copper; Fluorescence quenching; Large unilamellar vesicles.