High-throughput fluorometric assay for membrane–protein interaction

Abstract

Membrane–protein interaction plays key roles in a wide variety of biological processes. To facilitate rapid and sensitive measurement of membrane binding of soluble proteins, we developed a fluorescence- based quantitative assay that is universally applicable to all proteins. This fluorescence-quenching assay employs fluorescence protein (FP)-tagged proteins whose fluorescence intensity is greatly decreased when they bind vesicles containing synthetic lipid dark quenchers, such as N-dimethylaminoazobenzenesulfonylphosphatidylethanolamine (dabsyl-PE). This simple assay can be performed with either a spectrofluorometer or a plate reader and optimized for different proteins with various combinations of FPs and quenching lipids. The assay allows rapid, sensitive, and accurate determination of lipid specificity and affinity for various lipid binding domains and proteins, and also highthroughput screening of small molecules that modulate membrane binding of proteins.