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Updated: May 16, 2026

Characterization of Membrane Transporters by Heterologous Expression in E. coli and Production of Membrane Vesicles
Published on: December 31, 2019
Membrane vesicle ABC transporter assays for drug safety assessment
Carlo J van Staden1, Ryan E Morgan, Bharath Ramachandran
1Amgen, Inc., Thousand Oaks, California, USA.
Abstract:
The use of plasma membrane vesicles that overexpress the bile salt export pump (BSEP) or multidrug resistance-associated protein 2, 3, or 4 (MRP2-4) with an in vitro vacuum filtration system offers a rapid and reliable means for screening drug candidates for their effects on transporter function in hepatocytes and thus their potential for causing drug-induced liver injury (DILI). Comparison of transporter activity in the presence and absence of ATP allows for determination of a specific assay window for each transporter. This window is used to determine the degree to which each test compound inhibits transporter activity. This assay battery is helpful for prioritizing and rank-ordering compounds within a chemical series with respect to each other and in the context of known inhibitors of transporter activity and/or liver injury. This model can be used to influence the drug development process at an early stage and provide rapid feedback regarding the selection of compounds for advancement to in vivo safety evaluations. A detailed protocol for the high-throughput assessment of ABC transporter function is provided, including specific recommendations for curve-fitting to help ensure consistent results.
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