Combined localization and real-time functional studies using a GFP-tagged ABCG2 multidrug transporter

Area of Science:

• Molecular Biology
• Cell Biology
• Pharmacology

Background:

• ATP-binding cassette sub-family G member 2 (ABCG2) is a half-transporter implicated in multidrug resistance in cancer cells.
• Current methods for studying ABCG2 function and localization are often complex and require extensive cell manipulation.
• Development of advanced assays is crucial for understanding ABCG2-mediated drug resistance and for drug discovery.

Purpose of the Study:

• To develop a novel, direct method for monitoring ABCG2 expression, dimerization, localization, and function in living cells.
• To validate the functionality of an N-terminally GFP-tagged ABCG2 construct (GFP-G2) for cellular studies.
• To establish a real-time transport assay for identifying ABCG2 substrates and modulators.

Main Methods:

• Generation and characterization of an N-terminally GFP-tagged ABCG2 protein (GFP-G2).
• Assessment of GFP-G2 functionality using drug-stimulated ATPase activity, vesicular transport assays, and subcellular localization studies.
• Real-time monitoring of ABCG2 transport activity in HEK-293 cells by measuring GFP fluorescence and Hoechst 33342 dye uptake.

Main Results:

• The GFP-G2 construct is fully functional and accurately reflects ABCG2 expression, localization, and conformational changes in living cells.
• Drug-stimulated ATPase activity and transport assays confirmed the functional integrity of GFP-G2.
• The real-time assay successfully identified ABCG2 substrates and modulators, demonstrating its utility for functional studies.

Conclusions:

• N-terminally GFP-tagged ABCG2 (GFP-G2) provides a robust tool for direct, real-time monitoring of ABCG2 in living cells.
• This approach simplifies the study of ABCG2 cellular functions, substrate identification, and drug modulation.
• The developed assay eliminates the need for cloning, drug selection, or further cell characterization, streamlining research.