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Bian T, Autry JM, Casemore D, Li J, Thomas DD, He G, Xing C. Direct detection of SERCA calcium transport and small-molecule inhibition in giant unilamellar vesicles. Biochem Biophys Res Commun 2016; 481:206-211. [PMID: 27815070 DOI: 10.1016/j.bbrc.2016.10.096] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 10/12/2016] [Indexed: 10/20/2022]
Abstract
We have developed a charge-mediated fusion method to reconstitute the sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) in giant unilamellar vesicles (GUV). Intracellular Ca2+ transport by SERCA controls key processes in human cells such as proliferation, signaling, and contraction. Small-molecule effectors of SERCA are urgently needed as therapeutics for Ca2+ dysregulation in human diseases including cancer, diabetes, and heart failure. Here we report the development of a method for efficiently reconstituting SERCA in GUV, and we describe a streamlined protocol based on optimized parameters (e.g., lipid components, SERCA preparation, and activity assay requirements). ATP-dependent Ca2+ transport by SERCA in single GUV was detected directly using confocal fluorescence microscopy with the Ca2+ indicator Fluo-5F. The GUV reconstitution system was validated for functional screening of Ca2+ transport using thapsigargin (TG), a small-molecule inhibitor of SERCA currently in clinical trials as a prostate cancer prodrug. The GUV system overcomes the problem of inhibitory Ca2+ accumulation for SERCA in native and reconstituted small unilamellar vesicles (SUV). We propose that charge-mediated fusion provides a widely-applicable method for GUV reconstitution of clinically-important membrane transport proteins. We conclude that GUV reconstitution is a technological advancement for evaluating small-molecule effectors of SERCA.
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Affiliation(s)
- Tengfei Bian
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, 2231 6th St SE, Minneapolis, MN 55455, United States; State Key Laboratory of Fine Chemicals, R&D Center of Membrane Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Joseph M Autry
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 321 Church St SE, Minneapolis, MN 55455, United States; Biophysical Technology Center, Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 321 Church St SE, Minneapolis, MN 55455, United States
| | - Denise Casemore
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, 2231 6th St SE, Minneapolis, MN 55455, United States
| | - Ji Li
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 321 Church St SE, Minneapolis, MN 55455, United States; Biophysical Technology Center, Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 321 Church St SE, Minneapolis, MN 55455, United States
| | - David D Thomas
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 321 Church St SE, Minneapolis, MN 55455, United States
| | - Gaohong He
- State Key Laboratory of Fine Chemicals, R&D Center of Membrane Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Chengguo Xing
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, 2231 6th St SE, Minneapolis, MN 55455, United States.
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