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Characterization of MC4R Regulation of the Kir7.1 Channel Using the Tl+ Flux Assay

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Potassium Channels

Part of the book series: Methods in Molecular Biology ((MIMB,volume 1684))

Abstract

The family of inward rectifying potassium channels (Kir channels) plays crucial roles in the regulation of heart rhythms, renal excretion, insulin release, and neuronal activity. Their dysfunction has been attributed to numerous diseases such as cardiac arrhythmia, kidney failure and electrolyte imbalance, diabetes mellitus, epilepsy, retinal degeneration, and other neuronal disorders. We have recently demonstrated that the melanocortin-4 receptor (MC4R), a Gαs-coupled GPCR, regulates Kir7.1 activity through a mechanism independent of Gαs and cAMP. In contrast to the many other members of the Kir channel family, less is known about the biophysical properties, regulation, and physiological functions of Kir7.1. In addition to using conventional patch clamp techniques, we have employed a high-throughput Tl+ flux assay to further investigate the kinetics of MC4R-Kir7.1 signaling in vitro. Here, we discuss the employment of the Tl+ flux assay to study MC4R -mediated regulation of Kir7.1 activity and to screen compounds for drug discovery.

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Acknowledgments

We thank Dr. Jerod Denton for providing DNA plasmids, compounds, as well as cell lines throughout this project. This work was funded by T32 GM07347, F30DK108476, and RO1DK070332.

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Authors and Affiliations

  1. Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN, 37232, USA

    Michael J. Litt & Masoud Ghamari-Langroudi

  2. Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI, 48109, USA

    Roger D. Cone

Authors
  1. Michael J. Litt
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  2. Roger D. Cone
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  3. Masoud Ghamari-Langroudi
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Corresponding author

Correspondence to Masoud Ghamari-Langroudi .

Editor information

Editors and Affiliations

  1. Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon, USA

    Show-Ling Shyng

  2. Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon, USA

    Francis I. Valiyaveetil

  3. The Vollum Institute, Oregon Health and Science University, Portland, Oregon, USA

    Matt Whorton

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Litt, M.J., Cone, R.D., Ghamari-Langroudi, M. (2018). Characterization of MC4R Regulation of the Kir7.1 Channel Using the Tl+ Flux Assay. In: Shyng, SL., Valiyaveetil, F., Whorton, M. (eds) Potassium Channels. Methods in Molecular Biology, vol 1684. Humana Press, New York, NY. https://doi.org/10.1007/978-1-4939-7362-0_16

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  • DOI: https://doi.org/10.1007/978-1-4939-7362-0_16

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  • Publisher Name: Humana Press, New York, NY

  • Print ISBN: 978-1-4939-7361-3

  • Online ISBN: 978-1-4939-7362-0

  • eBook Packages: Springer Protocols

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