Fluorescence Fluctuation Spectroscopy enables quantification of potassium channel subunit dynamics and stoichiometry

Abstract Voltage-gated potassium (Kv) channels are a family of membrane proteins that facilitate K+ ion diffusion across the plasma membrane, regulating both resting and action potentials. Kv channels comprise four pore-forming α subunits, each with a voltage sensing domain, and they are regulated b...

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Autores principales:	Giulia Tedeschi, Lorenzo Scipioni, Maria Papanikolaou, Geoffrey W. Abbott, Michelle A. Digman
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/61bfca97e07e488baa0efdbdd7d5c962
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spelling	oai:doaj.org-article:61bfca97e07e488baa0efdbdd7d5c9622021-12-02T15:45:21ZFluorescence Fluctuation Spectroscopy enables quantification of potassium channel subunit dynamics and stoichiometry10.1038/s41598-021-90002-22045-2322https://doaj.org/article/61bfca97e07e488baa0efdbdd7d5c9622021-05-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-90002-2https://doaj.org/toc/2045-2322Abstract Voltage-gated potassium (Kv) channels are a family of membrane proteins that facilitate K+ ion diffusion across the plasma membrane, regulating both resting and action potentials. Kv channels comprise four pore-forming α subunits, each with a voltage sensing domain, and they are regulated by interaction with β subunits such as those belonging to the KCNE family. Here we conducted a comprehensive biophysical characterization of stoichiometry and protein diffusion across the plasma membrane of the epithelial KCNQ1-KCNE2 complex, combining total internal reflection fluorescence (TIRF) microscopy and a series of complementary Fluorescence Fluctuation Spectroscopy (FFS) techniques. Using this approach, we found that KCNQ1-KCNE2 has a predominant 4:4 stoichiometry, while non-bound KCNE2 subunits are mostly present as dimers in the plasma membrane. At the same time, we identified unique spatio-temporal diffusion modalities and nano-environment organization for each channel subunit. These findings improve our understanding of KCNQ1-KCNE2 channel function and suggest strategies for elucidating the subunit stoichiometry and forces directing localization and diffusion of ion channel complexes in general.Giulia TedeschiLorenzo ScipioniMaria PapanikolaouGeoffrey W. AbbottMichelle A. DigmanNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-15 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Giulia Tedeschi Lorenzo Scipioni Maria Papanikolaou Geoffrey W. Abbott Michelle A. Digman Fluorescence Fluctuation Spectroscopy enables quantification of potassium channel subunit dynamics and stoichiometry
description	Abstract Voltage-gated potassium (Kv) channels are a family of membrane proteins that facilitate K+ ion diffusion across the plasma membrane, regulating both resting and action potentials. Kv channels comprise four pore-forming α subunits, each with a voltage sensing domain, and they are regulated by interaction with β subunits such as those belonging to the KCNE family. Here we conducted a comprehensive biophysical characterization of stoichiometry and protein diffusion across the plasma membrane of the epithelial KCNQ1-KCNE2 complex, combining total internal reflection fluorescence (TIRF) microscopy and a series of complementary Fluorescence Fluctuation Spectroscopy (FFS) techniques. Using this approach, we found that KCNQ1-KCNE2 has a predominant 4:4 stoichiometry, while non-bound KCNE2 subunits are mostly present as dimers in the plasma membrane. At the same time, we identified unique spatio-temporal diffusion modalities and nano-environment organization for each channel subunit. These findings improve our understanding of KCNQ1-KCNE2 channel function and suggest strategies for elucidating the subunit stoichiometry and forces directing localization and diffusion of ion channel complexes in general.
format	article
author	Giulia Tedeschi Lorenzo Scipioni Maria Papanikolaou Geoffrey W. Abbott Michelle A. Digman
author_facet	Giulia Tedeschi Lorenzo Scipioni Maria Papanikolaou Geoffrey W. Abbott Michelle A. Digman
author_sort	Giulia Tedeschi
title	Fluorescence Fluctuation Spectroscopy enables quantification of potassium channel subunit dynamics and stoichiometry
title_short	Fluorescence Fluctuation Spectroscopy enables quantification of potassium channel subunit dynamics and stoichiometry
title_full	Fluorescence Fluctuation Spectroscopy enables quantification of potassium channel subunit dynamics and stoichiometry
title_fullStr	Fluorescence Fluctuation Spectroscopy enables quantification of potassium channel subunit dynamics and stoichiometry
title_full_unstemmed	Fluorescence Fluctuation Spectroscopy enables quantification of potassium channel subunit dynamics and stoichiometry
title_sort	fluorescence fluctuation spectroscopy enables quantification of potassium channel subunit dynamics and stoichiometry
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/61bfca97e07e488baa0efdbdd7d5c962
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_version_	1718385753211273216

Fluorescence Fluctuation Spectroscopy enables quantification of potassium channel subunit dynamics and stoichiometry

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