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Ion channels can be allosterically regulated by membrane domains near a de-mixing critical point

Ion channels are embedded in the plasma membrane, a compositionally diverse two-dimensional liquid that has the potential to exert profound influence on their function. Recent experiments suggest that this membrane is poised close to an Ising critical point, below which cell-derived plasma membrane...

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Detalles Bibliográficos
Autores principales: Kimchi, Ofer, Veatch, Sarah L., Machta, Benjamin B.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Rockefeller University Press 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6279359/
https://www.ncbi.nlm.nih.gov/pubmed/30455180
http://dx.doi.org/10.1085/jgp.201711900
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author Kimchi, Ofer
Veatch, Sarah L.
Machta, Benjamin B.
author_facet Kimchi, Ofer
Veatch, Sarah L.
Machta, Benjamin B.
author_sort Kimchi, Ofer
collection PubMed
description Ion channels are embedded in the plasma membrane, a compositionally diverse two-dimensional liquid that has the potential to exert profound influence on their function. Recent experiments suggest that this membrane is poised close to an Ising critical point, below which cell-derived plasma membrane vesicles phase separate into coexisting liquid phases. Related critical points have long been the focus of study in simplified physical systems, but their potential roles in biological function have been underexplored. Here we apply both exact and stochastic techniques to the lattice Ising model to study several ramifications of proximity to criticality for idealized lattice channels, whose function is coupled through boundary interactions to critical fluctuations of membrane composition. Because of diverging susceptibilities of system properties to thermodynamic parameters near a critical point, such a lattice channel’s activity becomes strongly influenced by perturbations that affect the critical temperature of the underlying Ising model. In addition, its kinetics acquire a range of time scales from its surrounding membrane, naturally leading to non-Markovian dynamics. Our model may help to unify existing experimental results relating the effects of small-molecule perturbations on membrane properties and ion channel function. We also suggest ways in which the role of this mechanism in regulating real ion channels and other membrane-bound proteins could be tested in the future.
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spelling pubmed-62793592019-06-03 Ion channels can be allosterically regulated by membrane domains near a de-mixing critical point Kimchi, Ofer Veatch, Sarah L. Machta, Benjamin B. J Gen Physiol Research Articles Ion channels are embedded in the plasma membrane, a compositionally diverse two-dimensional liquid that has the potential to exert profound influence on their function. Recent experiments suggest that this membrane is poised close to an Ising critical point, below which cell-derived plasma membrane vesicles phase separate into coexisting liquid phases. Related critical points have long been the focus of study in simplified physical systems, but their potential roles in biological function have been underexplored. Here we apply both exact and stochastic techniques to the lattice Ising model to study several ramifications of proximity to criticality for idealized lattice channels, whose function is coupled through boundary interactions to critical fluctuations of membrane composition. Because of diverging susceptibilities of system properties to thermodynamic parameters near a critical point, such a lattice channel’s activity becomes strongly influenced by perturbations that affect the critical temperature of the underlying Ising model. In addition, its kinetics acquire a range of time scales from its surrounding membrane, naturally leading to non-Markovian dynamics. Our model may help to unify existing experimental results relating the effects of small-molecule perturbations on membrane properties and ion channel function. We also suggest ways in which the role of this mechanism in regulating real ion channels and other membrane-bound proteins could be tested in the future. Rockefeller University Press 2018-12-03 /pmc/articles/PMC6279359/ /pubmed/30455180 http://dx.doi.org/10.1085/jgp.201711900 Text en © 2018 Kimchi et al. http://www.rupress.org/terms/https://creativecommons.org/licenses/by-nc-sa/4.0/This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms/). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 International license, as described at https://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Research Articles
Kimchi, Ofer
Veatch, Sarah L.
Machta, Benjamin B.
Ion channels can be allosterically regulated by membrane domains near a de-mixing critical point
title Ion channels can be allosterically regulated by membrane domains near a de-mixing critical point
title_full Ion channels can be allosterically regulated by membrane domains near a de-mixing critical point
title_fullStr Ion channels can be allosterically regulated by membrane domains near a de-mixing critical point
title_full_unstemmed Ion channels can be allosterically regulated by membrane domains near a de-mixing critical point
title_short Ion channels can be allosterically regulated by membrane domains near a de-mixing critical point
title_sort ion channels can be allosterically regulated by membrane domains near a de-mixing critical point
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6279359/
https://www.ncbi.nlm.nih.gov/pubmed/30455180
http://dx.doi.org/10.1085/jgp.201711900
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