Recent Experiments Support a Microemulsion Origin of Plasma Membrane Domains: Dependence of Domain Size on Physical Parameters
It is widely, but not universally, believed that the lipids of the plasma membrane are not uniformly distributed, but that “rafts” of sphingolipids and cholesterol float in a “sea” of unsaturated lipids. The physical origin of such heterogeneities is often attributed to a phase coexistence between t...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-07-01
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| Series: | Membranes |
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| Online Access: | https://www.mdpi.com/2077-0375/10/8/167 |
| _version_ | 1797561184100024320 |
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| author | David W. Allender M. Schick |
| author_facet | David W. Allender M. Schick |
| author_sort | David W. Allender |
| collection | DOAJ |
| description | It is widely, but not universally, believed that the lipids of the plasma membrane are not uniformly distributed, but that “rafts” of sphingolipids and cholesterol float in a “sea” of unsaturated lipids. The physical origin of such heterogeneities is often attributed to a phase coexistence between the two different domains. We argue that this explanation is untenable for several reasons. Further, we note that the results of recent experiments are inconsistent with this picture. However, they are quite consistent with an alternate explanation, namely, that the plasma membrane is a microemulsion of the two kinds of regions. To show this, we briefly review a simplified version of this theory and its phase diagram. We also explicate the dependence of the predicted domain size on four physical parameters. They are the energy cost of gradients in the composition, the spontaneous curvature of the membrane, its bending modulus and its surface tension. Taking values of the latter two from experiment, we obtain domain sizes for several different cell types that vary from 58 to 88 nm. |
| first_indexed | 2024-03-10T18:10:28Z |
| format | Article |
| id | doaj.art-d1c11caa0f4e41959ef7135366ff72d8 |
| institution | Directory Open Access Journal |
| issn | 2077-0375 |
| language | English |
| last_indexed | 2024-03-10T18:10:28Z |
| publishDate | 2020-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Membranes |
| spelling | doaj.art-d1c11caa0f4e41959ef7135366ff72d82023-11-20T08:10:16ZengMDPI AGMembranes2077-03752020-07-0110816710.3390/membranes10080167Recent Experiments Support a Microemulsion Origin of Plasma Membrane Domains: Dependence of Domain Size on Physical ParametersDavid W. Allender0M. Schick1Department of Physics, University of Washington, Seattle, WA 98195, USADepartment of Physics, University of Washington, Seattle, WA 98195, USAIt is widely, but not universally, believed that the lipids of the plasma membrane are not uniformly distributed, but that “rafts” of sphingolipids and cholesterol float in a “sea” of unsaturated lipids. The physical origin of such heterogeneities is often attributed to a phase coexistence between the two different domains. We argue that this explanation is untenable for several reasons. Further, we note that the results of recent experiments are inconsistent with this picture. However, they are quite consistent with an alternate explanation, namely, that the plasma membrane is a microemulsion of the two kinds of regions. To show this, we briefly review a simplified version of this theory and its phase diagram. We also explicate the dependence of the predicted domain size on four physical parameters. They are the energy cost of gradients in the composition, the spontaneous curvature of the membrane, its bending modulus and its surface tension. Taking values of the latter two from experiment, we obtain domain sizes for several different cell types that vary from 58 to 88 nm.https://www.mdpi.com/2077-0375/10/8/167plasma membraneraftsmicroemulsionphase-separationdomain size |
| spellingShingle | David W. Allender M. Schick Recent Experiments Support a Microemulsion Origin of Plasma Membrane Domains: Dependence of Domain Size on Physical Parameters Membranes plasma membrane rafts microemulsion phase-separation domain size |
| title | Recent Experiments Support a Microemulsion Origin of Plasma Membrane Domains: Dependence of Domain Size on Physical Parameters |
| title_full | Recent Experiments Support a Microemulsion Origin of Plasma Membrane Domains: Dependence of Domain Size on Physical Parameters |
| title_fullStr | Recent Experiments Support a Microemulsion Origin of Plasma Membrane Domains: Dependence of Domain Size on Physical Parameters |
| title_full_unstemmed | Recent Experiments Support a Microemulsion Origin of Plasma Membrane Domains: Dependence of Domain Size on Physical Parameters |
| title_short | Recent Experiments Support a Microemulsion Origin of Plasma Membrane Domains: Dependence of Domain Size on Physical Parameters |
| title_sort | recent experiments support a microemulsion origin of plasma membrane domains dependence of domain size on physical parameters |
| topic | plasma membrane rafts microemulsion phase-separation domain size |
| url | https://www.mdpi.com/2077-0375/10/8/167 |
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