Adhesion stabilizes robust lipid heterogeneity in supercritical membranes at physiological temperature.
Adhesion stabilizes robust lipid heterogeneity in supercritical membranes at physiological temperature.
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DOI：
10.1016/j.bpj.2012.12.047
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发表时间：
2013-02
影响因子：
3.4
通讯作者：
Jiang Zhao;Jing Wu;S. Veatch
中科院分区：
文献类型：
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作者：
Jiang Zhao;Jing Wu;S. Veatch
细胞之间的接触区域经常富含或缺乏某些蛋白质或脂质物质。在这里，我们探讨了一个可能的物理基础，可能有助于这种膜的异质性使用模型系统的一个巨大的囊泡拴在一个平面支持的双层。囊泡含有共存的液体有序（Lo）和液体无序（Ld）相在低温下，并使用痕量的粘附分子，优先分配到一个液相中拴系。我们发现，当粘附分子分别分配到Ldor Lophase时，Ldmarker DiI-C12在粘附区域富集或耗尽。值得注意的是，当膜具有非常接近临界点的组成时，即使在高于溶解性相变>15°C的温度下，粘附也使富含或耗尽DiI-C12的扩展区域稳定。在从活的RBL-2 H3细胞分离的质膜囊泡中也观察到稳定的粘附区，并且在37°C下在从胆固醇水平改变的细胞分离的囊泡中探针分配减少。探针分区是在很好的定量协议与预测的二维伊辛模型与两种类型的模型膜的一个弱的应用领域。这些研究实验表明，大而稳定的域结构可以介导的超临界波动的单相膜中的脂质。
Regions of contact between cells are frequently enriched in or depleted of certain protein or lipid species. Here, we explore a possible physical basis that could contribute to this membrane heterogeneity using a model system of a giant vesicle tethered to a planar supported bilayer. Vesicles contain coexisting liquid-ordered (Lo) and liquid-disordered (Ld) phases at low temperatures and are tethered using trace quantities of adhesion molecules that preferentially partition into one liquid phase. We find that the Ldmarker DiI-C12is enriched or depleted in the adhered region when adhesion molecules partition into Ldor Lophases, respectively. Remarkably, adhesion stabilizes an extended zone enriched or depleted of DiI-C12even at temperatures >15°C above the miscibility phase transition when membranes have compositions that are in close proximity to a critical point. A stable adhesion zone is also observed in plasma membrane vesicles isolated from living RBL-2H3 cells, and probe partitioning at 37°C is diminished in vesicles isolated from cells with altered cholesterol levels. Probe partitioning is in good quantitative agreement with predictions of the two-dimensional Ising model with a weak applied field for both types of model membranes. These studies experimentally demonstrate that large and stable domain structure can be mediated by lipids in single-phase membranes with supercritical fluctuations.