Lowering line tension with high cholesterol content induces a transition from macroscopic to nanoscopic phase domains in model biomembranes.
Lowering line tension with high cholesterol content induces a transition from macroscopic to nanoscopic phase domains in model biomembranes.
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高胆固醇含量降低线张力会导致模型生物膜从宏观相域转变为纳米相域。
DOI：
10.1016/j.bbamem.2018.11.010
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Feigenson,GeraldW
中科院分区：
文献类型：
--
作者：
Tsai,Wen-Chyan;Feigenson,GeraldW
化学简化的脂质混合物在这里用作细胞质膜外质小叶的模型。在这样的模型中，已经描述了在液体无序（Ld）+液体有序（Lo）共存状态中由线张力控制的相分离和形态转变[1]。在这里，我们研究了两种四组分脂质混合物在不同的胆固醇馏分：脑鞘磷脂（BSM）或1，2-二硬脂酰-sn-甘油-3-磷酸胆碱（DSPC）/1，2-二油酰-sn-甘油-3-磷酸胆碱（DOPC）/1-棕榈酰-2-油酰-sn-甘油-3-磷酸胆碱（POPC）/胆固醇（Chol）。在巨单层囊泡（GUV）上，当POPC被DOPC取代时，显示出Ld + Lo相结构域的纳米级到宏观级的转变，并且这种转变还取决于胆固醇分数。两种脂质混合物中，线张力随胆固醇摩尔分数的增加而降低。对于三元BSM/DOPC/Chol混合物，公布的相图[19]需要修改，以表明当胆固醇摩尔分数>~0.33时，共存相域变为纳米级。
Chemically simplified lipid mixtures are used here as models of the cell plasma membrane exoplasmic leaflet. In such models, phase separation and morphology transitions controlled by line tension in the liquid-disordered (Ld) + liquid-ordered (Lo) coexistence regime have been described [1]. Here, we study two four-component lipid mixtures at different cholesterol fractions: brain sphingomyelin (BSM) or 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC)/1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/cholesterol (Chol). On giant unilamellar vesicles (GUVs) display a nanoscopic-to-macroscopic transition of Ld + Lo phase domains as POPC is replaced by DOPC, and this transition also depends on the cholesterol fraction. Line tension decreases with increasing cholesterol mole fractions in both lipid mixtures. For the ternary BSM/DOPC/Chol mixture, the published phase diagram [19] requires a modification to show that when cholesterol mole fraction is >~0.33, coexisting phase domains become nanoscopic.