Fluorescent quantification of size and lamellarity of membrane nanotubes
Fluorescent quantification of size and lamellarity of membrane nanotubes
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DOI：
10.1007/s00249-014-0989-2
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发表时间：
2014-12-01
影响因子：
2
通讯作者：
Bendix, Poul M.
中科院分区：
文献类型：
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作者：
Baroji, Younes F.;Oddershede, Lene B.;Bendix, Poul M.
膜纳米管普遍存在于细胞系统中，其曲率和形状的光谱由其固有的物理特性以及它们与局部细胞环境的相互作用决定。在拥挤的细胞质中需要很高的弯曲弹性，其中管子经常需要在亚微米长度尺度上在轴向上显著弯曲。我们通过测量自由悬浮在溶液中的重组膜纳米管的持续长度并通过荧光显微镜成像来确定自发形成的膜纳米管的硬度。通过对管径的量化，我们首次证明了持续长度与半径成线性关系。虽然大多数管子是单层的，但管子半径和持续长度之间的预测线性比例使我们能够识别水化后自发形成的多层结构的管子。我们提供了第一个实验证据，证明了脂质荧光团的照射可以对脂双层产生深远的影响，我们敏感地检测到它是管持续长度随时间的连续变化。本文提出的新的分析和方法有可能通过支架蛋白来定量膜管的结构增强。
Membrane nanotubes, ubiquitous in cellular systems, adopt a spectrum of curvatures and shapes that are dictated by their intrinsic physical characteristics as well as their interactions with the local cellular environment. A high bending flexibility is needed in the crowded cytoplasm where tubes often need to bend significantly in the axial direction at sub-micron length scales. We find the stiffness of spontaneously formed membrane nanotubes by measuring the persistence length of reconstituted membrane nanotubes freely suspended in solution and imaged by fluorescence microscopy. By quantifying the tube diameter we demonstrate for the first time that the persistence length scales linearly with radius. Although most tubes are uni-lamellar, the predicted linear scaling between tube radius and persistence length allows us to identify tubes that spontaneously form as multilamellar structures upon hydration. We provide the first experimental evidence that illumination of lipid fluorophores can have a profound effect on the lipid bilayer which we sensitively detect as a continuous change in the tube persistence length with time. The novel assay and methodology here presented has potential for quantification of the structural reinforcement of membrane tubes by scaffolding proteins.