Kusumi Akihiro, Nakada Chieko, Ritchie Ken, Murase Kotono, Suzuki Kenichi, Murakoshi Hideji, Kasai Rinshi S, Kondo Junko, Fujiwara Takahiro
Kusumi Membrane Organizer Project, Exploratory Research for Advanced Technology Organization, Department of Biological Science and Institute for Advanced Research, Nagoya University, Nagoya 464-8602, Japan.
Annu Rev Biophys Biomol Struct. 2005;34:351-78. doi: 10.1146/annurev.biophys.34.040204.144637.
Recent advancements in single-molecule tracking methods with nanometer-level precision now allow researchers to observe the movement, recruitment, and activation of single molecules in the plasma membrane in living cells. In particular, on the basis of the observations by high-speed single-particle tracking at a frame rate of 40,000 frames s(1), the partitioning of the fluid plasma membrane into submicron compartments throughout the cell membrane and the hop diffusion of virtually all the molecules have been proposed. This could explain why the diffusion coefficients in the plasma membrane are considerably smaller than those in artificial membranes, and why the diffusion coefficient is reduced upon molecular complex formation (oligomerization-induced trapping). In this review, we first describe the high-speed single-molecule tracking methods, and then we critically review a new model of a partitioned fluid plasma membrane and the involvement of the actin-based membrane-skeleton "fences" and anchored-transmembrane protein "pickets" in the formation of compartment boundaries.
单分子追踪方法在纳米级精度方面的最新进展，如今使研究人员能够在活细胞中观察质膜内单个分子的运动、募集和激活。特别是，基于以40,000帧/秒的帧率进行高速单粒子追踪的观察结果，有人提出，流动性质膜在整个细胞膜中被划分为亚微米级的区室，并且几乎所有分子都存在跳跃扩散。这可以解释为什么质膜中的扩散系数明显小于人工膜中的扩散系数，以及为什么分子形成复合物（寡聚化诱导捕获）时扩散系数会降低。在本综述中，我们首先描述高速单分子追踪方法，然后批判性地审视一种划分的流动性质膜新模型，以及基于肌动蛋白的膜骨架“围栏”和锚定跨膜蛋白“桩子”在区室边界形成中的作用。
