Brangwynne Clifford P, Koenderink Gijsje H, MacKintosh Frederick C, Weitz David A
Max Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany.
Trends Cell Biol. 2009 Sep;19(9):423-7. doi: 10.1016/j.tcb.2009.04.004. Epub 2009 Aug 21.
All substances exhibit constant random motion at the microscopic scale. This is a direct consequence of thermal agitation, and leads to diffusion of molecules and small particles in a liquid. In addition to this nondirected motion, living cells also use active transport mechanisms, such as motor activity and polymerization forces that depend on linear biopolymers and are therefore fundamentally directed in nature. Nevertheless, it has become increasingly clear that such active processes can also drive significant random fluctuations that can appear surprisingly like thermal diffusion of particles, but faster. Here, we discuss recent progress in quantifying this behavior and identifying its origins and consequences. We suggest that it represents an important and biologically tunable mechanism for transport in living cells.
所有物质在微观尺度上都呈现出持续的随机运动。这是热搅动的直接结果，并导致分子和小颗粒在液体中扩散。除了这种无定向运动外，活细胞还利用主动运输机制，例如依赖线性生物聚合物的运动活性和聚合作用力，因此本质上是有方向性的。然而，越来越明显的是，这种主动过程也会驱动显著的随机涨落，这些涨落可能惊人地类似于粒子的热扩散，但速度更快。在这里，我们讨论在量化这种行为以及确定其起源和后果方面的最新进展。我们认为，这代表了活细胞中一种重要的、可通过生物学调节的运输机制。
