Mondal Anupam, Kolomeisky Anatoly B
Center for Theoretical Biological Physics, Rice University, Houston, Texas; Department of Chemistry, Rice University, Houston, Texas.
Center for Theoretical Biological Physics, Rice University, Houston, Texas; Department of Chemistry, Rice University, Houston, Texas; Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas.
Biophys Rep (N Y). 2025 Mar 12;5(1):100197. doi: 10.1016/j.bpr.2025.100197. Epub 2025 Jan 28.
All living systems display remarkable spatial and temporal precision, despite operating in intrinsically fluctuating environments. It is even more surprising given that biological phenomena are regulated by multiple chemical reactions that are also random. Although the underlying molecular mechanisms of surprisingly high precision in biology remain not well understood, a novel theoretical picture that relies on the coupling of relevant stochastic processes has recently been proposed and applied to explain different phenomena. To illustrate this approach, in this review, we discuss two systems that exhibit precision control: spatial regulation in bacterial cell size and temporal regulation in the timing of cell lysis by λ bacteriophage. In cell-size regulation, it is argued that a balance between stochastic cell growth and cell division processes leads to a narrow distribution of cell sizes. In cell lysis, it is shown that precise timing is due to the coupling of holin protein accumulation and the breakage of the cellular membrane. The stochastic coupling framework also allows us to explicitly evaluate dynamic properties for both biological systems, eliminating the need to utilize the phenomenological concept of thresholds. Excellent agreement with experimental observations is observed, supporting the proposed theoretical ideas. These observations also suggest that the stochastic coupling method captures the important aspects of molecular mechanisms of precise cellular regulation, providing a powerful new tool for more advanced investigations of complex biological phenomena.
尽管生物系统在本质上波动的环境中运行，但所有生物系统都展现出显著的空间和时间精度。考虑到生物现象是由同样具有随机性的多种化学反应所调控的，这一点就更加令人惊讶。尽管生物学中惊人高精度背后的分子机制仍未得到很好的理解，但最近有人提出了一种基于相关随机过程耦合的新理论框架，并将其应用于解释不同的现象。为了说明这种方法，在这篇综述中，我们讨论了两个展现出精确控制的系统：细菌细胞大小的空间调控以及λ噬菌体细胞裂解时间的时间调控。在细胞大小调控方面，有人认为随机的细胞生长和细胞分裂过程之间的平衡导致了细胞大小的窄分布。在细胞裂解方面，研究表明精确的时间控制是由于孔蛋白积累与细胞膜破裂之间的耦合。随机耦合框架还使我们能够明确评估这两个生物系统的动态特性，从而无需使用阈值这一唯象学概念。研究发现与实验观察结果高度吻合，支持了所提出的理论观点。这些观察结果还表明，随机耦合方法抓住了精确细胞调控分子机制的重要方面，为更深入研究复杂生物现象提供了一个强大的新工具。
