Department of Biology, Howard Hughes Medical Institute, University of Washington, Seattle, WA 98105, USA.
Department of Applied Physics, California Institute of Technology, Pasadena, CA 91125, USA.
Cell Syst. 2021 Sep 22;12(9):924-944.e2. doi: 10.1016/j.cels.2021.06.002. Epub 2021 Jul 1.
Despite abundant measurements of bacterial growth rate, cell size, and protein content, we lack a rigorous understanding of what sets the scale of these quantities and when protein abundances should (or should not) depend on growth rate. Here, we estimate the basic requirements and physical constraints on steady-state growth by considering key processes in cellular physiology across a collection of Escherichia coli proteomic data covering ≈4,000 proteins and 36 growth rates. Our analysis suggests that cells are predominantly tuned for the task of cell doubling across a continuum of growth rates; specific processes do not limit growth rate or dictate cell size. We present a model of proteomic regulation as a function of nutrient supply that reconciles observed interdependences between protein synthesis, cell size, and growth rate and propose that a theoretical inability to parallelize ribosomal synthesis places a firm limit on the achievable growth rate. A record of this paper's transparent peer review process is included in the supplemental information.
尽管已经对细菌生长率、细胞大小和蛋白质含量进行了大量测量，但我们仍然缺乏对这些数量的尺度以及蛋白质丰度何时应该（或不应该）取决于生长率的确切理解。在这里，我们通过考虑涵盖约 4000 种蛋白质和 36 种生长率的大肠杆菌蛋白质组数据集中的关键细胞生理过程，来估计稳态生长的基本要求和物理限制。我们的分析表明，细胞主要针对在生长率连续体上进行细胞倍增的任务进行了调整；特定的过程不会限制生长率或决定细胞大小。我们提出了一个蛋白质组调节模型，作为养分供应的函数，该模型调和了蛋白质合成、细胞大小和生长率之间的观察到的相互依存关系，并提出理论上无法使核糖体合成并行化对可实现的生长率施加了严格的限制。本论文的透明同行评审过程记录包含在补充信息中。
