Kafri Moshe, Metzl-Raz Eyal, Jonas Felix, Barkai Naama
Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel.
Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
FEMS Yeast Res. 2016 Nov;16(7). doi: 10.1093/femsyr/fow081. Epub 2016 Sep 19.
The minimal description of a growing cell consists of self-replicating ribosomes translating the cellular proteome. While neglecting all other cellular components, this model provides key insights into the control and limitations of growth rate. It shows, for example, that growth rate is maximized when ribosomes work at full capacity, explains the linear relation between growth rate and the ribosome fraction of the proteome and defines the maximal possible growth rate. This ribosome-centered model also highlights the challenge of coordinating cell growth with related processes such as cell division or nutrient production. Coordination is promoted when ribosomes don't translate at maximal capacity, as it allows escaping strict exponential growth. Recent data support the notion that multiple cellular processes limit growth. In particular, increasing transcriptional demand may be as deleterious as increasing translational demand, depending on growth conditions. Consistent with the idea of trade-off, cells may forgo maximal growth to enable more efficient interprocess coordination and faster adaptation to changing conditions.
对生长中细胞的最小描述包括自我复制的核糖体翻译细胞蛋白质组。在忽略所有其他细胞成分的情况下，该模型为生长速率的控制和限制提供了关键见解。例如，它表明当核糖体满负荷工作时生长速率最大化，解释了生长速率与蛋白质组中核糖体比例之间的线性关系，并定义了最大可能生长速率。这个以核糖体为中心的模型还突出了协调细胞生长与细胞分裂或营养物质产生等相关过程的挑战。当核糖体不以最大能力进行翻译时，协调会得到促进，因为这允许摆脱严格的指数生长。最近的数据支持多种细胞过程限制生长这一观点。特别是，根据生长条件，增加转录需求可能与增加翻译需求一样有害。与权衡的观点一致，细胞可能会放弃最大生长以实现更有效的过程间协调并更快地适应不断变化的条件。
