Hefei National Laboratory for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui, China.
Hefei National Laboratory for Physical Sciences at the Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui, China.
Biophys J. 2022 Jan 18;121(2):319-326. doi: 10.1016/j.bpj.2021.12.012. Epub 2021 Dec 9.
In bacterial chemotaxis, the output of chemosensing, the concentration of the response regulator CheY-P that was constantly adjusted by the opposing action of the kinase CheA and the phosphatase CheZ, serves as the input of the ultrasensitive flagellar motor that drives bacterial motility. The steady-state kinase activity exhibits large cell-to-cell variation that may result in similar variation in CheY-P concentration. Here, we found that the in vivo phosphatase activity is highly cooperative with respect to CheY-P concentration, and this suppresses the cell-to-cell variation of CheY-P concentration so that it falls within the operational range of the flagellar motor. Therefore, the cooperativity of the CheZ and CheY-P interaction we identified here provided a mechanism of robust coupling between the output of chemosensing and the input of the flagellar motor. Suppression of cell heterogeneity by cooperativity of protein-protein interaction is likely a common feature in many biological signaling systems.
在细菌趋化性中，化学感应的输出，即响应调节剂 CheY-P 的浓度，通过激酶 CheA 和磷酸酶 CheZ 的拮抗作用不断调节，作为超敏鞭毛马达的输入，驱动细菌运动。稳态激酶活性表现出很大的细胞间变异性，这可能导致 CheY-P 浓度的类似变异性。在这里，我们发现 CheY-P 浓度的磷酸酶活性具有高度的协同性，这抑制了 CheY-P 浓度的细胞间变异性，使其落入鞭毛马达的工作范围。因此，我们在这里确定的 CheZ 和 CheY-P 相互作用的协同性为化学感应输出和鞭毛马达输入之间的稳健耦合提供了一种机制。蛋白质-蛋白质相互作用的协同性抑制细胞异质性可能是许多生物信号系统的共同特征。
