Department of Life Sciences , Imperial College , London , UK.
Interface Focus. 2014 Dec 6;4(6):20140002. doi: 10.1098/rsfs.2014.0002.
Chemotaxis is vital cellular movement in response to environmental chemicals. Unlike the canonical chemotactic pathway in Escherichia coli, Rhodobacter sphaeroides has both transmembrane and cytoplasmic sensory clusters, with the latter possibly interacting with essential components in the electron transport system. However, the effect of the cytoplasmic sensor and the mechanism of signal integration from both sensory clusters remain unclear. Based on a minimal model of the chemotaxis pathway in this species, we show that signal integration at the motor level produces realistic chemotactic behaviour in line with experimental observations. Our model also suggests that the core pathway of R. sphaeroides, at least its ancestor, may represent a metabolism-dependent selective stopping strategy, which alone can steer cells to favourable environments. Our results not only clarify the potential roles of the two sensory clusters but also put in question the current definitions of attractants and repellents.
趋化作用是细胞对环境化学物质做出反应的重要运动方式。不同于大肠杆菌中的经典趋化途径，球形红杆菌既有跨膜感觉簇又有细胞质感觉簇，后者可能与电子传递系统中的基本组成部分相互作用。然而，细胞质传感器的作用以及两个感觉簇的信号整合机制仍不清楚。基于该物种趋化途径的一个最小模型，我们表明，在运动水平上的信号整合产生了与实验观察一致的现实趋化行为。我们的模型还表明，球形红杆菌的核心途径，至少其祖先，可能代表一种依赖代谢的选择性停止策略，该策略本身可以引导细胞向有利的环境移动。我们的研究结果不仅阐明了两个感觉簇的潜在作用，还对当前的趋化剂和抑制剂的定义提出了质疑。
