Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Im Neuenheimer Feld, Heidelberg, Germany.
EMBO J. 2010 Aug 18;29(16):2724-33. doi: 10.1038/emboj.2010.178.
Spatial organization of signalling is not an exclusive property of eukaryotic cells. Despite the fact that bacterial signalling pathways are generally simpler than those in eukaryotes, there are several well-documented examples of higher-order intracellular signalling structures in bacteria. One of the most prominent and best-characterized structures is formed by proteins that control bacterial chemotaxis. Signals in chemotaxis are processed by ordered arrays, or clusters, of receptors and associated proteins, which amplify and integrate chemotactic stimuli in a highly cooperative manner. Receptor clusters further serve to scaffold protein interactions, enhancing the efficiency and specificity of the pathway reactions and preventing the formation of signalling gradients through the cell body. Moreover, clustering can also ensure spatial separation of multiple chemotaxis systems in one bacterium. Assembly of receptor clusters appears to be a stochastic process, but bacteria evolved mechanisms to ensure optimal cluster distribution along the cell body for partitioning to daughter cells at division.
信号的空间组织并非真核细胞所独有的。尽管细菌信号通路通常比真核生物中的信号通路更简单，但在细菌中已经有几个经过充分记录的高级细胞内信号结构的例子。其中最突出和研究得最好的结构是由控制细菌趋化性的蛋白质形成的。趋化性信号通过受体和相关蛋白的有序排列或簇进行处理，以高度协作的方式放大和整合趋化刺激。受体簇进一步作为蛋白质相互作用的支架，提高途径反应的效率和特异性，并防止通过细胞体形成信号梯度。此外，聚类还可以确保一个细菌中多个趋化性系统的空间分离。受体簇的组装似乎是一个随机过程，但细菌已经进化出机制来确保最佳的簇分布沿细胞体，以便在分裂时分配给子细胞。
