Hecht G B, Lane T, Ohta N, Sommer J M, Newton A
Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, NJ 08544, USA.
EMBO J. 1995 Aug 15;14(16):3915-24. doi: 10.1002/j.1460-2075.1995.tb00063.x.
Signal transduction pathways mediated by sensor histidine kinases and cognate response regulators control a variety of physiological processes in response to environmental conditions. Here we show that in Caulobacter crescentus these systems also play essential roles in the regulation of polar morphogenesis and cell division. Previous studies have implicated histidine kinase genes pleC and divJ in the regulation of these developmental events. We now report that divK encodes an essential, cell cycle-regulated homolog of the CheY/Spo0F subfamily and present evidence that this protein is a cognate response regulator of the histidine kinase PleC. The purified kinase domain of PleC, like that of DivJ, can serve as an efficient phosphodonor to DivK and as a phospho-DivK phosphatase. Based on these and earlier genetic results we propose that PleC and DivK are members of a signal transduction pathway that couples motility and stalk formation to completion of a late cell division cycle event. Gene disruption experiments and the filamentous phenotype of the conditional divK341 mutant reveal that DivK also functions in an essential signal transduction pathway required for cell division, apparently in response to another histidine kinase. We suggest that phosphotransfer mediated by these two-component signal transduction systems may represent a general mechanism regulating cell differentiation and cell division in response to successive cell cycle checkpoints.
由传感组氨酸激酶和同源反应调节因子介导的信号转导途径可控制多种生理过程，以响应环境条件。我们在此表明，在新月柄杆菌中，这些系统在极性形态发生和细胞分裂的调节中也起着重要作用。先前的研究表明组氨酸激酶基因pleC和divJ参与了这些发育事件的调节。我们现在报告，divK编码CheY/Spo0F亚家族的一个必需的、受细胞周期调控的同源物，并提供证据表明该蛋白是组氨酸激酶PleC的同源反应调节因子。纯化的PleC激酶结构域与DivJ的激酶结构域一样，可作为DivK的有效磷酸供体，并作为磷酸化DivK磷酸酶。基于这些以及早期的遗传学结果，我们提出PleC和DivK是一个信号转导途径的成员，该途径将运动性和柄形成与晚期细胞分裂周期事件的完成联系起来。基因破坏实验以及条件性divK341突变体的丝状表型表明，DivK也在细胞分裂所需的一个必需信号转导途径中发挥作用，显然是对另一种组氨酸激酶作出反应。我们认为，由这些双组分信号转导系统介导的磷酸转移可能代表一种普遍机制，用于响应连续的细胞周期检查点来调节细胞分化和细胞分裂。
