Ebersbach Gitte, Briegel Ariane, Jensen Grant J, Jacobs-Wagner Christine
Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA.
Cell. 2008 Sep 19;134(6):956-68. doi: 10.1016/j.cell.2008.07.016.
Cell polarization is an integral part of many unrelated bacterial processes. How intrinsic cell polarization is achieved is poorly understood. Here, we provide evidence that Caulobacter crescentus uses a multimeric pole-organizing factor (PopZ) that serves as a hub to concurrently achieve several polarizing functions. During chromosome segregation, polar PopZ captures the ParB*ori complex and thereby anchors sister chromosomes at opposite poles. This step is essential for stabilizing bipolar gradients of a cell division inhibitor and setting up division near midcell. PopZ also affects polar stalk morphogenesis and mediates the polar localization of the morphogenetic and cell cycle signaling proteins CckA and DivJ. Polar accumulation of PopZ, which is central to its polarizing activity, can be achieved independently of division and does not appear to be dictated by the pole curvature. Instead, evidence suggests that localization of PopZ largely relies on PopZ multimerization in chromosome-free regions, consistent with a self-organizing mechanism.
细胞极化是许多不相关细菌过程中不可或缺的一部分。目前对于内在细胞极化是如何实现的了解甚少。在此，我们提供证据表明，新月柄杆菌利用一种多聚体极组织因子（PopZ），它作为一个枢纽同时实现多种极化功能。在染色体分离过程中，位于两极的PopZ捕获ParB*ori复合物，从而将姐妹染色体锚定在相对的两极。这一步骤对于稳定细胞分裂抑制剂的双极梯度并在细胞中部附近建立分裂至关重要。PopZ还影响极柄形态发生，并介导形态发生和细胞周期信号蛋白CckA和DivJ的极性定位。PopZ的极性积累是其极化活性的核心，可以独立于分裂实现，并且似乎不受极曲率的支配。相反，有证据表明PopZ的定位很大程度上依赖于其在无染色体区域的多聚化，这与一种自组织机制一致。
