Hinz Aaron J, Larson David E, Smith Christopher S, Brun Yves V
Department of Biology, Jordan Hall 142, Indiana University, Bloomington, IN 47405-3700, USA.
Mol Microbiol. 2003 Feb;47(4):929-41. doi: 10.1046/j.1365-2958.2003.03349.x.
Regulation of polar development and cell division in Caulobacter crescentus relies on the dynamic localization of several proteins to cell poles at specific stages of the cell cycle. The polar organelle development protein, PodJ, is required for the synthesis of the adhesive holdfast and pili. Here we show the cell cycle localization of PodJ and describe a novel role for this protein in controlling the dynamic localization of the developmental regulator PleC. In swarmer cells, a short form of PodJ is localized at the flagellated pole. Upon differentiation of the swarmer cell into a stalked cell, full length PodJ is synthesized and localizes to the pole opposite the stalk. In late predivisional cells, full length PodJ is processed into a short form which remains localized at the flagellar pole after cell division and is degraded during swarmer to stalked cell differentiation. Polar localization of the developmental regulator PleC requires the presence of PodJ. In contrast, the polar localization of PodJ is not dependent on the presence of PleC. These results indicate that PodJ is an important determinant for the localization of a major regulator of cell differentiation. Thus, PodJ acts directly or indirectly to target PleC to the incipient swarmer pole, to establish the cellular asymmetry that leads to the synthesis of holdfasts and pili at their proper subcellular location.
新月柄杆菌中极性发育和细胞分裂的调控依赖于几种蛋白质在细胞周期特定阶段动态定位于细胞极。极性细胞器发育蛋白PodJ是合成粘性菌毛和菌毛所必需的。在这里,我们展示了PodJ的细胞周期定位,并描述了该蛋白在控制发育调节因子PleC动态定位方面的新作用。在游动细胞中,一种短形式的PodJ定位于有鞭毛的极。当游动细胞分化为有柄细胞时,全长PodJ被合成并定位于与柄相对的极。在晚前期细胞中,全长PodJ被加工成短形式,在细胞分裂后仍定位于鞭毛极,并在游动细胞向有柄细胞分化过程中降解。发育调节因子PleC的极性定位需要PodJ的存在。相反,PodJ的极性定位不依赖于PleC的存在。这些结果表明,PodJ是细胞分化主要调节因子定位的重要决定因素。因此,PodJ直接或间接地将PleC靶向到初始游动极,以建立细胞不对称性,从而在其适当的亚细胞位置合成菌毛和菌毛。