McGrath Patrick T, Iniesta Antonio A, Ryan Kathleen R, Shapiro Lucy, McAdams Harley H
Department of Physics, Stanford University, Stanford, CA 94305, USA.
Cell. 2006 Feb 10;124(3):535-47. doi: 10.1016/j.cell.2005.12.033.
Regulated proteolysis is essential for cell cycle progression in both prokaryotes and eukaryotes. We show here that the ClpXP protease, responsible for the degradation of multiple bacterial proteins, is dynamically localized to specific cellular positions in Caulobacter where it degrades colocalized proteins. The CtrA cell cycle master regulator, that must be cleared from the Caulobacter cell to allow the initiation of chromosome replication, interacts with the ClpXP protease at the cell pole where it is degraded. We have identified a novel, conserved protein, RcdA, that forms a complex with CtrA and ClpX in the cell. RcdA is required for CtrA polar localization and degradation by ClpXP. The localization pattern of RcdA is coincident with and dependent upon ClpX localization. Thus, a dynamically localized ClpXP proteolysis complex in concert with a cytoplasmic factor provides temporal and spatial specificity to protein degradation during a bacterial cell cycle.
受调控的蛋白水解对于原核生物和真核生物的细胞周期进程至关重要。我们在此表明，负责多种细菌蛋白降解的ClpXP蛋白酶动态定位于柄杆菌特定的细胞位置，在那里它降解共定位的蛋白。细胞周期主调控因子CtrA必须从柄杆菌细胞中清除，以允许染色体复制的起始，它在细胞极与ClpXP蛋白酶相互作用并在那里被降解。我们鉴定出一种新的保守蛋白RcdA，它在细胞中与CtrA和ClpX形成复合物。RcdA是CtrA极性定位以及被ClpXP降解所必需的。RcdA的定位模式与ClpX的定位一致且依赖于ClpX的定位。因此，一个动态定位的ClpXP蛋白水解复合物与一种细胞质因子协同作用，为细菌细胞周期中的蛋白降解提供了时间和空间特异性。
