The Interplay of ClpXP with the Cell Division Machinery in Escherichia coli
The Interplay of ClpXP with the Cell Division Machinery in Escherichia coli
复制标题
DOI：
10.1128/jb.01317-10
复制
发表时间：
2011-04-01
影响因子：
3.2
通讯作者：
Wickner, Sue
中科院分区：
文献类型：
--
作者：
Camberg, Jodi L.;Hoskins, Joel R.;Wickner, Sue
ClpXP是一种双组分蛋白酶，由识别和展开特定底物的atp依赖性伴侣ClpX和丝氨酸蛋白酶ClpP组成。大肠杆菌中的一种ClpXP底物是FtsZ，它对细胞分裂至关重要。FtsZ在分裂发生的细胞中间聚合并形成FtsZ环。为了研究ClpXP在细胞分裂中的作用，我们检测了clpX和clpP缺失对几种细胞分裂缺陷菌株的影响。总之，我们的研究结果表明，ClpXP通过降解FtsZ以及可能在FtsZ环组装下游发挥作用的其他细胞分裂成分来调节细胞分裂。在ftsZ84菌株中，由于ftsZ的突变，该菌株对丝化具有温度敏感性，我们观察到clpX或clpP的缺失抑制了丝化并减少了ftsZ84的降解。这些结果与ClpXP通过降解调节FtsZ水平在细胞分裂中发挥作用一致。在另一种分裂缺陷菌株Delta minC中，clpX或clpP的额外缺失会延迟细胞分裂并加剧丝化。我们的研究结果表明，ClpXP通过一种需要atp依赖性降解的机制来调节缺乏MinC的细胞的分裂。然而，体内抗生素追踪实验表明，Delta minC菌株的FtsZ降解速度比野生型慢，这表明可能存在另一种被ClpXP降解的细胞分裂成分。综上所述，这些研究表明ClpXP可能会降解多种细胞分裂蛋白，从而调节分裂所需成分的精确平衡。
ClpXP is a two-component protease composed of ClpX, an ATP-dependent chaperone that recognizes and unfolds specific substrates, and ClpP, a serine protease. One ClpXP substrate in Escherichia coli is FtsZ, which is essential for cell division. FtsZ polymerizes and forms the FtsZ ring at midcell, where division occurs. To investigate the role of ClpXP in cell division, we examined the effects of clpX and clpP deletions in several strains that are defective for cell division. Together, our results suggested that ClpXP modulates cell division through degradation of FtsZ and possibly other cell division components that function downstream of FtsZ ring assembly. In the ftsZ84 strain, which is temperature sensitive for filamentation due to a mutation in ftsZ, we observed that deletion of clpX or clpP suppresses filamentation and reduces FtsZ84 degradation. These results are consistent with ClpXP playing a role in cell division by modulating the level of FtsZ through degradation. In another division-defective strain, Delta minC, the additional deletion of clpX or clpP delays cell division and exacerbates filamentation. Our results demonstrate that ClpXP modulates division in cells lacking MinC by a mechanism that requires ATP-dependent degradation. However, antibiotic chase experiments in vivo indicate that FtsZ degradation is slower in the Delta minC strain than in the wild type, suggesting there may be another cell division component degraded by ClpXP. Taken together these studies suggest that ClpXP may degrade multiple cell division proteins, thereby modulating the precise balance of the components required for division.