Sinorhizobium meliloti CtrA Stability Is Regulated in a CbrA-Dependent Manner That Is Influenced by CpdR1
Sinorhizobium meliloti CtrA Stability Is Regulated in a CbrA-Dependent Manner That Is Influenced by CpdR1
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苜蓿中华根瘤菌 CtrA 稳定性以 CbrA 依赖性方式调节，并受 CpdR1 影响
DOI：
10.1128/jb.02593-14
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发表时间：
2015
影响因子：
3.2
通讯作者：
Gibson, Katherine E.
中科院分区：
文献类型：
--
作者：
Schallies, Karla B.;Sadowski, Craig;Meng, Julia;Chien, Peter;Gibson, Katherine E.
CbrA是一种DivK的类似DivJ/Plec的组氨酸激酶，在苜蓿中华根瘤菌的细胞周期进程和共生中是必需的。CbrA的缺失会导致CtrA及其磷酸化水平的增加。虽然许多已知的CtrA磷酸化和蛋白分解调节因子在苜蓿中是系统发育保守的，但后者缺乏降解CtrA所需的POPA调节因子。为了研究CtrA在紫花苜蓿中是否发生蛋白降解，对CtrA的稳定性进行了评价。在指数生长过程中，CtrA是不稳定的，因此很可能以细胞周期调节的方式被降解。CbrA的丢失显著增加了CtrA的稳定性，但通过构件性异位表达无法磷酸化的CpdR1变体(CpdR1D53A)，这种表型恢复到野生型的表型。CpdR1D53A的加入完全抑制了cbrA突变的细胞周期缺陷，这与CtrA稳定性的调节一致，在调节紫花苜蓿细胞周期的正常进展中发挥了关键作用。重要的是，在CpdR1D53A的存在下，brA突变的共生缺陷也被抑制。因此，CbrA和CpdR1对CtrA稳定性的调节与自由生活的细胞周期结果和共生有关。重要的是，细胞周期是细菌生长、繁殖和发育分化所必需的基本过程。我们的目标是了解一个双组分的信号转导网络如何在自由生活的生长和宿主定植期间指导细胞周期事件。苜蓿中华根瘤菌与植物的固氮共生与新的细胞周期事件有关。这项研究确定了基本反应调节因子的调节稳定性、自由生活细胞周期进展和共生之间的联系。
CbrA is a DivJ/PleC-like histidine kinase of DivK that is required for cell cycle progression and symbiosis in the alphaproteobacterium Sinorhizobium meliloti. Loss ofcbrAresults in increased levels of CtrA as well as its phosphorylation. While many of the known Caulobacter crescentus regulators of CtrA phosphorylation and proteolysis are phylogenetically conserved within S. meliloti, the latter lacks the PopA regulator that is required for CtrA degradation in C. crescentus. In order to investigate whether CtrA proteolysis occurs in S. meliloti, CtrA stability was assessed. During exponential growth, CtrA is unstable and therefore likely to be degraded in a cell cycle-regulated manner. Loss ofcbrAsignificantly increases CtrA stability, but this phenotype is restored to that of the wild type by constitutive ectopic expression of a CpdR1 variant that cannot be phosphorylated (CpdR1D53A). Addition of CpdR1D53Afully suppressescbrAmutant cell cycle defects, consistent with regulation of CtrA stability playing a key role in mediating proper cell cycle progression in S. meliloti. Importantly, thecbrAmutant symbiosis defect is also suppressed in the presence of CpdR1D53A. Thus, regulation of CtrA stability by CbrA and CpdR1 is associated with free-living cell cycle outcomes and symbiosis.IMPORTANCEThe cell cycle is a fundamental process required for bacterial growth, reproduction, and developmental differentiation. Our objective is to understand how a two-component signal transduction network directs cell cycle events during free-living growth and host colonization. The Sinorhizobium meliloti nitrogen-fixing symbiosis with plants is associated with novel cell cycle events. This study identifies a link between the regulated stability of an essential response regulator, free-living cell cycle progression, and symbiosis.
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影响因子：
16
作者：
Flynn, JM;Neher, SB;Baker, TA
通讯作者：
Baker, TA
DOI：
10.1073/pnas.0604554103
发表时间：
2006-07-18
影响因子：
11.1
作者：
Iniesta, Antonio A.;McGrath, Patrick T.;Shapiro, Lucy
通讯作者：
Shapiro, Lucy
影响因子：
16
作者：
Abel S;Chien P;Wassmann P;Schirmer T;Kaever V;Laub MT;Baker TA;Jenal U
通讯作者：
Jenal U
影响因子：
16.6
作者：
Deghelt, Michael;Mullier, Caroline;Sternon, Jean-Francois;Francis, Nayla;Laloux, Geraldine;Dotreppe, Delphine;Van der Henst, Charles;Jacobs-Wagner, Christine;Letesson, Jean-Jacques;De Bolle, Xavier
通讯作者：
De Bolle, Xavier
影响因子：
2.8
作者：
Cheng, Jiujun;Sibley, Christopher D.;Finan, Turlough M.
通讯作者：
Finan, Turlough M.