The ClpPX protease is required for radioresistance and regulates cell division after γ-irradiation in Deinococcus radiodurans
The ClpPX protease is required for radioresistance and regulates cell division after γ-irradiation in Deinococcus radiodurans
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DOI：
10.1111/j.1365-2958.2007.06003.x
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发表时间：
2007-12-01
影响因子：
3.6
通讯作者：
Sommer, Suzanne
中科院分区：
文献类型：
--
作者：
Servant, Pascale;Jolivet, Edmond;Sommer, Suzanne
细菌中的蛋白质降解涉及多种细胞对环境刺激的反应，以及去除潜在毒性受损的蛋白质或蛋白质聚集体。atp依赖性蛋白酶在这些过程中起关键作用。在这里，我们单独灭活了耐辐射球菌中属于Clp或Lon家族的所有atp依赖性蛋白酶。测试突变体在γ辐照后的存活率和对tRNA类似物嘌呤霉素的敏感性，以评估每次破坏对辐射抗性的影响，以及对错误折叠蛋白质的蛋白质水解的影响。我们发现ClpPX蛋白酶的失活显著降低了在高γ辐照剂量下的细胞存活率，而Lon1和Lon2蛋白酶的失活降低了对嘌呤霉素的耐药性，这表明它们在消除受损蛋白方面发挥作用。缺乏ClpPX蛋白酶的突变体表现出DNA双链断裂修复动力学的改变，并在DNA修复完成后的极长滞后期后恢复细胞分裂。在此停滞期，大部分Delta clpPX照射的细胞显示去致密的类核和异常的间隔，部分细胞缺乏DNA。我们认为ClpPX蛋白酶参与控制DNA损伤后细胞的染色体分离和细胞分裂。
Protein degradation in bacteria is involved in diverse cellular responses to environmental stimuli and in removing potentially toxic damaged proteins or protein aggregates. ATP-dependent proteases play a key role in these processes. Here, we have individually inactivated all the ATP-dependent proteases belonging to the Clp or Lon families in Deinococcus radiodurans. The mutants were tested for survival after gamma-irradiation and for sensitivity to the tRNA analogue puromycin in order to assess the impact of each disruption on radioresistance, as well as on proteolysis of misfolded proteins. We found that inactivation of the ClpPX protease significantly decreased cell survival at elevated gamma-irradiation doses, while inactivation of Lon1 and Lon2 proteases reduced resistance to puromycin, suggesting that they play a role in eliminating damaged proteins. Mutants devoid of ClpPX protease displayed altered kinetics of DNA double-strand break repair and resumed cell division after an exceedingly long lag phase following completion of DNA repair. During this stasis period, most of the Delta clpPX irradiated cells showed decondensed nucleoids and abnormal septa and some cells were devoid of DNA. We propose that the ClpPX protease is involved in the control of proper chromosome segregation and cell division in cells recovering from DNA damage.