The HtrA-like serine protease PepD interacts with and modulates the Mycobacterium tuberculosis 35-kDa antigen outer envelope protein.
The HtrA-like serine protease PepD interacts with and modulates the Mycobacterium tuberculosis 35-kDa antigen outer envelope protein.
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HTRA样丝氨酸蛋白酶PEPD与结核分枝杆菌相互作用并调节35 kDa抗原外膜蛋白。
DOI：
10.1371/journal.pone.0018175
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发表时间：
2011-03-22
期刊：
影响因子：
3.7
通讯作者：
Zahrt TC
中科院分区：
文献类型：
--
作者：
White MJ;Savaryn JP;Bretl DJ;He H;Penoske RM;Terhune SS;Zahrt TC
结核分枝杆菌仍然是一个重大的全球健康问题，这主要是因为它能够在宿主的肉芽肿内长期存活。当结核杆菌居住在肉芽肿内时，很可能会暴露在压力下，导致结构发生变化的异常蛋白质的形成。细菌编码应激反应决定因素，如蛋白酶和伴侣，以处理错误折叠或未折叠的蛋白质。PepD编码一种类似HtrA的丝氨酸蛋白酶，被认为是处理结核分枝杆菌暴露于胞外压力后改变的蛋白质。PepD在体外既是一种蛋白水解酶，又是一种伴侣蛋白，在体内对结核分枝杆菌的毒力是必需的。PepD直接受胁迫反应的双组分信号转导系统MprAB调节，间接受胞外功能(ECF)sigma因子SiGe调节。PepD的缺失也影响结核分枝杆菌中其他应激反应决定因素的表达。为了进一步了解PepD在结核分枝杆菌应激适应中的作用，采用蛋白质组学的方法来鉴定该蛋白的结合蛋白和可能的底物。利用亚细胞分离技术，确定野生型和PepD变异体的细胞定位。纯化的污垢分枝杆菌或结核分枝杆菌表达的PepD变异体的纯化组分和全细胞裂解物被免疫沉淀检测PepD，并进行LC-MS/MS分析。利用这一策略，编码PSPA噬菌体休克蛋白同源物的35 kDa抗原被鉴定为PepD的主要结合伙伴和底物。我们推测，PepD对35 kDa抗原的蛋白水解性切割有助于维持分枝杆菌细胞壁的动态平衡，并在胞外应激期间调节特定的应激反应途径。
Mycobacterium tuberculosis remains a significant global health concern largely due to its ability to persist for extended periods within the granuloma of the host. While residing within the granuloma, the tubercle bacilli are likely to be exposed to stress that can result in formation of aberrant proteins with altered structures. Bacteria encode stress responsive determinants such as proteases and chaperones to deal with misfolded or unfolded proteins. pepD encodes an HtrA-like serine protease and is thought to process proteins altered following exposure of M. tuberculosis to extra-cytoplasmic stress. PepD functions both as a protease and chaperone in vitro, and is required for aspects of M. tuberculosis virulence in vivo. pepD is directly regulated by the stress-responsive two-component signal transduction system MprAB and indirectly by extracytoplasmic function (ECF) sigma factor SigE. Loss of PepD also impacts expression of other stress-responsive determinants in M. tuberculosis. To further understand the role of PepD in stress adaptation by M. tuberculosis, a proteomics approach was taken to identify binding proteins and possible substrates of this protein. Using subcellular fractionation, the cellular localization of wild-type and PepD variants was determined. Purified fractions as well as whole cell lysates from Mycobacterium smegmatis or M. tuberculosis strains expressing a catalytically compromised PepD variant were immunoprecipitated for PepD and subjected to LC-MS/MS analyses. Using this strategy, the 35-kDa antigen encoding a homolog of the PspA phage shock protein was identified as a predominant binding partner and substrate of PepD. We postulate that proteolytic cleavage of the 35-kDa antigen by PepD helps maintain cell wall homeostasis in Mycobacterium and regulates specific stress response pathways during periods of extracytoplasmic stress.
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影响因子：
3.2
作者：
Guo, Xinzheng V.;Monteleone, Mercedes;Schnappinger, Dirk
通讯作者：
Schnappinger, Dirk
影响因子：
3.7
作者：
Dutta NK;Mehra S;Kaushal D
通讯作者：
Kaushal D
影响因子：
3.6
作者：
Kobayashi, Ryuji;Suzuki, Toshiharu;Yoshida, Masasuke
通讯作者：
Yoshida, Masasuke
DOI：
10.1073/pnas.0508936102
发表时间：
2005-12-06
影响因子：
11.1
作者：
Isaac, DD;Pinkner, JS;Silhavy, TJ
通讯作者：
Silhavy, TJ
影响因子：
3.2
作者：
He, HJ;Zahrt, TC
通讯作者：
Zahrt, TC