Protein Kinase B ( PknB) of Mycobacterium tuberculosis Is Essential for Growth of the Pathogen in Vitro as well as for Survival within the Host
Protein Kinase B ( PknB) of Mycobacterium tuberculosis Is Essential for Growth of the Pathogen in Vitro as well as for Survival within the Host
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DOI：
10.1074/jbc.m114.563536
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发表时间：
2014-05-16
影响因子：
4.8
通讯作者：
Nandicoori, Vinay Kumar
中科院分区：
文献类型：
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作者：
Chawla, Yogesh;Upadhyay, Sandeep;Nandicoori, Vinay Kumar
背景：结核分枝杆菌PknB在调节细胞分裂和细胞壁合成中起关键作用。结果：我们提出了一个全面的评价的重要性，PknB的各个领域在调节细胞存活。结论：PknB的细胞内激酶结构域和细胞质外PASTA结构域对于细胞生存至关重要。重要性：结核分枝杆菌蛋白激酶B（Mycobacterium tuberculosis protein kinase B，PknB）是一种具有胞内激酶结构域的蛋白激酶，通过跨膜结构域与含有4个PASTA结构域的胞外区相连。本研究描述了在无毒力和毒性分枝杆菌的生存能力的背景下，PknB的不同领域的综合分析。我们发现细胞存活所必需的PknB表达的严格调节，PknB的耗尽或过度表达导致细胞死亡。虽然PknB介导的激酶活性是细胞存活所必需的，但缺乏跨膜或胞外结构域的活性激酶不能补充不表达PknB的条件突变体。通过构建嵌合激酶，我们发现细胞内激酶结构域在强毒株中具有独特的功能，不能被其他激酶取代。有趣的是，我们发现，虽然在无毒M.因此，所有四个PASTA结构域在M.结核PknB相对维斯必需PASTA结构域的数量和激酶结构域功能的特异性的差异行为表明，与无毒分枝杆菌相比，PknB介导的生长和信号传导事件在毒力方面不同。为确定PknB在介导病原体在宿主中存活中的作用而进行的小鼠感染研究表明，PknB不仅对病原体在体外的生长至关重要，而且对病原体在宿主中的存活也至关重要。
Background:Mycobacterium tuberculosis PknB plays a critical role in modulating cell division and cell wall synthesis. Results: We present a comprehensive evaluation of the importance of various domains of PknB in modulating cell survival. Conclusion: The intracellular kinase domain and extracytoplasmic PASTA domains of PknB are essential for cell survival. Significance: PknB is essential for both in vitro growth and survival of the pathogen in vivo.The Mycobacterium tuberculosis protein kinase B (PknB) comprises an intracellular kinase domain, connected through a transmembrane domain to an extracellular region that contains four PASTA domains. The present study describes the comprehensive analysis of different domains of PknB in the context of viability in avirulent and virulent mycobacteria. We find stringent regulation of PknB expression necessary for cell survival, with depletion or overexpression of PknB leading to cell death. Although PknB-mediated kinase activity is essential for cell survival, active kinase lacking the transmembrane or extracellular domain fails to complement conditional mutants not expressing PknB. By creating chimeric kinases, we find that the intracellular kinase domain has unique functions in the virulent strain, which cannot be substituted by other kinases. Interestingly, we find that although the presence of the C-terminal PASTA domain is dispensable in the avirulent M. smegmatis, all four PASTA domains are essential in M. tuberculosis. The differential behavior of PknB vis-a-vis the number of essential PASTA domains and the specificity of kinase domain functions suggest that PknB-mediated growth and signaling events differ in virulent compared with avirulent mycobacteria. Mouse infection studies performed to determine the role of PknB in mediating pathogen survival in the host demonstrate that PknB is not only critical for growth of the pathogen in vitro but is also essential for the survival of the pathogen in the host.