<p>The obligate intracellular bacterium <i>Coxiella burnetii</i> establishes an intracellular replicative niche termed the <i>Coxiella</i>-containing vacuole (CCV), which has been characterised as a bacterially modified phagolysosome. How <i>C. burnetii</i> withstands the acidic and degradative properties of this compartment is not well understood. We demonstrate that the key lysosomal protease cathepsin B is actively and selectively removed from <i>C. burnetii-</i>infected cells through a mechanism involving the Dot/Icm type IV-B secretion system effector CvpB. Overexpression of cathepsin B leads to defects in CCV biogenesis and bacterial replication, indicating that removal of this protein represents a strategy to reduce the hostility of the intracellular niche. In addition, we show that <i>C. burnetii</i> infection of mammalian cells induces the secretion of a wider cohort of lysosomal proteins, including cathepsin B, to the extracellular milieu via a mechanism dependent on retrograde traffic. This study reveals that <i>C. burnetii</i> is actively modulating the hydrolase cohort of its replicative niche to promote intracellular success and demonstrates that infection incites the secretory pathway to maintain lysosomal homoeostasis.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Coxiella burnetii manipulates the lysosomal protease cathepsin B to facilitate intracellular success

  • Lauren E. Bird,
  • Bangyan Xu,
  • Andrew D. Hobbs,
  • Alexander R. Ziegler,
  • Nichollas E. Scott,
  • Patrice Newton,
  • David R. Thomas,
  • Laura E. Edgington-Mitchell,
  • Hayley J. Newton

摘要

The obligate intracellular bacterium Coxiella burnetii establishes an intracellular replicative niche termed the Coxiella-containing vacuole (CCV), which has been characterised as a bacterially modified phagolysosome. How C. burnetii withstands the acidic and degradative properties of this compartment is not well understood. We demonstrate that the key lysosomal protease cathepsin B is actively and selectively removed from C. burnetii-infected cells through a mechanism involving the Dot/Icm type IV-B secretion system effector CvpB. Overexpression of cathepsin B leads to defects in CCV biogenesis and bacterial replication, indicating that removal of this protein represents a strategy to reduce the hostility of the intracellular niche. In addition, we show that C. burnetii infection of mammalian cells induces the secretion of a wider cohort of lysosomal proteins, including cathepsin B, to the extracellular milieu via a mechanism dependent on retrograde traffic. This study reveals that C. burnetii is actively modulating the hydrolase cohort of its replicative niche to promote intracellular success and demonstrates that infection incites the secretory pathway to maintain lysosomal homoeostasis.