ClpV recycles VipA/VipB tubules and prevents non-productive tubule formation to ensure efficient type VI protein secretion
ClpV recycles VipA/VipB tubules and prevents non-productive tubule formation to ensure efficient type VI protein secretion
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DOI：
10.1111/mmi.12147
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发表时间：
2013-03-01
影响因子：
3.6
通讯作者：
Mogk, Axel
中科院分区：
文献类型：
--
作者：
Kapitein, Nicole;Boenemann, Gabriele;Mogk, Axel
多组分VI型分泌系统（T6 SS）通过刺穿靶膜介导效应蛋白的转运。T6 SS被认为是一种可收缩的纳米机器，其功能类似于有尾噬菌体的细胞穿刺装置。T6 SS成员VipA/VipB形成管状复合物，并被预测通过经由收缩提供用于分泌的能量而类似于病毒尾鞘蛋白发挥功能。ATP酶ClpV在体外分解VipA/VipB小管，但小管分解的生理相关性仍不清楚。在这里，我们表明，VipA/VipB小管定位近垂直于霍乱弧菌细胞的内膜，并表现出重复的周期的伸长，收缩和拆卸。VipA/VipB小管在体内被ClpV修饰，并在clpV细胞中变得静止，表明ClpV是小管去除所需的。VipA/VipB小管在clpV细胞中错误定位，并表现出小管伸长频率降低，表明ClpV还抑制收缩的非生产性VipA/VipB小管的自发形成。ClpV活性限于VipA/VipB的收缩状态，允许在T6 SS组装处形成功能性细长小管。将不相关的ATP酶靶向VipA/VipB足以在体内取代ClpV功能，表明ClpV活性由VipA/VipB构象自主调节。
The multicomponent type VI secretion system (T6SS) mediates the transport of effector proteins by puncturing target membranes. T6SSs are suggested to form a contractile nanomachine, functioning similar to the cell-puncturing device of tailed bacteriophages. The T6SS members VipA/VipB form tubular complexes and are predicted to function in analogy to viral tail sheath proteins by providing the energy for secretion via contraction. The ATPase ClpV disassembles VipA/VipB tubules in vitro, but the physiological relevance of tubule disintegration remained unclear. Here, we show that VipA/VipB tubules localize near-perpendicular to the inner membrane of Vibrio cholerae cells and exhibit repetitive cycles of elongation, contraction and disassembly. VipA/VipB tubules are decorated by ClpV in vivo and become static in clpV cells, indicating that ClpV is required for tubule removal. VipA/VipB tubules mislocalize in clpV cells and exhibit a reduced frequency of tubule elongation, indicating that ClpV also suppresses the spontaneous formation of contracted, non-productive VipA/VipB tubules. ClpV activity is restricted to the contracted state of VipA/VipB, allowing formation of functional elongated tubules at a T6SS assembly. Targeting of an unrelated ATPase to VipA/VipB is sufficient to replace ClpV function in vivo, suggesting that ClpV activity is autonomously regulated by VipA/VipB conformation.