Sorting of an integral outer membrane protein via the lipoprotein-specific Lol pathway and a dedicated lipoprotein pilotin
Sorting of an integral outer membrane protein via the lipoprotein-specific Lol pathway and a dedicated lipoprotein pilotin
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DOI：
10.1111/j.1365-2958.2011.07596.x
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发表时间：
2011-05-01
影响因子：
3.6
通讯作者：
Pugsley, Anthony P.
中科院分区：
文献类型：
--
作者：
Collin, Severine;Guilvout, Ingrid;Pugsley, Anthony P.
脂蛋白普尔斯是一种专门的伴侣蛋白，在克雷伯氏菌或大肠杆菌中，需要将分泌素PulD靶向外膜，并保护其免受蛋白水解。在这里，我们提出了间接的证据，PulD的原聚体不组装成分泌素十二聚体之前，他们到达外膜，和普尔斯到达外膜的可溶性异源二聚体与一般脂蛋白伴侣LolA。然而，我们不能找到任何直接的证据PulD原聚体与PulS-LolA异二聚体。相反，在产生PulD和永久锁定的PulS-LolA二聚体（其中LolA携带阻止脂蛋白转移到外膜中的LolB的R43 L取代）的细胞中，在内膜中发现LolAR 43 L，可能仍然与结合到PulD的普尔斯相关，PulD由于LolAR 43 L取代而被错误地靶向。据推测，PulD原聚体通常与结合到LolA的普尔斯一起穿过周质，但是当后者不能分离时（由于lolA中的突变），PulD原聚体形成插入内膜的十二聚体。
P>The lipoprotein PulS is a dedicated chaperone that is required to target the secretin PulD to the outer membrane in Klebsiella or Escherichia coli, and to protect it from proteolysis. Here, we present indirect evidence that PulD protomers do not assemble into the secretin dodecamer before they reach the outer membrane, and that PulS reaches the outer membrane in a soluble heterodimer with the general lipoprotein chaperone LolA. However, we could not find any direct evidence for PulD protomer association with the PulS-LolA heterodimer. Instead, in cells producing PulD and a permanently locked PulS-LolA dimer (in which LolA carries an R43L substitution that prevents lipoprotein transfer to LolB in the outer membrane), LolAR43L was found in the inner membrane, probably still associated with PulS bound to PulD that had been incorrectly targeted because of the LolAR43L substitution. It is speculated that PulD protomers normally cross the periplasm together with PulS bound to LolA but when the latter cannot be separated (due to the mutation in lolA), the PulD protomers form dodecamers that insert into the inner membrane.