A conserved extended signal peptide region directs posttranslational protein translocation via a novel mechanism
A conserved extended signal peptide region directs posttranslational protein translocation via a novel mechanism
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DOI：
10.1099/mic.0.29091-0
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发表时间：
2007-01-01
期刊：
影响因子：
2.8
通讯作者：
Henderson, Ian R.
中科院分区：
文献类型：
--
作者：
Desvaux, Mickael;Scott-Tucker, Anthony;Henderson, Ian R.
V型分泌家族的成员是革兰氏阴性菌中最普遍的分泌蛋白。该家族的一个子集，包括肠杆菌科丝氨酸蛋白酶的原型成员Pet，具有不寻常的信号肽，其可分为称为N1（带电）、H1（疏水）、N2、H2和C（切割位点）结构域的五个区域。N1和H1区，作者命名为扩展信号肽区（ESPR），表现出显着的保守性。相比之下，N2，H2和C区显示出显着的变异性，并让人想起典型的SEC依赖性信号序列。尽管进行了多次研究，但ESPIR的功能仍然不清楚。在这里，它表明，具有ESPR的蛋白质在翻译后的方式易位。ESPR的存在严重损害内膜易位。突变分析表明，ESPR通过采用特定的构象，或通过在内膜移位之前与细胞质或内膜辅因子相互作用来延迟内膜移位。
Members of the type V secretion family are among the most prevalent secreted proteins in Gram-negative bacteria. A subset of this family, including Pet, the prototypical member of the Enterobacteriaceae serine proteases, possess unusual signal peptides which can be divided into five regions termed N1 (charged), H1 (hydrophobic), N2, H2 and C (cleavage site) domains. The N1 and H1 regions, which the authors have named the extended signal peptide region (ESPR), demonstrate remarkable conservation. In contrast, the N2, H2 and C regions show significant variability, and are reminiscent of typical Sec-dependent signal sequences. Despite several investigations, the function of the ESPIR remains obscure. Here, it is shown that proteins possessing the ESPR are translocated in a posttranslational fashion. The presence of the ESPR severely impairs inner membrane translocation. Mutational analysis suggests that the ESPR delays inner membrane translocation by adopting a particular conformation, or by interacting with a cytoplasmic or inner membrane co-factor, prior to inner membrane translocation.