Complete maturation of the plastid protein translocation channel requires a type I signal peptidase.
Complete maturation of the plastid protein translocation channel requires a type I signal peptidase.
复制标题
质体蛋白易位通道的完全成熟需要I型信号肽酶。
DOI：
10.1083/jcb.200506171
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发表时间：
2005-11-07
影响因子：
7.8
通讯作者：
Ohme-Takagi, Masaru
中科院分区：
文献类型：
--
作者：
Inoue, Kentaro;Baldwin, Amy J;Shipman, Rebecca L;Matsui, Kyoko;Theg, Steven M;Ohme-Takagi, Masaru
质体外被膜Toc75上的蛋白质转运通道对植物从胚胎阶段开始的生存能力是必不可少的。它在细胞核中编码，并与在成熟过程中裂解的二分转运肽合成。尽管Toc75具有重要的功能，但其完全成熟的分子机制和生物学意义仍不清楚。在这项研究中，我们表明，I型信号肽酶（SPase I）负责这一过程。首先，我们证明了细菌SPase I在体外将Toc75前体转化为其成熟形式。接下来，我们表明，破坏的基因编码质体SPase I（Plsp1）导致积累的不成熟形式的Toc75，严重减少质体内膜的发展，和幼苗致死表型。这些表型通过Plsp 1互补DNA的过表达而被拯救。Plsp1似乎既靶向包膜又靶向类囊体膜，因此，它可能具有多种功能。
The protein translocation channel at the plastid outer envelope membrane, Toc75, is essential for the viability of plants from the embryonic stage. It is encoded in the nucleus and is synthesized with a bipartite transit peptide that is cleaved during maturation. Despite its important function, the molecular mechanism and the biological significance of the full maturation of Toc75 remain unclear. In this study, we show that a type I signal peptidase (SPase I) is responsible for this process. First, we demonstrate that a bacterial SPase I converted Toc75 precursor to its mature form in vitro. Next, we show that disruption of a gene encoding plastidic SPase I (Plsp1) resulted in the accumulation of immature forms of Toc75, severe reduction of plastid internal membrane development, and a seedling lethal phenotype. These phenotypes were rescued by the overexpression of Plsp1 complementary DNA. Plsp1 appeared to be targeted both to the envelope and to the thylakoidal membranes; thus, it may have multiple functions.