Department of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, WI, 53706, USA.
Photosynth Res. 2018 Dec;138(3):277-287. doi: 10.1007/s11120-018-0541-9. Epub 2018 Jun 27.
Chloroplasts inherited systems and strategies for protein targeting, translocation, and integration from their cyanobacterial ancestor. Unlike cyanobacteria however, chloroplasts in green algae and plants contain two distinct SEC translocase/integrase systems: the SEC1 system in the thylakoid membrane and the SEC2 system in the inner envelope membrane. This review summarizes the mode of action of SEC translocases, identification of components of the SEC2 system, evolutionary history of SCY and SECA genes, and previous work on the co- and post-translational targeting of lumenal and thylakoid membrane proteins to the SEC1 system. Recent work identifying substrates for the SEC2 system and potential features that may contribute to inner envelope targeting are also discussed.
叶绿体从其蓝藻祖先那里继承了蛋白质靶向、易位和整合的系统和策略。然而，与蓝细菌不同的是，绿藻和植物中的叶绿体含有两个不同的 SEC 易位酶/整合酶系统：类囊体膜中的 SEC1 系统和内囊体膜中的 SEC2 系统。本综述总结了 SEC 易位酶的作用模式、SEC2 系统成分的鉴定、SCY 和 SECA 基因的进化历史，以及以前关于腔和类囊体膜蛋白到 SEC1 系统的共翻译和翻译后靶向的工作。还讨论了最近确定 SEC2 系统底物的工作以及可能有助于内囊体靶向的潜在特征。
