Inaba Takehito, Alvarez-Huerta Mayte, Li Ming, Bauer Jörg, Ewers Carolin, Kessler Felix, Schnell Danny J
Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003, USA.
Plant Cell. 2005 May;17(5):1482-96. doi: 10.1105/tpc.105.030700. Epub 2005 Apr 13.
The translocon at the inner envelope membrane of chloroplasts (Tic) plays a central role in plastid biogenesis by coordinating the sorting of nucleus-encoded preproteins across the inner membrane and coordinating the interactions of preproteins with the processing and folding machineries of the stroma. Despite these activities, the precise roles of known Tic proteins in translocation, sorting, and preprotein maturation have not been defined. In this report, we examine the in vivo function of a major Tic component, Tic110. We demonstrate that Arabidopsis thaliana Tic110 (atTic110) is essential for plastid biogenesis and plant viability. The downregulation of atTic110 expression results in the reduced accumulation of a wide variety of plastid proteins. The expression of dominant negative mutants of atTic110 disrupts assembly of Tic complexes and the translocation of preproteins across the inner envelope membrane. Together, these data suggest that Tic110 plays a general role in the import of nuclear-encoded preproteins as a common component of Tic complexes.
叶绿体内膜转位因子（Tic）通过协调核编码前体蛋白在内膜上的分选以及前体蛋白与基质加工和折叠机制的相互作用，在质体生物发生中发挥核心作用。尽管有这些功能，但已知的Tic蛋白在转位、分选和前体蛋白成熟中的精确作用尚未明确。在本报告中，我们研究了主要Tic组分Tic110的体内功能。我们证明拟南芥Tic110（atTic110）对质体生物发生和植物活力至关重要。atTic110表达的下调导致多种质体蛋白积累减少。atTic110显性负突变体的表达破坏了Tic复合物的组装以及前体蛋白在内膜上的转位。这些数据共同表明，Tic110作为Tic复合物的共同组分，在核编码前体蛋白的导入中起普遍作用。
