Toc34 is a preprotein receptor regulated by GTP and phosphorylation
Toc34 is a preprotein receptor regulated by GTP and phosphorylation
复制标题
DOI：
10.1073/pnas.080491597
复制
发表时间：
2000-04-25
影响因子：
11.1
通讯作者：
Schleiff, E
中科院分区：
文献类型：
--
作者：
Sveshnikova, N;Soll, J;Schleiff, E
叶绿体中存在的大多数蛋白质在胞质溶胶中合成，并在胞质分裂后转运到细胞器中。一个多组分的易位机制位于外和内被膜的叶绿体被确定，但许多亚基的行动方式仍然不清楚。在这里，我们描述了发生在外膜处的易位早期步骤的调节。外被膜转位子亚基Toc34可以被磷酸化，并且GTP结合受磷酸化调节。体外Toc34作为含有叶绿体靶向信号的蛋白质的受体。Toc34与转运肽的相互作用受到高度调节，并且依赖于CTP与Toc34的结合以及前蛋白的转运肽的磷酸化。
Most proteins present in chloroplasts are synthesized in the cytosol and are posttranslationally translocated into the organelle. A multicomponent translocation machinery located in both the outer and the inner envelope of chloroplasts was identified, but the mode of action of many subunits remains unclear. Here, we describe the regulation of an early step of translocation occurring at the outer envelope. The outer envelope translocon subunit Toc34 can be phosphorylated, and GTP binding is regulated by phosphorylation. In vitro. Toc34 acts as a receptor for proteins containing a chloroplast-targeting signal. Interaction of Toc34 with the transit peptide is highly regulated and depends on CTP binding to Toc34 and on phosphorylation of the transit peptide of the preprotein.