Schwerter Daniel P, Grimm Immanuel, Platta Harald W, Erdmann Ralf
Abteilung für Systembiochemie, Institut für Biochemie und Pathobiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum.
Biochemie Intrazellulärer Transportprozesse, Medizinische Fakultät der Ruhr-Universität Bochum, D-44780 Bochum.
Biol Chem. 2017 May 1;398(5-6):607-624. doi: 10.1515/hsz-2016-0293.
In peroxisomal matrix protein import two processes directly depend on the binding and hydrolysis of ATP, both taking place at the late steps of the peroxisomal import cycle. First, ATP hydrolysis is required to initiate a ubiquitin-transfer cascade to modify the import (co-)receptors. These receptors display a dual localization in the cytosol and at the peroxisomal membrane, whereas only the membrane bound fraction receives the ubiquitin modification. The second ATP-dependent process of the import cycle is carried out by the two AAA+-proteins Pex1p and Pex6p. These ATPases form a heterohexameric complex, which is recruited to the peroxisomal import machinery by the membrane anchor protein Pex15p. The Pex1p/Pex6p complex recognizes the ubiquitinated import receptors, pulls them out of the membrane and releases them into the cytosol. There the deubiquitinated receptors are provided for further rounds of import. ATP binding and hydrolysis are required for Pex1p/Pex6p complex formation and receptor export. In this review, we summarize the current knowledge on the peroxisomal import cascade. In particular, we will focus on the ATP-dependent processes, which are so far best understood in the model organism Saccharomyces cerevisiae.
在过氧化物酶体基质蛋白输入过程中，有两个过程直接依赖于ATP的结合与水解，这两个过程均发生在过氧化物酶体输入循环的后期。首先，需要ATP水解来启动泛素转移级联反应，以修饰输入（共）受体。这些受体在细胞质和过氧化物酶体膜上呈现双重定位，而只有膜结合部分会接受泛素修饰。输入循环的第二个ATP依赖过程由两个AAA +蛋白Pex1p和Pex6p执行。这些ATP酶形成一个异源六聚体复合物，该复合物通过膜锚定蛋白Pex15p被招募到过氧化物酶体输入机制中。Pex1p / Pex6p复合物识别泛素化的输入受体，将它们从膜中拉出并释放到细胞质中。在那里，去泛素化的受体可用于进一步的输入循环。Pex1p / Pex6p复合物的形成和受体输出需要ATP结合和水解。在本综述中，我们总结了目前关于过氧化物酶体输入级联反应的知识。特别是，我们将重点关注ATP依赖过程，到目前为止，在模式生物酿酒酵母中对这些过程的了解最为深入。
