Systems Biochemistry, Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, Ruhr-University Bochum, Universitätsstr. 150, 44780, Bochum, Germany.
Protein J. 2019 Jun;38(3):351-362. doi: 10.1007/s10930-019-09835-6.
Blobel and coworkers discovered in 1978 that peroxisomal proteins are synthesized on free ribosomes in the cytosol and thus provided the grounds for the conception of peroxisomes as self-containing organelles. Peroxisomes are highly adaptive and versatile organelles carrying out a wide variety of metabolic functions. A striking feature of the peroxisomal import machinery is that proteins can traverse the peroxisomal membrane in a folded and even oligomeric state via cycling receptors. We outline essential steps of peroxisomal matrix protein import, from targeting of the proteins to the peroxisomal membrane, their translocation via transient pores and export of the corresponding cycling import receptors with emphasis on the situation in yeast. Peroxisomes can contribute to the adaptation of cells to different environmental conditions. This is realized by changes in metabolic functions and thus the enzyme composition of the organelles is adopted according to the cellular needs. In recent years, it turned out that this organellar diversity is based on an elaborate regulation of gene expression and peroxisomal protein import. The latter is in the focus of this review that summarizes our knowledge on the composition and function of the peroxisomal protein import machinery with emphasis on novel alternative protein import pathways.
1978 年，Blobel 和同事们发现过氧化物酶体蛋白是在细胞质中的游离核糖体上合成的，这为过氧化物酶体作为独立细胞器的概念提供了依据。过氧化物酶体是高度适应性和多功能的细胞器，执行着各种各样的代谢功能。过氧化物酶体输入机制的一个显著特点是，蛋白质可以在折叠状态甚至寡聚状态下通过循环受体穿越过氧化物酶体膜。我们概述了过氧化物酶体基质蛋白输入的基本步骤，从蛋白质靶向过氧化物酶体膜，到通过瞬时孔的易位，以及相应的循环输入受体的输出，重点介绍了酵母中的情况。过氧化物酶体可以帮助细胞适应不同的环境条件。这是通过改变代谢功能来实现的，因此细胞器的酶组成根据细胞的需要进行调整。近年来，事实证明，这种细胞器的多样性是基于基因表达的精细调控和过氧化物酶体蛋白的输入。后者是这篇综述的重点，总结了我们对过氧化物酶体蛋白输入机制的组成和功能的认识，重点介绍了新的替代蛋白输入途径。
