Department of Plant Biology, Cornell University, Ithaca, New York 14853; email:
Annu Rev Plant Biol. 2015;66:75-111. doi: 10.1146/annurev-arplant-043014-115547. Epub 2015 Jan 12.
Plastids, mitochondria, and peroxisomes are key organelles with dynamic proteomes in photosynthetic eukaryotes. Their biogenesis and activity must be coordinated and require intraorganellar protein maturation, degradation, and recycling. The three organelles together are predicted to contain ∼200 presequence peptidases, proteases, aminopeptidases, and specific protease chaperones/adaptors, but the substrates and substrate selection mechanisms are poorly understood. Similarly, lifetime determinants of organellar proteins, such as N-end degrons and tagging systems, have not been identified, but the substrate recognition mechanisms likely share similarities between organelles. Novel degradomics tools for systematic analysis of protein lifetime and proteolysis could define such protease-substrate relationships, degrons, and protein lifetime. Intraorganellar proteolysis is complemented by autophagy of whole organelles or selected organellar content, as well as by cytosolic protein ubiquitination and degradation by the proteasome. This review summarizes (putative) plant organellar protease functions and substrate-protease relationships. Examples illustrate key proteolytic events.
质体、线粒体和过氧化物酶体是光合真核生物中具有动态蛋白质组的关键细胞器。它们的生物发生和活性必须协调，并需要细胞器内蛋白质的成熟、降解和再循环。这三个细胞器预计共包含约 200 种前导肽酶、蛋白酶、氨肽酶和特定的蛋白酶伴侣/适配器，但底物和底物选择机制知之甚少。同样，细胞器蛋白的寿命决定因素，如 N 端降解物和标记系统，尚未确定，但底物识别机制在细胞器之间可能具有相似性。用于系统分析蛋白质寿命和蛋白水解的新型降解组学工具可以定义这种蛋白酶-底物关系、降解物和蛋白质寿命。细胞器内的蛋白水解作用由整个细胞器或选定的细胞器内容的自噬、以及细胞质中蛋白质的泛素化和蛋白酶体的降解来补充。这篇综述总结了（假定的）植物细胞器蛋白酶的功能和底物-蛋白酶关系。示例说明了关键的蛋白水解事件。
