The CLP and PREP protease systems coordinate maturation and degradation of the chloroplast proteome in Arabidopsis thaliana
The CLP and PREP protease systems coordinate maturation and degradation of the chloroplast proteome in Arabidopsis thaliana
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CLP 和 PREP 蛋白酶系统协调拟南芥叶绿体蛋白质组的成熟和降解
DOI：
10.1111/nph.18426
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发表时间：
2022
期刊：
影响因子：
9.4
通讯作者：
van Wijk, Klaas J.
中科院分区：
文献类型：
--
作者：
Rowland, Elden;Kim, Jitae;Friso, Giulia;Poliakov, Anton;Ponnala, Lalit;Sun, Qi;van Wijk, Klaas J.
多肽酶网络控制植物叶绿体和线粒体中的蛋白平衡。本研究揭示了拟南芥中叶绿体基质中的CLP伴侣蛋白水解酶系统和PREP1，2多肽酶之间的遗传和功能上的强相互作用，它们位于叶绿体基质和线粒体基质中。利用定量蛋白质组学和N末端蛋白质组学(TILS)分析了在CLP或PREP蛋白中存在缺陷的高位突变体。CLP蛋白系统(clpr1-2，clpr2-1，clp1-1，clpt1，clpt2)与这两个prep同源物(prep1，prep2)具有很强的协同作用，导致了胚胎的生长和表型。即使只缺少一个PREP蛋白，也观察到了协同作用，这表明PREP1和PREP2具有不同的底物。蛋白质组的表型是由CLP蛋白酶能力的丧失所驱动的，而PREP多肽酶对其影响很小。叶绿体N端蛋白质组研究表明，许多核编码的叶绿体蛋白在prepre1 prep2、clpt1clpt2和prepre1prep2clpt1clpt2中交替处理N端。由于折叠胁迫和较低水平的CTP裂解片段积累，叶绿体蛋白水解酶能力的丧失干扰了基质加工肽酶(SPP)的活性。被切割的CTP的PREP1，2蛋白分解被未知的酶所补充。提出了一个分级叶绿体蛋白分解网络中CLP和PREP活性的模型。
A network of peptidases governs proteostasis in plant chloroplasts and mitochondria. This study reveals strong genetic and functional interactions in Arabidopsis between the chloroplast stromal CLP chaperone‐protease system and the PREP1,2 peptidases, which are dually localized to chloroplast stroma and the mitochondrial matrix.Higher order mutants defective in CLP or PREP proteins were generated and analyzed by quantitative proteomics and N‐terminal proteomics (terminal amine isotopic labeling of substrates (TAILS)).Strong synergistic interactions were observed between the CLP protease system (clpr1‐2,clpr2‐1,clpc1‐1,clpt1,clpt2)and both PREP homologs (prep1,prep2) resulting in embryo lethality or growth and developmental phenotypes. Synergistic interactions were observed even when only one of the PREP proteins was lacking, suggesting that PREP1 and PREP2 have divergent substrates. Proteome phenotypes were driven by the loss of CLP protease capacity, with little impact from the PREP peptidases. Chloroplast N‐terminal proteomesshowed that many nuclear encoded chloroplast proteins have alternatively processed N‐termini inprep1prep2,clpt1clpt2andprep1prep2clpt1clpt2.Loss of chloroplast protease capacity interferes with stromal processing peptidase (SPP) activity due to folding stress and low levels of accumulated cleaved cTP fragments. PREP1,2 proteolysis of cleaved cTPs is complemented by unknown proteases. A model for CLP and PREP activity within a hierarchical chloroplast proteolysis network is proposed.