Proteomic discovery of cellular substrates of the ClpXP protease reveals five classes of ClpX-recognition signals
Proteomic discovery of cellular substrates of the ClpXP protease reveals five classes of ClpX-recognition signals
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DOI：
10.1016/s1097-2765(03)00060-1
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发表时间：
2003-03-01
期刊：
影响因子：
16
通讯作者：
Baker, TA
中科院分区：
文献类型：
--
作者：
Flynn, JM;Neher, SB;Baker, TA
ClpXP是一种参与DNA损伤修复、稳定期基因表达和ssrA介导的蛋白质质量控制的蛋白酶。然而，迄今为止，仅鉴定了少数ClpXP底物。使用ClpP的标记和失活变体，E. coliClpXP中进行体内捕获、纯化并通过质谱鉴定。超过50种被捕获的蛋白质包括转录因子、代谢酶以及参与饥饿和氧化应激反应的蛋白质。对捕获的蛋白质的序列的分析揭示了五个重复的基序：两个位于蛋白质的C末端，和三个N末端基序。缺失分析、融合蛋白和点突变确定了来自每个基序类的序列被ClpXP降解的靶向蛋白。这些结果代表了AAA+家族ATP酶底物识别的一般规则的描述，并提出了调节蛋白质降解的策略。
ClpXP is a protease involved in DNA damage repair, stationary-phase gene expression, and ssrA-mediated protein quality control. To date, however, only a handful of ClpXP substrates have been identified. Using a tagged and inactive variant of ClpP, substrates of E. coli ClpXP were trapped in vivo, purified, and identified by mass spectrometry. The more than 50 trapped proteins include transcription factors, metabolic enzymes, and proteins involved in the starvation and oxidative stress responses. Analysis of the sequences of the trapped proteins revealed five recurring motifs: two located at the C terminus of proteins, and three N-terminal motifs. Deletion analysis, fusion proteins, and point mutations established that sequences from each motif class targeted proteins for degradation by ClpXP. These results represent a description of general rules governing substrate recognition by a AAA+ family ATPase and suggest strategies for regulation of protein degradation.