The membrane-embedded FtsH proteases found in bacteria, chloroplasts, and mitochondria are involved in diverse cellular processes including protein quality control and regulation. The genome of the model cyanobacterium Synechocystis sp PCC 6803 encodes four FtsH homologs designated FtsH1 to FtsH4. The FtsH3 homolog is present in two hetero-oligomeric complexes: FtsH2/3, which is responsible for photosystem II quality control, and the essential FtsH1/3 complex, which helps maintain Fe homeostasis by regulating the level of the transcription factor Fur. To gain a more comprehensive insight into the physiological roles of FtsH hetero-complexes, we performed genome-wide expression profiling and global proteomic analyses of Synechocystis mutants conditionally depleted of FtsH3 or FtsH1 grown under various nutrient conditions. We show that the lack of FtsH1/3 leads to a drastic reduction in the transcriptional response to nutrient stress of not only Fur but also the Pho, NdhR, and NtcA regulons. In addition, this effect is accompanied by the accumulation of the respective transcription factors. Thus, the FtsH1/3 complex is of critical importance for acclimation to iron, phosphate, carbon, and nitrogen starvation in Synechocystis.plantcell;31/12/2912/FX1F1fx1.

中文翻译：

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FtsH1/3 蛋白水解复合物的消耗会抑制蓝藻集胞藻菌株 PCC 6803 中的营养应激反应。

在细菌、叶绿体和线粒体中发现的膜嵌入 FtsH 蛋白酶参与多种细胞过程，包括蛋白质质量控​​制和调节。模型蓝藻集胞藻 PCC 6803 的基因组编码四种 FtsH 同源物，命名为 FtsH1 至 FtsH4。FtsH3 同源物存在于两个异源寡聚复合物中：FtsH2/3（负责光系统 II 质量控制）和必需的 FtsH1/3 复合物（通过调节转录因子 Fur 的水平帮助维持 Fe 稳态）。为了更全面地了解 FtsH 异质复合物的生理作用，我们对在各种营养条件下生长的条件性耗尽 FtsH3 或 FtsH1 的集胞藻突变体进行了全基因组表达谱和全局蛋白质组分析。我们发现，FtsH1/3 的缺乏不仅会导致 Fur，而且还会导致 Pho、NdhR 和 NtcA 调节子对营养胁迫的转录反应急剧减少。此外，该效应伴随着各转录因子的积累。因此，FtsH1/3 复合物对于集胞藻 (Synechocystis.plantcell) 适应铁、磷酸盐、碳和氮饥饿至关重要；31/12/2912/FX1F1fx1。