Unravelling the role of the mitochondrial CLPXP complex in protein quality control, aging and development of Podospora anserina

线粒体ClpXP是一种位于线粒体基质中的蛋白酶复合体，其生物学作用目前尚不清楚。在酵母中，CLPP缺失，但CLPX参与了许多线粒体途径(如线粒体基因组的维持)。在秀丽线虫中，ClpXP参与UPRmt，在哺乳动物中，其在这一过程中的作用是有争议的。然而，在最近的一项研究中，CLPP在控制与急性髓系白血病相关的能量代谢方面的功能被报道。在一种对这个特征不佳的蛋白质复合体进行功能表征的方法中，我们在真菌衰老模型Podospora anserina中确定了一些潜在的底物和相互作用伙伴。所鉴定的蛋白质有力地支持了PaCLPXP在控制细胞能量代谢中的作用。此外，我们发现，切除PaCLPXP组件会导致寿命延长和强烈地诱导自噬。这项研究计划更新的主要重点是阐明导致自噬诱导的分子机制，特别是PaCLPXP在这一过程中的控制作用。基于我们最近的发现，我们将(I)寻找并表征参与PaCLPXP依赖的线粒体到核信号转导的潜在转录调控因子，(Ii)将研究PaCLPXP的选定底物和相互作用伙伴。更具体地说，我们将分析在Anserina野生型和PaClpP缺失菌株的转录组分析中确定的差异表达的候选转录因子的作用。此外，我们还将通过分析野生型和PaClpXP突变体中关键酶的活性和相关代谢物的丰度来研究PaCLPXP在控制细胞能量代谢中的作用。从这些研究中，我们期待着关于线粒体ClpXP在控制细胞内稳态的复杂细胞网络中的生物学功能的重要新的令人兴奋的信息，这对于生物系统的正确发育和长期健康寿命是至关重要的。

The biological role of the mitochondrial CLPXP, a protease complex located in the mitochondrial matrix, is currently unsufficiently understood. In yeast, CLPP is missing but CLPX is implicated in a number of mitochondrial pathways (e.g. mitochondrial genome maintenance). In Caenorhabditis elegans CLPXP is involved in UPRmt, in mammals, its role in this process is controversially discussed. However, in a recent study a function of CLPP in the control of the energy metabolism related to acute myeloid leukemia was reported. In an approach towards the functional characterization of this poorly characterized protein complex, we identified a number of potential substrates and interaction partners in the fungal aging model Podospora anserina. The identified proteins strongly support a role of PaCLPXP in the control of cellular energy metabolism. Moreover, we found that ablation of PaCLPXP components results in an increased lifespan and a robust induction of autophagy. The main focus of the proposed renewal of this research project is the elucidation of the molecular mechanisms leading to autophagy induction and in particular the role of PaCLPXP in the control of this process. Based on our recent findings, we will (i) search for and characterize potential transcriptional regulators which are involved in PaCLPXP-dependent mitochondria-to-nucleus signaling and (ii) will study selected substrates and interaction partners of PaCLPXP. More specifically, we will analyze the role of candidate transcription factors identified as differentially expressed in a transcriptome analysis of the P. anserina wild type and the PaClpP deletion strain. In addition, we will study the role of PaCLPXP in controlling the cellular energy metabolism via the analysis of the activity of key enzymes and of the abundance of relevant metabolites in the wild type and PaClpXP mutants. From these investigations we expect important new exciting information about the biological function of mitochondrial CLPXP in the complex cellular network controlling cellular homeostasis that is of utmost importance for correct development and a long healthy lifespan of biological systems.