Chen Runtai, Tabatabaei Dakhili Seyed Amirhossein, Gerulskis Rokas, Zhao Yuan-Yuan, Lockhart Steven, Tonoyan Lusine, Siraki Arno G, Huang Guocheng, Kinnaird Adam, Freed Darren H, Minteer Shelley D, Michelakis Evangelos D, Ussher John R, Sutendra Gopinath
Department of Medicine, University of Alberta, Edmonton, Alberta, Canada; Cardiovascular Research Institute, University of Alberta, Edmonton, Alberta, Canada; Cancer Research Institute of Northern Alberta, University of Alberta, Edmonton, Alberta, Canada.
Cardiovascular Research Institute, University of Alberta, Edmonton, Alberta, Canada; Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, Canada.
J Biol Chem. 2025 Aug 5;301(9):110555. doi: 10.1016/j.jbc.2025.110555.
The mitochondrial electron transport chain (ETC) is a four complex unit that could be considered the most essential infrastructure within the mitochondria, as it primarily functions to generate the mitochondrial membrane potential (ΔΨm), which can then be utilized for ATP synthesis or heat production. Another important aspect of ETC function is the generation of mitochondrial reactive oxygen species (mtROS), which are essential physiologic signaling mediators that can be toxic to the cell if their levels become too high. Currently, it remains unresolved how a highly utilized and functioning ETC can sense excessive mtROS generation and adapt, to enhance ΔΨm. Here, we identified a redox hub consisting of cysteine (Cys) residues 64, 75, 78, and 92 within Ndufs1 of complex I of the ETC. Oxidation of these Cys residues promotes the incorporation of complex I into the respirasome supercomplex. Mechanistically, oxidation of the redox hub increased the distance between Fe-S clusters N5 and N6a in complex I, compromising complex I activity. This impairment was rescued by integration with complex III and IV into the respirasome supercomplex. Compared to parental cells or Ndufs1-KO cells, C92D (an oxidation mimetic) Ndufs1-knockin A549 cells had higher levels of ETC supercomplexes, ΔΨm and oxygen consumption rates, while isolated mitochondrial membranes generated more electrical current when integrated onto a biobattery platform. Disruption of ETC supercomplexes with MitoTam increased the therapeutic efficacy of mtROS inducing chemotherapeutics in both C92D Ndufs1-knockin or metastatic lung cancer cells. These findings provide new insights into how the ETC can initiate supercomplex transformation.
线粒体电子传递链（ETC）是一个由四个复合体组成的单元，可以被认为是线粒体内最基本的结构，因为它的主要功能是产生线粒体膜电位（ΔΨm），然后可用于ATP合成或产热。ETC功能的另一个重要方面是线粒体活性氧（mtROS）的产生，mtROS是重要的生理信号介质，如果其水平过高会对细胞有毒性。目前，高度活跃且功能正常的ETC如何感知过量的mtROS产生并进行适应性调节以增强ΔΨm仍未得到解决。在这里，我们在ETC复合体I的Ndufs1中鉴定出一个由半胱氨酸（Cys）残基64、75、78和92组成的氧化还原中心。这些Cys残基的氧化促进复合体I并入呼吸体超复合体。从机制上讲，氧化还原中心的氧化增加了复合体I中Fe-S簇N5和N6a之间的距离，损害了复合体I的活性。通过与复合体III和IV整合到呼吸体超复合体中，这种损伤得以挽救。与亲代细胞或Ndufs1基因敲除细胞相比，C92D（一种氧化模拟物）Ndufs1基因敲入的A549细胞具有更高水平的ETC超复合体、ΔΨm和氧消耗率，而分离的线粒体膜在整合到生物电池平台上时产生更多电流。用MitoTam破坏ETC超复合体增加了mtROS诱导化疗药物在C92D Ndufs1基因敲入细胞或转移性肺癌细胞中的治疗效果。这些发现为ETC如何启动超复合体转变提供了新的见解。
