Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI, 48201, USA.
Instituto de Investigaciones Químicas, Universidad de Sevilla - CSIC, 41092, Sevilla, Spain.
Nat Commun. 2023 Jul 13;14(1):4166. doi: 10.1038/s41467-023-39820-8.
Skeletal muscle is more resilient to ischemia-reperfusion injury than other organs. Tissue specific post-translational modifications of cytochrome c (Cytc) are involved in ischemia-reperfusion injury by regulating mitochondrial respiration and apoptosis. Here, we describe an acetylation site of Cytc, lysine 39 (K39), which was mapped in ischemic porcine skeletal muscle and removed by sirtuin5 in vitro. Using purified protein and cellular double knockout models, we show that K39 acetylation and acetylmimetic K39Q replacement increases cytochrome c oxidase (COX) activity and ROS scavenging while inhibiting apoptosis via decreased binding to Apaf-1, caspase cleavage and activity, and cardiolipin peroxidase activity. These results are discussed with X-ray crystallography structures of K39 acetylated (1.50 Å) and acetylmimetic K39Q Cytc (1.36 Å) and NMR dynamics. We propose that K39 acetylation is an adaptive response that controls electron transport chain flux, allowing skeletal muscle to meet heightened energy demand while simultaneously providing the tissue with robust resilience to ischemia-reperfusion injury.
骨骼肌比其他器官更能耐受缺血再灌注损伤。细胞色素 c（Cytc）的组织特异性翻译后修饰通过调节线粒体呼吸和细胞凋亡参与缺血再灌注损伤。在这里，我们描述了 Cytc 的一个乙酰化位点，赖氨酸 39（K39），该位点在缺血猪骨骼肌中被定位，并在体外被 sirtuin5 去除。使用纯化蛋白和细胞双敲除模型，我们表明 K39 乙酰化和乙酰模拟 K39Q 取代通过减少与 Apaf-1、半胱天冬酶切割和活性以及心磷脂过氧化物酶活性的结合，增加细胞色素 c 氧化酶（COX）活性和 ROS 清除，同时抑制细胞凋亡。这些结果与 K39 乙酰化（1.50 Å）和乙酰模拟 K39Q Cytc（1.36 Å）的 X 射线晶体结构和 NMR 动力学进行了讨论。我们提出 K39 乙酰化是一种适应性反应，它控制电子传递链通量，使骨骼肌能够满足更高的能量需求，同时为组织提供对缺血再灌注损伤的强大抵抗力。
