Shimazu Tadahiro, Kataoka Ayane, Suzuki Takehiro, Dohmae Naoshi, Shinkai Yoichi
Cellular Memory Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan.
Biomolecular Characterization Unit, Technology Platform Division, RIKEN Center for Sustainable Resource Science, Wako, Saitama 351-0198, Japan.
iScience. 2025 Jul 29;28(9):113233. doi: 10.1016/j.isci.2025.113233. eCollection 2025 Sep 19.
Protein acetylation plays crucial roles in diverse biological functions, including mitochondrial metabolism. Although SIRT3 catalyzes the removal of acetyl groups in mitochondria, the addition of the acetyl groups is thought to be primarily controlled in an enzyme-independent manner due to the absence of potent acetyltransferases. In this study, we developed an engineered mitochondria-localized acetyltransferase, named engineered mitochondrial acetyltransferase (eMAT). eMAT localized in the mitochondrial matrix and introduced robust global protein lysine acetylation, including 413 proteins with 1,119 target lysine residues. Notably, 74% of the acetylated proteins overlapped with previously known acetylated proteins, indicating that the eMAT-mediated acetylation system is physiologically relevant. Functionally, eMAT negatively regulated mitochondrial energy metabolism, inhibited cell growth, and promoted cellular senescence, suggesting that mitochondrial hyper-acetylation drives metabolic inhibition and cellular senescence. SIRT3 counteracted eMAT-induced acetylation and metabolic inhibition, restored cell growth, and protected cells from senescence, highlighting the contribution of SIRT3 in maintaining energy metabolism and preventing cellular senescence.
蛋白质乙酰化在包括线粒体代谢在内的多种生物学功能中发挥着关键作用。尽管SIRT3催化线粒体中乙酰基的去除，但由于缺乏有效的乙酰转移酶，乙酰基的添加被认为主要以非酶依赖的方式受到控制。在本研究中，我们开发了一种工程化的线粒体定位乙酰转移酶，命名为工程化线粒体乙酰转移酶（eMAT）。eMAT定位于线粒体基质，并引入了强大的全局蛋白质赖氨酸乙酰化，包括413种含有1119个靶赖氨酸残基的蛋白质。值得注意的是，74%的乙酰化蛋白质与先前已知的乙酰化蛋白质重叠，表明eMAT介导的乙酰化系统具有生理相关性。在功能上，eMAT负向调节线粒体能量代谢，抑制细胞生长，并促进细胞衰老，这表明线粒体过度乙酰化驱动代谢抑制和细胞衰老。SIRT3抵消了eMAT诱导的乙酰化和代谢抑制，恢复了细胞生长，并保护细胞免于衰老，突出了SIRT3在维持能量代谢和预防细胞衰老中的作用。
