Zhang Yong, Zhao Zhiyun, Ke Bilun, Wan Lin, Wang Hui, Ye Jianping
Antioxidant and Gene Regulation Laboratory, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, United States of America.
Laboratory of Transplantation Immunology, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, China.
PLoS One. 2016 Mar 1;11(3):e0150454. doi: 10.1371/journal.pone.0150454. eCollection 2016.
It is generally accepted that ATP regulates mitochondrial function through the AMPK signaling pathway. However, the AMPK-independent pathway remains largely unknown. In this study, we investigated ATP surplus in the negative regulation of mitochondrial function with a focus on pyruvate dehydrogenase (PDH) phosphorylation and protein acetylation. PDH phosphorylation was induced by a high fat diet in the liver of obese mice, which was associated with ATP elevation. In 1c1c7 hepatoma cells, the phosphorylation was induced by palmitate treatment through induction of ATP production. The phosphorylation was associated with a reduction in mitochondria oxygen consumption after 4 h treatment. The palmitate effect was blocked by etomoxir, which inhibited ATP production through suppression of fatty acid β-oxidation. The PDH phosphorylation was induced by incubation of mitochondrial lysate with ATP in vitro without altering the expression of PDH kinase 2 (PDK2) and 4 (PDK4). In addition, acetylation of multiple mitochondrial proteins was induced by ATP in the same conditions. Acetyl-CoA exhibited a similar activity to ATP in induction of the phosphorylation and acetylation. These data suggest that ATP elevation may inhibit mitochondrial function through induction of the phosphorylation and acetylation of mitochondrial proteins. The results suggest an AMPK-independent mechanism for ATP regulation of mitochondrial function.
普遍认为，ATP通过AMPK信号通路调节线粒体功能。然而，不依赖AMPK的通路在很大程度上仍不清楚。在本研究中，我们以丙酮酸脱氢酶（PDH）磷酸化和蛋白质乙酰化为重点，研究了ATP过剩在线粒体功能负调控中的作用。肥胖小鼠肝脏中，高脂饮食诱导了PDH磷酸化，这与ATP升高有关。在1c1c7肝癌细胞中，棕榈酸酯处理通过诱导ATP生成诱导了磷酸化。处理4小时后，磷酸化与线粒体氧消耗减少有关。依托莫昔芬可阻断棕榈酸酯的作用，它通过抑制脂肪酸β-氧化抑制ATP生成。体外将线粒体裂解物与ATP孵育可诱导PDH磷酸化，而不改变PDH激酶2（PDK2）和4（PDK4）的表达。此外，在相同条件下，ATP可诱导多种线粒体蛋白的乙酰化。乙酰辅酶A在诱导磷酸化和乙酰化方面表现出与ATP相似的活性。这些数据表明，ATP升高可能通过诱导线粒体蛋白的磷酸化和乙酰化来抑制线粒体功能。研究结果提示了一种不依赖AMPK的ATP调节线粒体功能的机制。
