Sirtuins deacetylate and activate mammalian acetyl-CoA synthetases
Sirtuins deacetylate and activate mammalian acetyl-CoA synthetases
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DOI：
10.1073/pnas.0604392103
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发表时间：
2006-07-05
影响因子：
11.1
通讯作者：
Denu, John M.
中科院分区：
文献类型：
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作者：
Hallows, William C.;Lee, Susan;Denu, John M.
沉默信息调节器 2 (Sir2) 酶（或 Sirtuins）是 NAD(+) 依赖性脱乙酰酶，可调节基因沉默、衰老和能量代谢。先前的研究表明几种转录因子是 Sirtuin 的靶标。在这里，我们研究了哺乳动物去乙酰化酶是否可以直接控制代谢酶的活性。我们证明哺乳动物乙酰辅酶A合成酶（AceCS）受到可逆乙酰化的调节，并且sirtuins通过去乙酰化激活AceCS。通过使用质谱法和特异性抗乙酰基-AceCS 抗体，鉴定了小鼠 AceCS1 在 Lys-661 上的位点特异性乙酰化。 SIRT1 是七个人类 Sir2 同源物中唯一能够在细胞共表达实验中使 AceCS1 去乙酰化的成员。 SIRT1 表达还导致 AceCS1 依赖性的乙酸盐脂肪酸合成显着增加。使用纯化的酶，只有 SIRT1 和 SIRT3 对乙酰化 AceCS1 表现出高催化效率。在哺乳动物中，已鉴定出两种 AceCS：细胞质 AceCS1 和线粒体 AceCS2。由于 SIRT3 定位于线粒体，我们研究了 AceCS2 是否也可能受到乙酰化的调节，特别是被线粒体 SIRT3 脱乙酰化。 AceCS2 在乙酰化后完全失活，并通过 SIRT3 脱乙酰化迅速重新激活。小鼠 AceCS2 的 Lys-635 被鉴定为目标残基。使用可逆乙酰化来调节酶活性，我们提出了一个通过 SIRT1 控制 AceCS1 和通过 SIRT3 控制 AceCS2 的模型。
Silent Information Regulator 2 (Sir2) enzymes (or sirtuins) are NAD(+)-dependent deacetylases that modulate gene silencing, aging and energy metabolism. Previous work has implicated several transcription factors as sirtuin targets. Here, we investigated whether mammalian sirtuins could directly control the activity of metabolic enzymes. We demonstrate that mammalian Acetyl-CoA synthetases (AceCSs) are regulated by reversible acetylation and that sirtuins activate AceCSs by deacetylation. Site-specific acetylation of mouse AceCS1 on Lys-661 was identified by using mass spectrometry and a specific anti-acetyl-AceCS antibody. SIRT1 was the only member of seven human Sir2 homologues capable of deacetylating AceCS1 in cellular coexpression experiments. SIRT1 expression also led to a pronounced increase in AceCS1-dependent fatty-acid synthesis from acetate. Using purified enzymes, only SIRT1 and SIRT3 exhibited high catalytic efficiency against acetylated AceCS1. In mammals, two AceCSs have been identified: cytoplasmic AceCS1 and mitochondrial AceCS2. Because SIRT3 is localized to the mitochondria, we investigated whether AceCS2 also might be regulated by acetylation, and specifically deacetylated by mitochondrial SIRT3. AceCS2 was completely inactivated upon acetylation and was rapidly reactivated by SIRT3 deacetylation. Lys-635 of mouse AceCS2 was identified as the targeted residue. Using reversible acetylation to modulate enzyme activity, we propose a model for the control of AceCS1 by SIRT1 and of AceCS2 by SIRT3.