Arylamine N-acetyltransferase 1 (NAT1) is a phase II xenobiotic-metabolizing enzyme that also has a role in cancer cell growth and metabolism. Recently, it was reported that NAT1 undergoes lysine acetylation, an important post-translational modification that can regulate protein function. In the current study, we use site-directed mutagenesis to identify K100 and K188 as major sites of lysine acetylation in the NAT1 protein. Acetylation of ectopically expressed NAT1 in HeLa cells was decreased by C646, an inhibitor of the protein acetyltransferases p300/CREB-binding protein (CBP). Recombinant p300 directly acetylated NAT1 in vitro. Acetylation of NAT1 was enhanced by the sirtuin (SIRT) inhibitor nicotinamide but not by the histone deacetylase inhibitor trichostatin A. Cotransfection of cells with NAT1 and either SIRT 1 or 2, but not SIRT3, significantly decreased NAT1 acetylation. NAT1 activity was evaluated in cells after nicotinamide treatment to enhance acetylation or cotransfection with SIRT1 to inhibit acetylation. The results indicated that NAT1 acetylation impaired its enzyme kinetics, suggesting decreased acetyl coenzyme A binding. In addition, acetylation attenuated the allosteric effects of ATP on NAT1. Taken together, this study shows that NAT1 is acetylated by p300/CBP in situ and is deacetylated by the sirtuins SIRT1 and 2. It is hypothesized that post-translational modification of NAT1 by acetylation at K100 and K188 may modulate NAT1 effects in cells. SIGNIFICANCE STATEMENT: There is growing evidence that arylamine N-acetyltransferase 1 has an important cellular role in addition to xenobiotic metabolism. Here, we show that NAT1 is acetylated at K100 and K188 and that changes in protein acetylation equilibrium can modulate its activity in cells.

中文翻译：

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赖氨酸乙酰化对人类芳胺N-乙酰基转移酶1活性的调节：p300 / CREB结合蛋白和Sirtuins 1和2的作用。

芳胺N-乙酰基转移酶1（NAT1）是II期异种生物代谢酶，在癌细胞的生长和代谢中也起作用。最近，有报道说NAT1进行赖氨酸乙酰化，这是一种重要的翻译后修饰，可以调节蛋白质功能。在当前的研究中，我们使用定点诱变来确定K100和K188是NAT1蛋白中赖氨酸乙酰化的主要位点。C646（一种乙酰基转移酶p300 / CREB结合蛋白（CBP）的抑制剂）可减少HeLa细胞中异位表达的NAT1的乙酰化。重组p300在体外直接乙酰化NAT1。sirtuin（SIRT）抑制剂烟酰胺可增强NAT1的乙酰化作用，而组蛋白脱乙酰基酶抑制剂曲古抑菌素A不会增强NAT1的乙酰化作用。将细胞与NAT1和SIRT 1或2而不与SIRT3共转染，大大降低了NAT1的乙酰化。在烟酰胺处理后的细胞中评估NAT1活性以增强乙酰化作用或与SIRT1共转染以抑制乙酰化作用。结果表明，NAT1乙酰化会削弱其酶动力学，表明乙酰辅酶A的结合减少。此外，乙酰化减弱了ATP对NAT1的变构作用。两者合计，这项研究表明NAT1原位被p30​​0 / CBP乙酰化，而被沉默寡糖调节蛋白SIRT1和2脱乙酰。据推测，NAT1在K100和K188上被乙酰化后翻译后修饰可能会调节细胞中NAT1的作用。意义声明：越来越多的证据表明，芳基胺N-乙酰基转移酶1除异物代谢外，还具有重要的细胞作用。这里，