Metabolism-mediated epigenetic changes represent an adapted mechanism for cellular signaling, in which lysine acetylation and methylation have been the historical focus of interest. We recently discovered a β-hydroxybutyrate–mediated epigenetic pathway that couples metabolism to gene expression. However, its regulatory enzymes and substrate proteins remain unknown, hindering its functional study. Here, we report that the acyltransferase p300 can catalyze the enzymatic addition of β-hydroxybutyrate to lysine (Kbhb), while histone deacetylase 1 (HDAC1) and HDAC2 enzymatically remove Kbhb. We demonstrate that p300-dependent histone Kbhb can directly mediate in vitro transcription. Moreover, a comprehensive analysis of Kbhb substrates in mammalian cells has identified 3248 Kbhb sites on 1397 substrate proteins. The dependence of histone Kbhb on p300 argues that enzyme-catalyzed acylation is the major mechanism for nuclear Kbhb. Our study thus reveals key regulatory elements for the Kbhb pathway, laying a foundation for studying its roles in diverse cellular processes.

代谢介导的表观遗传变化代表了细胞信号传导的一种适应机制，其中赖氨酸乙酰化和甲基化一直是人们关注的历史焦点。我们最近发现了一种 β-羟基丁酸介导的表观遗传途径，该途径将新陈代谢与基因表达相结合。然而，其调节酶和底物蛋白仍然未知，阻碍了其功能研究。在这里，我们报告了酰基转移酶 p300 可以催化 β-羟基丁酸与赖氨酸 (Kbhb) 的酶促加成，而组蛋白脱乙酰酶 1 (HDAC1) 和 HDAC2 可以酶促去除 Kbhb。我们证明 p300 依赖性组蛋白 Kbhb 可以直接介导体外转录。此外，对哺乳动物细胞中 Kbhb 底物的综合分析已确定 1397 个底物蛋白上的 3248 个 Kbhb 位点。组蛋白 Kbhb 对 p300 的依赖性认为酶催化的酰化是核 Kbhb 的主要机制。因此，我们的研究揭示了 Kbhb 通路的关键调控元件，为研究其在不同细胞过程中的作用奠定了基础。