Acetylation of importin-α nuclear import factors by CBP/p300
Acetylation of importin-α nuclear import factors by CBP/p300
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DOI：
10.1016/s0960-9822(00)00445-0
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发表时间：
2000-04-20
期刊：
影响因子：
9.2
通讯作者：
Kouzarides, T
中科院分区：
文献类型：
--
作者：
Bannister, AJ;Miska, EA;Kouzarides, T
组蛋白乙酰化酶最初被鉴定是因为它们能够乙酰化组蛋白底物[1-3]。乙酰化酶也可以靶向其他蛋白质，如转录因子[4-7]。我们询问乙酰化酶CREB结合蛋白（CBP）是否可以乙酰化不直接参与转录的蛋白质。参与多种细胞过程的大量蛋白质被测试作为重组CBP的底物。该筛选确定了两种参与核输入的蛋白质，Rch 1（人输入素-α）和输入素-α 7，作为CBP的靶点。Rch 1内的乙酰化位点被映射到一个单一的残基，Lys 22。通过比较Lys 22与CBP和密切相关的乙酰化酶p300的其他已知底物的序列，我们确定G/SK（在单字母氨基酸代码中）作为一致的乙酰化基序。甘氨酸和赖氨酸的突变严重损害了Rch 1的乙酰化，支持GK是CBP/p300乙酰化识别基序的一部分的观点。使用针对乙酰化Rch 1肽的抗体，我们表明Rch 1在体内在Lys 22处被乙酰化，CBP或p300可以介导该反应。Lys 22位于第二个核输入因子importin-β的结合位点内。Lys 22的乙酰化促进了与importin-β的体外相互作用。总的来说，这些结果表明，乙酰化不是唯一的蛋白质参与转录。乙酰化可以调节多种生物过程，包括核输入。
Histone acetylases were originally identified because of their ability to acetylate histone substrates [1-3]. Acetylases can also target other proteins such as transcription factors [4-7]. We asked whether the acetylase CREB-binding protein (CBP) could acetylate proteins not directly involved in transcription. A large panel of proteins, involved in a variety of cellular processes, were tested as substrates for recombinant CBP. This screen identified two proteins involved in nuclear import, Rch1 (human importin-alpha) and importin-alpha 7, as targets for CBP. The acetylation site within Rch1 was mapped to a single residue, Lys22. By comparing the context of Lys22 with the sequences of other known substrates of CBP and the closely related acetylase p300, we identified G/SK (in the single-letter amino acid code) as a consensus acetylation motif. Mutagenesis of the glycine, as well as the lysine, severely impaired Rch1 acetylation, supporting the view that GK is part of a recognition motif for acetylation by CBP/p300. Using an antibody raised against an acetylated Rch1 peptide, we show that Rch1 was acetylated at Lys22 in vivo and that CBP or p300 could mediate this reaction. Lys22 lies within the binding site for a second nuclear import factor, importin-beta. Acetylation of Lys22 promoted interaction with importin-beta in vitro. Collectively, these results demonstrate that acetylation is not unique to proteins involved in transcription. Acetylation may regulate a variety of biological processes, including nuclear import.