Utilizing targeted mass spectrometry to demonstrate Asf1-dependent increases in residue specificity for Rtt109-Vps75 mediated histone acetylation.
Utilizing targeted mass spectrometry to demonstrate Asf1-dependent increases in residue specificity for Rtt109-Vps75 mediated histone acetylation.
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DOI：
10.1371/journal.pone.0118516
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Andrews AJ
中科院分区：
文献类型：
--
作者：
Kuo YM;Henry RA;Huang L;Chen X;Stargell LA;Andrews AJ
在酿酒酵母中，Rtt 109是一种赖氨酸乙酰转移酶（KAT），与组蛋白伴侣Vps 75或Asf 1结合。有人提出，这些分子伴侣改变Rtt 109的选择性或它优先乙酰化的残基。在本研究中，我们利用了一种无标记的定量质谱为基础的方法来确定的稳态动力学参数的乙酰化Rtt 109-Vps 75催化H3单体，H3/H4四聚体，和H3/H4-Asf 1复合物。这些结果表明，在这些组蛋白构象中，只有H3 K9和H3 K23在稳态条件下显著乙酰化，Asf 1通过Rtt 109-Vps 75促进H3/H4乙酰化。Asf 1以1：1的最大化学计量比（Asf 1与H3/H4）同等地增加了这两个残基的Rtt 109-Vps 75特异性，但不改变这两个残基之间的选择性。这些数据表明，H3/H4-Asf 1复合物是Rtt 109-Vps 75的底物，而不改变残基之间的选择性。Rtt 109或Asf 1在体内的缺失导致H3 K9乙酰化的相同减少，表明Asf 1是体外和体内有效的H3 K9乙酰化所必需的。此外，我们发现，当那些组蛋白已经具有修饰时，如在从鸡红细胞纯化的组蛋白上发现的那些，Rtt 109-Vps 75的乙酰化偏好可以指向H3 K56。总的来说，Vps 75和Asf 1都增强了Rtt 109对H3/H4的乙酰化，尽管通过不同的机制，但对残基选择性几乎没有影响。重要的是，这些结果提供了组蛋白伴侣可以通过与酶或底物相互作用来更有效地乙酰化组蛋白的证据。
In Saccharomyces cerevisiae, Rtt109, a lysine acetyltransferase (KAT), associates with a histone chaperone, either Vps75 or Asf1. It has been proposed that these chaperones alter the selectivity of Rtt109 or which residues it preferentially acetylates. In the present study, we utilized a label-free quantitative mass spectrometry-based method to determine the steady-state kinetic parameters of acetylation catalyzed by Rtt109-Vps75 on H3 monomer, H3/H4 tetramer, and H3/H4-Asf1 complex. These results show that among these histone conformations, only H3K9 and H3K23 are significantly acetylated under steady-state conditions and that Asf1 promotes H3/H4 acetylation by Rtt109-Vps75. Asf1 equally increases the Rtt109-Vps75 specificity for both of these residues with a maximum stoichiometry of 1:1 (Asf1 to H3/H4), but does not alter the selectivity between these two residues. These data suggest that the H3/H4-Asf1 complex is a substrate for Rtt109-Vps75 without altering selectivity between residues. The deletion of either Rtt109 or Asf1 in vivo results in the same reduction of H3K9 acetylation, suggesting that Asf1 is required for efficient H3K9 acetylation both in vitro and in vivo. Furthermore, we found that the acetylation preference of Rtt109-Vps75 could be directed to H3K56 when those histones already possess modifications, such as those found on histones purified from chicken erythrocytes. Taken together, Vps75 and Asf1 both enhance Rtt109 acetylation for H3/H4, although via different mechanisms, but have little impact on the residue selectivity. Importantly, these results provide evidence that histone chaperones can work together via interactions with either the enzyme or the substrate to more efficiently acetylate histones.
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DOI：
10.1126/science.1135862
发表时间：
2007-02-02
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Driscoll R;Hudson A;Jackson SP
通讯作者：
Jackson SP
影响因子：
5.7
作者：
Lin, Chengqi;Yuan, Y. Adam
通讯作者：
Yuan, Y. Adam
影响因子：
5.3
作者：
Fillingham, Jeffrey;Recht, Judith;Greenblatt, Jack F.
通讯作者：
Greenblatt, Jack F.
影响因子：
3.8
作者：
Downs, Jessica A.
通讯作者：
Downs, Jessica A.
影响因子：
16.8
作者：
通讯作者：
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