Structural and kinetic analysis of prolyl-isomerization/phosphorylation cross-talk in the CTD code.
Structural and kinetic analysis of prolyl-isomerization/phosphorylation cross-talk in the CTD code.
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DOI：
10.1021/cb3000887
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发表时间：
2012-08-17
影响因子：
4
通讯作者：
Zhang, Yan
中科院分区：
文献类型：
--
作者：
Zhang, Mengmeng;Wang, Xiaodong J.;Chen, Xi;Bowman, Marianne E.;Luo, Yonghua;Noel, Joseph P.;Ellington, Andrew D.;Etzkorn, Felicia A.;Zhang, Yan
真核生物RNA聚合酶II的C-末端结构域（CTD）是RNA聚合酶II介导的转录的重要调节因子。它由多个重复的共有序列Tyr1Ser2Pro3Thr4Ser5Pro6Ser7组成。Ser2和Ser5是体内主要的磷酸化位点，而Pro3和Pro6可以采用顺式或反式构象。CTD的转录调节是由丝氨酸的磷酸化和两个脯氨酸的脯氨酰异构化介导的。有趣的是，磷酸化位点通常靠近脯氨酸，因此相邻脯氨酸的构象可能影响相应激酶和磷酸酶的特异性。这两种调节机制之间的相互作用的实验证据一直难以捉摸。Pin1是一种高度保守的磷酸化特异性肽基脯氨酰异构酶（PPIase），在体内识别磷酸化的丝氨酸/苏氨酸（pSer/Thr）-脯氨酸基序，CTD是其主要底物之一。在本研究中，我们提供了结构快照和动力学证据，支持脯氨酰异构化和磷酸化之间的串扰的概念。我们确定了Pin1的结构与两个底物电子等排体结合，模拟含有pSer/Thr-Pro基序的顺式或反式构象的肽。结果明确地证明了顺式和反式锁定烯烃电子等排体作为与蛋白质靶结合的肽的紧密几何模拟物的效用。在此结果的基础上，我们确定了一个具体的情况下，Pin1差异影响由两种磷酸酶（Scp1和Ssu72）催化的去磷酸化速率，这两种磷酸酶靶向CTD七肽重复序列中的相同丝氨酸残基，但对相邻脯氨酸残基的异构化状态具有不同的偏好。这些数据首次阐明了脯氨酸异构化的调节如何在动力学上影响转录调控中的信号转导。
The C-terminal domain (CTD) of eukaryotic RNA polymerase II is an essential regulator for RNA polymerase II-mediated transcription. It is composed of multiple repeats of a consensus sequence Tyr1Ser2Pro3Thr4Ser5Pro6Ser7. Ser2 and Ser5 are the major phosphorylation sites in vivo while Pro3 and Pro6 can adopt either cis or trans conformations. CTD regulation of transcription is mediated both by phosphorylation of the serines and prolyl isomerization of the two prolines. Interestingly, the phosphorylation sites are typically close to prolines, thus the conformation of the adjacent proline could impact the specificity of the corresponding kinases and phosphatases. Experimental evidence of cross-talk between these two regulatory mechanisms has been elusive. Pin1 is a highly conserved phosphorylation-specific peptidyl-prolyl isomerase (PPIase) that recognizes the phospho-Ser/Thr (pSer/Thr)-Pro motif with CTD as one of its primary substrates in vivo. In the present study, we provide structural snapshots and kinetic evidence that support the concept of cross-talk between prolyl isomerization and phosphorylation. We determined the structures of Pin1 bound with two substrate isosteres that mimic peptides containing pSer/Thr-Pro motifs in cis or trans conformations. The results unequivocally demonstrate the utility of both cis- and trans-locked alkene isosteres as close geometric mimics of peptides bound to a protein target. Building on this result, we identified a specific case in which Pin1 differentially affects the rate of dephosphorylation catalyzed by two phosphatases (Scp1 and Ssu72) that target the same serine residue in the CTD heptad repeat but that have different preferences for the isomerization state of the adjacent proline residue. These data exemplify for the first time how modulation of proline isomerization can kinetically impact signal transduction in transcription regulation.
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DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
64.8
作者：
Meinhart, A;Cramer, P
通讯作者：
Cramer, P
影响因子：
3.5
作者：
Kops, O;Zhou, XZ;Lu, KP
通讯作者：
Lu, KP
影响因子：
5.6
作者：
Daum, Sebastian;Luecke, Christian;Schiene-Fischer, Cordelia
通讯作者：
Schiene-Fischer, Cordelia
影响因子：
4.8
作者：
Morris, DP;Phatnani, HP;Greenleaf, AL
通讯作者：
Greenleaf, AL