Extended regulation interface coupled to the allosteric network and disease mutations in the PP2A-B56δ holoenzyme.
Extended regulation interface coupled to the allosteric network and disease mutations in the PP2A-B56δ holoenzyme.
复制标题
扩展的调节接口耦合到 PP2A-B56δ 全酶的变构网络和疾病突变。
DOI：
10.1101/2023.03.09.530109
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Chung,Wen
中科院分区：
文献类型：
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作者：
Wu,Cheng-Guo;Balakrishnan,VijayaK;Parihar,PankajS;Konovolov,Kirill;Chen,Yu-Chia;Merrill,RonaldA;Wei,Hui;Carragher,Bridget;Sundaresan,Ramya;Cui,Qiang;Wadzinski,BrianE;Swingle,MarkR;Musiyenko,Alla;Honkanen,Richard;Chung,Wen
越来越多与毁灭性人类疾病相关的突变通过全基因组/外显子测序进行诊断。在蛋白磷酸酶2A（PP 2A）的调节亚基B56δ（由PPP 2 R5 D编码）中发现了复发性从头错义突变，可导致智力残疾（ID）、大头畸形、帕金森氏症和广泛的神经系统症状。单粒子冷冻电镜结构表明，PP 2A-B56 δ全酶具有封闭的潜伏形式和开放的活性形式。在封闭形式中，B56δ末端的长而无序的臂相互折叠，并与全酶核心折叠，建立了磷酸酶活性位点和底物结合蛋白沟的双重自抑制。所得的界面跨越190个碱基，并含有不利的接触，激活磷酸化位点，几乎所有的残基与ID相关的突变。我们的研究表明，这种动态界面接近于对激活磷酸化反应的变构网络，并通过突变而发生全局改变。此外，我们发现ID突变扰乱激活磷酸化速率，与野生型变体相比，严重的变体显着增加有丝分裂持续时间和错误率。
An increasing number of mutations associated with devastating human diseases are diagnosed by whole-genome/exon sequencing. Recurrent de novo missense mutations have been discovered in B56δ (encoded by PPP2R5D), a regulatory subunit of protein phosphatase 2A (PP2A), that cause intellectual disabilities (ID), macrocephaly, Parkinsonism, and a broad range of neurological symptoms. Single-particle cryo-EM structures show that the PP2A-B56δ holoenzyme possesses closed latent and open active forms. In the closed form, the long, disordered arms of B56δ termini fold against each other and the holoenzyme core, establishing dual autoinhibition of the phosphatase active site and the substrate-binding protein groove. The resulting interface spans over 190 Å and harbors unfavorable contacts, activation phosphorylation sites, and nearly all residues with ID-associated mutations. Our studies suggest that this dynamic interface is close to an allosteric network responsive to activation phosphorylation and altered globally by mutations. Furthermore, we found that ID mutations perturb the activation phosphorylation rates, and the severe variants significantly increase the mitotic duration and error rates compared to the wild variant.