Structure-Functional Analyses of CRHSP-24 Plasticity and Dynamics in Oxidative Stress Response
Structure-Functional Analyses of CRHSP-24 Plasticity and Dynamics in Oxidative Stress Response
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CRHSP-24 塑性和氧化应激反应动力学的结构功能分析
DOI：
10.1074/jbc.m110.177436
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发表时间：
2011-03-18
影响因子：
4.8
通讯作者：
Rao, Zihe
中科院分区：
文献类型：
--
作者：
Hou, Hai;Wang, Fengsong;Rao, Zihe
冷休克结构域（CSD）是进化上保守的核酸结合结构域，其表现出与RNA、ssDNA和dsDNA的结合活性。哺乳动物CRHSP-24含有CSD，但其结构-功能关系仍然难以捉摸。在这里，我们报告的晶体结构的人CRHSP-24和表征的CRHSP-24之间的应激颗粒和加工机构在氧化应激反应的分子贩运。通过单波长反常色散确定的CRHSP-24的结构表现出α-螺旋和由五个弯曲的反平行β链形成的紧凑的β-桶。CSD的配体结合活性由残基Ser（41）至Leu（43）协调。有趣的是，一个磷酸化模拟S41 D突变体废除了ssDNA结合在体外，并导致CRHSP-24释放从应力颗粒在体内没有明显的改变其本地化的加工机构。这类新的磷酸化调节的CSD和核酸之间的相互作用是独特的应力颗粒可塑性。重要的是，CRHSP-24与应激颗粒的结合被PP 4/PP 2A抑制剂calyculin A阻断，因为PP 2A催化CRHSP-24的Ser（41）的去磷酸化。因此，我们推测CRHSP-24通过应激颗粒和加工体之间的动态和时间关联参与氧化应激反应。
The cold shock domain (CSD) is an evolutionarily conserved nucleic acid binding domain that exhibits binding activity to RNA, ssDNA, and dsDNA. Mammalian CRHSP-24 contains CSD, but its structure-functional relationship has remained elusive. Here we report the crystal structure of human CRHSP-24 and characterization of the molecular trafficking of CRHSP-24 between stress granules and processing bodies in response to oxidative stress. The structure of CRHSP-24 determined by single-wavelength anomalous dispersion exhibits an alpha-helix and a compact beta-barrel formed by five curved anti-parallel beta strands. Ligand binding activity of the CSD is orchestrated by residues Ser(41) to Leu(43). Interestingly, a phosphomimetic S41D mutant abolishes the ssDNA binding in vitro and causes CRHSP-24 liberated from stress granules in vivo without apparent alternation of its localization to the processing bodies. This new class of phosphorylation-regulated interaction between the CSD and nucleic acids is unique in stress granule plasticity. Importantly, the association of CRHSP-24 with stress granules is blocked by PP4/PP2A inhibitor calyculin A as PP2A catalyzes the dephosphorylation of Ser(41) of CRHSP-24. Therefore, we speculate that CRHSP-24 participates in oxidative stress response via a dynamic and temporal association between stress granules and processing bodies.