OLA1 protects cells in heat shock by stabilizing HSP70.
OLA1 protects cells in heat shock by stabilizing HSP70.
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DOI：
10.1038/cddis.2013.23
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发表时间：
2013-02-14
影响因子：
9
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中科院分区：
文献类型：
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热休克反应是一种进化上保守的细胞防御机制，以快速合成热休克蛋白（HSPs）为特征。HSP 70是一种高度可诱导的分子伴侣，可帮助受损蛋白质的重折叠或清除，从而在维持细胞内稳态和耐热性方面发挥重要作用。迄今为止，已经在转录水平上广泛描述了HSP 70表达的诱导。然而，HSP 70的翻译后调节，如蛋白质稳定性，仅部分了解。在这项研究中，我们调查的作用，OLA 1（Obg样ATP酶1），以前未知的胞质ATP酶，在调节HSP 70的营业额。通过RNAi或靶向基因破坏下调哺乳动物细胞中的OLA 1导致HSP 70的稳态水平降低，热诱导的HSP 70受损，并且功能上增加细胞对热休克的敏感性。相反，OLA 1的过表达与升高的HSP 70蛋白水平和改善的耐热性相关。蛋白-蛋白相互作用实验表明，OLA 1与HSP 70羧基端可变区的结合阻碍了CHIP（HSP 70结合蛋白的C端）的募集，CHIP是HSP 70的E3泛素连接酶，从而阻止了HSP 70的CHIP介导的泛素化。这些发现提示了一种新的分子机制，通过这种机制，OLA 1稳定HSP 70，导致HSP 70上调以及热休克期间存活率增加。
The heat-shock response is an evolutionarily conserved cellular defense mechanism against environmental stresses, characterized by the rapid synthesis of heat-shock proteins (HSPs). HSP70, a highly inducible molecular chaperone, assists in refolding or clearance of damaged proteins, thereby having a central role in maintaining intracellular homeostasis and thermotolerance. To date, induction of HSP70 expression has been described extensively at the transcriptional level. However, post-translational regulation of HSP70, such as protein stability, is only partially understood. In this study, we investigated the role of OLA1 (Obg-like ATPase 1), a previously uncharacterized cytosolic ATPase, in regulating the turnover of HSP70. Downregulation of OLA1 in mammalian cells by either RNAi or targeted gene disruption results in reduced steady-state levels of HSP70, impaired HSP70 induction by heat, and functionally, increased cellular sensitivity to heat shock. Conversely, overexpression of OLA1 correlates with elevated HSP70 protein levels and improved thermal resistance. Protein–protein interaction assays demonstrated that binding of OLA1 to the HSP70 carboxyl terminus variable domain hinders the recruitment of CHIP (C-terminus of Hsp70-binding protein), an E3 ubiquitin ligase for HSP70, and thus prevents HSP70 from the CHIP-mediated ubiquitination. These findings suggest a novel molecular mechanism by which OLA1 stabilizes HSP70, leading to upregulation of HSP70 as well as increased survival during heat shock.