PolyQ 扩增突变亨廷顿蛋白在两步聚集机制中短暂冷冲击后形成包涵体,ACS Chemical Neuroscience

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PolyQ 扩增突变亨廷顿蛋白在两步聚集机制中短暂冷冲击后形成包涵体
ACS Chemical Neuroscience ( IF 4.1 ) Pub Date : 2022-12-27 , DOI: 10.1021/acschemneuro.2c00585
Ana Raquel Castro E Costa ₁ , Sachin Mysore ₁ , Praneet Paruchuri ₁ , Kuang Yu Chen ₂ , Alice Y Liu ₁

Affiliation

不溶性蛋白质聚集物的年龄依赖性形成是许多神经退行性疾病的标志。我们对驱动聚 Q 扩展的突变亨廷顿 (mHtt) 蛋白聚集成不溶性包涵体 (IB) 的细胞化学感兴趣。使用亨廷顿病的诱导细胞模型，我们表明，4°C 下的短暂冷休克 (CS)，然后在 25-37°C 温度下恢复孵育，可强烈且快速地诱导弥漫性 PolyQ 扩展的亨廷顿外显子 1 增强^的压缩绿色荧光蛋白嵌合蛋白（mHtt）转化为圆形、微米大小的胞质IBs。这种短暂的 CS 诱导的 mHtt IB 形成与微管完整性或从头蛋白质合成无关。毫摩尔浓度的氯化钠的添加会加速，而尿素会抑制这种短暂的 CS 诱导的 mHtt IB 形成。这些结果表明，CS 的低温将本质上无序的 mHtt 的构象动力学限制为不稳定的中间结构，以促进在较高恢复温度下形成 IB 的去溶剂化和疏水相互作用。这项工作以及我们之前对热休克蛋白伴侣和渗透剂在驱动 mHtt IB 形成中的影响的观察，强调了 mHtt 结构和刚性化对于 mHtt IB 两步机制中氢键介导的交联的首要作用活细胞中的形成。

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PolyQ-Expanded Mutant Huntingtin Forms Inclusion Body Following Transient Cold Shock in a Two-Step Aggregation Mechanism

Age-dependent formation of insoluble protein aggregates is a hallmark of many neurodegenerative diseases. We are interested in the cell chemistry that drives the aggregation of polyQ-expanded mutant Huntingtin (mHtt) protein into insoluble inclusion bodies (IBs). Using an inducible cell model of Huntington’s disease, we show that a transient cold shock (CS) at 4 °C followed by recovery incubation at temperatures of 25–37 °C strongly and rapidly induces the compaction of diffuse polyQ-expanded Huntingtin^Exon1-enhanced green fluorescent protein chimera protein (mHtt) into round, micron size, cytosolic IBs. This transient CS-induced mHtt IB formation is independent of microtubule integrity or de novo protein synthesis. The addition of millimolar concentrations of sodium chloride accelerates, whereas urea suppresses this transient CS-induced mHtt IB formation. These results suggest that the low temperature of CS constrains the conformation dynamics of the intrinsically disordered mHtt into labile intermediate structures to facilitate de-solvation and hydrophobic interaction for IB formation at the higher recovery temperature. This work, along with our previous observation of the effects of heat shock protein chaperones and osmolytes in driving mHtt IB formation, underscores the primacy of mHtt structuring and rigidification for H-bond-mediated cross-linking in a two-step mechanism of mHtt IB formation in living cells.

更新日期：2022-12-27

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