Destabilization of DJ-1 by familial substitution and oxidative modifications: Implications for Parkinson's disease
Destabilization of DJ-1 by familial substitution and oxidative modifications: Implications for Parkinson's disease
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DOI：
10.1021/bi7001778
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发表时间：
2007-05-15
期刊：
影响因子：
2.9
通讯作者：
Rochet, Jean-Christophe
中科院分区：
文献类型：
--
作者：
Hulleman, John D.;Mirzaei, Hamid;Rochet, Jean-Christophe
帕金森病是一种以氧化应激和蛋白质聚集为特征的神经退行性疾病。DJ-1是一种具有抗氧化剂和伴侣活性的同源二聚体蛋白质，可减轻这两种毒性现象。DJ-1的神经保护功能通过半胱氨酸106的氧化来调节，半胱氨酸106是一种可以充当氧化应激传感器的残基。DJ-1基因中的功能缺失突变与早发性PD有关，并且年龄依赖性DJ-1过度氧化被认为有助于散发性PD。家族性突变体L166 P不能二聚化并迅速降解，表明蛋白质不稳定是该突变体功能障碍的原因。在这项研究中，我们研究了DJ-1的结构和稳定性如何受到其他两种致病性取代（M26 I和E64 D）以及过氧化氢的过度氧化的影响。而重组野生型蛋白和E64 D都采用了稳定的二聚体结构，M26 I显示出增加的聚集倾向和减少的二级结构。与M26 I类似，过度氧化的野生型DJ-1表现出二级结构减少，并且这种性质与二聚体的不稳定性相关。工程突变体C106 A具有更大的热力学稳定性，并且比野生型蛋白质更能抵抗氧化诱导的不稳定。这些结果表明：（i）M26 I取代和过度氧化使二聚体DJ-1不稳定，和（ii）半胱氨酸106的氧化有助于DJ-1不稳定。我们的研究结果为家族性和散发性PD中DJ-1功能障碍提供了结构基础，并且他们表明二聚体稳定化是治疗这两种形式的疾病的合理治疗策略。
Parkinson's disease (PD) is a neurodegenerative disorder characterized by oxidative stress and protein aggregation. Both toxic phenomena are mitigated by DJ-1, a homodimeric protein with proposed antioxidant and chaperone activities. The neuroprotective function of DJ-1 is modulated by oxidation of cysteine 106, a residue that may act as an oxidative stress sensor. Loss-of-function mutations in the DJ-1 gene have been linked to early onset PD, and age-dependent over-oxidation of DJ-1 is thought to contribute to sporadic PD. The familial mutant L166P fails to dimerize and is rapidly degraded, suggesting that protein destabilization accounts for the dysfunction of this mutant. In this study, we investigated how the structure and stability of DJ-1 are impacted by two other pathogenic substitutions (M26I and E64D) and by over-oxidation with H2O2. Whereas the recombinant wild-type protein and E64D both adopted a stable dimeric structure, M26I showed an increased propensity to aggregate and decreased secondary structure. Similar to M26I, over-oxidized wild-type DJ-1 exhibited reduced secondary structure, and this property correlated with destabilization of the dimer. The engineered mutant C106A had a greater thermodynamic stability and was more resistant to oxidation-induced destabilization than the wild-type protein. These results suggest that (i) the M26I substitution and over-oxidation destabilize dimeric DJ-1, and (ii) the oxidation of cysteine 106 contributes to DJ-1 destabilization. Our findings provide a structural basis for DJ-1 dysfunction in familial and sporadic PD, and they suggest that dimer stabilization is a reasonable therapeutic strategy to treat both forms of this disorder.