Yu Junping, Lyubchenko Yuri L
Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE 68198, USA.
J Neuroimmune Pharmacol. 2009 Mar;4(1):10-6. doi: 10.1007/s11481-008-9115-5. Epub 2008 Jul 17.
Misfolding and aggregation of proteins are common threads linking a number of important human health problems, including various neurodegenerative disorders such as Parkinson's disease in particular. The first and perhaps most important elements in most neurodegenerative processes are misfolding and aggregation of specific proteins. Despite the crucial importance of protein misfolding and abnormal interactions, very little is currently known about the molecular mechanism underlying these processes. Factors that lead to protein misfolding and aggregation in vitro are poorly understood, in addition to the complexities involved in the formation of protein nanoparticles with different morphologies (e.g. nanopores and other species) in vivo. A clear understanding of the molecular mechanisms of misfolding and aggregation will facilitate rational approaches to prevent protein misfolding mediated pathologies. To accomplish this goal and to elucidate the mechanism of protein misfolding, we developed a novel nanotechnology tool capable of detecting protein misfolding. We applied single molecule probing technique to characterize misfolding and self-assembly of alpha-synuclein dimers, which is the very first step of the aggregation process. Using AFM force spectroscopy approach, we were able to detect protein misfolding via enhanced interprotein interaction. Moreover, such an important characteristic as the lifetime of dimers formed by misfolded alpha-synuclein was measured. These data suggest that compared to highly dynamic monomeric forms, alpha-synuclein dimers are practically static and thus can play a role of aggregation nuclei for the formation of aggregates. Importantly, two different dissociation channels were detected suggesting that aggregation process can follow different pathways. The application of these findings for understanding of the aggregation phenomenon and the development of the disease is discussed.
蛋白质错误折叠和聚集是一系列重要人类健康问题的共同特征，尤其包括各种神经退行性疾病，如帕金森病。在大多数神经退行性过程中，首要且可能最重要的因素是特定蛋白质的错误折叠和聚集。尽管蛋白质错误折叠和异常相互作用至关重要，但目前对于这些过程背后的分子机制知之甚少。除了体内形成具有不同形态（如纳米孔和其他种类）的蛋白质纳米颗粒所涉及的复杂性之外，导致蛋白质在体外错误折叠和聚集的因素也了解甚少。清楚了解错误折叠和聚集的分子机制将有助于采取合理方法预防蛋白质错误折叠介导的病变。为实现这一目标并阐明蛋白质错误折叠的机制，我们开发了一种能够检测蛋白质错误折叠的新型纳米技术工具。我们应用单分子探测技术来表征α-突触核蛋白二聚体的错误折叠和自组装，这是聚集过程的第一步。使用原子力显微镜力谱方法，我们能够通过增强的蛋白质间相互作用检测蛋白质错误折叠。此外，还测量了由错误折叠的α-突触核蛋白形成的二聚体的寿命这一重要特征。这些数据表明，与高度动态的单体形式相比，α-突触核蛋白二聚体实际上是静态的，因此可以在聚集体形成中充当聚集核的角色。重要的是，检测到了两种不同的解离通道，这表明聚集过程可以遵循不同的途径。本文讨论了这些发现对于理解聚集现象和疾病发展的应用。
