LRRK2 and Neurodegeneration

描述（由申请人提供）：LRRK 2突变是帕金森病（PD）的常见遗传原因。与LRRK 2相关的疾病与α-突触核蛋白病理学和tau病理学两者相关。LRRK 2与多种病理类型的关联表明，LRRK 2的生物学可以为我们理解神经退行性变的机制提供特别的见解。我们的研究表明，LRRK 2改变细胞对压力的反应。表达野生型LRRK 2赋予C.例如，线虫对与增加的蛋白质错误折叠和保护免受线粒体毒素（如鱼藤酮和百草枯）相关的应激具有显著的敏感性。LRK-1的敲除，C. elegans同源物LRRK 2，具有相反的作用，并使C.线虫对蛋白酶体抑制的敏感性较低，对鱼藤酮的敏感性较高。C.表达PD相关LRRK 2突变体的线虫显示出比野生型LRRK 2更大的毒性。这些观察结果得到了人类细胞系中蛋白结合研究的支持，并表明LRRK 2的作用需要蛋白折叠机制和应激激酶级联反应。敲除和结合研究显示了功能和物理相互作用的证据，鉴定了几种结合蛋白，包括CHIP，MKK 3，6和7，以及JIP 2和4，以及与hsp 60和70的功能联系。LRRK 2和MKK 6之间的相互作用似乎在PD的病理生理学中特别重要，因为LRRK 2中的PD相关突变显示出对MKK 6具有选择性的结合增加。这些结合蛋白中的许多具有共同的功能，因为它们介导细胞应激反应的不同元件。我们假设LRRK 2通过与蛋白质错误折叠途径和应激激酶级联相关的蛋白质相互作用来协调细胞应激反应。该假说的第二个要素是与PD相关的LRRK 2突变通过增加通过应激激酶级联的信号传导来增强细胞死亡和神经变性。第一个目标将研究LRRK 2如何改变对细胞损伤的反应。这一目标也将研究LRRK 2结合蛋白的敲低如何改变LRRK 2在C. elegans细胞系和LRRK 2诱导型人细胞系。第二个目标是确定LRRK 2与其结合蛋白相互作用的结构机制。第三个目的是研究野生型、G2019 S和R1441 C LRRK 2的表达如何改变由与C.优雅这一目标将阐明野生型LRRK 2是否正常保护免受与PD相关的病理生理变化，以及LRRK 2中PD相关的突变是否增强这些变化。

DESCRIPTION (provided by applicant): Mutations in LRRK2 are a common genetic cause of Parkinson's disease (PD). Diseases associated with LRRK2 are associated with both alpha-synuclein pathology and with tau pathology. The association of LRRK2 with multiple types of pathologies suggests that the biology of LRRK2 could provide particular insight to our understanding of mechanisms of neurodegeneration. Our studies suggest that LRRK2 modifies cellular responses to stress. Expressing wild type LRRK2 confers to C. elegans striking sensitization to stresses associated with increased protein misfolding and protection against mitochondrial toxins, such as rotenone and paraquat. Knockdown of lrk-1, the C. elegans homologue of LRRK2, has the opposite effects and renders C. elegans less vulnerable to proteasomal inhibition and more vulnerable to rotenone. C. elegans expressing PD-associated LRRK2 mutants show more toxicity than seen with wild type LRRK2. These observations are supported by protein-binding studies in human cell lines and suggest that the action of LRRK2 requires the protein folding machinery and the stress kinase cascade. The knockdown and binding studies show evidence of functional and physical interactions with identification of several binding proteins including CHIP, MKK3, 6 and 7, and JIP2 & 4, as well as functional links to hsp60 and 70. The interaction between LRRK2 and MKK6 appears to be particularly important in the pathophysiology of PD because the PD-related mutations in LRRK2 show increased binding that is selective for MKK6. Many of these binding proteins share a common function in that they mediate different elements of the cellular stress response. We hypothesize that LRRK2 coordinates the cellular stress response through its interaction with proteins linked to the protein misfolding pathways and the stress kinase cascades. A secondary element of this hypothesis is that mutations in LRRK2 associated with PD enhance cell death and neurodegeneration by increasing signaling through the stress kinase cascades. The first aim will investigate how LRRK2 modifies the response to cell injury. This aim will also examine how knockdown of LRRK2 binding proteins modifies the actions of LRRK2 in C. elegans lines and LRRK2 inducible human cell lines. The second aim will determine the structural mechanisms by which LRRK2 interacts with its binding proteins. The third aim examines how expression of wild type, G2019S and R1441C LRRK2 modify toxicity and inclusion formation caused by genetic changes related to PD (alpha-synuclein and tau) in C. elegans. This aim will elucidate whether wild type LRRK2 normally protects against pathophysiological changes associated with PD, and whether PD-related mutations in LRRK2 enhance these changes.