Leucine rich repeat kinase 2 and dominantly inherited Parkinson disease

富含亮氨酸重复序列激酶2（LRRK2）突变是遗传性帕金森病伴年龄依赖性痴呆的病因。该蛋白是一个大的复杂激酶，具有几种已报道的蛋白质相互作用和多种功能。一些突变增加激酶活性，本项目的总体目标是扩展我们先前的观察，即LRRK2的激酶活性在与该基因突变相关的发病机制中很重要。 我们目前的工作包括检查激酶结构域内外突变对激酶活性的影响。已经表明GTP与LRRK2的ROC结构域结合增加激酶活性。然而，我们发现这可能不是鸟苷酸与ROC结构域结合的直接影响。然而，在ROC结构域中的LRRK2中的突变完全消除了结合鸟苷核苷酸的能力，确实降低了激酶活性，这表明可能存在调节该区域的结构效应。我们目前正在通过检查激酶结构域之外的其他突变来跟踪这些数据，这些突变具有类似的限制激酶活性的作用。 我们将我们对基因表达的兴趣与LRRK2突变模型相结合，特别关注激酶结构域的突变。已经表明LRRK2可以以多种方式调节基因表达，包括通过与microRNA加工酶的相互作用。这将预测LRRK2将对基因表达产生强烈影响。然而，我们在转染的细胞系、来自LRRK2患者的成纤维细胞或来自在大脑其他部位建立病理学的年龄时LRRK2表达的大脑区域中没有发现支持这一观点的证据。总的来说，这些数据表明，如果LRRK2影响基因表达，它可能是通过间接机制。

Leucine rich repeat kinase 2 (LRRK2) mutations are causal for inherited Parkinsons disease with age-dependent penetrance. The protein is a large complex kinase with several reported protein interactions and mutliple proposed functions. Some mutations increase kinase activity, and the overall aim of this project is to extend our prior observations that kinase activity of LRRK2 is important in pathogenesis association with mutations in this gene. Our current work includes examination of the effects of mutations both inside and outside of the kinase domain on kinase activity. It has been suggested that GTP binding to the ROC domain of LRRK2 increases kinase activity. However, we have found instead that this is likely not a direct effect of binding of the guanosine nucleotide to the ROC domain. However, mutations in LRRK2 in the ROC domain that completely abolish the capacity to bind guanosine nucleotides do decrease kinase activity, suggesting that there may be structural effects of modulating this region. We are currently following this data up by examining other mutations outside of the kinase domain that have similar effects of limiting kinase activity. We have combined our interest in gene expression with models of LRRK2 mutation, particularly focusing on mutations in the kinase domain. It has been suggested that LRRK2 may modulate gene expression in a number of ways, including by interaction with microRNA processing enzymes. This would predict that LRRK2 would have strong effects on gene expression. However, we did not find evidence to support this idea in transfected cell lines, in fibroblasts from LRRK2 patients or from brain regions where LRRK2 is expressed taken at ages where pathology was established in other parts of the brain. Overall, these data suggest that if LRRK2 influences gene expression it is likely by indirect mechanisms.