Identification of interacting molecules with α-synuclein and of their function in the pathology of neurodegenerative diseases

α-突触核蛋白是一类路易体疾病（LBD），包括帕金森病（PD）和弥散性路易体病（弥散性路易体病）发病机制的关键分子之一，因为其一，该蛋白的某些突变导致家族性PD，其二，它是路易体的主要蛋白质成分。鉴定和表征与该蛋白相互作用的分子对于阐明LBD的致病机制是必不可少的。本项目着重于以下两点；首先，鉴定与α-synuclein相互作用的新分子；其次，详细分析synuclein与已知相互作用分子的相互作用。关于第一点，我们以A53T pd致病性突变synuclein为诱饵，筛选了一个人胎儿大脑cDNA文库，获得了一些候选克隆，目前正在进行鉴定。此外，通过用GST-synucleins检测代谢放射性同位素标记的COS-1蛋白，我们鉴定了一个表观分子量为72 kDa的多肽。它与GST-α-synuclein相互作用，但不单独与GST相互作用。关于后一点，我们主要关注synphilin，这是我们项目期间报道的一种与α-synuclein相互作用的蛋白质。与先前报道的结果相反，我们的结果表明，与N端和c端截断的synphilin与synuclein的相互作用相比，全长野生型synphilin与synuclein的相互作用非常短，如果有的话，这表明N端或c端区域的存在对相互作用有抑制作用。

α-Synuclein is regarded as one of the key molecules when considering the pathogenic mechanisms of a group of Lewy body diseases (LBD), including Parkinson's disease (PD) and diffuse Lewy body disease, in that, first, some mutations of this protein cause familial PD and, second, it is a main proteineous component of the Lewy bodies. Identification and characterization of molecules interacting with this protein is indispensable for the elucidation of the pathogenic mechanisms of LBD.This project focused on the following two points ; first, identification of new molecules interacting with α-synuclein, and second, detailed analyses of the interaction between synuclein and the known interacting molecules. In regard to the first point, we screened a human fetal brain cDNA library using A53T PD-pathogenic mutant synuclein as a bait and obtained some candidate clones, characterization of which is now under way. In addition, by probing metabolically radioisotope-labeled COS-1 proteins with GST-synucleins, we identified a polypeptide with the apparent molecular weight of 72 kDa. which interacts with GST-α-synuclein but not with GST alone. Concerning the latter point, we mainly concentrated on synphilin, which was reported during the period of our project as a protein interacting with α-synuclein. In contradiction to the previously reported results, our results indicate that, as compared with the interaction of an N- and C-terminally truncated synphilin with synuclein, that of full-length wild type one is very week if any, suggesting that presence of either of the N-terminal or C-terminal region acts inhibitory on the interaction.