Department of Neuropathology, Heinrich Heine University Medical School, Düsseldorf, Germany.
Biol Psychiatry. 2011 Oct 1;70(7):604-10. doi: 10.1016/j.biopsych.2011.03.027. Epub 2011 May 4.
Both disrupted-in-schizophrenia 1 (DISC1) and dysbindin have been identified as schizophrenia candidate genes in independent genetic linkage studies. The proteins have been assigned distinct subcellular locations and functions. We investigated whether both proteins converge into a common pathway specific for schizophrenia or mental diseases.
DISC1 and dysbindin were expressed as recombinant proteins with or without a fluorescent protein-tag in human or mouse neuroblastoma cells and as recombinant proteins in E. coli. Postmortem brains of patients with mental diseases from the Stanley Research Medical Institute's Consortium Collection were used to demonstrate molecular interactions in biochemically purified protein fractions.
First, upon overexpression in neuroblastoma cells, DISC1 formed aggresomes that recruited homologous soluble C-terminal DISC1 fragment or heterologous dysbindin. Domains involved in binding could be mapped to DISC1 (316-597) and dysbindin (82-173), indicating a specific interaction. In addition, recruitment was demonstrated when externally added, purified DISC1 aggresomes penetrated recipient cells after coincubation. Second, a direct interaction between soluble DISC1 protein and dysbindin was demonstrated in a cell free system using E. coli-expressed proteins. Third, co-aggregation of DISC1 and dysbindin was demonstrated in postmortem brains for a subgroup of cases with chronic mental disease but not healthy control subjects.
A direct interaction of soluble and insoluble DISC1 protein with dysbindin protein demonstrates convergence of so far considered independent mental disease genes by direct molecular interaction. Our findings highlight protein aggregation and recruitment as a biological mechanism in mental disease.
在独立的遗传连锁研究中，精神分裂症相关蛋白 1（DISC1）和神经束蛋白已被鉴定为精神分裂症的候选基因。这两种蛋白具有不同的亚细胞定位和功能。我们研究了这两种蛋白是否会汇聚到一个特定的精神分裂症或精神疾病的共同通路中。
在人类或鼠神经母细胞瘤细胞中，以带或不带荧光蛋白标签的形式表达 DISC1 和神经束蛋白，或以重组蛋白的形式在大肠杆菌中表达。使用来自斯坦利研究医学研究所联盟收集的患有精神疾病的患者死后大脑的生物化学纯蛋白级分来证明分子相互作用。
首先，在神经母细胞瘤细胞中过表达时，DISC1 形成了包含同源可溶性 C 端 DISC1 片段或异源神经束蛋白的聚集物。参与结合的结构域可以映射到 DISC1（316-597）和神经束蛋白（82-173），表明存在特异性相互作用。此外，当外部添加的纯化 DISC1 聚集物在共孵育后穿透受者细胞时，也观察到了募集。其次，在无细胞系统中使用大肠杆菌表达的蛋白证明了可溶性 DISC1 蛋白与神经束蛋白之间的直接相互作用。第三，在患有慢性精神疾病的病例亚组的尸检大脑中，但在健康对照组中没有，证明了 DISC1 和神经束蛋白的共聚集。
可溶性和不溶性 DISC1 蛋白与神经束蛋白的直接相互作用证明了迄今为止被认为是独立的精神疾病基因通过直接的分子相互作用而汇聚。我们的发现强调了蛋白聚集和募集作为精神疾病的一种生物学机制。
