Zhao Jinghui, Ren Yong, Jiang Qian, Feng Jian
Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, NY 14214, USA.
J Cell Sci. 2003 Oct 1;116(Pt 19):4011-9. doi: 10.1242/jcs.00700. Epub 2003 Aug 19.
Parkin is a protein-ubiquitin E3 ligase linked to Parkinson's disease. Although several substrates of parkin have been identified, the subcellular location for parkin to recognize and ubiquitinate its targets is unclear. Here we report that parkin was accumulated in the centrosome when SH-SY5Y or transfected HEK293 cells were treated with the proteasome inhibitor lactacystin. The specific recruitment of parkin was dependent on concentration and duration of the treatment, and was accompanied by the centrosomal accumulation of ubiquitinated proteins and CDCrel-1, a substrate of parkin. The recruitment of parkin was apparently mediated through its binding to gamma-tubulin, which has been shown to accumulate in the centrosome in response to misfolded proteins. Furthermore, the effect was abrogated by the microtubule-depolymerizing drug colchicine or the microtubule-stabilizing drug taxol, which indicates that the intact microtubule network is required for the centrosomal recruitment of parkin. Taken together, our data suggest that the lactacystin-induced accumulation of parkin in the centrosome plays a significant role in the ubiquitination of misfolded substrates accumulated there. This process may provide a subcellular locale for parkin to ubiquitinate and degrade protein aggregates critically involved in the pathogenesis of Parkinson's disease.
帕金蛋白是一种与帕金森病相关的蛋白质泛素E3连接酶。尽管已经鉴定出帕金蛋白的几种底物，但其识别并泛素化靶标的亚细胞定位尚不清楚。在此，我们报道，当用蛋白酶体抑制剂乳胞素处理SH-SY5Y细胞或转染的HEK293细胞时，帕金蛋白会在中心体中积累。帕金蛋白的特异性募集取决于处理的浓度和持续时间，并伴随着泛素化蛋白和帕金蛋白的底物CDCrel-1在中心体的积累。帕金蛋白的募集显然是通过其与γ-微管蛋白的结合介导的，γ-微管蛋白已被证明会因错误折叠的蛋白质而在中心体中积累。此外，微管解聚药物秋水仙碱或微管稳定药物紫杉醇可消除这种效应，这表明完整的微管网络是帕金蛋白募集到中心体所必需的。综上所述，我们的数据表明，乳胞素诱导的帕金蛋白在中心体中的积累在那里积累的错误折叠底物的泛素化中起重要作用。这一过程可能为帕金蛋白提供一个亚细胞区域，以泛素化和降解与帕金森病发病机制密切相关的蛋白质聚集体。
