ABCB6参与TYRP1转运的作用研究

Tyrosinase-related protein-1 (TYRP1) is one of the members of tyrosinase-related protein family in melanocyte. It not only has dihydroxyindole carboxylic acid oxidase activity, but also stabilizes tyrosinase on the melanosomal membrane. Some data show that the route that TYRP-1 transits the secretory pathway is different from that of tyrosinase in the same cell. However, it is not completely understood how TYRP1 traffics to melanosome so far. ABCB6，a novel agent involved in the process of skin pigmentation,was identified from patients with dyschromatosis universalis hereditaria by our team in 2013. Our recent confocal microscopy showed that most of the mutated ABCB6 accumulated in the Golgi complex and was accompanied with TYRP1, which is supposed to localize in the melanosome. These data suggest that ABCB6 might be a critical mediator in TYRP1 trafficking to melanosome. To verify this hypothesis, we will demonstrate that ABCB6 interferes in the process of melanogensis via TYRP1 using Real-time PCR and Western blot technique. We will also find out its binding target during the TYRP1 transportion using confocal laser scanning microscope and co-immunoprecipitation. At last, we will clarify their interaction relationship among ABCB6, TYRP1 and the target protein by confocal laser scanning microscope and co-immunoprecipitation. The mechanism of TYRP1 trafficing will be further understood and it will shed new light on other lysosome-related organelles when we accomplish this project.

黑素细胞的酪氨酸酶相关蛋白-1(TYRP1) 不仅是5,6二羟基吲哚2-羧酸氧化酶，能催化底物反应，还可作为酪氨酸酶的分子伴侣而稳定其活性，在黑素小体成熟过程中发挥重要作用。然而TYRP1转运机制迄今仍未阐明。ABCB6是本课题组于2013年鉴定的一个新型色素代谢相关蛋白。近期的亚细胞定位研究又发现：突变型ABCB6主要潴留于核周高尔基体，同时滞留的蛋白还有TYRP1，以致其不能正常定位于黑素小体。这提示ABCB6可能参与TYRP1转运。为验证此推测，本项目拟通过激光共聚焦显微镜和免疫共沉淀技术等首先证实黑素细胞ABCB6通过TYRP1影响黑素合成，再鉴定ABCB6在TYRP1转运通路中的作用靶点，最后探明ABCB6、TYRP1与靶蛋白之间的作用关系，并探索其作用机制。本项目的完成将完善TYRP1的转运机制，丰富对黑素小体的认识，并为其它溶酶体相关细胞器的研究提供参考线索。

黑素细胞的酪氨酸酶相关蛋白-1(TYRP1) 不仅是5,6二羟基吲哚2-羧酸氧化酶，能催化底物反应，还可作为酪氨酸酶的分子伴侣而稳定其活性，在黑素小体成熟过程中发挥重要作用。然而TYRP1转运机制迄今仍未阐明。ABCB6是本课题组于2013年鉴定的一个新型色素代谢相关蛋白。突变型ABCB6主要潴留于核周高尔基体，同时滞留的蛋白还有TYRP1，以致其不能正常定位于黑素小体。这提示ABCB6可能参与TYRP1转运。本项目对ABCB6、TYRP1与靶蛋白Rab32、Rab38间相互关系进行研究，阐明ABCB6突变后可导致Tyr，Tyrp1和Dct滞留于高尔基体TGN中，无法正确的转运至胞浆的黑素小体中。导致黑素细胞中黑素含量显著降低。