泛素连接酶LNX1促进外源PBK的泛素化和降解

 目的 研究LNX1对其相互作用蛋白PBK的泛素化和降解。方法 克隆、原核表达、纯化了一系列重组人LNX1截断体蛋白和LNX1全长蛋白；在体外泛素化体系中研究其对PBK的泛素化，哺乳动物细胞内研究其对外源PBK的泛素化和降解。结果 在体外泛素化体系中LNX1泛素化PBK，并研究了不同LNX1截断体对PBK泛素化的影响；发现在哺乳动物细胞内外源LNX1促进外源PBK的泛素化，进而导致其通过蛋白酶体降解。结论 研究发现了LNX1对外源PBK的泛素化和降解，为研究LNX1的生理功能提供了重要线索。

Ubiquitin ligase LNX1 promotes the ubiquitination and degradation of exogenous PBK

Objective To study the role of LNX1 in the ubiquitination of PBK, a reported LNX1 interactor. Methods A series of recombinant human LNX1 truncations and full-length LNX1 proteins were cloned, bacterial expressed, and purified. In vitro ubiquitination system was used to study the ubiquitination of PBK by LNX1. The ubiquitination and degradation of exogenous PBK was studied in mammalian cells. Results LNX1 promoted the ubiquitination of PBK in in vitro ubiquitination system and the impact of LNX1 truncations to the ubiquitination of PBK was also studied. LNX1 promoted the ubiquitination of exogenous PBK in mammalian cells, leading to its proteasome dependent degradation. Conclusion This research found that ubiquitin ligase LNX1 promotes the ubiquitination and degradation of exogenous PBK, which provides important clues for study the physiologic function of LNX1.