Tip110 与 YB-1 相互作用并调节彼此的功能。

BACKGROUND

Tip110 plays important roles in tumor immunobiology, pre-mRNA splicing, expression regulation of viral and host genes, and possibly protein turnover. It is clear that our understanding of Tip110 biological function remains incomplete.

RESULTS

Herein, we employed an immunoaffinity-based enrichment approach combined with protein mass spectrometry and attempted to identify Tip110-interacting cellular proteins. A total of 13 major proteins were identified to be complexed with Tip110. Among them was Y-box binding protein 1 (YB-1). The interaction of Tip110 with YB-1 was further dissected and confirmed to be specific and involve the N-terminal of both Tip110 and YB-1 proteins. A HIV-1 LTR promoter-driven reporter gene assay and a CD44 minigene in vivo splicing assay were chosen to evaluate the functional relevance of the Tip110/YB-1 interaction. We showed that YB-1 potentiates the Tip110/Tat-mediated transactivation of the HIV-1 LTR promoter while Tip110 promotes the inclusion of the exon 5 in CD44 minigene alternative splicing.

CONCLUSIONS

Tip110 and YB-1 interact to form a complex and mutually regulate each other's biological functions.

背景

Tip110 在肿瘤免疫生物学、前体 mRNA 剪接、病毒和宿主基因的表达调控以及可能的蛋白质周转中发挥着重要作用。显然，我们对 Tip110 生物学功能的理解仍然不完整。

结果

在此，我们采用基于免疫亲和的富集方法结合蛋白质质谱技术，试图鉴定与 Tip110 相互作用的细胞蛋白。总共鉴定出 13 种主要蛋白质与 Tip110 复合物。其中包括 Y 盒结合蛋白 1（YB-1）。进一步剖析并证实了 Tip110 与 YB-1 的相互作用是特异性的，涉及 Tip110 和 YB-1 蛋白的 N 端。选择 HIV-1 LTR 启动子驱动的报告基因测定和 CD44 内含子 minigene 体内剪接测定来评估 Tip110/YB-1 相互作用的功能相关性。我们表明，YB-1 增强了 Tip110/Tat 介导的 HIV-1 LTR 启动子的转录激活，而 Tip110 促进了 CD44 minigene 内含子的选择剪接中外显子 5 的包含。