Targeting and Regulation of O-GlcNAc Transferase at M Phase

O-GlcNAc是通过糖部分N乙酰葡糖胺在丝氨酸/苏氨酸氨基酸处对蛋白质的共价修饰。O-GlcNAc修饰不延伸为更复杂的寡糖结构，仅在细胞核和细胞质蛋白上发现。这种修饰是高度动态的，并响应细胞外环境的信号，如激素，压力和营养素。以前，我证明了0-GlcNAc对于真核细胞中细胞周期的正常进展是至关重要的; O-GlcNAc转移酶（OGT）（添加修饰的酶）或O-GlcNAc酶（OGA）（去除修饰的酶）引起有丝分裂退出延迟。此外，OGT和OGA可以在与有丝分裂激酶如极光激酶B的信号传导复合物中发现。本研究的目的是研究OGT与有丝分裂结构如纺锤体和有丝分裂蛋白的相互作用。我们 假设OGT在M期进展过程中与各种蛋白质形成复合物，然后靶向OGT纺锤体和中间体。我计划使用多种技术，例如使用GFP-OGT上的FRAP（光漂白后荧光恢复）来测量OGT在纺锤体/中体的动力学，定量蛋白质组学来鉴定OGT靶向蛋白，并最终鉴定Aurora Kinase B的功能将OGT靶向有丝分裂底物和结构。我们的预期贡献是重要的，因为我们 希望能深入了解有丝分裂靶向蛋白对OGT的调节，以及这些相互作用在癌症等疾病中是如何解耦的。

O-GlcNAc is the covalent modification of proteins at serine/threonine amino acids by the sugar moiety Nacetylglucosamine. The O-GlcNAc modification is not elongated to more complex oligosaccharide structures and is found only on nuclear and cytoplasmic proteins. The modification is highly dynamic and responds to signals of the extracellular environment such hormones, stress, and nutrients. Previously, I demonstrated that 0-GlcNAc is critical for the proper progression of the cell cycle in eukaryotic cells; gain of function of either 0-GlcNAc transferase (OGT), the enzyme which adds the modification, or 0-GlcNAcase (OGA), the enzyme which removes the modification, causes mitotic exit delays. Furthermore, OGT and OGA can be found in a signaling complex with mitotic kinases such as Aurora Kinase B. The goal of this proposal is to investigate the interactions of OGT with mitotic structures such as the spindle and with mitotic proteins. We hypothesize that OGT forms complexes with various proteins during M phase progression that then targets OGT the spindle and midbody. I plan to use multiple techniques such as using FRAP (Fluorescent Recovery after Photo-bleaching) on GFP-OGT to measure the kinetics of OGT at spindle/midbody, quantitative proteomics to identify OGT targeting proteins, and finally identifying the function of Aurora Kinase B in targeting OGT to mitotic substrates and structures. Our expected contribution is significant because we expect to find insight into the regulation of OGT by mitotic targeting proteins and how these interactions are uncoupled in diseases such as cancer.