Interrogating the b-catenin interactome for novel modulators of Wnt signaling.

成体干细胞在生物体的整个生命过程中维持和再生组织系统。造血干细胞（HSC）在骨髓中产生和补充血液系统，并且具有用于移植目的的治疗性开发的巨大潜力。具体地，促进HSC的离体扩增、维持和储存的因子在多种骨髓疾病的治疗中是高度期望的，所述骨髓疾病包括白血病、贫血、骨髓增生性病症、骨髓增生异常综合征、自身免疫病症、HIV感染和镰状细胞病。经典Wnt/β-连环蛋白信号转导是一种进化上保守的信号转导级联，涉及正常发育和疾病。特别是，成体干细胞利用这一途径来驱动自我更新和/或增殖决定。已知Wnt信号传导驱动HSC的自我更新和增殖，然而驱动这些过程的分子机制还不清楚。该途径的中心介质β-连环蛋白首先在细胞质中稳定，然后易位到细胞核中，在细胞核中作为Wnt靶基因的转录共激活因子。β-连环蛋白的稳定性、定位和活性在很大程度上受蛋白质-蛋白质相互作用的控制，最近的研究表明，β-连环蛋白的相互作用组（以及实际上整个Wnt响应蛋白质组）在细胞类型之间变化很大。该项目的目的是研究血细胞中的β-连环蛋白相互作用网络，以确定驱动HSC自我更新/增殖命运的Wnt信号转导的新型调节剂。学生将使用计算和湿实验室技术的组合来识别和验证组织特异性相互作用伙伴（参见下面的培训和方法）。该项目更广泛的基本影响将是了解Wnt信号传导的核心生化机制如何通过组织或环境特异性相互作用进行调节，使Wnt信号传导在不同的细胞/组织中发挥作用。该项目还可能导致工业合作，以开发针对Wnt信号传导和相关蛋白质的新型药物。

Adult stem cells maintain and regenerate tissue systems throughout the life of an organism. Haematopoietic stem cells (HSC) generate and replenish the blood system in the bone marrow and have great potential to be exploited therapeutically for transplantation purposes. Specifically, factors that promote the ex vivo expansion, maintenance and storage of HSCs are highly desirable in the treatment of multiple bone marrow diseases including leukaemia, anaemia, myeloproliferative disorders, myelodysplastic syndrome, autoimmune conditions, HIV infection and sickle cell disease. Canonical Wnt/Beta-catenin signalling is an evolutionary conserved signal transduction cascade implicated in both normal development and disease. In particular, adult stem cells utilise this pathway to drive self-renewal and/or proliferation decisions. Wnt signalling is known to drive the self-renewal and proliferation of HSCs, however the molecular mechanisms driving these processes are not well understood. The central mediator of the pathway, Beta-catenin, first stabilises in the cytoplasm before translocation into the nucleus where is serves as a transcriptional co-activator of Wnt target genes. Beta-catenin's stability, localisation and activity is governed heavily through protein-protein interactions and recent studies have demonstrated that Beta-catenin's interactome (and indeed overall Wnt-responsive proteome) varies considerably between cell types. The aim of this project is to characterise the Beta-catenin interaction network in blood cells for the purposes of identifying novel regulators of Wnt signalling that drive self-renewal/proliferation fate in HSC. The student will use a combination of computational and wet lab techniques to both identify and validate tissue-specific interaction partners (see Training and Methods below). The broader fundamental impact of this project will be in understanding how the core biochemical mechanisms of Wnt signalling are modulated through tissue or context specific interactions allowing Wnt signalling to function in diverse cells/tissues. This project may also lead to industrial collaboration for the development of novel agents for targeting Wnt signalling and associated proteins of interest.