The role of E-cadherin in regulating signalling pathways

新颖性、研究计划和短期目标- e -钙粘蛋白具有广泛的生物学功能，在胚胎发育、成体细胞向胚胎干细胞样细胞的重编程和成体组织维持/稳态中起着至关重要的作用。迄今为止，大多数研究都集中在生长因子、细胞外信号、转录因子和细胞内信号通路如何调节E-cadherin表达，但一个基本问题一直被忽视，也尚未得到回答，即动态的E-cadherin表达及其细胞内伙伴是否以及在多大程度上反过来影响它们的调节因子，共同控制胚胎发育和成人细胞的稳态和功能。这将是我们研究项目的长期目标。本项目的短期目标（和假设）将确定E-cadherin的细胞内伴侣和rap1调控的E-cadherin循环是否会对NF-kB、Wnt和AKT信号活性和成体细胞功能产生不同的影响（图1）。我们的最新进展和前期工作与本拟研究项目相关-我实验室的学员已经证明E-cadherin能够主动调节胚胎干细胞中的Wnt信号传导（stem cells 2010和2015，Mol Cell Proteomics 2011等）。我们最近观察到，e -cadherin高水平的成年细胞显著抑制NF-kB，同时上调Wnt和Akt活性；Wnt抑制对其他信号通路和干细胞相关蛋白表达的影响不同（初步数据）。短期目标-成体细胞，功能的获得和丧失以及多学科方法将用于三个目标。在Aim 1中，第1组学员将确定E-cadherin的哪些细胞内伴侣（a-catenin、ß-catenin和p120）影响NF-kB、Wnt和AKT活性、干细胞相关基因/蛋白和细胞功能（增殖、凋亡、迁移和细胞周期）。在目标2中，第二组受训者将确定rap1调节的e -钙粘蛋白回收影响三种信号活动的程度。在Aim 3中，学员将确定一种信号的抑制或激活（使用基因过表达、siRNA/shRNA敲低和小分子激活剂/抑制剂）是否会以e -钙粘蛋白细胞内伴侣依赖的方式对其他两种途径和细胞功能产生不同的影响。作为我们研究计划的一部分，从该项目中获得的知识将为目前未知的E-cadherin细胞内伴侣和rap1调节的E-cadherin循环在调节NF-kB、Wnt和Akt信号通路中的作用提供新的见解，这些信号通路对成人细胞功能至关重要。这将对细胞生物学产生广泛的影响，也将为学员提供一个很好的平台，为他们在学术界或生物技术公司的职业生涯做准备。

Novelty, research program and short-term goal - E-cadherin exhibits broad biological functions and is crucial during embryonic development, reprogramming of adult cells to embryonic stem-like cells and adult tissue maintenance/homeostasis. While the majority of studies thus far focus on how growth factors, extracellular signals, transcriptional factors, and intracellular signaling pathways regulate E-cadherin expression, a fundamental question that has been largely overlooked and yet to be answered is whether and to what extent the dynamic E-cadherin expression and its intracellular partners, in turn, affect their regulators to co-control embryonic development and adult cell homeostasis and functions. This will be the long-term goal of our research program. The short-term goal of this proposed project (and hypothesis) will determine whether intracellular partners of E-cadherin and Rap1-regulated E-cadherin recycling differentially affect NF-kB, Wnt and AKT signaling activities and adult cell functions (Fig 1). Our recent progress and preliminary work related to this proposed research project - The trainees in my lab have demonstrated that E-cadherin is capable of actively regulating Wnt signaling in embryonic stem cells (Stem Cells 2010 and 2015, Mol Cell Proteomics 2011, etc.). We recently observed that E-cadherinhigh adult cells markedly inhibits NF-kB whereas upregulating Wnt and Akt activity; Wnt inhibition differentially affects other signaling pathways and the expression of stem cell-associated proteins (preliminary data). Short term objectives - Adult cells, gain- and loss-of-function and multidisciplinary approaches will be used in three aims. In Aim 1, group 1 trainees will determine which intracellular partners of E-cadherin (a-catenin, ß-catenin, and p120) affect NF-kB, Wnt, and AKT activities, stem cell-associated genes/proteins and cell functions (proliferation, apoptosis, migration and cell cycle). In Aim 2, group 2 trainees will determine the extent by which Rap1-regulated E-cadherin recycling affects three signaling activity. In Aim 3, trainees will determine whether inhibition or activation of one signaling (using gene overexpression, siRNA/shRNA knockdown, and small-molecule activators/inhibitors) differentially affects other two pathways and cell functions in an E-cadherin-intracellular partners-dependent manner. Significance - As part of our research program, knowledge gained from this proposed project will provide new insights into the currently unknown roles of intracellular partners of E-cadherin and Rap1-regulated E-cadherin cycling in the regulation of NF-kB, Wnt, and Akt signaling pathways that are crucial for adult cell functions. This will have broad impacts in cell biology, and will also offer an excellent platform for trainees to prepare their careers for academia or biotechnology companies.