对干细胞不对称分裂中Dlg介导的蛋白复合物的结构与功能研究

干细胞不对称分裂是干细胞维持其自我更新和分化功能的关键过程，在多细胞生物发育、组织修复、肿瘤发生过程中都发挥着重要的作用，近年来成为干细胞和肿瘤生物学研究领域的热点之一。纺锤体沿着细胞极性轴的定向是不对称分裂过程的重要步骤。许多进化中保守的蛋白复合物参与调控这一过程，其中包括两个重要的信号通路：Pins/Mud介导的信号通路（Gai/LGN/NuMA）和Dlg介导的信号通路（LGN/Dlg4/KIF13B）。我们之前研究了Pins/Mud介导的信号通路的蛋白复合物的结构生物学基础。但Dlg介导的信号通路的分子机制尚不明确。本项目计划详细研究LGN/Dlg4/KIF13B复合物的相互作用机制、解析蛋白复合物的三维结构、并利用MDCK细胞株研究该蛋白复合物在纺锤体旋转定向过程中的作用机理。研究成果将为全面了解干细胞不对称分裂分子机制提供结构信息并为治疗相关疾病的药物的设计开发提供理论基础。

Stem cells, defined by their ability of self-renew and differentiation, play critical roles in development, tissue repair and tumorigenesis. Asymmetric cell division (ACD), the process by which a mother cell gives rise to two distinct daughter cells, is a fundamental process widely used to regulate stem cell function and generate cellular diversity during development in metazoa. Establishment of the mitotic spindle along the axis of cell polarity is one of the most important steps in ACD. Recent studies have demonstrated that many conserved protein complexes are involved in regulation of mitotic spindle orientation in ACD, including two signaling pathways: Pins/Mud-mediated pathway （Ga/LGN/NuMA） and Dlg-mediated pathway （LGN/Dlg4/KIF13B）. We previously studied the molecular mechanism underlying the complex formation of Ga/LGN/NuMA and LGN/mInsc. However, little is known about how Dlg-mediated complex assembles. Here, we plan to systematically study the molecular details of LGN/Dlg4/KIF13B interactions using biochemical and structural tools. In addition, we will study the function of Dlg-mediated protein complex in spindle orientation in ACD in vivo using the MDCK cell system.We hope that our biochemical and structural discorveries will largely improve our understanding the molecular basis of ACD and provide valuable information for the drug design of related diseases.