Decoding the mechanisms of cell-cell fusion

项目摘要/摘要 细胞-细胞融合是多细胞的受孕、发育和生理学的关键 并参与多种生物过程，如受精、肌肉发生、 胎盘发育、骨重建、免疫反应、肿瘤发生和 干细胞介导的组织再生。细胞融合失败会导致不育等缺陷， 先天性肌病、骨质疏松症、免疫缺陷和先兆子痫。机械师 了解细胞融合不仅对基础生物学很重要，而且还可能为 为其在治疗环境中的操作提供依据。我的实验室一直在使用果蝇成肌细胞 融合作为一个模型来研究细胞融合的一般机制。我们已经做了一个 史无前例地发现细胞融合是一个不对称的过程，其中一个细胞(攻击 细胞)利用肌动蛋白推动的膜突起入侵其融合伙伴(接收细胞)以 促进融合孔的形成。基于我们从体内成肌细胞融合中学到的见解，我们 已经在非融合、非肌肉细胞系中重组了高效细胞融合 并揭示了FusoGen接合中侵入性膜突起的新功能。 此外，我们还发现了在接收融合中的动态机械感觉响应 并证明了机械张力是细胞融合的驱动力。我们的研究 到目前为止，已经对肌动蛋白细胞骨架在促进 细胞膜并列融合。在未来五年，我们将把我们的研究扩展到 两个新方向。首先，我们将推断我们在果蝇身上发现的机制 并研究哺乳动物细胞中肌动蛋白细胞骨架的潜在功能 融合，以及跨膜融合蛋白如何与肌动蛋白细胞骨架协调 以促进细胞融合。第二，我们将识别和表征新的跨膜蛋白， 包括新的融合子，在使用重组细胞融合培养系统的细胞融合中 模特。我们将继续使用跨学科的方法，包括遗传学、分子 生物学、生物化学、生物物理学、实时成像、超分辨率显微镜和电子 显微镜在我们提议的研究中的应用。通过从果蝇扩展到老鼠，从 肌动蛋白从细胞骨架到跨膜蛋白，我们的研究不仅将获得重大的新见解 细胞间融合的基本原理，也对广泛产生深远的影响 研究领域广泛，包括膜生物学、细胞生物学和发育生物学。

PROJECT SUMMARY/ABSTRACT Cell-cell fusion is critical to the conception, development and physiology of multicellular organisms, and is involved in a variety of biological processes, such as fertilization, myogenesis, placenta development, bone remodeling, immune response, tumorigenesis, and aspects of stem cells-mediated tissue regeneration. Failure in cell fusion leads to defects such as infertility, congenital myopathy, osteopetrosis, immune deficiency, and pre-eclampsia. A mechanistic understanding of cell fusion is not only important for fundamental biology but may also provide basis for its manipulation in therapeutic settings. My lab has been using Drosophila myoblast fusion as a model to study the general mechanisms underlying cell fusion. We have made an unprecedented discover that cell fusion is an asymmetric process in which one cell (attacking cell) invades its fusion partner (receiving cell) using actin-propelled membrane protrusions to promote fusion pore formation. Building on insights we learned from myoblast fusion in vivo, we have reconstituted high-efficiency cell fusion in an otherwise non-fusogenic, non-muscle cell line and uncovered a novel function for invasive membrane protrusions in fusogen engagement. Furthermore, we have discovered dynamic mechanosensory responses in the receiving fusion partner and demonstrated that mechanical tension is a driving force for cell fusion. Our studies to date have provided significant insights into the function of the actin cytoskeleton in promoting cell membrane juxtaposition and fusion. In the next five years, we will expand our research into two new directions. First, we will extrapolate the mechanisms that we uncovered in Drosophila to mammals and investigate the potential function of the actin cytoskeleton in mammalian cell fusion, as well as how transmembrane fusogenic proteins coordinate with the actin cytoskeleton to promote cell fusion. Second, we will identify and characterize novel transmembrane proteins, including new fusogens, in cell fusion using the reconstituted cell-fusion culture system as a model. We will continue to use an interdisciplinary approach including genetics, molecular biology, biochemistry, biophysics, live imaging, super-resolution microscopy and electron microscopy in our proposed research. By expanding from Drosophila to mouse, and from the actin cytoskeleton to transmembrane proteins, our research will not only gain major new insights into the fundamental principles of cell-cell fusion, but also have far-reaching impact on a broad range of fields, including membrane biology, cell biology and developmental biology.