Mechanisms of Wg/Wnt regulation by glypican Dlp

项目总结 WNT信号是一条进化上保守的途径，它调节几种细胞行为，如 细胞的增殖、存活、分化和迁移以促进组织的动态平衡。值得注意的是，工作组/工作组 信号通路对组织构型很重要，在上皮性肿瘤中经常被解除调控。隐藏的WNT 配体分布在细胞外空间，促进靶细胞的旁分泌和远程信号传递。 WNTs的这些旁分泌和远程功能依赖于细胞外WNTs的可用性，这在一定程度上 是由细胞表面的糖蛋白(DLP)决定的。在这项提案中，我将重点介绍分子机制 这决定了DLP对WNT可用性和信号的调节。 DLP在调节Wnt信号转导中的作用被描述为“双相”：通过持续的结合和释放， DLP同时促进远程信号和限制旁分泌信号，确保适当的配体 在这两个范围内都有供应。佩奇-麦考实验室建立了果蝇生殖室，这是一种卵子发生的组织 作为研究定义Wnt信号范围的机制的模型，并确定了一种新的DLP/MMP2 (基质金属蛋白酶2)模块，调节旁分泌和在生殖器中的远程Wnt信号。 具体地说，我发现MMP2对DLP的蛋白水解性切割改变了它的亚细胞定位和功能，从而 调整WNT的可用性。此外，我的初步数据表明，DLP/MMP2可能调节Wnt信号 在上皮性肿瘤中促进肿瘤生长。在目标1中，我将研究发生的分子事件 在DLP的蛋白水解酶的下游，以调节Wg/Wnt的可用性和信号在生殖器和 肿瘤。 细胞外Wnt的分布与其产生和分泌密切相关。我发现DLP可以 在源细胞中调节Wg(Wnt-1)的产生。生殖器菌源细胞产生的WG是 受到严格的调控，这种调控对正常的卵子发生至关重要。此外，我发现DLP与 与细胞内通讯的非配基蛋白质(这一发现以前没有报道) 细胞骨架机械，潜在地调节细胞黏附和/或形状。在《目标2》中，我将调查小说 DLP调节Wnt配体的产生和Wg的远程分布以促进远程的机制 WG信令。这些研究将揭示以前不为人知的细胞表面标志蛋白在 调控Wnt信号并阐明多细胞发育策略的新范例 维持组织动态平衡的生物体。

PROJECT SUMMARY Wnt signaling is an evolutionarily conserved pathway that regulates several cellular behaviors such as cell proliferation, survival, differentiation, and migration to promote tissue homeostasis. Of note, the Wg/Wnt signaling pathway is important for tissue patterning and is often deregulated in epithelial cancers. Secreted Wnt ligands are distributed in the extracellular space to promote paracrine and long-range signaling in target cells. These paracrine and long-range functions of Wnts are dependent on extracellular Wnt availability, which in part is dictated by cell-surface glypican, Dally-like protein (Dlp). In this proposal, I will focus on molecular mechanisms that dictate Dlp-mediated regulation of Wnt availability and signaling. Dlp’s role in regulating Wnt signaling has been described as ‘biphasic’: By continual binding and release, Dlp simultaneously promotes long-range signaling and restricts paracrine signaling, ensuring proper ligand availability at both ranges. The Page-McCaw lab established Drosophila germarium, a tissue where oogenesis occurs, as a model to study mechanisms that define Wnt signaling ranges, and identified a novel Dlp/Mmp2 (Matrix Metalloprotease 2) module that modulates paracrine and long-range Wnt signaling in the germarium. Specifically, I found that proteolytic cleavage of Dlp by Mmp2 alters its subcellular localization and function to modulate Wnt availability. Additionally, my preliminary data suggest that Dlp/Mmp2 may regulate Wnt signaling in epithelial tumors to promote tumor growth. In Aim 1, I will investigate the molecular events that occur downstream of proteolytic cleavage of Dlp to modulate Wg/Wnt availability and signaling in the germarium and tumors. The extracellular Wnt distribution is tightly linked with its production and secretion. I found that Dlp can modulate Wg (Wnt-1) production in source cells in the germarium. Wg production in source cells in germaria is tightly regulated and this regulation is crucial for proper oogenesis. Additionally, I found that Dlp interacts with non-ligand proteins (a finding that has not been previously reported) that communicate with intracellular cytoskeletal machinery, potentially to modulate cell adhesion and/or shape. In Aim 2, I will investigate novel mechanisms of how Dlp regulates Wnt ligand production and long-range Wg distribution to facilitate long-range Wg signaling. These investigations will uncover previously unappreciated roles of cell-surface glypicans in regulating Wnt signaling and elucidate novel paradigms of developmental strategies employed in multicellular organisms to maintain tissue homeostasis.