Mechanisms of Wg/Wnt regulation by glypican Dlp

项目摘要 Wnt信号转导是一种进化上保守的途径，调节多种细胞行为，如 细胞增殖、存活、分化和迁移以促进组织稳态。值得注意的是， 信号传导途径对于组织图案化是重要的，并且在上皮癌中经常失调。分泌的Wnt 配体分布在细胞外空间中以促进靶细胞中的旁分泌和长距离信号传导。 Wnt的这些旁分泌和长程功能依赖于细胞外Wnt的可用性，这部分地影响了Wnt的功能。 由细胞表面磷脂酰肌醇蛋白聚糖Dally样蛋白（Dlp）决定。在这个建议中，我将集中在分子机制 其指示Dlp介导的Wnt可用性和信号传导的调节。 Dlp在调节Wnt信号传导中的作用被描述为“双相”：通过持续的结合和释放， Dlp同时促进长距离信号传导和限制旁分泌信号传导，确保适当的配体 在两个范围内可用。佩奇-麦考实验室建立了果蝇生殖器，一种卵子发生的组织， 发生，作为一个模型来研究定义Wnt信号传导范围的机制，并确定了一种新的Dlp/Mmp 2 （基质金属蛋白酶2）模块，其调节生殖器中的旁分泌和长距离Wnt信号传导。 具体地说，我发现Mmp 2对Dlp的蛋白水解切割改变了其亚细胞定位和功能， 调节Wnt可用性。此外，我的初步数据表明，Dlp/Mmp 2可能调节Wnt信号转导， 在上皮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的蛋白水解切割下游调节生殖菌中的Wg/Wnt可用性和信号传导， 肿瘤的 细胞外Wnt的分布与其产生和分泌密切相关。我发现DLP可以 调节生殖室中源细胞中Wg（Wnt-1）的产生。来源细胞中的Wg产量是 严格调控，这种调控对卵子发生至关重要。此外，我发现Dlp与 非配体蛋白（以前没有报道的发现），与细胞内 细胞骨架机器，潜在地调节细胞粘附和/或形状。在目标2中，我将研究小说 Dlp如何调节Wnt配体产生和长距离Wg分布以促进长距离Wnt配体的产生和分布的机制。 Wg信令。这些研究将揭示细胞表面磷脂酰肌醇蛋白聚糖以前未被重视的作用， 调节Wnt信号传导，并阐明多细胞生物学中采用的发育策略的新范式。 维持组织内环境稳定。

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.