Sending and receiving Hedgehog and Wnt signals

发送和接收 Hedgehog 和 Wnt 信号

• 批准号: 10797274
• 负责人: ADRIAN SALIC
• 金额: $ 9.51万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-05-01 至 2024-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10797274
• 关键词: Administrative Supplement; Adult; Biochemistry; Carrier Proteins; Cell Maintenance; Cell membrane; Cell surface; Cells; Cellular biology; Chemicals; Cholesterol; Complex; Congenital Abnormality; Development; Embryonic Development; Erinaceidae; Family; Fatty Acids; Funding; Genetic Diseases; Health; Human; Ligands; Lipids; Malignant Neoplasms; Membrane; Membrane Proteins; Molecular; Palmitates; Pathogenesis; Pathway interactions; Physiology; Play; Protein Secretion; Reader; Role; SHH gene; Signal Pathway; Signal Transduction; Sonic Hedgehog Pathway; Tumor Suppressor Proteins; WNT Signaling Pathway; adult stem cell; cancer therapy; cancer type; experimental study; intercellular communication; multimodality; novel; palmitoleate; patched protein; protein function; receptor; recruit; release factor; smoothened signaling pathway

Application for an Administrative Supplement to: 5R01 GM122920-6 “Sending and receiving Hedgehog and Wnt signals” Abstract Embryogenesis and adult physiology are orchestrated by a handful of cell-cell signaling pathways[1]. The two pathways that are the focus of the present proposal, Hedgehog (Hh) and Wnt, play critical roles in development[2] and adult stem cell maintenance[3]. Insufficient Hh or Wnt signaling is the cause of numerous birth defects[4], while excessive activation is involved in many cancers[3a, 5]. A common feature of Hh and Wnt signaling is that they are both triggered by lipid-modified secreted proteins[6]: Hh ligands are modified with cholesterol[7] and palmitate[8], while Wnts are modified with palmitate/palmitoleate[9]. While lipidation is essential for signaling function, it makes Hh and Wnt ligands strongly membrane-attached[10], raising the question of how they spread far from producing cells. We first investigated this question for the Hh ligand, Sonic hedgehog (Shh)[11]. We discovered that Shh is released as a soluble and potent complex with a secreted carrier protein, Scube2[12], and that Scube2-Shh formation is catalyzed by the transporter Dispatched1[13] (Disp1), powered by the plasma membrane Na+ gradient[14]. Scube2-Shh then delivers Shh to its receptor, the tumor suppressor membrane protein Patched1 (Ptch1)[15], triggering Hh pathway activation[16]. We discovered that the Shh co- receptors, comprising the homologous membrane proteins Cdon and Boc and the unrelated GPI-anchored Gas1[17], are essential for moving Shh from Scube2 to Ptch1[18]. Our results defined a pathway whereby Cdon/Boc recruit Scube2-Shh to the cell surface, after which Gas1 promotes Shh transfer to Ptch1. Finally, we recently discovered two families of secreted proteins that function as novel release factors and carriers for Wnt ligands, paralleling the mechanism of Shh release. Our findings open several critical questions about Hh and Wnt signaling. We propose combining biochemistry, structural, chemical and cell biology to accomplish the following aims: 1) To determine precisely how Shh is released form the membrane of producing cells; 2) To elucidate how Gas1 catalyzes Shh-Ptch1 complex formation, to trigger Hh signaling; 3) To determine how Wnt ligands are secreted and then delivered to responding cells. These studies are important to undertake for the following reasons: A) They will elucidate the pathways of Shh secretion and Shh-Ptch1 complex assembly, two crucial but poorly understood steps in Hh signaling; B) They will define novel mechanisms for the release of Wnt ligands from cells and for how they activate signaling in responding cells; C) They will define novel targets for blocking Hh and Wnt signaling in cancer, such as their specific release and delivery pathways; and D) Our novel chemical probes for studying lipids will be broadly applicable to the cell biology of cholesterol and fatty acids.

行政补充申请： 5R01 GM122920 - 6 "发送和接收Hedgehog和Wnt信号" 摘要 胚胎发生和成年生理学是由少数细胞-细胞信号传导途径协调的[1]。两 作为本提案重点的途径，Hedgehog（Hh）和Wnt，在以下方面发挥关键作用： 干细胞的发育[2]和成体干细胞的维持[3]。Hh或Wnt信号传导不足是导致许多细胞凋亡的原因。 出生缺陷[4]，而过度激活涉及许多癌症[3a，5]。Hh和Wnt的共同特征 信号传导是它们都是由脂质修饰的分泌蛋白触发的[6]：Hh配体被修饰为 [7]和棕榈酸酯[8]，而Wnt用棕榈酸酯/棕榈油酸酯修饰[9]。虽然脂化是必不可少的， 对于信号传导功能，它使Hh和Wnt配体牢固地附着在膜上[10]，这就提出了一个问题，即如何 它们远离生产细胞。我们首先研究了Hh配体Sonic hedgehog的这个问题 （嘘）[11].我们发现Shh作为一种可溶性和有效的复合物与分泌的载体蛋白一起释放， Scube2 [12]，Scube2-Shh的形成是由转运蛋白Dispatched1 [13]（Disp1）催化的，动力来自 质膜Na+梯度[14]。然后Scube2-Shh将Shh传递给其受体，肿瘤抑制因子 膜蛋白Patched1（Ptch1）[15]，触发Hh通路激活[16]。我们发现嘘- 受体，包括同源的膜蛋白Cdon和Boc和无关的GPI锚定的 Gas 1 [17]是将Shh从Scube 2移动到Ptch 1 [18]的关键。我们的研究结果定义了一条途径， Cdon/Boc将Scube2-Shh募集到细胞表面，之后Gas1促进Shh转移到Ptch1。最后我们 最近发现了两个分泌蛋白家族，它们作为Wnt的新型释放因子和载体发挥作用 配体，平行的机制Shh的释放。我们的研究结果打开了几个关键的问题， Wnt信号。我们建议结合生物化学，结构，化学和细胞生物学来完成 以下目的：1）精确地确定Shh如何从生产细胞的膜释放; 2） 阐明Gas1如何催化Shh-Ptch1复合物的形成，以触发Hh信号传导; 3）确定Wnt 分泌配体，然后将其递送至应答细胞。 这些研究很重要，原因如下：A）它们将阐明Shh的途径 分泌和Shh-Ptch 1复合物组装，这是Hh信号传导中的两个关键但知之甚少的步骤; B）它们 将定义Wnt配体从细胞中释放的新机制，以及它们如何激活细胞中的信号传导。 C）它们将定义用于阻断癌症中Hh和Wnt信号传导的新靶点，例如它们的免疫应答。 特定的释放和传递途径;和D）我们用于研究脂质的新型化学探针将被广泛应用于 适用于胆固醇和脂肪酸的细胞生物学。