Mechanisms of Smoothened Activation in Hedgehog Signaling

Hedgehog 信号传导平滑激活机制

• 批准号: 10365068
• 负责人: Aashish Manglik
• 金额: $ 33.15万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-02-01 至 2025-11-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10365068
• 关键词: Address; Adult; Basal cell carcinoma; Binding; Binding Sites; Biochemical; Biochemistry; Biophysics; Brain; Cells; Childhood; Cholesterol; Communication; Complex; Cryoelectron Microscopy; Data; Development; Erinaceidae; Extracellular Domain; Foundations; Genetic Transcription; Human; In Vitro; Integral Membrane Protein; Link; Lipid Binding; Lipids; Malignant Neoplasms; Mass Spectrum Analysis; Membrane; Modeling; Molecular; Mutagenesis; NMR Spectroscopy; Organ; Organism; Pathway interactions; Pattern; Pharmaceutical Preparations; Physiological; Publishing; Regenerative Medicine; Regulation; Research; Resistance; Resolution; Signal Transduction; Signal Transduction Pathway; Site; Skin Carcinoma; Sterols; Structure; Therapeutic; Tissues; Transmembrane Domain; Urochordata; X-Ray Crystallography; antagonist; design; hedgehog signal transduction; inhibitor; insight; medulloblastoma; molecular dynamics; nanobodies; programs; resistance mechanism; smoothened signaling pathway; structural biology; tumor

PROJECT SUMMARY/ABSTRACT MECHANISMS OF SMOOTHENED ACTIVATION IN HEDGEHOG SIGNALING. The Hedgehog (Hh) signaling pathway coordinates development in humans and most metazoans. In adult tissues, aberrant Hh pathway activation drives various cancers, including basal cell carcinoma of the skin and pediatric brain medulloblastoma. An unusual mechanism enables Hh signal transduction. In the basal state, the transporter- like molecule Patched1 (PTCH1) represses Smoothened (SMO), a seven-transmembrane protein. Hh inhibits PTCH1, which unleashes SMO activity causing downstream transcription. A leading mechanistic hypothesis is that cellular sterols activate SMO, but are sequestered by PTCH1 in the absence of Hh. Connecting the putative transport function of PTCH1 to SMO activation remains one of the central mysteries in understanding how the Hh signal is transduced across the membrane. A critical gap is how, and which, sterols directly influence SMO activation. This proposal will address these questions in two aims. The first aim focuses on which sterols activate SMO. Here, we will combine biochemistry, structural biology, and signaling studies to define which sterols can activate SMO and how they do so. In the second aim, we focus on how sterol binding to distinct sites on SMO influences Hh pathway activity. We will use X-ray crystallography, cryo-electron microscopy, and NMR spectroscopy to generate an integrated high-resolution perspective on where sterols bind to SMO, and how they influence SMO activity. These studies will provide a mechanistic picture on how the Hh signal is transduced across the membrane. Such insights may enable the design of SMO inhibitors less susceptible to tumor resistance or Hh pathway modulators for regenerative medicine.

项目概要/摘要 Hedgehog 信号传导的平滑激活机制。刺猬 (Hh) 信号 途径协调人类和大多数后生动物的发育。在成人组织中，异常的 Hh 通路 激活会导致各种癌症，包括皮肤基底细胞癌和儿童脑癌 髓母细胞瘤。一种不寻常的机制能够实现 Hh 信号转导。在基础状态下，转运蛋白- 类似分子 Patched1 (PTCH1) 会抑制 Smoothened (SMO)，这是一种七次跨膜蛋白。 Hh 抑制 PTCH1，释放 SMO 活性，导致下游转录。一个主要的机制假设是 细胞甾醇激活 SMO，但在 Hh 不存在的情况下被 PTCH1 隔离。连接 PTCH1 到 SMO 激活的假定转运功能仍然是理解的核心谜团之一 Hh 信号如何跨膜转导。一个关键的差距是如何以及哪些直接甾醇 影响SMO激活。该提案将通过两个目标解决这些问题。第一个目标集中于 哪些甾醇可激活 SMO。在这里，我们将结合生物化学、结构生物学和信号研究 定义哪些甾醇可以激活 SMO 以及它们如何激活。在第二个目标中，我们关注甾醇如何结合 SMO 上的不同位点影响 Hh 通路活性。我们将使用 X 射线晶体学、冷冻电子 显微镜和核磁共振波谱生成关于甾醇的综合高分辨率视角 与 SMO 结合，以及它们如何影响 SMO 活性。这些研究将提供一幅关于如何 Hh 信号跨膜转导。这些见解可能有助于 SMO 抑制剂的设计 对再生医学的肿瘤耐药性或 Hh 通路调节剂敏感。