Mechanisms of Smoothened Activation in Hedgehog Signaling

Hedgehog 信号传导平滑激活机制

• 批准号: 10552682
• 负责人: Aashish Manglik
• 金额: $ 32.3万
• 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/10552682
• 关键词: 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; Molecular Conformation; Mutagenesis; NMR Spectroscopy; Organism; Pathway interactions; Pattern; Pharmaceutical Preparations; Physiological; Predisposition; Publishing; Regenerative Medicine; Regulation; Repression; Research; Resistance; Resolution; Signal Pathway; Signal Transduction; Signal Transduction Pathway; Site; Skin Carcinoma; Sterols; Structure; Therapeutic; Tissues; Transmembrane Domain; Urochordata; X-Ray Crystallography; antagonist; body system; 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.

项目摘要/摘要 刺猬信号传导中平滑活化的机制。刺猬（HH）信号传导 途径协调人类和大多数后生动物的发展。在成年组织中，异常HH途径 激活驱动各种癌症，包括皮肤和小儿大脑的基底细胞癌 髓母细胞瘤。一种异常的机制可以实现HH信号转导。在基础状态下，转运蛋白 像分子修补1（PTCH1）一样，抑制了七跨膜蛋白的平滑（SMO）。 HH抑制 PTCH1，释放了导致下游转录的SMO活性。主要的机械假设是 该细胞固醇激活SMO，但在没有HH的情况下被PTCH1隔离。连接 PTCH1向SMO激活的推定运输功能仍然是理解的中心奥秘之一 HH信号如何在整个膜上转导。一个关键的差距是固醇直接以及哪个 影响SMO激活。该建议将以两个目的解决这些问题。第一个目标重点 固醇激活SMO。在这里，我们将结合生物化学，结构生物学和信号研究 定义哪些固醇可以激活SMO以及它们如何进行。在第二个目标中，我们专注于固醇如何结合 对于SMO的不同位点会影响HH途径活动。我们将使用X射线晶体学，冷冻电子 显微镜和NMR光谱，以在固醇的位置生成集成的高分辨率透视图 与SMO结合，以及它们如何影响SMO活性。这些研究将提供有关如何 HH信号在整个膜上转导。这样的见解可以使SMO抑制剂的设计更少 容易受到肿瘤耐药性或HH途径调节剂的再生医学调节剂。