Molecular mechanisms of Hedgehog receptor function

Hedgehog受体功能的分子机制

基本信息

批准号：
8640198
负责人：
PHILIP A BEACHY
金额：
$ 29.83万
依托单位：
STANFORD UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-08-15 至 2016-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8640198
关键词：
Accounting Address Adult Affect Affinity Binding Biochemical Biological Assay C-terminal Cell Line Cell membrane Cell model Chemical Structure Chlamydomonas Cilia Congenital Abnormality Coupling Development Disease Drosophila genus Embryo Erinaceidae Event Family Family member Flagella Fractionation Genetic Genetic Transcription Human Insecta Integral Membrane Protein Ion Channel Ions Lead Lifting Light Link Lipids Malignant Neoplasms Mammalian Cell Mammals Maps Mass Spectrum Analysis Measures Mediating Mediator of activation protein Membrane Methods Microscopy Molecular Molecular Models Mus Mutation Natural regeneration Neoplasms Organ Pathway interactions Pattern Phenotype Physiology Plants Platyhelminths Play Protein Family Proteins Protons Reagent Regulation Resistance Role Series Signal Transduction Signaling Protein Source Specific qualifier value Teratogens Testing Therapeutic Tissues Transmembrane Transport Xenopus oocyte Yeasts base ciliopathy cyclopamine extracellular hedgehog signal transduction human SMO protein light effects member molecular modeling receptor receptor function response screening small molecule smoothened signaling pathway tissue regeneration trafficking

项目摘要

DESCRIPTION (provided by applicant): The Hedgehog (Hh) signaling pathway plays a central role in specifying the embryonic patterning of metazoan organs. Post-embryonically, Hh signaling mediates homeostatic regeneration of adult tissues and is associated with numerous cancers when inappropriately active. Despite its importance in development, physiology, and disease we fundamentally do not understand how the extracellular Hedgehog signal is transduced across the membrane. The central question is the mechanism by which the Hh receptor Patched (Ptc; Ptch1 in mammals), a transporter-like protein, acts to regulate Smoothened (Smo), a member of the seven transmembrane protein family. From flatworms to insects to mammals, Ptc inhibits Smo activity in the absence of Hh, and thisinhibition is lifted upon Hh binding to Ptc and its co-receptors, thu releasing Smo for pathway activation through a series of downstream events and consequent changes in gene transcription. Mechanistically, Ptch1 is thought to act as a proton-dependent transmembrane transporter of a lipidic modulator of Smo activity across the membrane, but this modulator remains to be identified. In addition, mammalian Hh signal transduction has been linked to the primary cilium, but the actual role of the primary cilium in transduction is not understood. To elucidate the molecular and cellular mechanisms of Hh receptor function in the cilium we propose to define intrinsic sequence requirements and cellular factors required for Ptch1/Smo ciliary trafficking and signal transduction, focusing in particular on signals and factors that are regulated by Hh pathway activity. We will identify endogenous small molecules that mediate Ptch1 regulation of Smo activity, having initially identified Chlamydomonas flagella as an enriched source of such a modulatory lipid. We will test whether Ptch1 functions as a transmembrane transporter that depends on a chemiosmotic gradient and investigate the effects of Ptch1 function on the dynamics of Smo ciliary trafficking. Our findings will be integrated into a detailed cellular and molecular account of Hh signal transduction, and may provide a basis for improvements in therapies for Hh pathway-dependent cancers.

描述（由申请人提供）：刺猬（HH）信号通路在指定后生器官的胚胎图案中起着核心作用。在胎儿后，HH信号传导介导了成年组织的体内稳态再生，并且在不适当的活性时与许多癌症有关。尽管它在发育，生理和疾病中的重要性，但我们从根本上并不了解如何在整个膜上转导细胞外刺猬信号。一个中心问题是HH受体修补的机制（哺乳动物中的PTC； PTCH1），一种转运蛋白样蛋白，可用于调节七个跨膜蛋白家族的成员平滑（SMO）。从扁虫到昆虫再到哺乳动物，PTC在没有HH的情况下抑制SMO活性，并且这种抑制作用在HH与PTC及其共受体的结合后取消，THU通过一系列下游事件释放SMO以激活途径，并在基因转录中释放出SMO。从机械上讲，PTCH1被认为是跨膜的SMO活性的脂质调节剂的质子依赖性跨膜转运蛋白，但该调节剂仍有待鉴定。此外，哺乳动物HH信号转导已与原代纤毛有联系，但是原代纤毛在转导中的实际作用尚不清楚。为了阐明纤毛中HH受体功能的分子和细胞机制，我们建议定义PTCH1/SMO睫状运输和信号转导所需的固有序列要求和细胞因子，尤其集中在信号和因素上，这些信号和因素受HH途径活性调节。我们将确定介导PTCH1调控SMO活性的内源性小分子，最初将衣原体鞭毛蛋白鞭毛鉴定为这种调节性脂质的丰富来源。我们将测试PTCH1是否作为依赖化学梯度的跨膜转运蛋白起作用，并研究PTCH1功能对SMO睫状运输动力学的影响。我们的发现将整合到HH信号转导的详细细胞和分子记录中，并可能为改善HH途径依赖性癌症治疗的基础提供基础。