Mechanism of Hedgehog Signal transduction across the plasma membrane

Hedgehog跨质膜信号转导机制

• 批准号: 8107874
• 负责人: Jin Jiang
• 金额: $ 32.17万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-03-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8107874
• 关键词: Animal Model; Animals; Beta-Adrenergic Receptor Kinase 1; Biochemical; Catalytic Domain; Cell Surface Proteins; Cell membrane; Cell surface; Cells; Complex; Cultured Cells; Cyclic AMP-Dependent Protein Kinases; Development; Developmental Process; Diagnosis; Dimerization; Disease; Drosophila G protein-coupled receptor kinase 2; Drosophila genus; Endocytosis; Erinaceidae; Event; Family; Genetic; Goals; Human; Integral Membrane Protein; Invertebrates; Investigation; Laboratories; Light; Malignant Neoplasms; Mediating; Molecular Conformation; Molecular Genetics; Outcome; Pathway interactions; Pattern; Phosphorylation; Phosphotransferases; Proteins; Publishing; Regulation; Role; Signal Transduction; Signaling Protein; Site; Sonic Hedgehog Pathway; System; Testing; Therapeutic; Transducers; Translating; Ubiquitination; Vertebrates; Work; casein kinase I; cell growth; drug development; hedgehog signal transduction; human SMO protein; improved; in vivo; interest; public health relevance; receptor; response; smoothened signaling pathway; therapeutic target; tool; trafficking; ubiquitin-protein ligase

DESCRIPTION (provided by applicant): The Hedgehog (Hh) family of secreted signaling proteins governs cell growth and patterning in numerous developmental processes in both vertebrates and invertebrates. Misregulation of Hh signaling activity has been implicated in many human disorders including cancer. The long-term goal of my laboratory is to understand how Hh controls cell growth and patterning, and how the graded Hh signals are transduced to elicit different developmental outcomes. The Hh signal reception system consists of two transmembrane proteins: a twelve-transmembrane protein Patched (Ptc) as the Hh receptor and a seven-transmembrane protein Smoothened (Smo) as the obligatory signal transducer. We have discovered that protein kinase A (PKA) and casein kinase 1 (CK1) positively regulate the Hh pathway by phosphorylating Smo, leading to its cell surface accumulation and conformational change to an active state. In addition, we found that Hh-induced phosphorylation promotes Smo interaction with the intracellular signaling complexes. We have also found that mammalian Smo undergoes a conformational change in response to Shh, which is regulated by a distinct set of kinases. These and other findings unveil interesting parallels between Drosophila and vertebrate Hh signaling mechanisms and provide new tools and hypotheses to dissect the Hh signaling mechanism in both systems. In this proposal, we will investigate the function and regulation of multiple Smo phosphorylation events in Hh signaling (Aim1), determine how phosphorylation regulates Smo cell surface expression (Aim 2), determine how Smo activates the intracellular signaling complex (Aim 3), and investigate the function and mechanism of Smo phosphorylation in Shh pathway activation (Aim 4). The proposed study should provide deeper understanding of the Hh signal transduction mechanism and shed new light into how graded Hh signals are translated into different developmental outcomes in both Drosophila and vertebrate systems. As abnormal elevation of Smo activity and Hh signaling contributes to many human cancers and Smo is a primary therapeutic target for drug development, our study may provide new avenues for improving diagnosis and therapeutics of Hh pathway related cancers. PUBLIC HEALTH RELEVANCE: Misregulation of Hh pathway activity has been implicated in many human disorders including cancer. Hence, understanding the Hh signaling mechanisms, as proposed by this project, may provide new avenues for improving diagnosis and therapeutics of cancer.

描述（由申请人提供）：Hedgehog （Hh）家族分泌的信号蛋白在脊椎动物和无脊椎动物的许多发育过程中调控细胞生长和模式。Hh信号活动的错误调节与包括癌症在内的许多人类疾病有关。我实验室的长期目标是了解Hh如何控制细胞生长和模式，以及分级Hh信号如何被转导以引发不同的发育结果。Hh信号接收系统由两种跨膜蛋白组成：一种是作为Hh受体的十二跨膜蛋白补丁（Ptc），一种是作为强制性信号换能器的七跨膜蛋白平滑（Smo）。我们发现蛋白激酶A （PKA）和酪蛋白激酶1 （CK1）通过磷酸化Smo正向调节Hh通路，导致Smo在细胞表面的积累和构象改变进入活性状态。此外，我们发现hh诱导的磷酸化促进Smo与细胞内信号复合物的相互作用。我们还发现哺乳动物的Smo基因对Shh的反应会发生构象变化，这是由一组不同的激酶调节的。这些和其他的发现揭示了果蝇和脊椎动物Hh信号机制之间有趣的相似之处，并为解剖这两个系统中的Hh信号机制提供了新的工具和假设。在本提案中，我们将研究Hh信号通路（Aim1）中多个Smo磷酸化事件的功能和调控，确定磷酸化如何调节Smo细胞表面表达（Aim 2），确定Smo如何激活细胞内信号复合物（Aim 3），并研究Smo磷酸化在Shh通路激活中的功能和机制（Aim 4）。该研究将提供对Hh信号转导机制的更深入理解，并揭示在果蝇和脊椎动物系统中，分级Hh信号如何转化为不同的发育结果。由于Smo活性和Hh信号的异常升高与许多人类癌症有关，并且Smo是药物开发的主要治疗靶点，我们的研究可能为改善Hh通路相关癌症的诊断和治疗提供新的途径。