Mechanisms of Vertebrate Hedgehog Signaling

脊椎动物刺猬信号传导机制

• 批准号: 8883203
• 负责人: ADRIAN SALIC
• 金额: $ 31.99万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8883203
• 关键词: Accounting; Binding; Biochemical; Biochemistry; Biological; Bortezomib; Cancer Diagnostics; Cell Communication; Cell Maintenance; Cell Nucleus; Cells; Cellular biology; Cilia; Clinical; Complex; Coupled; Coupling; Cyclic AMP-Dependent Protein Kinases; Cytoplasm; Cytoplasmic Protein; Dissociation; Embryo; Embryonic Development; Erinaceidae; Event; FDA approved; Gene Targeting; Genetic Transcription; Health; Human; Maintenance; Malignant Neoplasms; Mediating; Membrane Proteins; Modeling; Molecular; Multiple Myeloma; Pathogenesis; Pathway interactions; Pharmaceutical Preparations; Pharmacotherapy; Phosphorylation; Process; Proteasome Inhibition; Proteasome Inhibitor; Proteins; Proteolysis; Proteolytic Processing; Recruitment Activity; Regulation; Rest; Role; Signal Transduction; Testing; Therapeutic; Transcriptional Activation; Transcriptional Regulation; Velcade; Vertebrates; adult stem cell; hedgehog signal transduction; improved; inhibitor/antagonist; insight; multicatalytic endopeptidase complex; new therapeutic target; novel; research study; small molecule; smoothened signaling pathway; trafficking; transcription factor

DESCRIPTION (provided by applicant): The Hedgehog (Hh) signaling pathway has critical roles in embryonic development, adult stem cell maintenance and in many cancers. In vertebrates, Hh signaling is initiated at the primary cilium, from where the signal is relayed to the cytoplasm and then nucleus, to ultimately control expression of specific target genes, mediated by the Gli transcription factors. In the absence of stimulation, Gli proteins are kept off by at least three inhibitory mechanisms: 1) direct binding of Suppressor of Fused (SuFu); 2) partial degradation to repressor forms and 3) inhibition by protein kinase A (PKA). When cells receive an Hh signal, these inhibitions are overcome, allowing Gli activation. In spite of the importance of Hh signaling, we still do not understand many of the critical mechanisms involved in inhibiting and in activating Gli proteins, in the resting and stimulated states of the Hh pathway, respectively. We discovered that Hh stimulation recruits SuFu-Gli complexes to primary cilia and causes their dissociation, resulting in Gli activation; we found that this process is antagonized by PKA. This provided a novel mechanism for activation of Gli proteins and for the inhibitory effect of PKA. We also discovered that inhibition of the proteasome potently blocks Gli activity, suggesting that Gli turnover and transcriptional activation are intimately coupled. We propose to use a combination of biochemistry and cell biology, to elucidate the mechanism of the following critical events in vertebrate Hh signaling: A) How does Hh signaling activate Gli and inhibit SuFu? B) What is the function of SuFu-Gli recruitment to cilia in Hh signaling, and how does PKA block SuFu-Gli recruitment to cilia? C) How does inhibition of the proteasome block transcriptional activation by Gli proteins and how is the partial proteolysis of Gli proteins regulated? These studies are important for the following reasons: 1) They will elucidate basic mechanisms that control the critical Gli proteins, thus advancing our understanding of Hh signaling; 2) They will identify novel targets for Hh inhibition in cancer; and 3) Our finding that proteasome inhibitors potently block Hh signaling could have immediate therapeutic implications in cancer, particularly since the proteasome inhibitor bortezomib is an FDA-approved drug for the treatment of multiple myeloma.

描述（由申请人提供）：Hedgehog（Hh）信号通路在胚胎发育、成体干细胞维持和许多癌症中具有关键作用。在脊椎动物中，Hh信号传导起始于初级纤毛，信号从初级纤毛传递到细胞质，然后传递到细胞核，最终控制由Gli转录因子介导的特定靶基因的表达。在没有刺激的情况下，Gli蛋白通过至少三种抑制机制保持关闭：1）直接结合融合抑制因子（SuFu）; 2）部分降解为抑制因子形式和3）通过蛋白激酶A（PKA）抑制。当细胞接收到Hh信号时，这些抑制被克服，允许Gli激活。尽管Hh信号的重要性，我们仍然不了解许多关键的机制，分别在Hh通路的静息和刺激状态下，参与抑制和激活Gli蛋白。 我们发现Hh刺激招募SuFu-Gli复合物到初级纤毛并导致其解离，导致Gli激活;我们发现PKA拮抗该过程。这为Gli蛋白的激活和PKA的抑制作用提供了一种新的机制。我们还发现，抑制蛋白酶体有力地阻断Gli活性，这表明Gli营业额和转录激活密切相关。我们建议使用生物化学和细胞生物学的组合，阐明脊椎动物Hh信号转导中以下关键事件的机制：A）Hh信号转导如何激活Gli并抑制SuFu？ B）在Hh信号传导中SuFu-Gli募集到纤毛的功能是什么，PKA如何阻断SuFu-Gli募集到纤毛？ C）蛋白酶体的抑制如何阻断Gli蛋白的转录激活，以及Gli蛋白的部分蛋白水解如何调节？ 这些研究是重要的，原因如下：1）它们将阐明控制关键Gli蛋白的基本机制，从而推进我们对Hh信号传导的理解; 2）它们将确定癌症中Hh抑制的新靶点;和3）我们发现蛋白酶体抑制剂可以有效阻断Hh信号传导，这可能对癌症产生直接的治疗意义，特别是因为蛋白酶体抑制剂硼替佐米是FDA批准的用于治疗多发性骨髓瘤的药物。

项目成果

Oxysterol binding to the extracellular domain of Smoothened in Hedgehog signaling.

• DOI: 10.1038/nchembio.1290
• 发表时间: 2013-09
• 期刊: NATURE CHEMICAL BIOLOGY
• 影响因子: 14.8
• 作者: Nedelcu, Daniel;Liu, Jing;Xu, Yangqing;Jao, Cindy;Salic, Adrian
• 通讯作者: Salic, Adrian

A mechanism for vertebrate Hedgehog signaling: recruitment to cilia and dissociation of SuFu-Gli protein complexes.

• DOI: 10.1083/jcb.201004108
• 发表时间: 2010-10-18
• 期刊: The Journal of cell biology
• 作者: Tukachinsky H;Lopez LV;Salic A
• 通讯作者: Salic A

Dispatched and scube mediate the efficient secretion of the cholesterol-modified hedgehog ligand.

• DOI: 10.1016/j.celrep.2012.07.010
• 发表时间: 2012-08-30
• 期刊: Cell reports
• 影响因子: 8.8
• 作者: Tukachinsky H;Kuzmickas RP;Jao CY;Liu J;Salic A
• 通讯作者: Salic A

Cellular Cholesterol Directly Activates Smoothened in Hedgehog Signaling.

• DOI: 10.1016/j.cell.2016.08.003
• 发表时间: 2016-08-25
• 期刊: CELL
• 影响因子: 64.5
• 作者: Huang, Pengxiang;Nedelcu, Daniel;Watanabe, Miyako;Jao, Cindy;Kim, Youngchang;Liu, Jing;Salic, Adrian
• 通讯作者: Salic, Adrian