Understanding how ciliary gene mutations affect the processing and activity of Gli2 and Gli3 transcription factors

了解纤毛基因突变如何影响 Gli2 和 Gli3 转录因子的加工和活性

• 批准号: 10439864
• 负责人: BAOLIN WANG
• 金额: $ 36.66万
• 依托单位: WEILL MEDICAL COLL OF CORNELL UNIV
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10439864
• 关键词: Activator Appliances; Affect; Antibodies; Binding Proteins; C-terminal; Cell Proliferation; Cell surface; Cells; Centrioles; Centrosome; Cilia; Complex; Congenital Abnormality; Cyclic AMP-Dependent Protein Kinases; Data; Defect; Development; Embryonic Development; Erinaceidae; Exhibits; F-Box Proteins; Family; G-Protein-Coupled Receptors; GTP-Binding Protein alpha Subunits, Gs; Gene Mutation; Genes; Genetic Transcription; Glycogen Synthase Kinase 3; Goals; Human; Kidney; Length; Malignant Neoplasms; Mediating; Microtubules; Molecular; Mothers; Mus; Mutate; Mutation; Organ; Organelles; Pathway interactions; Phenotype; Phosphorylation; Play; Process; Proteins; Retina; Role; Sensory; Serine; Signal Transduction; Signaling Molecule; Signaling Protein; Site; Structure; Threonine; Transcription Coactivator; Ubiquitination; Vertebrates; Vesicle; Zinc Fingers; base; casein kinase I; cell fate specification; ciliopathy; drug development; embryo cell; extracellular; hedgehog signal transduction; human disease; insight; multicatalytic endopeptidase complex; mutant; receptor; smoothened signaling pathway; therapeutic target; transcription factor; ubiquitin-protein ligase

Abstract The primary cilium is a solitary microtubule-based organelle that protrudes from the cell surface and is found on most vertebrate cells. It serves as a sensory organelle in organs such as the kidney and retina and also functions in transducing extracellular signals such as Hedgehog (Hh), a secreted signaling molecule that is essential for embryo development and cell proliferation and differentiation. Defects in cilia structure and function are associated with a diverse array of developmental abnormalities, collectively termed “ciliopathies”. Hh signaling in vertebrates occurs in primary cilia and is primarily mediated by Gli2 and Gli3 zinc finger- containing transcription factors. Gli2 is primarily an activator, whereas Gli3 is mostly a repressor, though it also exhibits a weak activator function. Consistent with their functions, most full-length Gli3 (Gli3FL) is proteolytically processed to generate a C-terminally truncated repressor in the absence of Hh signaling, while only a small fraction of Gli2FL is processed. Gli2/Gli3 processing is induced by phosphorylation of the first four of the six serine/threonine residues at their C-termini by protein kinase A (PKA) and then by glycogen synthase kinase 3 (GSK3) and casein kinase 1 (CK1). The multi-phosphorylated Gli2/Gli3 are then ubiquitinated and partially degraded by the proteasome. Hh signaling inhibits Gli2/Gli3 processing by suppressing PKA-mediated phosphorylation of the first four PKA sites and also activates Gli2FL/Gli3FL by inhibiting the phosphorylation of the fifth and sixth PKA sites in their C-termini. Defects in cilia structure and function mostly affect Hh signaling. One near universal hallmark of ciliary gene mutants at the molecular level is the reduced Gli2/Gli3 processing. Interestingly, however, the levels of Gli2/Gli3 activity in ciliary gene mutants vary from none to elevated depending on mutated ciliary genes. This suggests that the mechanism by which ciliary proteins regulate Hh signaling is diverse and complex. While the effect of ciliary mutations on Hh signaling is well established, the molecular mechanisms underlying these effects are thus far unknown. The goal of this proposal is to elucidate the molecular mechanisms by which Gli2/Gli3 processing, stability, and activity are altered in ciliary gene mutants.

抽象的 原发性纤毛是一种固体微管细胞器，从细胞表面伸出，IS 在大多数脊椎动物细胞上发现。它是肾脏和视网膜等器官中的感官细胞器 还起作用的细胞外信号，例如刺猬（HH），这是一个分泌的信号分子， 对于胚胎发育以及细胞增殖和分化至关重要。纤毛结构的缺陷和 功能与一系列发育异常阵列有关，统称为“纤毛病”。 脊椎动物中的HH信号传导发生在原发性纤毛中，由Gli2和Gli3锌指 - 原发性介导 包含转录因子。 Gli2主要是激活剂，而Gli3主要是复制品，尽管它也是 表现出弱激活器功能。与其功能一致，大多数全长GLI3（GLI3FL）是蛋白水解的 在没有HH信号的情况下处理以生成C末端截断的反射器，而仅一个小 GLI2FL的一部分被处理。 Gli2/Gli3处理是通过六个中的前四个磷酸化诱导的 丝氨酸/苏氨酸通过蛋白激酶A（PKA）保留在其C-末端，然后由糖原合酶激酶3保留 （GSK3）和酪蛋白激酶1（CK1）。然后，多磷酸化的Gli2/Gli3被泛素化并部分 被蛋白酶体降解。 HH信号传导通过抑制PKA介导的抑制GLI2/GLI3处理 前四个PKA位点的磷酸化，还通过抑制磷酸化来激活GLI2FL/GLI3FL C-Termini中的第五和第六个PKA站点。 纤毛结构和功能的缺陷主要影响HH信号传导。纤毛的环球标志附近的一个 分子水平的基因突变体是降低的GLI2/GLI3处理。有趣的是， 睫状基因突变体中的Gli2/Gli3活性因突变纤毛基因而异。这 表明睫状蛋白调节HH信号传导的机制是潜水和复杂的。而 睫状突变对HH信号传导的影响已很好地确定，这些分子机制是这些机制 到目前为止，效果是未知的。该提议的目的是阐明分子机制 睫状基因突变体中GLI2/GLI3处理，稳定性和活性会改变。