Control of tissue growth and architecture by Drosophila Tsg101

果蝇 Tsg101 对组织生长和结构的控制

• 批准号: 8318078
• 负责人: Kenneth H Moberg
• 金额: $ 22.01万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8318078
• 关键词: Adult; Affect; Apical; Apoptosis; Architecture; Cancerous; Cell Cycle; Cell Death; Cell Proliferation; Cell division; Cells; Choristoma; Collection; Complex; Cultured Cells; Cytoplasmic Tail; Data; Defect; Development; Drosophila genus; Drosophila melanogaster; Epithelial; Epithelial Cells; Epithelium; Exhibits; Funding; Genes; Genetic; Genetic Screening; Goals; Grant; Growth; Growth Suppressor Genes; Homologous Gene; Human; Invertebrates; Lead; Lesion; Link; Malignant Neoplasms; Modeling; Molecular; Molecular Genetics; Mutation; Nuclear Receptor Coactivator 3; Oncogene Proteins; Oncogenes; Oncogenic; Organ; Organ Culture Techniques; Organism; Orthologous Gene; Pathway interactions; Pattern; Phenotype; Phosphorylation; Physiological; Play; Property; Proteins; Publishing; Recruitment Activity; Regulation; Regulatory Pathway; Research; Role; Signal Pathway; Signal Transduction; Sorting - Cell Movement; Steroid Receptors; Structure; Techniques; Testing; Time; Tissues; Transcription Coactivator; Tsg101 protein; Tumor Suppressor Proteins; Vertebrates; Work; apical membrane; basolateral membrane; cell growth; dosage; fly; imaginal disc; late endosome; mutant; neoplastic; notch protein; novel; overexpression; programs; trafficking; tumor

DESCRIPTION (provided by applicant): Altered expression of apicobasal polarity factors is associated with cancer in vertebrates and tissue overgrowth in model invertebrates, yet mechanisms by which these factors affect growth regulatory pathways are not well defined. We have previously identified the Drosophila melanogaster gene tsg101 (tumor susceptibility gene-101) as a factor that is required to simultaneously maintain tissue polarity and suppress tumor-like overgrowth of the larval imaginal discs, which are simple epithelial organs that give rise to most adult structures. We have shown that loss of tsg101 blocks endolysosomal turnover of the key apical membrane determinant Crumbs, and that this excess Crumbs protein accumulates at the apical membrane, spreads ectopically onto the basolateral membrane, and accumulates in late endosomes. As Crumbs nucleates an apical membrane- associated complex that interacts physically and functionally with the Par/aPKC and Scribble/Dlg polarity complexes, these defects in Crumbs regulation provide a ready explanation of the effect of tsg101 loss on epithelial polarity and architecture. Notably, over expressed Crumbs also drives substantial imaginal disc overgrowth, suggesting that this polarity factor has a second, more direct oncogenic role in tsg101 cells. In published work, we have found that the cytoplasmic tail of Crumbs contains a previously unrecognized growth-regulatory motif through which it interacts with and regulates the expanded protein, which is a key component of the conserved Hippo/Mst2 tumor suppressor pathway. These data show that Crumbs is a multi-functional protein capable of integrating junctional polarity signals with the well-established Hippo/Mst2 growth-regulatory pathway, and those lesions that disrupt Crumbs trafficking and localization may have very direct effects on the activity of this pathway. Our objectives in this proposal are to test the role of this newly discovered Crumbs-Hpo/Mst2 link in the excessive growth of tsg101 mutant tumors, and to identify novel components of the Crumbs-Hpo/Mst2 pathway from among a small collection of mutations we have identified as dominant-modifiers of Crumbs driven disc overgrowth. In particular, we will focus our analysis on the taiman gene, which encodes the fly homolog of the human Amplified in Breast Cancer-1 (AIB-1) oncogene, and that we believe acts as a transcriptional coactivator for the Crumbs-Hpo/Mst2 pathway. We will use standard genetic and molecular techniques in Drosophila organs and cultured cells to carry out the proposed studies.

描述（由申请人提供）：顶端基底极性因子的表达改变与脊椎动物的癌症和模型无脊椎动物的组织过度生长有关，但这些因子影响生长调节途径的机制尚未明确。我们之前已经鉴定出果蝇基因 tsg101（肿瘤易感基因-101）是同时维持组织极性和抑制幼虫成虫盘肿瘤样过度生长所需的因子，幼虫成虫盘是产生大多数成体结构的简单上皮器官。我们已经证明，tsg101 的缺失会阻碍关键顶膜决定因子 Crumbs 的内溶酶体周转，并且这种过量的 Crumbs 蛋白在顶膜处积累，异位扩散到基底外侧膜上，并在晚期内涵体中积累。由于 Crumbs 使顶膜相关复合物成核，该复合物与 Par/aPKC 和 Scribble/Dlg 极性复合物在物理和功能上相互作用，因此 Crumbs 调节中的这些缺陷为 tsg101 损失对上皮极性和结构的影响提供了现成的解释。 值得注意的是，过度表达的 Crumbs 还会导致显着的成虫盘过度生长，这表明该极性因子在 tsg101 细胞中具有第二种更直接的致癌作用。在已发表的工作中，我们发现 Crumbs 的细胞质尾部含有一个以前未被识别的生长调节基序，通过该基序它与扩展的蛋白质相互作用并对其进行调节，而扩展的蛋白质是保守的 Hippo/Mst2 肿瘤抑制途径的关键组成部分。这些数据表明，Crumbs 是一种多功能蛋白，能够将连接极性信号与成熟的 Hippo/Mst2 生长调节通路整合，而那些破坏 Crumbs 运输和定位的损伤可能对该通路的活性产生非常直接的影响。 我们在本提案中的目标是测试这个新发现的 Crumbs-Hpo/Mst2 链接在 tsg101 突变肿瘤过度生长中的作用，并从我们已确定为 Crumbs 驱动的椎间盘过度生长的显性修饰因子的一小部分突变中识别 Crumbs-Hpo/Mst2 途径的新成分。 我们特别将分析重点放在 taiman 基因上，该基因编码人类 Amplified in Breast Cancer-1 (AIB-1) 癌基因的果蝇同源物，我们认为该基因充当 Crumbs-Hpo/Mst2 途径的转录共激活因子。我们将在果蝇器官和培养细胞中使用标准遗传和分子技术来开展拟议的研究。