CAAX Processing and Cell Signaling in Dictyostelium

盘基网柄菌中的 CAAX 处理和细胞信号传导

• 批准号: 7798229
• 负责人: Edward C COX
• 金额: $ 30.25万
• 依托单位: PRINCETON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-01 至 2012-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7798229
• 关键词: Address; Amino Acid Motifs; Amino Acids; Animal Model; Antineoplastic Agents; Behavior; Biological Assay; Biological Models; Carbon; Cell Polarity; Cell Signaling Process; Cells; Cellular Morphology; Chemotaxis; Clinical Trials; Cyclic AMP; Cysteine; Development; Dictyostelium; Dimethylallyltranstransferase; Disease; Embryo; Essential Amino Acids; Family; Figs - dietary; G Protein-Coupled Receptor Genes; GTP-Binding Proteins; Genes; Genetic; Goals; Lead; Ligands; Lipids; Measures; Methylation; Methyltransferase; Molecular; Monomeric GTP-Binding Proteins; Mus; Mutation; Organism; Pathway interactions; Peptide Hydrolases; Pharmacotherapy; Play; Process; Proteins; Research; Role; S-Adenosylmethionine; Signal Transduction; Signaling Protein; Specific qualifier value; System; Technology; Time; Tissues; Transferase; acetaminophen cysteine; base; cancer cell; cell growth; demethylation; design; drug development; extracellular; genetic analysis; genome-wide; inhibitor/antagonist; member; molecular phenotype; mutant; prenyl; prenylation; research study; response; rho; thioether; tool; tumor; tumorigenic

DESCRIPTION (provided by applicant): A central issue in healthy and diseased cells is how cells sense signals from the outside, and how these signals are used to organize cellular responses. The small GTPase families Ras and Rho are intimately involved in these processes, and mutations in them often lead to the disease state. Thus it has been known for many years that activating mutations in Ras are common in cancer cells, and it is widely believed that Ras mutations are essential for the genesis of mammalian tumors. Most small GTPases carry a CAAX amino acid motif at their C terminus, where C is cysteine, AA are usually two aliphatic amino acids, and X specifies whether the protein will be modified with the 15 carbon farnesyl lipid or the 20 carbon geranylgeranyl lipid. Ras function in the cell requires the CAAX sequence, and for activated Ras to be tumorigenic, the CAAX sequence must be modified by a prenylation pathway. For this reason the pathway is a potential target for anticancer drug therapy. Recent drug development efforts have validated this assumption, with several promising new inhibitors of the pathway now in clinical trials. Much remains to be known about many the prenylation pathway: which of the small G proteins must be methylated for them to be modulated, how methylation levels are controlled by extra- and intracellular signals, how the three partners in the prenylation pathway are regulated if they are, the consequences for cell morphology and response to signals when various of the prenylation steps are reduced or absent, and the role that methylation plays in the very earliest steps of G-coupled response to ligand, are some of the outstanding questions addressed in this proposal. The aim of this research is to use Dictyostelium as a model system to understand these important questions. Preliminary experiments reveal that deletions in the methylation gene block early signaling and response to cAMP, but not cell growth. Various signaling proteins are mislocalized in this deletion, chemotaxis and cAMP responses are disrupted, and the ability of cells to develop into a coherent tissue is blocked. These observations will be extended using assays that will correlate cellular behavior with molecular changes, and by developing a panel of mutants deficient in each step in the prenylation pathway.

描述（由申请人提供）：健康和患病细胞中的一个核心问题是细胞如何从外部感知信号，以及如何使用这些信号来组织细胞反应。小型GTPase家族RAS和RHO密切参与了这些过程，其中突变经常导致疾病状态。因此，已经知道RAS中的激活突变在癌细胞中很常见，并且人们普遍认为RAS突变对于哺乳动物肿瘤的起源至关重要。大多数小的GTPase在其C末端携带CAAX氨基酸基序，其中C为半胱氨酸，AA通常是两个脂肪族氨基酸，X指定该蛋白是将蛋白质通过15个碳纤维脂质脂质还是20个碳脂质的含量进行修饰。细胞中的RAS功能需要CAAX序列，并且要使活化的Ras为肿瘤，CAAX序列必须通过前序途径进行修饰。因此，该途径是抗癌药物治疗的潜在靶标。最近的药物开发工作已经验证了这一假设，现在在临床试验中使用了几种有希望的新途径抑制剂。关于许多原始途径还有许多尚待了解：必须对其进行甲基化的哪些小G蛋白必须进行调节，甲基化水平如何受细胞外信号和细胞内信号的控制，预序途径中的三个伴侣如何受到细胞形态的影响以及对末日的影响，以及在各种方面的作用，以及在各种方面的作用，以及在各种方面的响应，并在各种方面均无作用。该提案中提出的一些杰出问题。这项研究的目的是将dictyostelium用作模型系统来理解这些重要问题。初步实验表明，甲基化基因的缺失早期信号传导和对cAMP的反应，但没有细胞生长。在此缺失中，各种信号蛋白被错误地定位，趋化性和cAMP反应受到破坏，并且细胞发展为相干组织的能力被阻断。这些观察结果将使用将细胞行为与分子变化相关的测定法进行扩展，并通过在原始途径中的每个步骤中开发一个突变体小组。