Collaborative Research: Mechanisms of Iron Transport in Insects

合作研究：昆虫铁转运机制

• 批准号: 1656388
• 负责人: Maureen Gorman
• 金额: $ 40.15万
• 依托单位: Kansas State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-02-01 至 2022-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1656388&HistoricalAwards=false
• 关键词: Collaborative; Research; Mechanisms; Iron; Transport

Iron is essential for many aspects of an animal's life, but iron is also potentially toxic. Because iron is both necessary and harmful, the amount, location and form of iron within an animal must be tightly controlled. In humans and other mammals, the physiological processes that provide the right amount of iron at the right times are partially understood. However, in insects and other invertebrate animals, these processes have not yet been discovered. The goal of this research project is to understand how iron is transported from one cell to another in insects using the fruit fly as a model system. The project will provide research experiences for undergraduate students from diverse backgrounds. Knowledge gained from this research will provide a framework for future studies of iron transport in blood-feeding insects such as mosquitoes, which must cope with a seemingly toxic amount of iron when they ingest a blood meal. A potential outcome of this project is the discovery of a more evolutionarily ancient iron transport mechanism that functions not only in insects but also in other invertebrate animals. In addition, information learned from this research may provide insight into the less-understood mechanisms of iron transport in humans. Finally, because insect management strategies rely on information about insect biology, the results of this project may contribute to the development of a new insect control strategy. The goal of the proposed research is to understand the physiological mechanisms of iron transport in insects. Four models that describe possible mechanisms of iron transport into cells will be tested using Drosophila melanogaster as the model insect species. OBJECTIVE 1: The first objective is to test the hypothesis that receptor-mediated endocytosis of iron-loaded ferritin or ferric-transferrin transports iron from hemolymph into cells. 1A) Ferritin and transferrin will be labeled with a fluorophore and then observed to determine whether cellular uptake occurs. 1B) Confocal microscopy will be used to evaluate whether ferritin or transferrin are present in endosomes. 1C) Essential components of the endocytosis pathways will be blocked, and the effect on iron uptake will be measured. OBJECTIVE 2: The second objective is to test the hypothesis that reduction of ferric ions in hemolymph leads to iron transport into cells. Hemolymph contains iron in the ferric form, but iron transporters in animals are specific to ferrous iron; therefore, iron uptake via an influx transporter is likely to require a reduction step. The functions of a known ferric reductase, CG8399, and a candidate ferric reductase, CG1275, will be studied. 2A) RNAi will be used to determine whether CG8399 or CG1275 contribute to cell surface ferric reductase activity. 2B) RNAi will be used to determine whether the activity of CG8399 or CG1275 influences the iron content of cells. 2C) A membrane-impermeant ferrous chelator will be evaluated for its ability to inhibit iron uptake.

铁对于动物生命的许多方面至关重要，但铁也具有潜在的毒性。由于铁既是必需的又是有害的，因此必须严格控制动物体内铁的含量、位置和形式。在人类和其他哺乳动物中，在正确的时间提供正确数量的铁的生理过程已被部分了解。然而，在昆虫和其他无脊椎动物中，这些过程尚未被发现。该研究项目的目标是利用果蝇作为模型系统，了解昆虫中铁如何从一个细胞转运到另一个细胞。该项目将为来自不同背景的本科生提供研究经验。从这项研究中获得的知识将为未来研究蚊子等吸血昆虫的铁运输提供框架，蚊子在摄入血粉时必须应对看似有毒的铁量。该项目的一个潜在成果是发现了一种在进化上更加古老的铁运输机制，该机制不仅在昆虫中起作用，而且在其他无脊椎动物中也起作用。此外，从这项研究中获得的信息可能有助于深入了解人类铁转运的鲜为人知的机制。最后，由于昆虫管理策略依赖于昆虫生物学信息，因此该项目的结果可能有助于开发新的昆虫控制策略。本研究的目的是了解昆虫铁转运的生理机制。将使用黑腹果蝇作为模型昆虫物种来测试描述铁转运到细胞中的可能机制的四个模型。目标 1：第一个目标是检验受体介导的载铁铁蛋白或铁转铁蛋白的内吞作用将铁从血淋巴转运到细胞中的假设。 1A) 铁蛋白和转铁蛋白将用荧光团标记，然后观察以确定是否发生细胞摄取。 1B) 共聚焦显微镜将用于评估内体中是否存在铁蛋白或转铁蛋白。 1C) 内吞途径的重要组成部分将被阻断，并测量对铁吸收的影响。目标 2：第二个目标是检验血淋巴中铁离子减少导致铁转运至细胞的假设。血淋巴中含有三价铁形式的铁，但动物体内的铁转运蛋白是二价铁特有的；因此，通过流入转运蛋白吸收铁可能需要减少步骤。将研究已知的三价铁还原酶 CG8399 和候选三价铁还原酶 CG1275 的功能。 2A) RNAi 将用于确定 CG8399 或 CG1275 是否有助于细胞表面铁还原酶活性。 2B) RNAi将用于确定CG8399或CG1275的活性是否影响细胞的铁含量。 2C) 将评估不透膜的亚铁螯合剂抑制铁吸收的能力。

项目成果

Structural insight into the novel iron‐coordination and domain interactions of transferrin‐1 from a model insect, Manduca sexta

• DOI: 10.1002/pro.3999
• 发表时间: 2020-11
• 期刊: Protein Science
• 影响因子: 8
• 作者: J. Weber;M. Kashipathy;K. Battaile;Eden P. Go;H. Desaire;M. Kanost;S. Lovell;M. Gorman