The roles of mDia2 in membrane remodeling and organelle clearance during reticulocyte formation

mDia2 在网织红细胞形成过程中膜重塑和细胞器清除中的作用

• 批准号: 10372107
• 负责人: Peng Ji
• 金额: $ 39.43万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-04-15 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10372107
• 关键词: Acetylation; Actins; Affect; Anemia; Biochemical; Biochemical Genetics; Biological Assay; Biology; Cell Cycle; Cell Nucleus; Cells; Cytokinesis; Cytoplasmic Protein; Data; Deacetylase; Defect; Development; Disease; Electron Transport Complex III; Enzymes; Erythroblasts; Erythrocyte Transfusion; Erythrocytes; Erythroid; Erythroid Cells; Erythropoiesis; Functional disorder; Generations; Genetic Transcription; Goals; HDAC6 gene; Hematopoietic; Image; In Vitro; Knockout Mice; Lead; Light; Lysine; Mass Spectrum Analysis; Mediating; Mediator of activation protein; Membrane; Microfilaments; Microscopy; Mitosis; Modification; Mus; Organelles; Pathway interactions; Phosphorylation; Play; Post-Translational Protein Processing; Process; Production; Protein Family; Publishing; Regulation; Reporting; Reticulocytes; Rho-associated kinase; Role; Serum Response Factor; Signal Transduction; Signal Transduction Pathway; Spectrin; Techniques; Transcriptional Regulation; Transplantation; Work; cell motility; genetic technology; in vivo; insight; mouse model; mutant; non-histone protein; novel; novel strategies; overexpression; polymerization; protein complex; transfusion medicine; treatment strategy

PROJECT SUMMARY Mammalian terminal erythropoiesis has been well studied in erythroid lineage commitment and various factors involved in differentiation and proliferation. Relatively little is known in the final steps of terminal differentiation, specifically from enucleation to reticulocyte maturation into red blood cells. Several outstanding questions in this field include what factors regulate the exit of last mitosis of erythroblast for enucleation, how nascent reticulocyte separate from the extruded nucleus, and what signals are involved in regulating the clearance of organelles in reticulocytes. Answers to these questions with mechanistic insights are important not only for our understanding of the basic biology of terminal erythropoiesis and pathophysiology of many red cell-related diseases, but also to provide clues for efficient strategies of in vitro or ex vivo generation of red blood cells in transfusion medicine. In this respect, we have been working on the role of mDia formins in terminal erythropoiesis and our recent novel unpublished findings may help shed light on the clues to these questions. Using a mDia2 hematopoietic-specific knockout mouse model, we revealed that mDia2 controls the motility of the nascent reticulocyte that is required for the detachment of the pyknotic nucleus. Reticulocytes in mDia2 deficient mice are rigid with extended spectrin chains, primarily due to the disrupted actin profilaments. mDia2 deficient reticulocytes also show defects in membrane remodeling and organelle clearance. We further revealed in our preliminary data that Chmp5, one of the major components of the ESCRT III complex, is a novel downstream mediator of mDia2. Our preliminary mechanistic studies indicated that mDia2 regulates the transcriptional activity of serum response factor (SRF) and Chmp5 is a potential novel target of SRF. These results led us to hypothesize that mDia2 regulates the ESCRT III complex to control membrane remodeling and organelle clearance during reticulocyte formation. In this project, we will use in vivo mouse models, transplantation assays, various biochemical assays, and cutting-edge microscopy to study 1) the functional roles of mDia2 in the formation and organelle clearance of reticulocytes. 2) the mechanism of mDia2-SRF- Chmp5 signaling in the regulation of reticulocyte membrane remodeling and organelle clearance, and 3) the post-translational modifications of mDia2 in its roles in reticulocyte maturation. Successful completion of our proposed studies has the potential to open a new field in signaling transduction that modulates enucleation to reticulocyte formation. Understanding the emerging roles of mDia2 as a master regulator of the late stage terminal erythropoiesis will have an important impact in this field as a paradigm.

项目摘要 哺乳动物末端红细胞生成在红细胞谱系和各种因素方面得到了很好的研究 参与分化和增殖。在终端分化的最后一步中，相对鲜为人知， 特别是从摘除到网状细胞成熟到红细胞中。在 该领域包括哪些因素调节了灌木粉红细胞的最后有丝分裂的退出，如何新生 网状细胞与挤出的核分开，以及在调节清除率中涉及哪些信号 网状细胞中的细胞器。通过机械见解解决这些问题的答案不仅对我们很重要 了解许多红细胞相关的终末红细胞生物的基本生物学 疾病，但也为在体外或体外生成红细胞的有效策略提供线索 输血医学。在这方面，我们一直在研究MDIA formins在终端中的作用 红血病和我们最近的小说未发表的发现可能有助于阐明这些问题的线索。 使用MDIA2造血特异性基因敲除小鼠模型，我们揭示了MDIA2控制着运动能力 脱离杂核所需的新生网状细胞。 MDIA2中的网状细胞 缺乏小鼠具有较刚性的谱线链，这主要是由于肌动蛋白的破坏。 MDIA2 缺陷的网状细胞还显示出膜重塑和细胞器间隙的缺陷。我们进一步 在我们的初步数据中揭示了CHMP5是ESCRT III复合物的主要组成部分之一，是一个 MDIA2的新型下游介体。我们的初步机械研究表明，MDIA2调节 血清反应因子（SRF）和CHMP5的转录活性是SRF的潜在新靶标。这些 结果使我们假设MDIA2调节ESCRT III复合物以控制膜重塑 在网状细胞形成过程中的细胞器清除率。在这个项目中，我们将使用体内鼠标模型， 移植测定，各种生化测定和研究的尖端显微镜研究1）功能 MDIA2在网状细胞的形成和细胞器清除中的作用。 2）MDIA2-SRF-的机制 CHMP5信号在调节网状细胞膜重塑和细胞器清除率中，以及3） MDIA2在网状细胞成熟中的作用中的翻译后修饰。成功完成我们 拟议的研究有可能在信号转导的信号转导方面打开一个新的领域，该领域将摘除次数调节为 网状细胞形成。了解MDIA2作为晚期的主管的新兴角色 终端红细胞生成将以范式在该领域产生重要影响。