Rac1 and Rac2 Guanosine Triphosphatases in Erythroid Function and Differentiation

Rac1 和 Rac2 鸟苷三磷酸酶在红细胞功能和分化中的作用

基本信息

批准号：
8197491
负责人：
Theodosia Anastasios Kalfa
金额：
$ 12.87万
依托单位：
CINCINNATI CHILDRENS HOSP MED CTR
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-02-11 至 2012-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8197491
关键词：
Actins Adhesions Affect Anemia Apoptosis Biological Assay Bone Marrow Cell Cycle Cell Lineage Cell Nucleus Cell Polarity Cell Survival Cells Cytoskeletal Proteins Cytoskeleton Data Defect Development Erythroblasts Erythrocyte Deformability Erythrocyte Membrane Erythrocytes Erythroid Erythroid Cells Erythropoiesis Evaluation F-Actin Flow Cytometry Gene Targeting Genetic Transcription Goals Growth Factor Receptors Guanosine Guanosine Triphosphate Phosphohydrolases Hematopoietic Hematopoietic stem cells Hemolytic Anemia Homing In Vitro Label Mammals Mechanics Mediating Membrane Biology Microtubules Molecular Morphogenesis Movement Mus Nature Pathogenesis Pathway interactions Phenotype Phosphorylation Play Poikilocytosis Population Process Protein Kinase C Proteins Proto-Oncogene Protein c-kit Regulation Relative (related person)Research Reticulocytes Reticulocytosis Rho-associated kinase Role Signal Pathway Signal Transduction Signaling Molecule Spectrin Spleen Staging Stem Cell Factor Stress Structure Testing Tropomyosin adducin cell type cofilin cytokine erythroid differentiation extracellular human disease in vitro Assay in vivo microcytic anemia polymerization rac GTP-Binding Proteins response rho therapeutic target tropomodulin

项目摘要

The Rho guanosine triphosphatases (GTPases) Rac1 and Rac2 regulate actin cytoskeleton, microtubule dynamics, gene transcription, proliferation, and survival in multiple cell types. They have been shown to have overlapping as well as distinct roles in actin organization, cell survival, and proliferation in various hematopoietic cell lineages. However their role in erythroid precursors and erythrocytes has not been evaluated. Using gene-targeted mice we have found that deficiency of Rac1 and Rac2 GTPases causes a significant phenotype in erythroid lineage: mild anemia with relative reticulocytosis, both hemolytic (abnormal structure of the erythrocyte cytoskeleton with decreased mechanical stability) and dyserythropoietic in nature. Erythropoiesis is affected mainly at the early stages, when stem cell factor (SCF) plays a critical role. We therefore hypothesize that Rac GTPases (1) dynamically regulate the structure and function of the erythrocyte cytoskeleton, and (2) play a critical role in homing, proliferation, survival, and differentiation of erythroid precursors, likely intersecting signaling pathways activatedvia the SCF receptor, c-Kit. To test our hypotheses, we propose a systematic characterization of the effects of Rac GTPase deficiency on the actin polymerization mechanics in the RBC cytoskeleton, with analysis of the actin-associated proteins and evaluation of possible cross-talk of Rac with other Rho GTPases and signaling molecules. In parallel, we will investigate the perturbations of erythropoiesis in Rac1"/";Rac2"/" mice, seeking the mechanism/s by which Rac GTPases, integrating multiple signals from one or more of the erythropoietic cytokines, affect erythropoiesis. These two proposed aims intent to explore and test how Rac GTPases regulate erythroid development, morphogenesis, and structure-function relation of the RBC cytoskeleton and its components. The central goal is to define critical molecular signaling pathways that participate in normal erythroid development and RBC structural membrane biology. In the long-term, this research is expected to offer new perspectives on the pathogenesis of hemolytic anemia and provide potential therapeutic targets in human disease characterized by abnormal erythropoiesis and decreased RBC survival.

Rho鸟苷三磷酸酶（GTPases）Rac1和Rac2调节肌动蛋白细胞骨架，微管动力学，基因转录，增殖和多种细胞类型的存活。他们曾经证明在肌动蛋白组织，细胞存活和增殖中具有重叠和不同的作用各种造血细胞谱系。但是它们在红细胞前体和红细胞中的作用尚未已评估。使用靶向基因的小鼠，我们发现Rac1和Rac2 GTPase的缺陷在红斑谱系中引起明显的表型：轻度贫血，相对网状细胞增多症，两者都溶血性（降低机械稳定性降低的红细胞细胞骨架的异常结构）和本质上是突变性的。红细胞因素时，红细胞生成的主要阶段主要受到影响（SCF）发挥关键作用。因此，我们假设RAC GTPases（1）动态调节红细胞细胞骨架的结构和功能，（2）在归巢，增殖中起关键作用，生存和红细胞前体的分化，可能与信号通路相交 SCF受体，C-Kit。为了检验我们的假设，我们提出了一个系统的表征 RAC GTPase缺乏RBC细胞骨架中肌动蛋白聚合力学的缺乏，并分析肌动蛋白相关的蛋白质和RAC可能与其他Rho GTPases的串扰评估以及信号分子。同时，我们将研究Rac1“/”; Rac2“/”中红细胞动物的扰动。小鼠，寻求RAC GTPases的机制，从一个或多个集成了多个信号红细胞生成细胞因子会影响红细胞生成。这两个旨在探索和测试的目的 RAC GTPases调节RBC的红细胞发育，形态发生和结构功能关系细胞骨架及其成分。中心目标是定义参与正常红细胞的关键分子信号通路开发和RBC结构膜生物学。从长远来看，这项研究应提供关于溶血性贫血发病机理的新观点，并在人类疾病的特征是异常红细胞生成和RBC存活降低。