RasGRP4-dependent Responses in Mast Cells

肥大细胞中 RasGRP4 依赖性反应

• 批准号: 7385094
• 负责人: Richard L Stevens
• 金额: $ 39.3万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-02-15 至 2010-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7385094
• 关键词: 1,2-diacylglycerol; Acetates; Affinity; Appendix; Asthma; Basophils; Binding; Bone Marrow; Boxing; C3H/HeJ Mouse; Carboxypeptidase; Cations; Cell Line; Cell Nucleus; Cells; Chromosomes; Complement; Complex; Cytokine Receptors; Cytoplasmic Granules; Cytosol; Data; Deacetylase; Development; Diacylglycerol Kinase; Diglycerides; Disease; Disruption; Dissociation; Eicosanoids; Endopeptidases; Event; Exhibits; Expressed Sequence Tags; Extravasation; Figs - dietary; Functional disorder; Genes; Genetic Transcription; Genetic Variation; Guanine Nucleotide Exchange Factors; Guanine Nucleotides; Guanosine Diphosphate; Guanosine Triphosphate; Hematopoietic; Human; Hypersensitivity; IgE; IgE Receptors; Immune; Immunoglobulins; Immunology; Infection; Inflammatory; Interleukins; KITLG gene; Knowledge; Lead; Leukotrienes; Mass Spectrum Analysis; Mediating; Mediator of activation protein; Molecular; Mononuclear; Mus; Neurofibromatosis Type 1 Protein; Pathway interactions; Peptide Hydrolases; Pharmacologic Substance; Play; Post-Transcriptional Regulation; Printing; Prostaglandin D2; Prostaglandins; Protein Family; Protein Isoforms; Proteinase-Activated Receptors; Proteins; RNA; RNA Splicing; Rattus; Receptor Protein-Tyrosine Kinases; Reperfusion Injury; Reverse Transcriptase Polymerase Chain Reaction; Rheumatoid Arthritis; Role; Signal Pathway; Signal Transduction; Signaling Pathway Gene; Signaling Protein; Single Nucleotide Polymorphism; Site; Small Interfering RNA; Stem Cell Factor; Testing; Tetradecanoylphorbol Acetate; Tissues; Vascular Endothelial Growth Factors; airway hyperresponsiveness; base; cell type; cytokine; embryonic stem cell; in vivo; leukemia; macrophage; mast cell; member; methacholine; microbial; mouse Gdi2 protein; mouse RasGRP4 protein; neurofibroma; neutrophil; phorbol ester receptor; phorbol-12-myristate; progenitor; progesterone 11-hemisuccinate-(2-iodohistamine); prostaglandin R2 D-isomerase; ras Proteins; response; sulfotransferase; transcription factor

DESCRIPTION (provided by applicant): We recently cloned the cDNAs and genes that encode the fourth member of the Ras Guanine Nucleotide Releasing Protein (RasGRP) family of signaling proteins. RasGRP4 is a mast cell (MC) restricted, cation-dependent, guanine nucleotide exchange factor. It also is a diacylglycerol/phorbol ester receptor that plays a prominent role in dictating which protease, cytokine, and eicosanoid mediators are expressed in MC lines. Allelic variants of RasGRP4 have been identified, as well as functionally different isoforms of RasGRP4 that are the result of differential splicing of its gene. Earlier gene-linkage studies of C3H/HeJ mice revealed a prominent site on chromosome 7A3-B1 that controls its intrinsic airway reactivity to methacholine. We recently found that the MCs developed from this hyporesponsive mouse produce a defective isoform of mRasGRP4. The accumulated data suggest that RasGRP4 is of critical importance in MC development and that the expression of abnormal isoforms of RasGRP4 can lead to MC dysfunction. Complementary approaches will be used in the proposed studies to test these hypotheses and to expand our knowledge concerning the recently identified RasGRP family of signaling proteins. In Specific Aim 1, the transcriptional and posttranscriptional mechanisms that regulate the expression of mouse and human RasGRP4 will be identified. In Specific Aim 2, the functional importance of allelic isoforms of RasGRP4 and its different domains will be evaluated. The predominant genes and signaling pathways in MCs that are regulated by RasGRP4 also will be identified, as well as the control mechanisms that dampen RasGRP4- dependent signaling events in MCs. In Specific Aim 3, RasGRP4-deficient, non transformed MCs will be created to evaluate the importance of this signaling protein in MC development and function in vivo. Because RasGRP4 is a MC-restricted signaling protein that appears to act downstream of the tyrosine kinase receptor Kit, it is anticipated that the obtained data will significantly advance our knowledge concerning the poorly defined Kit-dependent pathway that dominantly controls MC development and function. It also is anticipated that targeted disruption of RasGRP4 expression and/or activity in humans using pharmaceutical and other approaches will be beneficial in MC-dependent disorders.

描述（由申请人提供）：我们最近克隆了编码Ras鸟嘌呤核苷酸释放蛋白（RasGRP）信号蛋白家族第四个成员的cdna和基因。RasGRP4是肥大细胞（MC）限制性，阳离子依赖性，鸟嘌呤核苷酸交换因子。它也是一种二酰基甘油/酚酯受体，在决定蛋白酶、细胞因子和类二十烷介质在MC细胞系中的表达方面起着重要作用。已经鉴定了RasGRP4的等位基因变异，以及由于其基因的不同剪接而导致的RasGRP4的功能不同的同工型。早期对C3H/HeJ小鼠的基因连锁研究发现，染色体7A3-B1上有一个突出的位点控制其对甲胆碱的内在气道反应性。我们最近发现，从这种低反应小鼠中发育出来的MCs产生了一种缺陷的mRasGRP4亚型。积累的数据表明，RasGRP4在MC的发展中起着至关重要的作用，RasGRP4异常异构体的表达可导致MC功能障碍。补充的方法将在拟议的研究中使用，以检验这些假设，并扩大我们对最近发现的信号蛋白RasGRP家族的认识。在Specific Aim 1中，将确定调节小鼠和人类RasGRP4表达的转录和转录后机制。在Specific Aim 2中，将评估RasGRP4及其不同结构域的等位基因异构体的功能重要性。我们还将确定MCs中受RasGRP4调控的主要基因和信号通路，以及抑制MCs中依赖RasGRP4的信号事件的控制机制。在Specific Aim 3中，将构建缺乏rasgrp4的非转化MCs，以评估该信号蛋白在体内MCs发育和功能中的重要性。