Modulation of PLCgamma2-Mediated Signaling Via its C2-Domain in B Lymphocytes

通过 B 淋巴细胞中的 C2 结构域调节 PLCgamma2 介导的信号传导

基本信息

批准号：
7875500
负责人：
CARSTEN SCHMITZ
金额：
$ 22.96万
依托单位：
UNIVERSITY OF COLORADO DENVER
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-06-01 至 2012-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7875500
关键词：
Adverse effects Antibodies Antibody Formation Antigens B-Cell Development B-Lymphocytes Biochemical Birds Bone Marrow Bone Marrow Cells C-terminal C2 Domain Cations Cell Line Cell Lineage Cell Maturation Cell physiology Cells Chickens Complement Culture Media Development Diabetes Mellitus Divalent Cations Effectiveness Enzymes Event Fc Receptor Goals Graves&apos Disease Heart Homeostasis Human Hydrolysis Immune Immune System Diseases Immune response Immunity Immunoglobulin Class Switching Immunoglobulins Immunologic Deficiency Syndromes Impaired health Ion Channel Ions Isoenzymes Knowledge Malignant Neoplasms Mature B-Lymphocyte Mediating Molecular Monitor Mouse Strains Mus Mutation Nutritional PLCgamma2 Pathway interactions Phosphatidylinositols Phospholipase C Phosphorylation Phosphotransferases Physiological Process Proteins Psychological reinforcement Receptor Inhibition Receptor Signaling Receptors, Antigen, B-Cell Regulation Relative (related person)Signal Pathway Signal Transduction System Testing Thapsigargin Therapeutic Intervention Tyrosine Phosphorylation base cell type citrate carrier enzyme activity extracellular in vivo insight mouse model mutant novel public health relevance receptor-mediated signaling reconstitution response

项目摘要

DESCRIPTION (provided by applicant): Optimal immune responses require adequate ionic supply and carefully regulated ion-homeostasis. The adverse effects of low-Mg2+ conditions on immunity are well documented, but mechanistic insights into this Mg2+-sensitivity are lacking. The recently discovered protein TRPM7 is the unique fusion of an active Ser/Thr kinase with an ion channel, and a master regulator of Mg2+-homeostasis. TRPM7 has been shown to interact with several phospholipase C (PLC) isozymes. PLC proteins are at the heart of crucial signaling pathways required for the development and activation of virtually every immune cell type, including B-lymphocytes, which are the cellular architects of humoral immune responses. PLCg2 is central to B-cell receptor (BCR) signaling, and mediates B- cell maturation as well as activation. We propose that TRPM7-kinase modulates BCR- signaling in accordance to the availability of Mg2+ through Ser/Thr phosphorylation of PLCg2. The regulation of PLCg2 by Tyr-phosphorylation has been amply characterized, but its modulation by Ser/Thr phosphorylation is only postulated, although highly probable, since the vast majority of cellular phosphorylation events involve Ser/Thr residues. We have gathered preliminary experimental evidence in cell lines supporting our main hypothesis that the C2-domain of PLCg2 is a substrate of TRPM7-kinase, resulting in the Mg2+-sensitive modulation of BCR-elicited Ca2+-responses. This proposal aims at further exploring the effect of this novel phosphorylation event on PLCg2's localization, Tyr-phosphorylation and enzymatic activity, as well as to investigate its physiological relevance in vivo using a complementation approach in an existing mouse model of PLCg2 deficiency. PUBLIC HEALTH RELEVANCE: Alterations in ion homeostasis have severe effects on human health, impairing the effectiveness and appropriateness of immune responses, and causing or exacerbating grave diseases such as cancer or diabetes. The planned studies will contribute to expanding our knowledge about molecular mechanisms allowing for the adjustment of immune responses to the availability of the essential and most abundant intracellular divalent cation Mg2+. Understanding these regulatory processes represent potential opportunities to develop novel immunomodulatory strategies for therapeutic intervention. Given its focus on B-lymphocytes, this proposal is relevant to conditions such as auto-immune diseases, or various forms of immunodeficiencies.

描述（由申请人提供）：最佳的免疫反应需要充足的离子供应和仔细调节的离子稳态。低 Mg2+ 条件对免疫力的不利影响已有充分记录，但缺乏对这种 Mg2+ 敏感性的机制见解。最近发现的蛋白质 TRPM7 是活性 Ser/Thr 激酶与离子通道的独特融合体，是 Mg2+ 稳态的主要调节因子。 TRPM7 已被证明与多种磷脂酶 C (PLC) 同工酶相互作用。 PLC 蛋白是几乎所有免疫细胞类型（包括 B 淋巴细胞）发育和激活所需的关键信号传导通路的核心，B 淋巴细胞是体液免疫反应的细胞架构。 PLCg2 是 B 细胞受体 (BCR) 信号传导的核心，并介导 B 细胞成熟和激活。我们提出 TRPM7 激酶根据 Mg2+ 的可用性通过 PLCg2 的 Ser/Thr 磷酸化来调节 BCR 信号传导。 Tyr 磷酸化对 PLCg2 的调节已得到充分表征，但 Ser/Thr 磷酸化对 PLCg2 的调节仅是假设的，尽管可能性很大，因为绝大多数细胞磷酸化事件涉及 Ser/Thr 残基。我们已经在细胞系中收集了初步实验证据，支持我们的主要假设，即 PLCg2 的 C2 结构域是 TRPM7 激酶的底物，导致 BCR 引发的 Ca2+ 反应的 Mg2+ 敏感调节。该提案旨在进一步探索这种新型磷酸化事件对 PLCg2 定位、Tyr 磷酸化和酶活性的影响，并在现有 PLCg2 缺陷小鼠模型中使用补充方法研究其体内生理相关性。公共健康相关性：离子稳态的改变对人类健康产生严重影响，损害免疫反应的有效性和适当性，并引起或加剧癌症或糖尿病等严重疾病。计划中的研究将有助于扩大我们对分子机制的了解，从而根据细胞内必需且最丰富的二价阳离子 Mg2+ 的可用性调整免疫反应。了解这些调节过程代表了开发用于治疗干预的新型免疫调节策略的潜在机会。鉴于其重点关注 B 淋巴细胞，该提案与自身免疫性疾病或各种形式的免疫缺陷等疾病相关。