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

• 批准号: 8077419
• 负责人: CARSTEN SCHMITZ
• 金额: $ 18.93万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 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/8077419
• 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; Disease; Divalent Cations; Effectiveness; Enzymes; Event; Fc Receptor; Goals; Health; 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; receptor-mediated signaling; reconstitution; response

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.

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。