Molecular and functional properties of the TRPM2 catioin channel

TRPM2 阳离子通道的分子和功能特性

• 批准号: 7318490
• 负责人: REINHOLD PENNER
• 金额: $ 32.21万
• 依托单位: QUEEN'S MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-06-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7318490
• 关键词: Address; Adenine; Adenine Nucleotides; Adenosine Diphosphate Ribose; Affect; Agonist; Apoptosis; Apoptotic; Behavior; Beta Cell; Binding; Biochemical Pathway; Calcium; Calcium Signaling; Calmodulin; Cations; Cell Death; Cell membrane; Cell physiology; Cells; Cellular Stress; Complex; Coupling; Cyclic ADP-Ribose; Cytokine Receptors; Data; Diabetes Mellitus; Diabetic mouse; Dinucleoside Phosphates; Elements; Enhancers; Enzymes; Evaluation; Event; Family; Feedback; Generations; Homeostasis; Image; Individual; Ion Channel; Knock-out; Knockout Mice; Knowledge; Laboratories; Ligands; Magnesium; Mediating; Mediator of activation protein; Methods; Microglia; Modeling; Molecular; Molecular Target; Mus; Mutagenesis; NAADP; Pancreas; Perception; Physiology; Process; Production; Property; Protein Overexpression; Proteins; Reactive Oxygen Species; Recruitment Activity; Regulation; Research Personnel; Role; Second Messenger Systems; Sensory; Signal Pathway; Signal Transduction; Site; Source; Stream; Streptozocin; Stress; Structure of beta Cell of islet; System; T-Lymphocyte; Testing; Text; Tissues; base; cell type; cytokine; detector; extracellular; inhibitor/antagonist; member; monocyte; mouse model; mutant; neutrophil; novel; patch clamp; pyrophosphatase; reactive oxygen intermediate; receptor; research study; response; second messenger; sulfated glycoprotein 2; therapeutic target

DESCRIPTION (provided by applicant): The transient receptor potential (TRP) ion channel family recently emerged as harboring crucial channel proteins involved in processes such as sensory perception, magnesium homeostasis or apoptosis. We identified TRPM2, a member of the TRP family, as a calcium-permeable cation channel gated by the novel second messenger ADP-ribose (ADPR) through the channel's intrinsic pyrophosphatase domain. TRPM2 is expressed in a variety of cell types, including pancreatic beta cells and neutrophils. Recently, the role of the molecules in the metabolic network surrounding ADPR on the functional properties of TRPM2 have emerged. Here, the novel calcium-release compound cADPR and other adenine dinucleotides materialize as crucial factors in TRPM2 physiology and hence processes involving cellular calcium homeostasis. Based on its primary activation by ADPR and reactive oxygen species, TRPM2 may have a function in cellular stress and remains a prime candidate for being involved in the apoptotic process. To further our understanding of TRPM2 in cell physiology, we propose experiments in Specific Aim 1 that will focus on the function of TRPM2 in events initiated by adenine-nucleotides. We hypothesize that TRPM2 may function as dual calcium influx and calcium release channel by taking advantage of a TRPM2 overexpressing cell system and a TRPM2 knock-out mouse model. We will explore agonist-receptor interactions engaging the main candidate in generating adenine dinucleotides, namely CD38. We will investigate the involvement of TRPM2 in cell death using a streptozotocin-based mouse model for diabetes type-1. These experiments will be performed in an expression system and mouse neutrophils and beta cells isolated from wild-type, CD38, PARP and TRPM2 knock-out mice models using a combination of patch-clamp, imaging and apoptotic studies. In Specific Aim 2 we will investigate the molecular determinants of TRPM2 agonist binding and address the question whether calmodulin is the mediator of the calcium-dependent facilitation of TRPM2. Understanding TRPM2 and adenine-dinucleotide function in calcium signaling will refine our knowledge of calcium regulation in tissues expressing this ion channel and may provide new targets for therapeutic interference in processes involving TRPM2 function, including diabetes-causing cell death of pancreatic beta cells.

描述（由申请人提供）：瞬时受体电位（TRP）离子通道家族最近出现，含有参与感觉知觉、镁稳态或细胞凋亡等过程的关键通道蛋白。我们鉴定出 TRPM2（TRP 家族的成员）是一种钙渗透性阳离子通道，由新型第二信使 ADP-核糖 (ADPR) 通过该通道的内在焦磷酸酶结构域进行门控。 TRPM2 在多种细胞类型中表达，包括胰腺 β 细胞和中性粒细胞。最近，ADPR 周围代谢网络中的分子对 TRPM2 功能特性的作用已经出现。在这里，新型钙释放化合物 cADPR 和其他腺嘌呤二核苷酸成为 TRPM2 生理学以及涉及细胞钙稳态过程的关键因素。基于 ADPR 和活性氧的主要激活作用，TRPM2 可能在细胞应激中发挥作用，并且仍然是参与细胞凋亡过程的主要候选者。为了进一步了解 TRPM2 在细胞生理学中的作用，我们在特定目标 1 中提出了实验，重点关注 TRPM2 在腺嘌呤核苷酸引发的事件中的功能。我们假设TRPM2可能通过利用TRPM2过表达细胞系统和TRPM2敲除小鼠模型发挥双重钙流入和钙释放通道的作用。我们将探索激动剂-受体相互作用，以产生腺嘌呤二核苷酸，即 CD38。我们将使用基于链脲佐菌素的 1 型糖尿病小鼠模型来研究 TRPM2 在细胞死亡中的参与。这些实验将在表达系统中进行，并结合膜片钳、成像和细胞凋亡研究，从野生型、CD38、PARP 和 TRPM2 敲除小鼠模型中分离出小鼠中性粒细胞和 β 细胞。在具体目标 2 中，我们将研究 TRPM2 激动剂结合的分子决定因素，并解决钙调蛋白是否是 TRPM2 钙依赖性促进的介质的问题。了解 TRPM2 和腺嘌呤二核苷酸在钙信号传导中的功能将完善我们对表达该离子通道的组织中钙调节的了解，并可能为涉及 TRPM2 功能的过程（包括糖尿病引起的胰腺 β 细胞死亡）的治疗干扰提供新的靶标。