Regulators of Calcium Signaling

钙信号调节剂

• 批准号: 8678953
• 负责人: JOHN Anthony PUTKEY
• 金额: $ 29.24万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-15 至 2017-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8678953
• 关键词: Accounting; Affect; Affinity; Agonist; Alzheimer' s Disease; Animal Model; Apoptosis; Apoptotic; B-Lymphocytes; Binding; Biochemical; Biological; Biophysics; Buffers; Calcium Signaling; Calmodulin; Cell Death; Cell physiology; Cellular biology; Chimeric Proteins; Data; EF Hand Motifs; Epilepsy; Exhibits; Feedback; Foundations; GTP-Binding Proteins; Health; Hela Cells; Homeostasis; Huntington Disease; Hypothyroidism; Kidney; Knockout Mice; Lead; Learning; Ligands; Malignant Neoplasms; Mediating; Modeling; Molecular; Neuraxis; Neuronal Differentiation; Normal Cell; Parkinson Disease; Pathway interactions; Patients; Play; Process; Property; Proteins; Regulation; Reporting; Role; Schizophrenia; Signal Transduction; Signaling Protein; Structure; Synaptic plasticity; Testing; Tissues; Transgenic Mice; Work; anergy; base; design; genetic regulatory protein; insight; neurogranin; novel; premature; reproductive; sensor; urinary

DESCRIPTION (provided by applicant): It is well known that oscillations of intracellular Ca2+ control the activity of the ubiquitous and essential signaling protein, calmodulin (CaM). It is les widely recognized that CaM is also regulated by two small proteins, PEP-19 and neurogranin (Ng), which have no known intrinsic activity other than binding to CaM via an IQ motif. The mechanisms of action of these Regulators of CaM Signaling, or RCS proteins, are poorly understood even though they broadly affect CaM signaling to provide a level of control that is analogous to RGS and GAPs in G-protein signaling. The biological roles of RCS proteins are profound and diverse. Ng knockout mice exhibit learning deficits, deficiencies in synaptic plasticity and altered Ca2+ levels and dynamics. In addition, Ng levels are down regulated in hypothyroidism, Alzheimer disease and schizophrenic patients. PEP-19 is expressed in the central nervous system, but also in renal/urinary and reproductive tissues, and its levels are significantly altered during normal cell processes such as B-cell anergy, and by pathological conditions such as cancer and Huntington's disease. In addition, increased expression of PEP-19 inhibits apoptosis, protects against cell death due to Ca2+ overload, and causes premature neuronal differentiation in transgenic mice. Despite these profound biological impacts, the prevailing mechanistic model that RCS proteins simply buffer CaM does not explain their different cellular effects, or account for their important and divergent biochemical properties. This proposal provides new hypotheses based on our recent and preliminary data showing that Ca2+ exchange at the C-domain of CaM is greatly accelerated by PEP-19, while the Ca2+ binding affinity is greatly reduced by Ng, and that this is mediated by acidic sequences adjacent to the IQ motifs. We also show that PEP-19 sensitizes HeLa cells to ATP-dependent Ca2+ release, and that this dependent on its ability to modulate the Ca2+ binding properties of CaM. These data form the foundation for the following Aims: Aim 1: Define the structural basis for differential effects of RCS proteins on Ca2+ binding to CaM. Aim 2: Determine if RCS proteins play a general role in regulating ligand-dependent Ca2+ release. Aim 3: Identify properties of RCS proteins that mediate their effects on apoptosis

描述（由申请人提供）：众所周知，细胞内CA2+的振荡控制无处不在的基本信号蛋白钙调蛋白（CAM）的活性。 les广泛认识到，CAM也受两种小蛋白Pep-19和Neurogranin（NG）的调节，它们除了通过IQ基序与CAM结合外，它们没有已知的内在活性。这些CAM信号传导或RCS蛋白的调节剂的作用机制也很少理解，即使它们广泛影响CAM信号传导以提供类似于RGS和G蛋白信号传导中差距的控制水平。 RCS蛋白的生物学作用是深刻而多样的。 NG敲除小鼠表现出学习缺陷，突触可塑性缺陷以及CA2+水平和动态的改变。另外，在甲状腺功能减退症，阿尔茨海默氏病和精神分裂症患者中，NG水平下降。 PEP-19在中枢神经系统中表达，但在肾脏/尿和生殖组织中也表达，其水平在正常细胞过程（例如B细胞厌食）以及诸如癌症和亨廷顿氏病等病理状况的正常过程中会发生显着改变。此外，PEP-19的表达增加抑制了细胞凋亡，可预防CA2+过载引起的细胞死亡，并导致转基因小鼠的过早神经元分化。尽管有这些深远的生物学影响，但RCS蛋白简单的蛋白质的主要机械模型并不能解释其不同的细胞效应，也不能解释其重要和不同的生化特性。该建议提供了基于我们最近和初步数据的新假设，表明CAM的C-domain处的Ca2+交换大大加速了PEP-19，而Ca2+结合亲和力大大降低了NG，并且这是由邻近IQ主题的酸性序列介导的。我们还表明，PEP-19将HeLa细胞敏感到依赖ATP的Ca2+释放，这取决于其调节CAM的Ca2+结合特性的能力。这些数据构成了以下目的的基础：目标1：定义RCS蛋白对Ca2+与CAM结合的差异作用的结构基础。 AIM 2：确定RCS蛋白在调节配体依赖性Ca2+释放中是否发挥一般作用。 AIM 3：确定RCS蛋白的特性，介导其对凋亡的影响