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+ 的振荡控制着普遍存在且必需的信号蛋白钙调蛋白 (CaM) 的活性。人们普遍认识到，CaM 还受到两种小蛋白 PEP-19 和神经粒蛋白 (Ng) 的调节，这两种蛋白除了通过 IQ 基序与 CaM 结合外，没有已知的内在活性。这些 CaM 信号传导调节剂（RCS 蛋白）的作用机制人们知之甚少，尽管它们广泛影响 CaM 信号传导以提供类似于 G 蛋白信号传导中的 RGS 和 GAP 的控制水平。 RCS 蛋白的生物学作用是深远而多样的。 Ng 基因敲除小鼠表现出学习缺陷、突触可塑性缺陷以及 Ca2+ 水平和动力学改变。此外，甲状腺功能减退症、阿尔茨海默病和精神分裂症患者的 Ng 水平下调。 PEP-19 在中枢神经系统中表达，也在肾脏/泌尿和生殖组织中表达，其水平在正常细胞过程（例如 B 细胞无反应性）以及病理状况（例如癌症和亨廷顿舞蹈病）中发生显着改变。此外，PEP-19 表达增加可抑制细胞凋亡，防止细胞因 Ca2+ 超载而死亡，并导致转基因小鼠神经元过早分化。尽管有这些深远的生物学影响，RCS 蛋白只是缓冲 CaM 的流行机制模型并不能解释它们不同的细胞效应，也不能解释它们重要且不同的生化特性。该提议基于我们最近的初步数据提供了新的假设，这些数据表明 PEP-19 大大加速了 CaM C 结构域的 Ca2+ 交换，而 Ng 大大降低了 Ca2+ 结合亲和力，并且这是由酸性序列介导的与 IQ 图案相邻。我们还表明，PEP-19 使 HeLa 细胞对 ATP 依赖性 Ca2+ 释放敏感，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标的基础： 目标 1：定义 RCS 蛋白对 Ca2+ 与 CaM 结合的不同影响的结构基础。目标 2：确定 RCS 蛋白是否在调节配体依赖性 Ca2+ 释放中发挥一般作用。目标 3：确定 RCS 蛋白介导细胞凋亡影响的特性