Calcium-Dependent Protein Regulation

钙依赖性蛋白质调节

• 批准号: 7493384
• 负责人: JOHN Anthony PUTKEY
• 金额: $ 25.95万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7493384
• 关键词: Acceleration; Accounting; Affect; Affinity; Amino Acid Motifs; Binding; Biochemical; Calcineurin; Calcium; Calmodulin; Calmodulin-Binding Proteins; Cells; Complex; Computer Simulation; Cyclic AMP; Data; Defect; Dimensions; Disease; Enzymes; Exhibits; Family; Growth Associated Protein 43; Guanosine Triphosphate Phosphohydrolases; Kinetics; Knockout Mice; Lead; Learning; Mediating; Memory; Modeling; Nervous system structure; Neurons; Outcome; Phosphotransferases; Play; Property; Proteins; RGS Proteins; Range; Rate; Reagent; Regulation; Relative (related person); Research Personnel; Role; Sampling; Signal Pathway; Signal Transduction; Solutions; Structure; Testing; Time; Work; base; calmodulin-dependent protein kinase II; concept; design; experience; in vivo; mutant; neurogranin; novel; phosphoric diester hydrolase; protein function; research study; response

PEP-19, neurogranin and neuromodulin are Small Neuronal IQ motif (SNIQs) calmodulin (CaM) binding proteins found in high abundance throughout the nervous system. Neurogranin knockout mice exhibit altered learning and memory, and have diverse defects in neuronal Ca2+ dynamics and multiple neuronal signaling pathways. This suggests that SNIQs play a fundamental role in CaM-dependent cell regulation, but there is a lack of experimental evidence to support a unifying mechanism that could explain these diverse effects. The only known activity of SNIQs is there ability to bind calmodulin in the presence or absence of Ca2+. We present the novel finding that SNIQs greatly accelerate the intrinsically slow kinetics of Ca2+ binding to the C-domain of CaM to achieve greatly enhanced rate of Ca2+ exchange by PEP-19, or a large decrease in Ca2+ affinity by neurogranin. We also show that SNIQs can affect Ca2+ binding to CaM even in the presence of another Ca2+-dependent CaM-binding protein. These observations demonstrate the potential for SNIQs to modulate the response of CaM to diverse Ca2+ signals it experiences in neurons, and they have broad implications for signal transduction in neuronal compartments that are rich in CaM and CaM-binding proteins. The experiments in this proposal will define the biochemical and structural basis for modulation of Ca2+ binding to CaM by SNIQs. The Aims are: Identify Ca2+ modulatory domains in SNIQs and determine if they function when paired with other CaM binding motifs. Quantify binding and rate constants for dynamic interactions between Ca2+, CaM and SNIQs that define the ability of SNIQs to modulate the steady state and temporal activity of CaM. Characterize the relative ability of SNIQs to modulate the Ca2+ binding properties of CaM in the presence of CaM-dependent protein kinase II, calcineurin or cAMP phosphodiesterase. Determine the effect of SNIQs on CaM-dependent activity of these proteins. Define the structural basis for modulation of Ca2+ binding to CaM by SNIQs.

PEP-19、神经颗粒素和神经调节蛋白与小神经元 IQ 基序 (SNIQ) 钙调蛋白 (CaM) 结合 在整个神经系统中发现了大量的蛋白质。神经粒蛋白敲除小鼠表现出 学习和记忆发生改变，神经元 Ca2+ 动力学和多神经元存在多种缺陷 信号通路。这表明 SNIQ 在 CaM 依赖性细胞调节中发挥着重要作用， 但缺乏实验证据来支持可以解释这些现象的统一机制 多样的效果。 SNIQ 唯一已知的活性是在存在或存在的情况下能够结合钙调蛋白。 缺乏Ca2+。我们提出了新的发现，即 SNIQ 极大地加速了本质上缓慢的动力学 Ca2+ 与 CaM 的 C 结构域结合，以实现 PEP-19 大大提高的 Ca2+ 交换速率，或 神经粒蛋白导致 Ca2+ 亲和力大幅下降。我们还表明 SNIQ 可以影响 Ca2+ 与 CaM 的结合 即使存在另一种 Ca2+ 依赖性 CaM 结合蛋白。这些观察结果表明 SNIQs 调节 CaM 对神经元中经历的各种 Ca2+ 信号的反应的潜力，以及 它们对富含 CaM 的神经元区室中的信号转导具有广泛的影响 CaM 结合蛋白。本提案中的实验将定义生物化学和结构基础 SNIQs 调节 Ca2+ 与 CaM 的结合。目标是： 识别 SNIQ 中的 Ca2+ 调节域并确定它们与其他 CaM 配对时是否发挥作用 结合图案。 量化 Ca2+、CaM 和 SNIQ 之间动态相互作用的结合和速率常数，定义 SNIQ 调节 CaM 的稳态和时间活动的能力。 表征 SNIQ 在存在时调节 CaM 的 Ca2+ 结合特性的相对能力 CaM 依赖性蛋白激酶 II、钙调神经磷酸酶或 cAMP 磷酸二酯酶。确定效果 这些蛋白质的 CaM 依赖性活性的 SNIQ。 定义 SNIQ 调节 Ca2+ 与 CaM 结合的结构基础。