Calcium-Dependent Protein Regulation

钙依赖性蛋白质调节

• 批准号: 7117389
• 负责人: JOHN Anthony PUTKEY
• 金额: $ 26.73万
• 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 2009-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7117389
• 关键词: 3' 5' cyclic nucleotide phosphodiesterase; calcineurin; calcium ion; calmodulin; calmodulin dependent protein kinase; chemical binding; chemical kinetics; enzyme activity; fluorescence polarization; genetic regulation; mutant; nerve /myelin protein; nuclear magnetic resonance spectroscopy; protein structure function; 3' 5' cyclic nucleotide phosphodiesterase; calcineurin; calcium ion; calmodulin; calmodulin dependent protein kinase; chemical binding; chemical kinetics; enzyme activity; fluorescence polarization; genetic regulation; mutant; nerve /myelin protein; nuclear magnetic resonance spectroscopy; protein structure function

DESCRIPTION (provided by applicant): 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: 1. Identify Ca2+ modulatory domains in SNIQs and determine if they function when paired with other CaM binding motifs. 2. 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. 3. 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. 3. Define the structural basis for modulation of Ca2+ binding to CaM by SNIQs.

描述（由申请人提供）：PEP-19，神经素蛋白和神经统治蛋白是小型神经元基序（SNIQS）钙调蛋白（CAM）结合蛋白，在整个神经系统中都具有很高的丰度。神经元素敲除小鼠表现出改变的学习和记忆，并且在神经元Ca2+动力学和多个神经元信号通路中具有多种缺陷。这表明SNIQS在CAM依赖性细胞调节中起着基本作用，但是缺乏实验证据来支持可以解释这些不同效果的统一机制。 SNIQ的唯一已知活性是在存在或不存在Ca2+的情况下结合钙调蛋白的能力。我们提出了一个新发现的发现，即SNIQ大大加速了Ca2+与CAM的固有缓慢动力学的速度，以实现PEP-19的Ca2+交换速率大大提高，或者通过Neurogranin的Ca2+亲和力大大降低。我们还表明，即使存在另一种Ca2+依赖性的CAM结合蛋白，SNIQ也会影响Ca2+与CAM的结合。这些观察结果表明，SNIQ可以调节CAM对神经元中经历的CA2+信号的响应的潜力，并且它们对富含CAM和CAM结合蛋白的神经元隔室的信号转导具有广泛的影响。该提案中的实验将定义SNIQ对Ca2+结合CAM的生化和结构基础。目的是： 1。识别SNIQ中的Ca2+调节域，并确定与其他CAM结合基序配对时它们是否起作用。 2。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。 3。表征SNIQ在存在CAM依赖性蛋白激酶II，钙调蛋白或CAMP磷酸二酯酶的情况下调节CA2+结合特性的相对能力。确定SNIQ对这些蛋白的CAM依赖性活性的影响。 3。定义SNIQ对CA2+结合CAM的调制的结构基础。