Uncovering the molecular mechanism of learning and memory with an emphasis on Down Syndrome

项目摘要/摘要 钙/钙调蛋白依赖的激酶II(CaMKII)是一种丝氨酸/苏氨酸(Ser)/苏氨酸(Thr)激酶，在神经元和 心脏信号。CaMKII的不受调控/干扰的激活会导致几种病理情况，如 严重的学习和记忆障碍，心律失常和心力衰竭。由于生理上的原因 CaMKII激活状态的重要性，很明显，CaMKII的激活在细胞内受到严格的调控。 我提出的项目旨在从三个角度理解这一规定的分子基础： (1)有趣的是注意到这种钙反应激酶的序列在脊索动物中高度保守， 除了将激酶结构域连接到中心十二聚体/十四聚体的固有无序连接体 集线器。根据连接子的长度/组成，CaMKII被分为四种不同的异构体和展品 组织特异性表达和特异性亚细胞定位。这个本质上无序的链接器是假设的 调节CaMKII激活的容易程度，以响应不同幅度/频率的钙信号。我会研究一下 这个内在无序的连接子在单分子水平上调节CaMKII的激活的作用。(2)我们 最近在CaMKII中发现了一种独特的现象，称为亚基交换，由此激活了CaMKII 亚基可以转换为未激活的CaMKII。这可能是一种增强激活信号的机制 CaMKII，在最初的钙刺激措施退出很久之后。我会研究阻断亚单位交换的效果 在细胞中，最终我计划在CaMKII激活信号的传播和长期 增强/学习/记忆。(3)最后，我将重构CAMKII的监管电路，包括其 膜相关相互作用伙伴，如NMDA受体、多巴胺能D3受体和 磷酸酶，在支撑膜上。利用这个简化的模型，我将研究各种信号的影响 输入到这个电路，以检查突触对CaMKII的调节限制。 我需要在显微镜、质谱学和电生理测量方面的额外培训 回答这些问题。我已经组建了一个由导师和合作者组成的团队，他们将为我提供 为我的职业发展提供技术和智力方面的建议。我的短期目标(K99/早期R00阶段)是 应用新学到的技巧回答与激活和调节有关的问题 CaMKII及其在长时程增强、学习和记忆中的作用。这将使我处于有利的地位，继续我的长期- 学期目标：从分子的角度探讨心理健康的发展和维持。具体来说，我 想要研究唐氏综合征的分子机制，重点是激活，调节 唐氏综合征关键区域激酶DYRK1a的下游信号转导作用 治疗唐氏综合症神经病理。

PROJECT SUMMARY/ABSTRACT Calcium/calmodulin-dependent kinase II (CaMKII) is a Ser/Thr kinase, which plays a critical role in neuronal and cardiac signaling. Unregulated / perturbed activation of CaMKII leads to several pathological conditions, like severe impairment in learning and memory, cardiac arrhythmias and heart failure. Owing to the physiological importance of the activated state of CaMKII, it is obvious that the activation of CaMKII is tightly regulated in cells. My proposed project aims at understanding the molecular basis of this regulation from three perspectives: (1) It is interesting to note that the sequence of this Ca2+ responsive kinase is highly conserved in chordates, except an intrinsically disordered linker that connect the kinase domains to a central dodecameric/tetradecameric hub. Based on the length/composition of this linker, CaMKII is classified into four distinct isoforms and exhibits tissue-specific expression and specific subcellular localization. This intrinsically disordered linker is hypothesized to tune the ease of CaMKII activation in response to varying amplitude/frequency of Ca2+ signals. I will study the role of this intrinsically disordered linker in regulating the activation of CaMKII at a single molecule level. (2) We have recently discovered a unique phenomenon in CaMKII called subunit-exchange, whereby activated CaMKII subunits can exchange into unactivated CaMKII. This can be a mechanism to potentiate activation signal of CaMKII, long after the withdrawal of the initial Ca2+ stimulus. I will study the effect of blocking subunit exchange in cells and eventually I plan to establish a connection between spread of CaMKII activation signal and long-term potentiation/learning/memory. (3) Finally, I will reconstitute the regulatory circuit of CaMKII, including its membrane-associated interaction partners, such as the NMDA receptor, the dopaminergic D3 receptor and the phosphatases, on a supported membrane. Using, this simplistic model, I will study the effect of various signal inputs to this circuit to examine the regulatory constraints on CaMKII at the synapse. I need additional training in microscopy, mass spectrometry and electrophysiological measurements to address these questions. I have assembled a team of mentor and collaborators who will provide me with the technical and intellectual advice for my career development. My short-term (K99/early R00-phase) goal is to apply the newly learned techniques to answer pertinent questions related to the activation and regulation of CaMKII and its role in long-term potentiation, learning and memory. This will position me well to pursue my long- term goal to probe mental health development and maintenance from a molecular perspective. Specifically, I want to investigate the molecular mechanism underlying Down syndrome, focusing on the activation, regulation and downstream signaling effects of a Down syndrome critical region kinase DYRK1a, a promising drug target for Down syndrome neuropathologies.