Protein kinase A modulation of NMDA receptor gating and permeability

描述（由申请人提供）：NMDA受体与其他谷氨酸受体不同，因为它们对钙具有渗透性。这种钙渗透性是神经元长时程增强所必需的，是学习和记忆的细胞基础，也可能导致中风和癫痫等疾病的兴奋性毒性和细胞死亡。因此，了解影响NMDA受体门控和通透性的机制将为控制可塑性和兴奋性毒性的过程提供更多的见解。NMDA受体的门控和渗透性受到多种细胞外和细胞内信号的影响，包括蛋白激酶A（PKA），这是本提案的重点。PKA已被证明增加NMDA电流的幅度和钙成分，然后影响许多类型的神经元信号传导，包括长时程增强。然而，PKA调节NMDA受体的机制完全未知。因此，在本提案中，将使用两个目标研究NMDA受体的调节。第一个目标的目的是使用单个NMDA受体记录、药理学操作、动力学建模和定点诱变来确定PKA调节NMDA受体门控和渗透性的机制。在第二个目标中，调节PKA对NMDA受体的调节的因素将被研究，包括磷酸酶和神经调质。因此，这些实验的结果将确定PKA改变NMDA受体门控的机制，并将深入了解这种调节如何与其他细胞信号相互作用，并可能最终改变神经元输出。

DESCRIPTION (provided by applicant): NMDA receptors are unique from other glutamate receptors in that they are permeable to calcium. This calcium permeability is necessary for neuronal long-term potentiation, the cellular basis of learning and memory, and can also cause excitotoxicity and cell death in disease conditions like stroke and epilepsy. Therefore understanding mechanisms that influence gating and permeability of NMDA receptors will provide more insight to the processes that control plasticity and excitotoxicity. The gating and permeability of NMDA receptors is influenced by a variety of extracellular and intracellular signals, including protein kinase A (PKA), which is the focus of this proposal. PKA has been shown to increase both the amplitude and calcium component of NMDA currents, which then influences many types of neuronal signaling, including long-term potentiation. The mechanism by which PKA modulates NMDA receptors, however, is completely unknown. In this proposal, therefore, modulation of NMDA receptors will be investigated using two aims. The goal of the first aim is to determine the mechanism by which NMDA receptor gating and permeability are modulated by PKA using single NMDA receptor recordings, pharmacological manipulations, kinetic modeling, and site- directed mutagenesis. In the second aim, factors that regulate the modulation of NMDA receptors by PKA will be investigated, including phosphatases and neuromodulators. The results of these experiments will therefore determine the mechanism by which PKA alters NMDA receptor gating and will give insight as to how this modulation interacts with other cellular signals and may ultimately change neuronal output.