Structural and functional analysis of Cav1.2 mediated PM-ER contacts in the postsynaptic membrane

瞬时钙纳米结构域介导的神经元和特定突触内的信号是理解神经元通讯和可塑性的核心。除NMDAR外，电压门控钙通道(VGCC)通常是突触可塑性诱导的起始钙源，在突触可塑性中具有多种功能。一般来说，VGCC是激活-转录偶联所必需的，并参与钙信号的局部放大。VGCC作用多样性的一个长期已知但仅是初步探索的结构成分是它们与内质网(ER)的联系。为了揭示这种通讯的结构和功能动力学，我们将在这个项目中重点研究由CaV1.2通道和突触后脊椎内基质相互作用分子(STIM)蛋白之间的活性驱动的联系而形成的PM-ER接触。以往的工作表明，含有内质网的突触具有特殊的性质，这对于神经元网络内的信息传递和长期记忆的形成是重要的。通过使用定位和电子显微镜方法(电子冷冻断层扫描、sptPALM和UPAINT)，结合功能成像(钙)和电生理学，我们将研究PM-ER接触是如何初始化的，是什么稳定了这些接触，以及这些接触如何对突触可塑性的启动和表达做出贡献。

Transient calcium nanodomain mediated signaling inside neurons and particular synapses is central to understanding neuronal communication and plasticity. Beside NMDARs, being often the initial calcium source for plasticity induction, voltage gated calcium channels (VGCCs) show a large diversity of functions in synaptic plasticity. In general, VGCC are essential for excitation-transcription coupling and involved in the local amplification of calcium signaling. One long time known but only rudimentary explored structural component contributing to the diversity of VGCC action is their communication with the endoplasmatic reticulum (ER). To unravel the structural and functional dynamics of this communication, we will focus in this project on the formation of PM-ER contacts formed by the activity driven association between CaV1.2 channels and Stromal interaction molecule (STIM) proteins within postsynaptic spines. Previous work has been shown that ER containing synapses have particular properties, which are important for the information transfer within neuronal networks and long-term memory formation. By using localization and electron microscopy methods (electron cryo-tomography, sptPALM and UPAINT) in combination with functional imaging (calcium) and electrophysiology, we will investigate how PM-ER contacts are initialized, what stabilizes these contacts and how these contacts contribute to the initiation and expression of synaptic plasticity.