Functions and regulation of endoplasmic reticulum-plasma membrane junctions

内质网-质膜连接的功能和调节

• 批准号: 9028283
• 负责人: JEN LIOU
• 金额: $ 28.58万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-12-01 至 2020-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9028283
• 关键词: Binding; Binding Proteins; Biochemical Genetics; Cell membrane; Cell physiology; Cells; Cellular biology; Communication; Coupling; Defect; Disease; Electron Microscopy; Endoplasmic Reticulum; Eukaryotic Cell; Event; Extracellular Space; Homeostasis; Hydrolysis; Imaging Techniques; Interphase Cell; Knowledge; Lead; Life; Lipids; Lymphocyte Activation; Mammalian Cell; Mediating; Membrane; Membrane Proteins; Metabolism; Molecular; Monitor; Muscular Dystrophies; Organelles; Patients; Phosphatidic Acid; Phosphatidylinositol 4,5-Diphosphate; Phosphatidylinositol Transfer Protein; Phosphatidylinositols; Plus End of the Microtubule; Proteins; Regulation; Research; Role; STIM1 gene; Severe Combined Immunodeficiency; Shapes; Signal Pathway; Signal Transduction; Skeletal Muscle; Subcellular structure; Supporting Cell; Testing; Work; design; genetic approach; human disease; innovation; insight; interest; lipid metabolism; lipid transfer protein; live cell imaging; migration; nanomembrane; novel; novel strategies; protein function; public health relevance; receptor; synaptotagmin I; tool

 DESCRIPTION (provided by applicant): Endoplasmic reticulum (ER)-plasma membrane (PM) junctions are evolutionarily conserved subcellular structures where the ER is closely apposed to the PM. Emerging evidence suggests that ER-PM junctions are important for Ca2+ signaling and lipid metabolism. Nevertheless, the specific functions and regulation of ER-PM junctions remain unclear. We are particularly interested in the role of ER-PM junctions during receptor-induced cell signaling. Receptor stimulation triggers the hydrolysis of phosphatidylinositol (PI) 4,5-bisphosphate (PIP2) at the PM and the release of Ca2+ in the ER to activate cellular functions including proliferation, migration and secretion. To sustain cell signaling and maintain cell homeostasis, inter-organelle signaling between the ER and the PM is crucial to quickly replenish PM PIP2 and ER Ca2+ with PI in the ER and Ca2+ in the extracellular space, respectively. We have previously identified three proteins, Nir2, E-Syt1 and STIM1, involved in the replenishment of PM PIP2 and ER Ca2+ and localized to ER-PM junctions following receptor stimulation. The objective of this proposal is to investigate the mechanisms of how PIP2 and Ca2+ homeostasis are regulated by dynamic translocation of Nir2, E-Syt1 and STIM1 to ER-PM junctions during receptor-induced cell signaling. We will use molecular, biochemical and genetic approaches in combination with cutting-edge live-cell imaging and EM for the proposed studies. In addition, we will develop innovative tools to monitor signaling events at ER-PM junctions and manipulate selected pools of lipids involved in PIP2 homeostasis. In aim 1, we will determine how PM PIP2 is replenished by dynamic translocation of Nir2 to ER-PM junctions following receptor- induced hydrolysis. In aim 2, we will determine how ER-PM junctions are regulated by dynamic translocation of E-Syt1 following receptor-induced cytosolic Ca2+ increases. In aim 3, we will determine how store-operated Ca2+ entry is regulated by dynamic translocation of STIM1 to ER-PM junctions following ER Ca2+ depletion. We expect the proposed research will establish new paradigms for inter-organelle signaling at membrane junctions and will have a major impact on the fundamental concepts in cell biology and signal transduction.

 描述（由申请人提供）：内质网（ER）-质膜（PM）连接是进化上保守的亚细胞结构，其中ER与PM紧密并列。新出现的证据表明，ER-PM连接是重要的钙离子信号和脂质代谢。然而，ER-PM连接的具体功能和调节仍不清楚。我们特别感兴趣的是在受体诱导的细胞信号传导过程中ER-PM连接的作用。受体刺激触发PM处磷脂酰肌醇（PI）4，5-二磷酸（PIP 2）的水解和ER中Ca 2+的释放以激活细胞功能，包括增殖、迁移和分泌。为了维持细胞信号传导和维持细胞稳态，ER和PM之间的细胞器间信号传导对于分别用ER中的PI和细胞外空间中的Ca 2+快速补充PM PIP 2和ER Ca 2+是至关重要的。我们以前已经确定了三种蛋白质，Nir 2，E-Syt 1和STIM 1，参与PM PIP 2和ER Ca 2+的补充，并定位于受体刺激后的ER-PM连接。本研究的目的是探讨在受体介导的细胞信号转导过程中，Nir 2、E-Syt 1和STIM 1如何通过动态移位到ER-PM连接点来调节PIP 2和Ca 2+稳态的机制。我们将使用分子，生物化学和遗传学方法，结合尖端的活细胞成像和EM进行拟议的研究。此外，我们将开发创新的工具来监测ER-PM连接处的信号事件，并操纵参与PIP 2稳态的选定脂质池。在目标1中，我们将确定在受体诱导的水解后，PM PIP 2如何通过Nir 2动态易位到ER-PM连接点来补充。在目标2中，我们将确定如何ER-PM连接调节E-Syt 1受体诱导的胞浆Ca 2+增加后的动态易位。在目标3中，我们将确定如何通过在ER Ca 2+耗尽后STIM 1动态易位到ER-PM连接来调节钙库操作的Ca 2+进入。我们预计，拟议的研究将建立新的范式细胞器间信号在膜连接，并将在细胞生物学和信号转导的基本概念产生重大影响。