Molecular characterization of the multi-modal regulation of inositol 1,4,5-trisphosphate receptors

肌醇1,4,5-三磷酸受体多模式调节的分子表征

• 批准号: 9899264
• 负责人: Richard Kevin Hite
• 金额: $ 40万
• 依托单位: SLOAN-KETTERING INST CAN RESEARCH
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-01 至 2024-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9899264
• 关键词: Address; Apoptotic; Architecture; BCL-2 Protein; BCL2 gene; Binding; Binding Proteins; Binding Sites; Biochemical; Biological Assay; Biophysics; Cations; Cell Death; Cell Differentiation process; Cell physiology; Cells; Complex; Coupled; Cryoelectron Microscopy; Cytoplasm; Cytoplasmic Tail; Cytosol; Data; Defect; Disease; Electrophysiology (science); Endoplasmic Reticulum; Ensure; Enzymes; Equilibrium; Family; Fertilization; Goals; Growth; Health; Heart Diseases; Homeostasis; Human; ITPR1 gene; Inositol; Ion Channel; Ions; Length; Ligand Binding; Ligands; Link; Lipid Bilayers; Lipids; Location; MCL1 gene; Maintenance; Malignant Neoplasms; Measures; Mediating; Membrane Proteins; Migration Assay; Mitochondria; Molecular; Molecular Conformation; Mutagenesis; Neurobiology; Pathology; Permeability; Physiological; Physiological Processes; Physiology; Play; Process; Protein Family; Proteins; Rattus; Recombinants; Regulation; Research; Resolution; Role; Second Messenger Systems; Side; Signal Transduction; Stimulus; Structure; biophysical techniques; experimental study; improved; member; multimodality; mutant; nervous system disorder; programs; protein function; protein protein interaction; receptor; small molecule; structured data

PROJECT SUMMARY The objective of this project is to characterize the molecular mechanisms of the multi-modal ligand- dependent gating of inositol 1,4,5-trisphosphate receptors (IP3Rs). IP3Rs are ubiquitously expressed endoplasmic reticulum (ER) Ca2+ channels that play a key role in the maintenance of Ca2+ homeostasis by conducting Ca2+ stored in the ER into the cytoplasm. In the cytosol, numerous Ca2+-regulated proteins sense changes in local and global Ca2+ concentrations to regulate diverse cellular process including fertilization, cell death and differentiation. Because of the diversity of processes regulated by cytoplasmic Ca2+, IP3R-mediated Ca2+ conductance is precisely regulated by ions, small molecules and protein co-factors. The two primary regulatory ligands of IP3Rs are inositol 1,4,5-trisphosphate (IP3) and cytoplasmic Ca2+, both of which bind the channel to modulate the gating state of the pore. Whereas IP3 binding activates IP3Rs, cytoplasmic Ca2+ both activates the channel at low concentrations and inhibits the channel at high concentrations. The biphasic relationship between Ca2+ and IP3R activity ensures that cytoplasmic Ca2+ concentrations are properly regulated. Besides IP3 and Ca2+, IP3R activity is further shaped in cell-specific manner by other small molecules such as ATP, by enzymes that post-translationallly modify IP3Rs and by numerous protein co- factors. How the effects of these various factors are synthesized to determine IP3R gating state and thus regulate cellular Ca2+ signalling remain poorly understood at a molecular level. As dysregulation of IP3R activity is linked to cardiac disease, cancer, neurological disorders and other pathologies, understanding the regulation of IP3Rs will have broad relevance to human health and disease. The proposal aims to employ structural, biochemical and biophysical approaches to develop a mechanistic understanding of IP3R regulation, focusing on Ca2+, IP3 and three protein co-factors of the Bcl-2 family: Bcl-2, Mcl-1 and Bcl-xL. With these approaches we aim to understand i) how IP3 and Ca2+ binding jointly stabilize IP3Rs in an active conformation, ii) how excess Ca2+ inhibits ion conduction and iii) how the protein co-factors Bcl-2, Mcl-1 and Bcl-xL modulate channel activity in the presence of IP3 and Ca2+. The proposed studies will reveal principles of how multiple stimuli are integrated to regulate ion channel function. Due to the broad physiological role of IP3Rs, the finding derived from these studies will be relevant to a number of fields including ion channels, Ca2+ signaling, cell death and neurobiology. !

项目摘要 该项目的目的是表征多模式配体的分子机制 肌醇1,4,5-三磷酸受体（IP3RS）的依赖门控。 ip3rs无处不在 内质网（ER）CA2+通道在维持Ca2+稳态中起关键作用 将Ca2+存储在ER中的Ca2+进入细胞质。在细胞质中，许多Ca2+调节的蛋白质感 局部和全局Ca2+浓度的变化，以调节各种细胞过程，包括受精，细胞 死亡与差异化。由于受细胞质CA2+调节的过程多样性，IP3R介导 Ca2+电导由离子，小分子和蛋白质副因素精确调节。两个主要 IP3RS的调节配体是肌醇1,4,5-三磷酸（IP3）和细胞质Ca2+，它们都结合 调节孔的门控状态的通道。 IP3结合激活IP3R，而细胞质Ca2+均激活IP3R 以低浓度激活通道，并以高浓度抑制通道。双相 Ca2+和IP3R活性之间的关系可确保细胞质Ca2+浓度正确 受监管。除IP3和Ca2+外，IP3R活性还以细胞特异性的方式进一步。 通过后翻译后通过酶修饰IP3R的酶，以及许多蛋白 因素。这些各种因素的影响如何合成以确定IP3R门控状态，从而确定 调节细胞Ca2+信号传导在分子水平上仍然很少了解。随着IP3R活动的失调 与心脏病，癌症，神经系统疾病和其他病理有关，了解调节 IP3RS的与人类健康和疾病有关。 该提案旨在采用结构，生化和生物物理方法来开发机械 了解IP3R调节，重点是Bcl-2家族的Ca2+，IP3和三个蛋白质共同因素：Bcl-2， MCL-1和BCL-XL。通过这些方法，我们旨在了解I）IP3和Ca2+如何共同稳定 活性构象中的IP3R，ii）多余的Ca2+如何抑制离子传导和iii）蛋白质co因子如何 在IP3和Ca2+存在下，Bcl-2，Mcl-1和Bcl-XL调节通道活动。拟议的研究将 揭示了如何整合多个刺激以调节离子通道功能的原理。由于广泛 IP3RS的生理作用，这些研究得出的发现将与许多领域有关 包括离子通道，CA2+信号传导，细胞死亡和神经生物学。 呢