Structural dynamics of sphingosine-1-phosphate transporters as key therapeutic targets for immune system modulation and cancer

1-磷酸鞘氨醇转运蛋白作为免疫系统调节和癌症关键治疗靶点的结构动力学

• 批准号: 10586751
• 负责人: Reza Dastvan
• 金额: $ 40.81万
• 依托单位: SAINT LOUIS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-20 至 2027-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10586751
• 关键词: Adopted; Antibiotics; Binding Sites; Biological Assay; Cations; Cell membrane; Cells; Cellular Membrane; Coupled; Coupling; Cryoelectron Microscopy; Data; Defect; Detergents; Development; Disease; Drug Targeting; Electron Spin Resonance Spectroscopy; Electrons; Endothelial Cells; Family; Family member; Foundations; Goals; Growth; Homologous Gene; Human; Immune system; Immunosuppressive Agents; Immunotherapy; Impairment; In Vitro; Inorganic Phosphate Transporter; Ions; Ligands; Lipid Bilayers; Lipids; Lymphocyte; Malignant Neoplasms; Mammalian Cell; Maps; Mediating; Membrane; Membrane Lipids; Micelles; Modeling; Molecular Conformation; Multi-Drug Resistance; Mus; Mutation; Mycobacterium smegmatis; Neoplasm Metastasis; Neptunium; Physiologic pulse; Physiological; Play; Poison; Proteins; Protons; Public Health; Regulation; Research; Resolution; Role; Sampling; Signal Transduction; Spectrum Analysis; Sphingolipids; Spin Labels; Structure; Techniques; Testing; Therapeutic; biophysical techniques; cell motility; conformational conversion; efflux pump; extracellular; feasibility research; flexibility; genome-wide; in vivo; innovation; migration; mimetics; model building; molecular dynamics; molecular modeling; mutant; nanodisk; nanoscale; novel therapeutic intervention; particle; prevent; protonation; restraint; simulation; sphingosine 1-phosphate; stoichiometry; structural determinants; therapeutic target; tumor

Project Summary/Abstract The bioactive lipid sphingosine-1-phosphate (S1P) plays a key role in regulating the growth, survival and migration of mammalian cells. S1P is produced intracellularly and then released extracellularly to engage in its (patho)physiological roles. The Spinster (Spns) lipid transporters of the major facilitator superfamily (MFS) are critical for transporting S1P across cellular membranes. Of the three Spns proteins in humans, Spns2 functions as the main S1P transporter, which makes it a potential drug target for modulating S1P export and signaling. An endothelial cell-specific defect in Spns2 results in impaired egress of lymphocytes and prevents tumor metastasis in mice, strongly suggesting that Spns2 could be an effective target for reducing metastases by increasing the efficacy of immunotherapy. Thus, detailed characterization of the Spns2 mechanism is of high significance for the development of novel therapeutic strategies for diseases associated with S1P signaling and to target Spns2 as a potential immunosuppressant. The overall goal of this proposal is to define the functional mechanism of the Spns family of sphingolipid transporters. The mechanism of Spns2-mediated S1P transport across cellular membrane remains poorly understood, mainly due to the lack of structural information (Aims 1 and 2). In addition, the precise mechanism of Spns2 regulation is still unclear (Aim 3). We recently defined the proton- dependent conformational dynamics of a bacterial Spns transporter. Our approach capitalizes on a powerful pulsed EPR technique known as Double Electron Electron Resonance (DEER) spectroscopy, an effective nanometer-scale ruler, in the context of high-resolution structures. It is informed by functional studies and contextualized through collaborative molecular modeling. Using this integrated approach, we conduct a thorough mechanistic comparison between human Spns2 and its homologs. The objectives of this proposal are to define the cation- and substrate-coupled conformational cycle of human Spns2 and its bacterial homologs in lipid bilayers. To determine the conformational states involved in the alternating access mechanism, we will apply DEER spectroscopy under conditions expected to stabilize transport intermediates and combine the results with restraint-assisted molecular dynamics to map ligand-coupled conformational changes. Using a similar integrated approach to define the transport mechanism of other Spns family members and their prokaryotic homologs, we will identify the key commonalities and differences in their mechanisms, highlighting the mechanistic flexibility enabling their diverse function with transformative therapeutic potential.

项目总结/文摘