Deciphering the molecular mechanisms of sterol lipid trafficking in bacteria

破译细菌中甾醇脂质运输的分子机制

基本信息

批准号：
10711607
负责人：
Laura Dassama
金额：
$ 34.37万
依托单位：
STANFORD UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-07-01 至 2028-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10711607
关键词：
Archaea Bacteria Bacterial Proteins Bioinformatics Biological Borrelia burgdorferi Cardiometabolic Disease Cell physiology Chlamydia Cholesterol Dyslipidemias Eukaryota Eukaryotic Cell Event Family Genomic approach Genus Mycobacterium Homologous Gene Homologous Protein Hydrophobicity Knowledge Ligand Binding Ligands Lipids Lipoproteins Mammalian Cell Membrane Metabolism Methylococcus capsulatus Molecular Order Spirochaetales Pathogenicity Periplasmic Binding Proteins Proteins Regulation Reporting Research Resistance Rickettsia Signal Transduction Signaling Molecule Site Sterol Biosynthesis Pathway Sterols Structure Therapeutic Intervention Treponema pallidum Work cell envelope fluidity gut microbes gut microbiome gut microbiota hydrophilicity insight lipid metabolism lipid transport member microorganism interaction new therapeutic target pathogen phosphonate protein transport stress tolerance structural genomics trafficking

项目摘要

Project summary/abstract Sterols lipids, including cholesterol, are important for mammalian cell physiology. These molecules modulate the fluidity of biological membranes and are therefore implicated maintaining membrane integrity, stress tolerance, fusion events, etc. Sterols are also involved in intra- and intercellular signaling and are trafficked to sub-cellular membranes. Whereas decades of research have provided molecular insights into eukaryotic sterol synthesis, transport, regulation, and function, similar understanding of sterols is lacking for bacteria and archaea. While it is thought that archaea do not make or use sterols, some bacteria do make and transport sterols; many others are known to engage with sterols produced by eukaryotes. These bacteria include the pathogenic spirochetes (Borrelia burgdorferi, Treponema pallidum), Mycobacteria, Chlamydia, Rickettsia, and gut microbiota. For pathogens, the acquisition of sterols from the host is critical as they colonize and construct their cell envelopes. For gut microbes, interactions with cholesterol can alter the host lipid metabolism, thereby contributing to cardiometabolic diseases and dyslipidemia. Despite the preponderance of research about microbial interactions with these lipids, lacking are molecular insights into how the interactions occur and how they are regulated. We will address this knowledge gap, which we posit will reveal novel targets for therapeutic interventions in bacterial colonization and aberrant sterol lipid metabolism. Given that some bacteria produce sterols de novo, we reasoned that achieving an understanding of sterol handling in bacteria that make them could reveal insights into their handling in bacteria that use them. We therefore focused on Methylcoccus capsulatus, a bacterium reported to produce sterols nearly 40 years ago. Recent studies reported a significant divergence in sterol biosynthesis in M. capsulatus. We have since added to those reports one showing that sterol trafficking is also substantially different. We identified three proteins that traffic sterols: BstA, BstB, and BstC. BstA is a member of the resistance nodulation division family of transporters that work as transporters for a wide range of bacterial metabolites. BstB is a periplasmic binding protein with homologs involved in phosphonate transport. Finally, BstC is an outer membrane associated lipoprotein belonging to a family of transporters whose substrates are not known. The overall structures of the Bst proteins are markedly different from eukaryotic sterol transporters. However, they all contain ligand sites that are similar in the presentation of hydrophobic and hydrophilic residues. We posit that a modified structural genomics approach wherein the focus is on ligand sites instead of overall structure/sequence would enable the identification of functionally homologous proteins in bacteria. This work will use bioinformatics, quantitative ligand binding analyses, and structural approaches to identify and characterize sterol trafficking proteins in bacteria that make sterols, pathogens that hijack sterols, and gut flora that modulate host sterol metabolism.

项目概要/摘要甾醇脂质，包括胆固醇，对于哺乳动物细胞生理学很重要。这些分子调节生物膜的流动性，因此涉及维持膜的完整性，应激耐受、融合事件等。甾醇还参与细胞内和细胞间信号传导并被贩运到亚细胞膜。鉴于数十年的研究提供了对真核甾醇的分子见解合成、运输、调节和功能，细菌和古细菌对甾醇缺乏类似的了解。虽然人们认为古细菌不产生或使用甾醇，但一些细菌确实产生和运输甾醇。许多其他已知与真核生物产生的甾醇结合。这些细菌包括致病菌螺旋体（伯氏疏螺旋体、梅毒螺旋体）、分枝杆菌、衣原体、立克次体和肠道微生物群。对于病原体来说，从宿主获取甾醇对于它们定殖和构建其自身至关重要。细胞包膜。对于肠道微生物来说，与胆固醇的相互作用可以改变宿主的脂质代谢，从而导致心脏代谢疾病和血脂异常。尽管有关的研究占优势微生物与这些脂质的相互作用，缺乏对相互作用如何发生以及如何发生的分子见解他们受到监管。我们将解决这一知识差距，我们认为这将揭示治疗的新目标干预细菌定植和异常甾醇脂质代谢。鉴于某些细菌从头产生甾醇，我们推断，了解甾醇对制造它们的细菌进行处理可以揭示对使用它们的细菌进行处理的见解。我们因此，他们将重点放在了荚膜甲基球菌上，这种细菌在近 40 年前就被报道可以产生甾醇。最近的研究报告了荚膜囊藻中甾醇生物合成的显着差异。我们已经添加了与这些报告相比，有一份报告表明甾醇贩运也有很大不同。我们鉴定出三种蛋白质交通甾醇：BstA、BstB 和 BstC。 BstA 是转运蛋白耐药结瘤科家族的成员作为多种细菌代谢物的转运蛋白。 BstB 是一种周质结合蛋白参与膦酸转运的同系物。最后，BstC 是一种外膜相关脂蛋白属于底物未知的转运蛋白家族。 Bst蛋白的整体结构与真核甾醇转运蛋白明显不同。然而，它们都含有相似的配体位点疏水性和亲水性残基的呈现。我们假设改良的结构基因组学其中重点是配体位点而不是整体结构/序列的方法将使细菌中功能同源蛋白的鉴定。这项工作将使用生物信息学、定量配体结合分析和结构方法来识别和表征细菌中的甾醇运输蛋白产生甾醇、劫持甾醇的病原体以及调节宿主甾醇代谢的肠道菌群。