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

• 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
• 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; 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

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.

项目摘要/摘要 包括胆固醇在内的固醇脂质对于哺乳动物细胞生理很重要。这些分子 调节生物膜的流动性，因此与维持膜完整性有关， 胁迫耐受性，融合事件等。固醇也参与细胞内和细胞间信号，并被贩运 到亚细胞膜。而数十年的研究为真核固醇提供了分子见解 对于细菌和古细菌，缺乏合成，运输，调节和功能，对固醇的类似理解。 虽然认为古细菌不制作或使用固醇，但某些细菌确实会产生和运输固醇。许多 众所周知，其他人会与真核生物产生的固醇互动。这些细菌包括病原体 Spirochetes（Borrelia Burgdorferi，Treponema Pallidum），分枝杆菌，衣原体，立克西亚和肠道 微生物群。对于病原体，从宿主那里获取固醇至关重要，因为它们定居并建造了固醇 细胞信封。对于肠道微生物，与胆固醇的相互作用可以改变宿主脂质代谢，从而改变 导致心脏代谢性疾病和血脂异常。尽管有很多关于 与这些脂质的微生物相互作用，缺乏对相互作用方式以及如何进行的分子见解 他们受到监管。我们将解决这个知识差距，我们认为这将揭示治疗的新目标 细菌定植和异常固醇脂质代谢的干预措施。 鉴于某些细菌产生从头开始的固醇，我们认为对固醇有了了解 在细菌中处理使它们的细菌可以揭示其在使用细菌中的处理中的见解。我们 因此，侧重于甲虫囊肿，这是一种据报道可产生固醇近40年前的细菌。 最近的研究报道了囊膜张霉菌中固醇生物合成的显着差异。从那以后我们添加了 对于那些报告，表明固醇贩运也有很大不同。我们确定了三种蛋白质 交通固醇：BSTA，BSTB和BSTC。 BSTA是转运蛋白的抗性结节司家族的成员 该作用是多种细菌代谢物的转运蛋白。 BSTB是一种周围结合蛋白， 参与磷酸转运的同源物。最后，BSTC是外膜相关的脂蛋白 属于底物的转运蛋白家族。 BST蛋白的整体结构 与真核固醇转运蛋白明显不同。但是，它们都包含相似的配体位点 在疏水和亲水性残基的介绍中。我们认为修饰的结构基因组学 方法是将重点放在配体部位而不是整体结构/序列上 鉴定细菌中功能上同源蛋白。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，以识别和表征细菌中固醇运输蛋白的结合方法 制作固醇，劫持固醇的病原体和调节宿主固醇代谢的肠菌群。