Pore Formation by Cholesterol Dependent Cytolysins

胆固醇依赖性溶细胞素形成孔

• 批准号: 8121859
• 负责人: Rodney K. Tweten
• 金额: $ 43.01万
• 依托单位: UNIVERSITY OF OKLAHOMA HLTH SCIENCES CTR
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-04-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8121859
• 关键词: Binding; Cholesterol; Complement; Complement Membrane Attack Complex; Contracts; Couples; Cytolysins; Development; Disease; Employee Strikes; Eukaryotic Cell; Event; Exhibits; Family; Foundations; Fruit; Future; HIV; Immune; Lead; Malaria; Mediating; Membrane; Methods; Modeling; Molecular; NAD+ Nucleosidase; Pathogenesis; Pathway interactions; Play; Pleurotus ostreatus; Pneumococcal vaccine; Population; Process; Prophylactic treatment; Protein Family; Proteins; Role; Route; Site; Solutions; Specificity; Streptococcus pneumoniae; Streptococcus pyogenes; Structure; Testing; Therapeutic; Toxin; Toxoplasma; Vaccines; Work; Xenorhabdus luminescens; base; design; improved; insight; intermolecular interaction; keratinocyte; monomer; mutant; pathogen; pathogenic bacteria; perforin; protein folding; streptolysin O; therapy design; tumor

DESCRIPTION (provided by applicant): The cholesterol-dependent cytolysins (CDCs) are a large group of pore-forming toxins that contribute to the pathogenesis of many Gram-positive pathogenic bacteria. Our studies of the CDC pore-forming mechanism have led to a better understanding of their role in pathogenesis and have revealed new paradigms for cellular recognition and assembly of a membrane pore. These studies enabled us to rationally design a CDC-based component vaccine for Streptococcus pneumoniae, which is currently being used by the Gates Foundation in their vaccine effort for S. pneumoniae. Also, our discovery of a CD59 binding CDC has allowed others to develop a possible therapeutic that specifically targets HIV. In the current renewal we will continue our studies into the CDC mechanism to understand the molecular events that trigger pore formation. Understanding how the CDCs initiate pore formation will help us design therapies or improved vaccines that specifically target highly sensitive structural components necessary for their function. We will also continue our studies into the membrane recognition of cholesterol by the CDCs. Our studies have revealed a remarkable aspect of the CDCs' interaction with cholesterol: some CDCs can bind to an expanded population of membrane cholesterol of which only a fraction supports pore formation. It appears that the ability to bind a significant fraction of monomers to cholesterol at sites that do not support pore formation may be important to specific CDC functions. It was recently shown that the CDC of Streptococcus pyogenes, streptolysin O (SLO), transports a specific protein into eukaryotic cells by a pore-independent mechanism. These studies suggest that pore- independent effects of the CDCs may be a significant, but unexplored, mechanism by which the CDCs contribute to pathogenesis. Understanding how CDCs can bind to membrane cholesterol without triggering pore formation will reveal new paradigms for how CDCs function at the molecular level and how they contribute to pathogenesis. Finally, we will leverage our deep understanding of the CDC mechanism to initiate studies into the pore forming mechanism of the membrane attack complex/perforin (MACPF) family of proteins. The MACPF proteins are widespread and contribute to mammalian immune defense and disease causing prokaryotic and eukaryotic pathogens. Recent structural studies of MACPF proteins and our work on the CDCs has prompted others to speculate that the MACPF pore forming mechanism exhibits features of the CDC pore forming mechanism, possibly resulting from a common origin of the two protein families. We will leverage our expertise with the CDCs to initiate studies into the molecular mechanism of the MACPF proteins to test this hypothesis. We expect the study of the MACPF pore forming mechanism will form the basis of a significant effort to investigate other MACPF proteins that play important roles in immune defense (complement membrane attack complex), development (astrotactins), diseases caused by eukaryotic pathogens such as Toxoplasma and malaria, and tumor destruction (perforin). PUBLIC HEALTH RELEVANCE: The cholesterol-dependent cytolysins (CDCs) and the membrane attack complex/perforin (MACPF) proteins are large families of proteins involved in immune defense (MACPF) and are pathogenic factors for eukaryotic (MACPF) and prokaryotic (CDCs and MACPF) pathogens. Our studies into the basic mechanism of these proteins will allow us to better understand their contribution to diseases caused by bacterial and eukaryotic pathogens, and immune defense that will lead to a better understanding of and therapies for a wide variety of infectious and congenital diseases.

描述（由申请人提供）：胆固醇依赖性细胞素蛋白（CDC）是一大批毛孔形成的毒素，有助于许多革兰氏阳性致病细菌的发病机理。我们对CDC孔形成机制的研究使他们对它们在发病机理中的作用有了更好的了解，并揭示了膜孔的细胞识别和组装的新范式。这些研究使我们能够合理设计一种基于CDC的肺炎链球菌疫苗，盖茨基金会目前正在其疫苗用于肺炎链球菌的疫苗工作。同样，我们发现CD59结合CDC的发现使其他人能够开发出一种专门针对HIV的治疗性。在当前的续签中，我们将继续研究CDC机制，以了解触​​发孔形成的分子事件。了解CDC如何启动孔形成将有助于我们设计疗法或改进的疫苗，这些疫苗专门针对其功能所需的高度敏感的结构成分。我们还将继续研究CDC对胆固醇的膜识别。我们的研究揭示了CDC与胆固醇相互作用的一个显着方面：某些CDC可以与扩大的膜胆固醇人群结合，其中只有一小部分支持孔形成。看来，在不支持孔形成的位点结合一小部分单体与胆固醇的能力可能对特定的CDC功能很重要。最近显示，链球菌链球菌链霉菌素O（SLO）的CDC通过孔独立的机制将特定的蛋白质转运到真核细胞中。这些研究表明，CDC的毛孔独立作用可能是一种重要但未开发的机制，疾病预防症有助于发病机理。了解CDC如何与膜胆固醇结合而不触发孔隙形成将揭示CDC在分子水平的功能以及它们如何对发病机理的贡献的新范式。最后，我们将利用对CDC机制的深刻理解来开始研究蛋白质膜攻击复合蛋白（MACPF）家族的孔形成机理。 MACPF蛋白很普遍，并有助于哺乳动物免疫防御和疾病，导致原核和真核病原体。 MACPF蛋白的最新结构研究以及我们在CDC上的工作促使其他人推测MACPF孔形成机制具有CDC孔形成机制的特征，这可能是由于两个蛋白质家族的共同起源而产生的。我们将利用CDC的专业知识来启动对MACPF蛋白的分子机制的研究，以检验该假设。我们期望对MACPF孔形成机制进行研究，将构成重大努力的基础，以调查其他在免疫防御中起重要作用（补体膜攻击复合物），发育（Astrotactins），由真核生物病原体引起的疾病，如毒素病，如toxoplasma和Malaria和Malararia和肿瘤销毁（PulloRin（Pulforin））。 公共卫生相关性：依赖胆固醇的细胞赛（CDC）和膜攻击复合蛋白（MACPF）蛋白是参与免疫防御（MACPF）的大型蛋白质家族，是真核（MACPF）和原始人（CDCS和MACPF）病原体的致病因素。我们对这些蛋白质的基本机制的研究将使我们能够更好地了解它们对细菌和真核病原体引起的疾病的贡献，以及免疫防御，这将使人们对各种感染性和先天性疾病的了解和疗法更好地理解和疗法。