Choline phosphotransferase-dependent phospholipid synthesis in Treponema

描述（由申请人提供）：密螺旋体属螺旋体中存在的磷脂酰胆碱（PtdCho）生物合成的独特CDP-胆碱途径可能是这些生物体的寄生/致病生活方式的结果和贡献者，反映了它们与真核宿主的共同进化。我们假设T.齿垢PtdCho合成（1，2-二酰基甘油胆碱磷酸转移酶[CPT]）由TDE 0021编码，TDE 0021是一种明显的真核生物来源的基因。在许多真核生物中，这种酶也具有合成磷脂酰乙醇胺（PtdEtn）所需的1，2-二酰基甘油乙醇胺磷酸转移酶（EPT）活性。于T.当PtdCho合成的第一步被阻断时，PtdEtn（通过尚未鉴定的途径合成）被上调。我们假设T. Denticola TDE 0021编码CPT活性，也可能具有EPT活性，因此使其成为磷脂合成中的关键酶，并成为开发针对一系列粘膜和性病密螺旋体病的特异性抗密螺旋体药物的有吸引力的靶标。本申请涉及以下领域：目的1：表征T.合成PtdCho所需的牙垢。我们将确定T。denticola TDE 0021通过（A）构建和表征同基因TDE 0021突变体和（B）用T互补酿酒酵母CPT/EPT突变体编码CPT活性。齿垢菌TDE 0021 DNA。目的2：研究PtdEtn在T.齿垢我们将（A）识别和表征T。（B）表征在确定的PtdCho缺陷型T中导致PtdEtn水平增加的机制。齿垢突变体完成本项目的两个目标后，我们将在理解密螺旋体属（包括粘膜和性病病原体）独特磷脂合成途径的遗传组分和机制方面取得重大进展。所获得的知识将显着提高螺旋体膜生物学的理解，将提供一个基础，继续研究磷脂环境对微生物-宿主相互作用的作用，并可能提供新的治疗药物的开发基础。公共卫生相关性：该项目将表征包括粘膜和性病病原体在内的密螺旋体属中独特的磷脂合成途径的遗传成分和机制。这将有助于了解膜磷脂环境对微生物-宿主相互作用的作用，并可能为开发新的治疗药物提供基础。

DESCRIPTION (provided by applicant): The unique CDP-choline pathway for phosphatidylcholine (PtdCho) biosynthesis present in spirochetes of the genus Treponema is likely both a consequence of and a contributor to the commensal/pathogenic lifestyles of these organisms, reflecting their coevolution with eukaryotic hosts. We hypothesize that the final enzyme step in T. denticola PtdCho synthesis (1,2- diacylglycerol choline phosphotransferase [CPT]) is encoded by TDE0021, a gene of apparent eukaryotic origin. In many eukaryotes, this enzyme also has 1,2-diacylglycerol ethanolamine phosphotransferase (EPT) activity required for phosphatidylethanolamine (PtdEtn) synthesis. In T. denticola, PtdEtn (synthesized by an as-yet unidentified pathway) is upregulated when the first step in PtdCho synthesis is blocked. We hypothesize that T. denticola TDE0021 encodes CPT activity and may also have EPT activity, thus making it the key enzyme in phospholipid synthesis and an attractive target for development of specific anti-Treponema agents against a range of mucosal and venereal treponematoses. This application addresses the following areas: Aim 1: To characterize the CPT activity of T. denticola required for synthesis of PtdCho. We will determine if T. denticola TDE0021 encodes CPT activity by (A) construction and characterization of an isogenic TDE0021 mutant and (B) complementation of a Saccharomyces cerevisiae CPT/EPT mutant with T. denticola TDE0021 DNA. Aim 2: To characterize synthesis and expression of PtdEtn in T. denticola. We will (A) identify and characterize the T. denticola PtdEtn synthesis pathway, and (B) characterize the mechanism(s) responsible for increased levels of PtdEtn in a defined PtdCho-deficient T. denticola mutant. Upon completion of the two Aims of this project, we will have made significant progress toward understanding the genetic components and mechanisms of the unique phospholipid synthesis pathway in the genus Treponema, which includes both mucosal and venereal pathogens. The knowledge gained will significantly enhance understanding of spirochete membrane biology, will provide a basis for continued studies of the role of the phospholipid environment on microbe-host interactions, and may provide the basis for development of novel therapeutic agents. PUBLIC HEALTH RELEVANCE: This project will characterize genetic components and mechanisms comprising the unique phospholipid synthesis pathways in the genus Treponema, which includes both mucosal and venereal pathogens. This will contribute to understanding of the role of the membrane phospholipid environment on microbe-host interactions, and may provide a basis for development of novel therapeutic agents.