CHLAMYDIAL INVASION OF NON-PHAGOCYTIC CELLS

衣原体侵入非吞噬细胞

• 批准号: 6952914
• 负责人: REY A CARABEO
• 金额: $ 32.16万
• 依托单位: UNIVERSITY OF LOUISVILLE
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6952914
• 关键词: Chlamydia trachomatis; HeLa cells; actin binding protein; actins; bacteria infection mechanism; bacterial proteins; chlamydial disease; gene deletion mutation; guanine nucleotide binding protein; host organism interaction; immunoprecipitation; phagocytosis; phosphorylation; protein binding; protein protein interaction; protein structure function; proteomics

DESCRIPTION (provided by applicant): Chlamydia trachomatis is a Gram-negative obligate intracellular pathogen that is the causative agent of a wide spectrum of human diseases including trachoma and the sexually transmitted disease chlamydia. Successful infection of cells by chlamydia involves attachment, invasion, establishment of a protective vacuole called an inclusion, and inhibition of lysosomal fusion. With the advent of the C. trachomatis genome sequence and new cell biological and proteomic tools, the mechanisms involved in these processes are just beginning to be revealed, advancing our knowledge of chlamydia-host cell interactions. The long term goal is to define the molecular and biochemical mechanisms important for the successful establishment of infection by chlamydia. This proposal will specifically address the process of invasion. It is hypothesized that chlamydia uses multiple pathways of invading non-phagocytic cells. A recently identified molecule termed Tarp has been demonstrated to be translocated from the infecting elementary body across the host plasma membrane and into the cytosol where it is tyrosine phosphorylated by unknown host kinases, and recruit actin. As a phosphoprotein, Tarp may act as a signaling platform to recruit a number of adapter and effector molecules that mediate actin cytoskeletal remodeling. Specific Aim 1 will address the Rac GTPase dependent pathway and focus on the potential downstream mediators of actin recruitment. Specific Aim 2 will focus on the Tarp protein, the tyrosine kinase(s) responsible for its phosphorylation, the binding partners, their roles in chlamydial invasion, and the potential relationship of Tarp with the Rac GTPase. Specific Aim 3 will address the potential mechanism of actin recruitment by the Chlamydophila caviae Tarp homolog, which does not contain the multiple repeat sequences present in C. trachomatis serovars L2 and D. These studies would not only reveal important insights into the biology of chlamydia, but also the cellular process of signaling to the actin cytoskeleton that chlamydia subverts to facilitate its infection.

描述（由申请人提供）：沙眼衣原体是一种革兰氏阴性专性细胞内病原体，是包括沙眼和性传播疾病衣原体在内的多种人类疾病的病原体。衣原体成功感染细胞涉及附着、侵入、称为包涵体的保护性液泡的建立以及溶酶体融合的抑制。随着沙眼衣原体基因组序列和新的细胞生物学和蛋白质组学工具的出现，这些过程中涉及的机制才刚刚开始被揭示，从而推进了我们对衣原体-宿主细胞相互作用的了解。长期目标是确定对于衣原体成功感染重要的分子和生化机制。该提案将专门解决入侵过程。据推测，衣原体利用多种途径入侵非吞噬细胞。最近发现的一种称为 Tarp 的分子已被证明可以从感染基体穿过宿主质膜转移到细胞质中，在细胞质中它被未知的宿主激酶酪氨酸磷酸化，并招募肌动蛋白。作为一种磷蛋白，Tarp 可以充当信号平台来招募许多介导肌动蛋白细胞骨架重塑的接头分子和效应分子。具体目标 1 将解决 Rac GTPase 依赖性途径，并重点关注肌动蛋白募集的潜在下游介质。具体目标 2 将重点关注 Tarp 蛋白、负责其磷酸化的酪氨酸激酶、结合伴侣、它们在衣原体入侵中的作用以及 Tarp 与 Rac GTPase 的潜在关系。具体目标 3 将解决豚鼠衣原体 Tarp 同源物招募肌动蛋白的潜在机制，该同源物不包含沙眼衣原体血清型 L2 和 D 中存在的多个重复序列。这些研究不仅揭示了对衣原体生物学的重要见解，还包括向肌动蛋白细胞骨架发出信号的细胞过程，衣原体破坏该过程以促进其感染。