EncystR: A novel entry point for uncovering the regulation of encystation in Giardia

EncystR：揭示贾第鞭毛虫包囊调控的新切入点

• 批准号: 10190722
• 负责人: Alexander Richard Paredez
• 金额: $ 23.33万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-02-01 至 2023-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10190722
• 关键词: Amino Acid Transporter; Amino Acids; Biological Assay; Biology; Biotin; Cell Surface Receptors; Cell membrane; Cells; Client; Complement; Cyst; Data; Development; Diarrhea; Disease; Eukaryota; Event; Future; G-Protein-Coupled Receptors; Gel; Giardia; Giardiasis; Golgi Apparatus; Infection; Integral Membrane Protein; Intestines; Label; Ligand Binding; Lysosomes; Malabsorption Syndromes; Membrane; Metabolism; Microscopy; Molecular Conformation; Morphology; Multivesicular Body; Organelles; Outcome Study; Parasites; Pathway interactions; Phylogenetic Analysis; Physiologic pulse; Process; Proteins; Proton-Translocating ATPases; Publishing; Regulation; Role; Signal Transduction; Stimulus; Structure; Testing; Therapeutic; Time; Transmission Electron Microscopy; Vesicle; attenuation; base; detection of nutrient; experimental study; gastrointestinal; knock-down; metabolomics; novel; programs; protein transport; public health relevance; receptor; recruit; sensor; small molecule; solute; spatial relationship; theories; therapeutic target; trafficking; transcriptome sequencing

Project Summary Cyst formation is ubiquitous across the diversity of protists, yet its regulation is poorly understood in most species. Major morphological changes occur as the parasite Giardia transitions from proliferative trophozoites to infectious cysts. Importantly, these changes cause the parasites to release from the host intestine, thus this process could be targeted to clear infections. Despite its importance, very little is understood about the signaling events that trigger and sustain Giardia encystation. In an exciting breakthrough, we identified EncystR, a negative regulator of encystation, which represents a novel control point in this developmental program. EncystR is potentially the first encystation receptor identified for any parasite; how it connects with downstream regulation of encystation is unresolved. It has been shown that related proteins can function as sensors, protein trafficking receptors and solute transporters. EncystR localizes to the plasma membrane in vegetative trophozoites, and, upon encystation stimuli, EncystR is internalized. By following EncystR trafficking we identified a novel acidic compartment. This stage induced compartment is marked by ESCRT components typically involved in multivesicular body (MVB) formation. Giardia is thought to lack MVBs and conventional lysosomes, so this discovery was a surprise and represents another exciting therapeutic opportunity. EncystR is the furthest upstream regulator of encystation identified to date; therefore, uncovering its biology will lead to a deeper understanding of the regulation of encystation. Whether EncystR is a GPCR-like receptor that changes conformation upon ligand binding to recruit effector proteins, has a role in solute transport, a role in trafficking proteins to the novel compartment, or some combination remains unknown. Here, we focus on uncovering the mechanistic basis of EncystR’s role in regulating differentiation as well as the purpose of its trafficking to the novel acidic compartment. As the most upstream regulator of encystation identified to date, EncystR is a new entry point for probing this critical, disease-relevant process. The proposed studies will: (1) reveal the EncystR interactome; (2) determine whether or not EncystR transports small molecule metabolites; (3) define the spatial relationship between EncystR and the novel acidic compartment; and (4) uncover the fate of EncystR after reaching the acidic compartment. The outcomes of this study will facilitate the targeting of future mechanistic studies of EncystR and the delineation of the full regulatory cascade needed for encystation.

项目摘要 孢囊的形成在原生生物的多样性中是普遍存在的，但在大多数原生生物中对其调控知之甚少。 物种主要的形态学变化发生在贾第虫从增殖滋养体转变 传染性囊肿重要的是，这些变化导致寄生虫从宿主肠道释放，因此， 这一过程可以针对清除感染。尽管它的重要性，很少有人了解 引发和维持贾第虫包囊的信号事件。在一个令人兴奋的突破中，我们发现 EncystR是包囊形成的负调节因子，它代表了这种发育过程中的一个新的控制点。 程序. EncystR可能是第一个被鉴定为任何寄生虫的包囊受体;它如何与 包囊形成的下游调节尚未解决。已经表明，相关蛋白质可以作为 传感器、蛋白质运输受体和溶质转运蛋白。Encyst R定位于细胞质膜， 营养滋养体，并且，在包囊化刺激下，EncystR被内化。通过跟踪EncystR贩运 我们发现了一个新的酸性区室该阶段诱导的隔室由ESCRT组分标记 通常参与多泡体（MVB）的形成。贾第虫被认为缺乏MVB和常规 因此，这一发现是一个惊喜，代表了另一个令人兴奋的治疗机会。EncystR 是迄今为止发现的最远的包囊上游调节因子;因此，揭示其生物学将导致 对包囊形成的调控有了更深的理解。EncystR是否是GPCR样受体， 在配体结合后改变构象以募集效应蛋白，在溶质转运中起作用， 运输蛋白质到新的区室，或一些组合仍然未知。在这里，我们专注于 揭示了EncystR在调节分化中的作用的机制基础以及其目的， 运输到新的酸性区室。作为迄今为止发现的包囊形成的最上游调节因子， EncystR是探索这一关键的疾病相关过程的新切入点。拟议的研究将：（1） 揭示EncystR相互作用组;（2）确定EncystR是否转运小分子代谢物; (3)定义Encyst R和新的酸性区室之间的空间关系;以及（4）揭示Encyst R和新的酸性区室之间的命运。 在到达酸性隔室后的Encyst R。这项研究的结果将有助于确定目标， EncystR的未来机制研究和所需的完整调控级联的描绘 包囊形成。