Protein phosphorylation networks in Baylisascaris procyonis revealed by phosphoproteomic analysis

Background: Baylisascaris procyonis is an intestinal ascarid worm that parasitizes in raccoons and causes fatal neural, visceral, and ocular larva migrans in humans. Phosphorylated proteins and protein kinases have been studied as vaccine and drug target candidates against parasitic infections. However, no data are available on protein phosphorylation in the raccoon roundworm. Methods: In this study, the entire proteome of adult B. procyonis was enzymatically digested. Then, phosphopeptides were enriched using immobilized metal affinity chromatography (IMAC) and analyzed by liquid chromatography-mass spectrometry (LC-MS/MS). Results: Our phosphoproteome analysis displayed 854 unique phosphorylation sites mapped to 450 proteins in B. procyonis (3,308 phosphopeptides total). The annotated phosphoproteins were associated with various biological processes, including cytoskeletal remodeling, supramolecular complex assembly, and developmental regulation. The phosphopeptide functional enrichment revealed that B. procyonis phosphoproteins were mostly involved in the cytoskeleton cellular compartment, protein binding molecular function, and multiple biological processes, including regulating supramolecular fiber and cytoskeleton organization, and assembling cellular protein-containing complexes and organelles. The significantly enriched pathways of phosphoproteins included the insulin signaling pathway, tight junction, endocytosis, longevity-regulating, glycolysis/gluconeogenesis, and apelin signaling pathways. Domain analysis revealed that the Src homology 3 domain was significantly enriched. Conclusions: This study presents the first phosphoproteomic landscape of B. procyonis, elucidating phosphorylation-mediated regulation of cytoskeletal dynamics, host interaction pathways, and metabolic adaptations. The identified 450 phosphoproteins and enriched functional domains establish a foundation for targeting conserved mechanisms critical to B. procyonis survival.

背景：浣熊贝蛔虫（Baylisascaris procyonis）是一种寄生于浣熊体内的肠道蛔虫类寄生虫，可在人体内引发致命的神经、内脏及眼部幼虫移行症。磷酸化蛋白与蛋白激酶曾被作为抗寄生虫感染的疫苗与药物候选靶点展开研究，但目前尚无关于浣熊贝蛔虫蛋白质磷酸化的相关研究数据。
方法：本研究首先对成年浣熊贝蛔虫的全蛋白质组进行酶解，随后采用固定化金属亲和色谱（immobilized metal affinity chromatography, IMAC）富集磷酸肽，并通过液相色谱-串联质谱（liquid chromatography-mass spectrometry, LC-MS/MS）进行分析。
结果：本研究的磷酸化蛋白质组分析共鉴定到浣熊贝蛔虫中450个蛋白上的854个独特磷酸化位点，总计3308条磷酸肽。注释后的磷酸化蛋白参与多种生物学过程，包括细胞骨架重塑、超分子复合物组装及发育调控。磷酸肽功能富集分析显示，浣熊贝蛔虫的磷酸化蛋白主要定位于细胞骨架细胞组分，具备蛋白质结合的分子功能，并参与多种生物学过程，包括调控超分子纤维与细胞骨架组织、组装含细胞蛋白的复合物及细胞器。磷酸化蛋白显著富集的通路包括胰岛素信号通路、紧密连接、胞吞作用、寿命调控通路、糖酵解/糖异生通路以及阿普林（apelin）信号通路。结构域分析显示，Src同源3结构域（Src homology 3 domain, SH3）显著富集。
结论：本研究首次绘制了浣熊贝蛔虫的磷酸化蛋白质组图谱，阐明了磷酸化介导的细胞骨架动态调控、宿主互作通路及代谢适应机制。本研究鉴定得到的450个磷酸化蛋白及富集的功能结构域，为靶向浣熊贝蛔虫生存所必需的保守机制提供了研究基础。