鲫鱼尿激酶型纤溶酶原激活物受体(CaCD87)基因克隆及功能分析

Cloning and Functional Analysis of Urokinase-Type Plasminogen Activator Receptor (CaCD87) Gene in Crucian Carp

摘要: 基于转录组测序数据筛选获得鲫尿激酶型纤溶酶原激活物受体(CaCD87)，并对其蛋白结构预测与功能分析。通过基因克隆获得CaCD87编码序列，并对其序列特征、蛋白结构域、系统进化、蛋白互作网络、组织表达谱、GO功能注释及KEGG信号通路进行系统分析。结果显示，CaCD87基因cDNA全长812 bp，编码199个氨基酸，三级结构呈三叶草折叠，含两个串联LU结构域(第20~108和110~184位)。系统进化树显示，CaCD87与鲤、草鱼等鲤科鱼类亲缘最近，与银鲫同源性达91.46%。蛋白互作网络预测揭示其与PLAU、SERPINE1、PLG、ITGB2、ITGAM、EGFR等蛋白存在互作关系。组织表达谱分析表明CaCD87在脾脏中丰度最高，其次在肝脏、肾脏中表达。GO功能注释表明CaCD87参与纤溶调节、凝血调节、细胞黏附等生物学过程，定位于细胞表面、脂筏等细胞组分，具有信号受体结合功能。KEGG通路富集显示其参与补体与凝血级联、黏着斑、PI3K-Akt等通路，主要参与调控纤溶酶原激活及免疫细胞迁移功能。为鱼类CD87蛋白功能研究提供了基础数据。

Abstract: Based on transcriptome sequencing data, the crucian carp (Carassius auratus) urokinase-type plasminogen activator receptor (CaCD87) was identified, and its protein structure prediction and functional analysis were performed. The coding sequence of CaCD87 was obtained by gene cloning, and its sequence characteristics, protein domains, phylogeny, protein-protein interaction network, tissue expression profile, GO functional annotation, and KEGG pathway were systematically analyzed. The results showed that the full-length cDNA of the CaCD87 gene is 812 bp, encoding 199 amino acids. Its tertiary structure exhibits a three-leaf clover fold, containing two tandem LU domains (positions 20~108 and 110~184). Phylogenetic analysis revealed that CaCD87 is most closely related to cyprinid fishes such as common carp and grass carp, with a homology of 91.46% to silver crucian carp. Protein interaction network prediction indicated its interactions with PLAU, SERPINE1, PLG, ITGB2, ITGAM, EGFR, and other proteins. Tissue expression profiling showed that CaCD87 is most abundant in the spleen, followed by the liver and kidney. GO functional annotation demonstrated that CaCD87 participates in biological processes including fibrinolysis regulation, coagulation regulation, and cell adhesion; is localized in cellular components such as cell surface and lipid rafts; and possesses signal receptor binding function. KEGG pathway enrichment revealed its involvement in complement and coagulation cascades, focal adhesion, and the PI3K-Akt pathway, primarily in regulating plasminogen activation and immune cell migration. This study provides fundamental data for the functional research of CD87 protein.