Comprehensive proteomic characterization and functional annotation of common carp seminal plasma

Abstract

Context: Understanding the protein composition of seminal plasma is crucial for elucidating reproductive mechanisms and improving aquaculture practices. Proteomic studies provide insights into the biological functions of seminal plasma in fish, yet comprehensive datasets for carp remain limited. Aims: This study aimed to comprehensively characterize the proteome of carp seminal plasma, classify identified proteins on the basis of their cellular localization, and explore their functional roles in reproductive and physiological processes. Methods: Using high-throughput liquid chromatography–tandem mass spectrometry (LC–MS/MS)-based proteomic analysis and updated Cyprinus carpio genome annotation, we identified and classified proteins on the basis of homology to human genes and fish-specific annotations. Bioinformatic tools were employed to analyze their functions and involvement in key biological pathways. Key results: In total, 1402 proteins were identified, the highest number being reported for this species. Of the 1354 proteins homologous to human genes, 141 were secretory, 92 were both secretory and intracellular, and 1121 were intracellular. Additionally, 49 proteins were fish-specific, involved in immune response, detoxification, cold protection, and proteolytic defence. Bioinformatic analyses indicated roles in immune and stress responses, extracellular matrix organization, metabolism, and gene expression. The presence of extracellular vesicles was supported by the identification of 636 associated proteins. Reproductive-related proteins were linked to gamete generation, spermatogenesis, and sperm motility. Conclusions: This dataset represents the most comprehensive proteomic profile of carp seminal plasma, offering new insights into its biological functions. Implications: The findings enhance our understanding of carp reproductive biology and have potential applications in aquaculture, including sperm preservation, fertilization success, and disease resistance.