Comparative proteomic identification of capacitated and non-capacitated sperm of Yanbian Yellow Cattle

To investigate the proteomic differences between the capacitated and non-capacitated sperm of the Yanbian yellow cattle, semen was collected from three Yanbian yellow cattle, aged 3-5 years, pooled, and divided into capacitated and non-capacitated groups (n = 9) to be analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and liquid chromatography-mass spectrometry. Gene ontology enrichment, Kyoto Encyclopedia of Genes and Genomes pathway enrichment, and protein-protein interactions were used for bioinformatics analysis. The results showed that 598 were described as differentially expressed proteins during sperm capacitation. In the capacitated sperm, 89 proteins were up-regulated, and 509 proteins were downregulated, compared to the non-capacitated sperm. Western blot analysis confirmed that the expression of the Heat Shock 70-kDa Protein 5 (HSPA5) proteins was down-regulated. After HSPA5 inhibition, the level of tyrosine phosphorylation decreased, and the cleaved caspase 3 increased. The results showed that HSPA5 could regulate sperm capacitation and slow down apoptosis. Thus, providing a basis for studying the changes in protein expression during sperm capacitation, which can help identify the marker proteins potentially related to sperm capacitation. Hence, this study can deepen our understanding of the molecular processes involved in the sperm capacitation in Yanbian yellow cattle and provide a framework for future research.