Somashekar L, et al. – Objective of this research was to distinguish sperm proteomic signatures regulating sperm functions and fertility by comparing the sperm electrophoretic protein profiles and identifying the differentially abundant proteins among breeding bulls differing in fertility status and elucidating the possible role of one of the identified novel proteins, phosphatidylethanolamine–binding protein 4 (PEBP4) on sperm function and fertility. Results of this study showed that the positive correlation of PEBP4 in regulating sperm maturation, functions, and fertility and could be a potential marker for predicting semen quality and fertility.