Mapping the Proteome Landscape of Indian Zebu (Sahiwal) Spermatozoa using High-Resolution Mass Spectrometry and In-silico Annotation

Proteome of sperm cells provides earnest information related to protein structure, function, ex-pression, interactions, and localization in biological systems. Sahiwal is an indigenous Indian cat-tle breed that is acknowledged for its disease resistance, ease of calving, and drought resilience. The lack of any detailed data pertaining to comprehensive proteome profiling of Sahiwal sperms was the major objective behind this study. We conducted the first global in-silico quantitative high-resolution mass spectrometry-based Indian Zebu sperm protein profiling and identified a to-tal of 4651 sperm proteins. Moreover, we characterized the identified proteins at the sub-organellar level for a better understanding of their functional aspect. Gene Ontology analysis of sperm proteins segregated the proteins based on function, location, and mode of action. The study revealed that even though sperm contains extremely few organelles, evolution has struc-tured essentially all-important proteins in a single cell, despite their organellar specialization. It was also seen that sperm compensates for its lack of organelles by the presence of multitasking proteins. Almost all sperm proteins play an active role in spermatogenesis, motility, acrosome re-action, capacitation, and seminal plasma binding either directly or indirectly. Our results not only report the highest number of identified bovine sperm proteins, but also potentially serve as a foundation for empirical work on sperm functions, egg-sperm interaction, sperm-sex sorting bi-omarkers, sperm quality, and bull fertility.