Global profiling of the proteomic changes associated with the post-testicular maturation of mouse spermatozoa

Spermatozoa acquire fertilization potential during passage through a highly specialized region of the extratesticular ductal system known as the epididymis. In the absence of de novo gene transcription or protein translation, this functional transformation is extrinsically driven via the exchange of varied macromolecular cargo between spermatozoa and the surrounding luminal plasma. Key among these changes is a substantive remodeling of the sperm proteomic architecture, the scale of which has yet to be fully resolved. Here, we have exploited quantitative mass spectrometry-based proteomics to define the extent of changes associated with the maturation of mouse spermatozoa; reporting the identity of >6,000 proteins, encompassing the selective loss and gain of several hundred proteins. Further, we demonstrate epididymal-driven activation of RHOA-mediated signaling pathways is an important component of sperm maturation. These data contribute molecular insights into the complexity of proteomic changes associated with epididymal sperm maturation. [Display omitted] •Identification of >6,000 proteins provides insight into sperm cell proteome•Sperm cell proteome is dramatically remodeled during post-testicular maturation•Major changes are associated with the loss, as opposed to gain, of sperm proteins•Activated RHOA-mediated signaling pathways contribute to functional maturity of sperm Skerrett-Byrne et al. have characterized the epididymal sperm proteome undergoing functional maturation. Contrary to the long-held belief that epididymal maturation is primarily driven by the uptake/modification of additional proteins, this work demonstrates that spermatozoa shed over half their protein composition during this process.