Fig. 5.

Schematic of the life history of the sperm proteome. Each circle depicts a representative protein. The circle’s size indicates that protein’s abundance and its color represent protein origin. The sperm proteome transitions through the following three major stages during its posttesticular maturation: the canonical, transferred, and stored sperm proteomes. After spermatogenesis, male-derived sperm proteins and testis/RG-proteins are stored in the seminal vesicles and comprise the canonical sperm proteome. Upon mating, the canonical sperm proteome mixes with contents from the male reproductive glands, and the resulting ejaculate immediately interacts with the FRT. The transferred sperm proteome is transiently stored in the bursa and contains male-derived sperm proteins, testis/RG-proteins, and SFPs, as well as female contributions to the dual-derived sperm proteins and a small amount of uniquely female proteins. Finally, the transferred sperm proteome is transported to the female’s sperm-storage organs (seminal receptacle and spermathecae). SFPs are progressively lost and/or degraded, and female-derived proteins are progressively gained as sperm continue to interact with the FRT. The stored sperm proteome therefore contains fewer SFPs and testis/RG-proteins, greater female contributions to the dual-derived sperm proteins, and higher abundances of uniquely female proteins.