Seminal vesicle proteins SVS3 and SVS4 facilitate SVS2 effect on sperm capacitation

Abstract

Mammalian spermatozoa acquire their fertilizing ability in the female reproductive tract (sperm capacitation). On the other hand, seminal vesicle secretion, which is a major component of seminal plasma, inhibits the initiation of sperm capacitation (capacitation inhibition) and reduces the fertility of the capacitated spermatozoa (decapacitation). There are seven major proteins involved in murine seminal vesicle secretion (sVs1-7), and we have previously shown that sVs2 acts as both a capacitation inhibitor and a decapacitation factor, and is indispensable for in vivo fertilization. however, the effects of sVss other than sVs2 on the sperm have not been elucidated. since mouse Svs2-Svs6 genes evolved by gene duplication belong to the same gene family, it is possible that sVss other than sVs2 also have some effects on sperm capacitation. In this study, we examined the effects of sVs3 and sVs4 on sperm capacitation. Our results showed that both sVs3 and sVs4 are able to bind to spermatozoa, but sVs3 alone showed no effects on sperm capacitation. On the other hand, sVs4 acted as a capacitation inhibitor, although it did not show decapacitation abilities. Interestingly, sVs3 showed an affinity for sVs2 and it facilitated the effects of sVs2. Interaction of sVs2 and spermatozoa is mediated by the ganglioside GM1 in the sperm membrane; however, both sVs3 and sVs4 had weaker affinities for GM1 than sVs2. Therefore, we suggest that separate processes may cause capacitation inhibition and decapacitation, and sVs3 and sVs4 act on sperm capacitation cooperatively with sVs2.Reproduction (2016) 152 313-321

Comparative proteomics reveals protective effect of resveratrol on a high-fat diet-induced damage to mice testis

“…Tssk4 knockout resulted in serious defects in spermatozoa motility, because it is required for the structural integrity of spermatozoa flagellum (Wang et al 2015c). The Svs family plays important roles in regulating spermatozoa capacitation (Araki et al 2016). Pate4, another name Svs7, is necessary for fertility mainly due to its involvement in copulatory plug formation (Noda et al 2018).…”

Social status and ejaculate composition in the house mouse

“…Subordinate males might, therefore, benefit by investing more in the production of key proteins used in forming these plugs, potentially facilitating the production of plugs that are more difficult for rival males or females to dislodge. Rodent seminal fluid proteins also have known functions in influencing sperm motility and capacitation [30][31][32][33][34], differential investment that could reduce the disadvantage experienced by subordinate males under sperm competition.…”

Seminal vesicle secretory protein 7, PATE4, is not required for sperm function but for copulatory plug formation to ensure fecundity†

“…Some SVS proteins are required for the copulatory plug formation and sperm fertilizing ability [6–14, 20, 27, 38, 43]. We examined whether the lack of multiple factors including PATE4 from the seminal vesicles led to a more severe decrease in male fecundity using males with their seminal vesicle surgically removed {SV (−)} (Supplemental Figure S1C).…”

“…However, Svs2 single knockout (−/−) males hardly make copulatory plugs, leading to male subfertility [20]. In addition, SVS4 to SVS6 are not substrates of TGM4 [9] and are expected to play distinct roles, such as in capacitation inhibition [27] and serine protease inhibition [25]. Therefore, SVS1 to SVS6 may share some roles in plug formation, but the importance of each gene remains to be determined.…”