PROSAPOSIN IS DETECTED IN BULL SPERMATOZOA AND IT CHANGES ALONG EPIDIDYMAL TRANSIT

AGUILERA A; CARVELLI L; BOSCHÍN V; SOSA MA

Mendoza

Congreso; XLVIII Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular; 2012

Sociedad Argentina de Investigación Bioquímica y Biología Molecular

Mammalian epididymis participates in sperm maturation through its endocytic and secretory activity. Some secreted proteins are known to be targeted to sperm membrane. Prosaposin (PSAP) is a lysosomal protein, which is found in mammalian epididymal fluid and spermatozoa. Here, we intended to study the possible presence of PSAPin the plasma membrane of epidydimal spermatozoa from bull (Aberdeen Angus). The epididymides were dissected into caput, corpus and cauda and the sperm were obtained by slicing of the tissue and centrifugation. Using specific antibodies (by IFI and flow cytometry) we detected PSAP in the sperm of bulls and the signal was stronger in the gametes of the corpus. This protein was partially released by 0.3 M ClNa, indicating a noncovalent association with the gamete. All these results were confirmed by Western blot. In addition, we have observed that the protein is mainly located in the equatorial area of the head and also in the tail of the sperm. PSAP was also detected in luminal vesicles and mostly in caput and corpus, suggesting that the vesicles could be the vehicle of PSAP for acquisition by the spermatozoa. Intriguingly, most of the changes occurs in corpus, indicating that this region could be crucial for sperm maturation. These observations could provide new insights into molecular rearrangement and protein acquisition during epididymal maturation.