Glycosidases Interact Selectively With Mannose-6-Phosphate Receptors of Bull Spermatozoa

BOSCHIN V,; SOSA MA; AGUILERA AC,; CAVICCHIA JC,; CARVELLI L,

JOURNAL OF CELLULAR BIOCHEMISTRY

WILEY-LISS, DIV JOHN WILEY & SONS INC

Lugar: New York; Año: 2016

0730-2312

Glycosidases may play a role in sperm maturation during epididymal transit. In this work we describe the interaction of these enzymes with bull spermatozoa. We found that beta-galactosidase associated to spermatozoa can be released under low ionic strength conditions, whereas the interaction of N-acetyl-beta-D-glucosaminidase and beta-glucuronidase with spermatozoa appeared to be stronger. On the other hand, alpha-mannosidase and alpha-fucosidase cannot be removed from the gametes. In addition, part of N-acetyl-beta-D-glucosaminidase, beta-galactosidase and beta-glucuronidase can also be released by mannose-6-phosphate. Taking into account these data, we explored the presence of cation-independent- and cation-dependent-mannose-6-phosphate receptors in the spermatozoa and found that cation-independent mannose-6-phosphate receptor is highly expressed in bull spermatozoa and cation-dependent- mannose-6-phosphate receptor is expressed at a lesser extent. In addition, by immunofluorescence, we observed that cation-independent- mannose-6-phosphate receptor is mostly located at the acrosomal zone, whereas cation-dependent-mannose-6-phosphate receptor presents a different distribution pattern on spermatozoa during the epididymal transit. N-acetyl-beta-D-glucosaminidase and beta-glucuronidase isolated from epididymal fluid interacted mostly with cation-independent- mannose-6-phosphate receptor, while beta-galactosidase was recognized by both receptors. We concluded that glycosidases might play different roles in bull spermatozoa and that mannos-6-phosphate receptors may act as recruiters of some enzymes.