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

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

JOURNAL OF CELLULAR BIOCHEMISTRY

WILEY-LISS, DIV JOHN WILEY & SONS INC

Lugar: New York; Año: 2016 vol. 117 p. 2464 - 2472

0730-2312

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