Arylsulfatase a is present on the pig sperm surface and is involved in sperm-zona pellucida binding.
We have previously described the affinity of a pig sperm surface protein, P68, to mammalian zonae pellucidae (ZP). In this report, we identified P68 as arylsulfatase A (AS-A) based on the presence of P68 tryptic peptide sequences in the pig testis AS-A cDNA sequence. Our objective was to demonstrate the presence of AS-A on the sperm surface and to elucidate its role in ZP binding. Immunogold electron microscopy revealed the presence of AS-A on the sperm surface. Furthermore, live pig sperm and the extract of peripheral sperm plasma membrane proteins exhibited AS-A's desulfation activity. Significantly, the role of pig sperm surface AS-A in ZP binding was demonstrated by dose-dependent decreases of sperm-ZP binding upon sperm pretreatment with anti-AS-A IgG/Fab, and by the binding of Alexa-430-conjugated sperm surface AS-A to homologous ZP. ZP pretreatment with anti-pig-ZP3 antibody abolished AS-A binding, suggesting that ZP3, recognized as the pig sperm receptor, was AS-A's binding ligand. This was further confirmed by the ability of exogenous ZP3 to competitively inhibit AS-A-ZP binding. Similarly, purified ZP3alpha, a major sperm receptor component of ZP3, exhibited great inhibitory effect on AS-A-ZP binding. All of these results designated a new function of AS-A in gamete interaction.
Carmona
Euridice
E
Hormones/Growth/Development Research Group, Ottawa Health Research Institute, Ontario, Canada K1Y 4E9.
Weerachatyanukul
Wattana
W
Soboloff
Tanya
T
Fluharty
Arvan L
AL
White
Dawn
D
Promdee
Limthong
L
Ekker
Marc
M
Berger
Trish
T
Buhr
Mary
M
Tanphaichitr
Nongnuj
N
D000595:Amino Acid Sequence; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002553:Cerebroside-Sulfatase / Q000378:metabolism* / Q000502:physiology; D005260:Female; D008297:Male; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D013084:Sperm-Ovum Interactions; D013094:Spermatozoa / Q000378:metabolism* / Q000502:physiology; D013552:Swine; D015044:Zona Pellucida / Q000502:physiology*
D002553:Cerebroside-Sulfatase