title: Sperm capacitation induces an increase in lipid rafts having zona pellucida binding ability and containing sulfogalactosylglycerolipid.
abstract: Sperm gain full ability to bind to the zona(e) pellucida(e) (ZP) during capacitation. Since lipid rafts are implicated in cell adhesion, we determined whether capacitated sperm lipid rafts had affinity for the ZP. We demonstrated that lipid rafts, isolated as low-density detergent resistant membranes (DRMs), from capacitated pig sperm had ability to bind to homologous ZP. This binding was dependent on pig ZPB glycoprotein, a major participant in sperm binding. Capacitated sperm DRMs were also enriched in the male germ cell specific sulfogalactosylglycerolipid (SGG), which contributed to DRMs-ZP binding. Furthermore, SGG may participate in the formation of sperm DRMs due to its interaction with cholesterol, an integral component of lipid rafts, as shown by infrared spectroscopic studies. Since sperm capacitation is associated with cholesterol efflux from the sperm membrane, we questioned whether the formation of DRMs was compromised in capacitated sperm. Our studies indeed revealed that capacitation induced increased levels of sperm DRMs, with an enhanced ZP affinity. These results corroborated the implication of lipid rafts and SGG in cell adhesion and strongly suggested that the enhanced ZP binding ability of capacitated sperm may be attributed to increased levels and a greater ZP affinity of lipid rafts in the sperm plasma membrane.
authors.affiliation: Hormones/Growth/Development Group, Ottawa Health Research Institute, Ottawa, ON, Canada K1Y 4E9.
authors.forename: Maroun
authors.initials: M
authors.lastname: Bou Khalil
authors.forename: Krittalak
authors.initials: K
authors.lastname: Chakrabandhu
authors.forename: Hongbin
authors.initials: H
authors.lastname: Xu
authors.forename: Wattana
authors.initials: W
authors.lastname: Weerachatyanukul
authors.forename: Mary
authors.initials: M
authors.lastname: Buhr
authors.forename: Trish
authors.initials: T
authors.lastname: Berger
authors.forename: Euridice
authors.initials: E
authors.lastname: Carmona
authors.forename: Ngoc
authors.initials: N
authors.lastname: Vuong
authors.forename: Premkumari
authors.initials: P
authors.lastname: Kumarathasan
authors.forename: Patrick T T
authors.initials: PT
authors.lastname: Wong
authors.forename: Danielle
authors.initials: D
authors.lastname: Carrier
authors.forename: Nongnuj
authors.initials: N
authors.lastname: Tanphaichitr
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism*; D005260:Female; D005306:Fertilization / Q000502:physiology; D038983:Galactolipids / Q000502:physiology*; D008297:Male; D008563:Membrane Lipids / Q000378:metabolism; D021962:Membrane Microdomains / Q000378:metabolism*; D010766:Phosphorylation; D013075:Sperm Capacitation / Q000502:physiology*; D013077:Sperm Head / Q000502:physiology; D013552:Swine; D015044:Zona Pellucida / Q000502:physiology*
chemical_list: D038983:Galactolipids; D008563:Membrane Lipids; C414346:sulfogalactosylglycerolipid; D002784:Cholesterol