title: Seminal plasma proteins regulate the association of lipids and proteins within detergent-resistant membrane domains of bovine spermatozoa.
abstract: Maturing spermatozoa acquire full fertilization competence by undergoing major changes in membrane fluidity and protein composition and localization. In epididymal spermatozoa, several proteins are associated with cholesterol- and sphingolipid-enriched detergent-resistant membrane (DRM) domains. These proteins dissociate from DRM in capacitated sperm cells, suggesting that DRM may play a role in the redistribution of integral and peripheral proteins in response to cholesterol removal. Since seminal plasma regulates sperm cell membrane fluidity, we hypothesized that seminal plasma factors could be involved in DRM disruption and redistribution of DRM-associated proteins. Our results indicate that: 1) the sperm-associated proteins, P25b and adenylate kinase 1, are linked to DRM of epididymal spermatozoa, but were exclusively associated with detergent-soluble material in ejaculated spermatozoa; 2) seminal plasma treatment of cauda epididymal spermatozoa significantly lowered the content of cholesterol and the ganglioside, GM1, in DRM; and 3), seminal plasma dissociates P25b from DRM in epididymal spermatozoa. We found that the seminal plasma protein, Niemann-Pick C2 protein, is involved in cholesterol and GM1 depletion within DRM, then leading to membrane redistribution of P25b that occurs in a very rapid and capacitation-independent manner. Together, these data suggest that DRM of ejaculated spermatozoa are reorganized by specific seminal plasma proteins, which induce lipid efflux as well as dissociation of DRM-anchored proteins. This process could be physiologically relevant in vivo to allow sperm survival and attachment within the female reproductive tract and to potentiate recognition, binding, and penetration of the oocyte.
authors.affiliation: Centre de Recherche en Biologie de la Reproduction and Département d'Obstétrique-Gynécologie, Faculté de Médecine, Université Laval, Quebec City, Quebec, Canada G1V 4G2.
authors.forename: Julie
authors.initials: J
authors.lastname: Girouard
authors.forename: Gilles
authors.initials: G
authors.lastname: Frenette
authors.forename: Robert
authors.initials: R
authors.lastname: Sullivan
mesh_terms: D000263:Adenylate Kinase / Q000378:metabolism; D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism*; D002784:Cholesterol / Q000378:metabolism; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D005677:G(M1) Ganglioside / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism; D050356:Lipid Metabolism / Q000502:physiology*; D008297:Male; D008560:Membrane Fluidity / Q000502:physiology; D008565:Membrane Proteins / Q000378:metabolism*; D029589:Seminal Plasma Proteins / Q000378:metabolism*; D029607:Seminal Vesicle Secretory Proteins / Q000378:metabolism; D013075:Sperm Capacitation / Q000502:physiology; D013079:Sperm Maturation / Q000502:physiology; D013094:Spermatozoa / Q000166:cytology / Q000378:metabolism*; D033921:Vesicular Transport Proteins / Q000378:metabolism
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D007527:Isoenzymes; D008565:Membrane Proteins; D029589:Seminal Plasma Proteins; D029607:Seminal Vesicle Secretory Proteins; D033921:Vesicular Transport Proteins; C424303:seminal vesicle secretory protein 109, Bos taurus; D000090266:Chromobox Protein Homolog 5; D005677:G(M1) Ganglioside; D002784:Cholesterol; D000263:Adenylate Kinase; C110939:adenylate kinase 1