title: Protein composition of human epididymosomes collected during surgical vasectomy reversal: a proteomic and genomic approach.
abstract: BACKGROUND
  The epididymal epithelium secretes membranous vesicles, called epididymosomes, with which a complex mixture of proteins is associated. These vesicles transfer to spermatozoa selected proteins involved in sperm maturation. Epididymosomes in the human excurrent duct have been described, but their protein composition and possible functions are unknown.
  
  
  RESULTS
  Epididymosomes were collected during vasovasostomy procedures, purified and submitted to liquid chromatography with hybrid quadrupole time-of-flight mass spectrometry. From all the mass spectra generated, 1022 peptides allowed the identification of 146 different proteins. Identification of some of these proteins was confirmed by western blots. Furthermore, western blot showed that the protein composition of epididymosomes differed from that characterizing prostasomes; membranous vesicles secreted by the prostate. Organization of the epididymosomes proteome according to common functional features suggests that epididymosomes have multiple functions. In order to understand the origin of epididymosomes collected distally, microarray databases of caput, corpus and cauda epididymidis were analysed to determine where along the excurrent duct the encoded proteins associated to epididymosomes are synthesised. Results suggest that some proteins synthesized in the caput and corpus epididymidis are associated with epididymosomes collected distally.
  
  
  CONCLUSIONS
  Epididymosomes thus transit along the excurrent duct, and vesicles collected distally represent a mixed population.
authors.affiliation: Centre de Recherche en Biologie de la Reproduction and Département d'Obstétrique-Gynécologie, Université Laval, Quebec City, Quebec, Canada.
authors.forename: Véronique
authors.initials: V
authors.lastname: Thimon
authors.forename: Gilles
authors.initials: G
authors.lastname: Frenette
authors.forename: Fabrice
authors.initials: F
authors.lastname: Saez
authors.forename: Michel
authors.initials: M
authors.lastname: Thabet
authors.forename: Robert
authors.initials: R
authors.lastname: Sullivan
mesh_terms: D022162:Cytoplasmic Vesicles / Q000737:chemistry*; D004822:Epididymis / Q000737:chemistry* / Q000166:cytology; D023281:Genomics; D006801:Humans; D008297:Male; D011506:Proteins / Q000032:analysis*; D040901:Proteomics; D014669:Vasovasostomy
chemical_list: D011506:Proteins