title: Investigation of galectin-3 function in the reproductive tract by identification of binding ligands in human seminal plasma.
abstract: OBJECTIVE
  Galectin-3 is a β-galactoside binding protein with immunomodulatory properties and exerts its extracellular functions via interactions with glycoconjugate ligands. Therefore, to elucidate the function of galectin-3, binding ligands in human seminal plasma were investigated.
  
  
  METHODS
  Galectin-3 binding proteins were isolated from seminal plasma by affinity chromatography, and candidate ligands were identified by MS/MS. Biochemical methods were used to characterize the ability of galectin-3 to bind its ligands.
  
  
  RESULTS
  Identified galectin-3 ligands included CD13, MUC6, PAP, PSA, and ZAG. 1D and 2D electrophoretic analysis of seminal plasma demonstrated that CD13, PAP, PSA, and ZAG immunoreactivity co-migrated with galectin-3-reactive protein bands and spots at expected molecular weights and pIs. Inhibition assays indicated that CD13, PSA, PAP, and ZAG interact with galectin-3 in a protein-carbohydrate manner.
  
  
  CONCLUSIONS
  The galectin-3 binding ligands identified in this study indicate multiple roles for galectin-3 in the reproductive and immunological functions of seminal plasma.
authors.affiliation: Department of Biochemistry and Molecular Biology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Kovak
authors.forename: Sarika
authors.initials: S
authors.lastname: Saraswati
authors.forename: David J
authors.initials: DJ
authors.lastname: Schoen
authors.forename: Alan B
authors.initials: AB
authors.lastname: Diekman
mesh_terms: D054392:Adipokines; D000951:Antigens, Neoplasm / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000378:metabolism; D001798:Blood Proteins; D018826:CD13 Antigens / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D037502:Galectin 3 / Q000378:metabolism*; D037161:Galectins; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D037181:Lectins, C-Type / Q000378:metabolism; D008024:Ligands; D008297:Male; D055272:Mucin-6 / Q000378:metabolism; D000073718:Pancreatitis-Associated Proteins; D017430:Prostate-Specific Antigen / Q000378:metabolism; D011485:Protein Binding; D012661:Semen / Q000166:cytology*; D000090203:Zn-Alpha-2-Glycoprotein
chemical_list: D054392:Adipokines; D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D001798:Blood Proteins; D018826:CD13 Antigens; D002352:Carrier Proteins; D037502:Galectin 3; D037161:Galectins; D006023:Glycoproteins; D037181:Lectins, C-Type; D008024:Ligands; D055272:Mucin-6; D000073718:Pancreatitis-Associated Proteins; D017430:Prostate-Specific Antigen; C488891:AZGP1 protein, human; D000090203:Zn-Alpha-2-Glycoprotein; C428445:LGALS3 protein, human; C524734:MUC6 protein, human; C000612141:REG3A protein, human
keywords: Immunomodulation; inflammation; lectin; proteomics; semen