Investigation of Galectin-3 Function in the Reproductive Tract by Identification of Binding Ligands in Human Seminal Plasma

Authors

  • Matthew R. Kovak,

    1. Department of Biochemistry and Molecular Biology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA
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  • Sarika Saraswati,

    1. Department of Biochemistry and Molecular Biology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA
    Current affiliation:
    1. Department of Pathology, School of Medicine, Vanderbilt University, Nashville, TN, USA
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  • David J. Schoen,

    1. Department of Biochemistry and Molecular Biology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA
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  • Alan B. Diekman

    Corresponding author
    1. Department of Biochemistry and Molecular Biology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA
    • Correspondence

      Alan B. Diekman, Department of Biochemistry and Molecular Biology, College of Medicine, University of Arkansas for Medical Sciences, 4301 W. Markham St., Slot 516, Little Rock, AR 72205, USA. E-mail: diekmanalan@uams.edu

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Abstract

Problem

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.

Method of study

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.

Conclusion

The galectin-3 binding ligands identified in this study indicate multiple roles for galectin-3 in the reproductive and immunological functions of seminal plasma.

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