Galectin-3 is associated with prostasomes in human semen

Jennifer L. Jones, Sarika Saraswati, Ashley S. Block, Cheryl F. Lichti, Maha Mahadevan, Alan B. Diekman

Research output: Contribution to journalArticle

32 Scopus citations

Abstract

Galectin-3 is a β-galactoside-binding protein involved in immunomodulation, cell interactions, cancer progression, and pathogenesis of infectious organisms. We report the identification and characterization of galectin-3 in human semen. In the male reproductive tract, the ~30 kDa galectin-3 protein was identified in testis, epididymis, vas deferens, prostate, seminal vesicle, and sperm protein extracts. In seminal plasma, galectin-3 was identified in the soluble fraction and in prostasomes, cholesterol-rich, membranous vesicles that are secreted by the prostate and incorporated into seminal plasma during ejaculation. Two-dimensional immunoblot analysis of purified prostasomes identified five galectin-3 isoelectric variants with a pI range of 7.0 to 9.2. Affinity purification and tandem mass spectrometry of β-galactoside-binding proteins from prostasomes confirmed the presence of galectin-3 in prostasomes and identified a truncated galectin-3 variant. The intact galectin-3 molecule contains a carbohydrate recognition domain and a non-lectin domain that interacts with protein and lipid moieties. The identification of a monovalent galectin-3 fragment with conserved carbohydrate-binding activity indicates the functional relevance of this truncation and suggests a regulatory mechanism for galectin-3 in prostasomes. Surface biotinylation studies suggested that galectin-3 and the truncated galectin-3 variant are localized to the prostasome surface. Prostasomes are proposed to function in immunosuppression and regulation of sperm function in the female reproductive tract, are implicated in facilitating sexually-transmitted infections, and are indicated in prostate cancer progression. Given the overlap in functional significance, the identification of galectin-3 in prostasomes lays the groundwork for future studies of galectin-3 and prostasomes in reproduction, disease transmission, and cancer progression.

Original languageEnglish
Pages (from-to)227-236
Number of pages10
JournalGlycoconjugate Journal
Volume27
Issue number2
DOIs
StatePublished - Feb 1 2010

Keywords

  • Galectin-3
  • Lectin
  • Prostasomes
  • Prostate
  • Seminal plasma

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    Jones, J. L., Saraswati, S., Block, A. S., Lichti, C. F., Mahadevan, M., & Diekman, A. B. (2010). Galectin-3 is associated with prostasomes in human semen. Glycoconjugate Journal, 27(2), 227-236. https://doi.org/10.1007/s10719-009-9262-9