Glycodelin-A interacts with fucosyltransferase on human sperm plasma membrane to inhibit spermatozoa-zona pellucida binding

J Cell Sci. 2007 Jan 1;120(Pt 1):33-44. doi: 10.1242/jcs.03258. Epub 2006 Dec 5.

Abstract

Fertilization depends on successful binding of the spermatozoa to the zona pellucida of the oocyte. Glycodelin-A inhibits spermatozoa-zona pellucida binding. Previous data showed that glycodelin-A receptor(s) and zona pellucida protein receptor(s) on human spermatozoa are closely related. Using a chemical cross-linking approach, the glycodelin-A-sperm receptor complex was isolated. The receptor was identified to be fucosyltransferase-5 (FUT5) by mass spectrometry and confirmed with the use of anti-FUT5 antibodies. Sperm FUT5 was an externally oriented integral membrane protein in the acrosomal region of human spermatozoa. Biologically active FUT5 was purified from spermatozoa. Co-immunoprecipitation confirmed the interaction between glycodelin-A and sperm FUT5. Solubilized zona pellucida reduced the binding of glycodelin-A to sperm FUT5. An anti-FUT5 antibody and FUT5 acceptor blocked the binding of glycodelin-A to spermatozoa and the zona binding inhibitory activity of glycodelin-A. Sperm FUT5 bound strongly to intact and solubilized human zona pellucida. The equilibrium dissociation constant of sperm FUT5 binding to solubilized zona pellucida was 42.82 pmol/ml. These observations suggest that human sperm FUT5 is a receptor of glycodelin-A and zona pellucida proteins, and that glycodelin-A inhibits spermatozoa-zona binding by blocking the binding of sperm FUT5 to the zona pellucida.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies / pharmacology
  • Cell Membrane / enzymology
  • Female
  • Fucosyltransferases / immunology
  • Fucosyltransferases / isolation & purification
  • Fucosyltransferases / metabolism*
  • Glycodelin
  • Glycoproteins / isolation & purification
  • Glycoproteins / metabolism*
  • Humans
  • Immunoprecipitation
  • Male
  • Pregnancy Proteins / isolation & purification
  • Pregnancy Proteins / metabolism*
  • Protein Binding / physiology
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Sperm-Ovum Interactions / physiology*
  • Spermatozoa / enzymology*
  • Zona Pellucida / physiology*

Substances

  • Antibodies
  • Glycodelin
  • Glycoproteins
  • PAEP protein, human
  • Pregnancy Proteins
  • Fucosyltransferases
  • fucosyltransferase V