Cumulus-associated alpha2-macroglobulin derivative retains proconceptive glycodelin-C in the human cumulus matrix

Hum Reprod. 2009 Nov;24(11):2856-67. doi: 10.1093/humrep/dep265. Epub 2009 Jul 22.


Background: Glycodelin-C is a glycodelin isoform isolated from the cumulus matrix. It stimulates spermatozoa-zona pellucida binding. Here, we report the isolation and characterization of a novel glycodelin interacting protein (GIP) from human cumulus matrix.

Methods: GIP was purified by liquid chromatograph and identified by mass spectrometry. The interaction of GIP with glycodelin, matrix molecule and spermatozoa were investigated.

Results: Mass spectrometry analysis suggested that GIP contained the N-terminal region of alpha2-macroglobulin, confirmed by western blot with anti-alpha2-macroglobulin antibody. GIP bound to native but not deglycosylated glycodelin-C in native gel electrophoresis, suggesting that the binding was glycosylation-dependent. GIP did not bind to capacitated and uncapacitated human spermatozoa. The cumulus cells could convert exogenous labeled alpha2-macroglobulin into GIP in vitro. GIP interacted with hyaluronic acid, a major component of the cumulus matrix. Glycodelin-C bound to hyaluronic acid-coated agarose beads in the presence of GIP. Human spermatozoa acquired the hyaluronic acid-GIP-bound glycodelin-C during incubation in vitro.

Conclusion: The hyaluronic acid-GIP complex formed in the cumulus matrix retains and concentrates glycodelin-C in the cumulus matrix for displacing sperm-bound glycodelin-A and -F and stimulating the zona binding activity of the spermatozoa traversing through the cumulus mass.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatography, Liquid
  • Cumulus Cells / metabolism*
  • Extracellular Matrix Proteins / metabolism
  • Female
  • Glycodelin
  • Glycoproteins / metabolism*
  • Glycosylation
  • Humans
  • Hyaluronic Acid / metabolism
  • Male
  • Mass Spectrometry
  • Pregnancy Proteins / metabolism*
  • Protein Isoforms / metabolism
  • Spermatozoa / metabolism
  • alpha-Macroglobulins / metabolism*


  • Extracellular Matrix Proteins
  • Glycodelin
  • Glycoproteins
  • PAEP protein, human
  • Pregnancy Proteins
  • Protein Isoforms
  • alpha-Macroglobulins
  • Hyaluronic Acid