Is vitronectin the velcro that binds the gametes together?

Evidence has been presented that the adhesion of human spermatozoa to the oolemma is mediated by integrins recognizing the Arg-Gly-Asp sequence (RGD). Fibronectin and vitronectin, glycoproteins that contain functional RGD sequences, are both present on human spermatozoa, and integrins that recognize...

Full description

Saved in:
Bibliographic Details
Published in:Molecular human reproduction 1996-11, Vol.2 (11), p.859-866
Main Authors: Fusi, F M, Bernocchi, N, Ferrari, A, Bronson, R A
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Animals
Calcium - pharmacology
Cell Adhesion - drug effects
Cell Adhesion - physiology
Cricetinae
Female
Humans
In Vitro Techniques
Integrins - physiology
Male
Oligopeptides - pharmacology
Oligopeptides - physiology
Receptors, Fibronectin - antagonists & inhibitors
Receptors, Fibronectin - physiology
Receptors, Vitronectin - antagonists & inhibitors
Receptors, Vitronectin - physiology
Sperm Agglutination - drug effects
Sperm-Ovum Interactions - drug effects
Sperm-Ovum Interactions - physiology
Vitronectin - pharmacology
Vitronectin - physiology
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Evidence has been presented that the adhesion of human spermatozoa to the oolemma is mediated by integrins recognizing the Arg-Gly-Asp sequence (RGD). Fibronectin and vitronectin, glycoproteins that contain functional RGD sequences, are both present on human spermatozoa, and integrins that recognize these ligands have been detected on spermatozoa and eggs. In this work, we studied the effects of oligopeptides specifically designed to block fibronectin or vitronectin receptors on the interaction of human spermatozoa with zona-free hamster oocytes. GRGDdSP, a peptide blocking cell attachment to fibronectin, was without effect, while GdRGDSP, which blocks both fibronectin and vitronectin receptors, significantly inhibited the binding of human spermatozoa to the oolemma of zona-free hamster eggs, in a concentration-dependent manner, over a range 1-100 microM. As these experiments suggested that a vitronectin receptor plays a role in sperm-oolemmal adhesion, we performed a series of experiments studying the effects of exogenous vitronectin, when added to spermatozoa and oocytes, on gamete interactions. Sperm-oolemmal adherence, as well as sperm aggregation, was promoted by vitronectin, over range of 2.2 nM to 1 microM, but only in the presence of calcium ions. We propose that vitronectin released during the sperm acrosome reaction is recognized by both gametes and plays a role in their adhesion.
ISSN:1360-9947
DOI:10.1093/molehr/2.11.859