Reagents that activate GTP-binding proteins trigger the acrosome reaction in human spermatozoa.
The acrosome reaction is a specialized exocytotic process. In the mouse there is compelling evidence that receptor-mediated activation of GTP-binding proteins by factors in the zona pellucida of oocytes is a central event in the acrosome reaction. Several reagents are able to affect GTP-binding proteins directly, bypassing the receptor-ligand step for activation. We have assessed the effect of several of these compounds on human spermatozoa, monitoring cell vitality and the acrosome reaction simultaneously using the triple-stain technique. GTP gamma S and aluminium fluoride complexes promote sperm activation very efficiently; amphiphilic peptides capable of activating G(o) and Gi, also elicit the acrosome reaction. The results indicate that activation of heterotrimeric GTP-binding proteins is sufficient to trigger acrosome exocytosis in human spermatozoa.
Domínguez
L
L
Universidad Nacional de Cuyo, CONICET, Mendoza, Argentina.
Díaz
A
A
Fornés
M W
MW
Mayorga
L S
LS
D000177:Acrosome / Q000187:drug effects* / Q000502:physiology; D017607:Aluminum Compounds / Q000494:pharmacology; D000595:Amino Acid Sequence; D000001:Calcimycin / Q000494:pharmacology; D005459:Fluorides / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000187:drug effects* / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D008969:Molecular Sequence Data; D010455:Peptides; D012016:Reference Values; D013094:Spermatozoa / Q000187:drug effects* / Q000502:physiology; D014862:Wasp Venoms / Q000494:pharmacology
D017607:Aluminum Compounds; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D014862:Wasp Venoms; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D000001:Calcimycin; C037500:mastoparan; D019204:GTP-Binding Proteins; D005459:Fluorides; C032311:aluminum fluoride