How pig sperm prepares to fertilize: stable acrosome docking to the plasma membrane.
BACKGROUND
Mammalian sperms are activated in the oviduct. This process, which involves extensive sperm surface remodelling, is required for fertilization and can be mimicked under in vitro fertilization conditions (IVF).


RESULTS
Here we demonstrate that such treatments caused stable docking and priming of the acrosome membrane to the apical sperm head surface without the emergence of exocytotic membrane fusion. The interacting membranes could be isolated as bilamellar membrane structures after cell disruption. These membrane structures as well as whole capacitated sperm contained stable ternary trans-SNARE complexes that were composed of VAMP 3 and syntaxin 1B from the plasma membrane and SNAP 23 from the acrosomal membrane. This trans-SNARE complex was not observed in control sperm.


CONCLUSIONS
We propose that this capacitation driven membrane docking and stability thereof is a preparative step prior to the multipoint membrane fusions characteristic for the acrosome reaction induced by sperm-zona binding. Thus, sperm can be considered a valuable model for studying exocytosis.
Tsai
Pei-Shiue
PS
Department of Biochemistry and Cell Biology, Graduate School of Animal Health, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
Garcia-Gil
Núria
N
van Haeften
Theo
T
Gadella
Bart M
BM
D020101:Acrosome Reaction; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D005306:Fertilization; D047468:Immunoprecipitation; D008297:Male; D050600:SNARE Proteins / Q000378:metabolism; D013075:Sperm Capacitation; D013094:Spermatozoa / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D013552:Swine
D050600:SNARE Proteins