INVESTIGADORES
MAYORGA Luis Segundo
congresos y reuniones científicas
Título:
Sperm capacitation is necessary for snare assembly in neurotoxin resistant complexes.
Autor/es:
PAVAROTTI, MA; MAYORGA, LS
Lugar:
Buenos Aires
Reunión:
Congreso; SAIB 2013; 2013
Institución organizadora:
SAIB
Resumen:
Capacitation is a not well defined process required for the acrosome
reaction triggered by physiology stimuli. It can be achieved in vitro
by incubation under specific conditions. The role of capacitation
on the preparation of the membrane fusion mechanism responsible
for acrosomal exocytosis is unknown. SNAREs proteins are
fundamental proteins for membrane fusion inside cells. We have
previous shown that neurotoxin sensitive SNARE proteins are
necessary for acrosomal exocytosis. In capacitated resting sperm,
SNAREs are assembled in neurotoxin resistant cis-complexes. The
aim of this work was to study the dynamics of SNARE before and
after sperm capacitation. For this purpose, we developed a
membrane permeant neurotoxin by crosslinking a polyarginin peptide
to recombinant Tetanus toxin light chain. SNAREs were insensible
to the permeant neurotoxin in capacitated sperm. However, the
toxin efficiently inhibited exocytosis when SNAREs complexes
were disassembled upon stimulation. In contrast, SNAREs were
sensible to the neurotoxin in not capacitated sperm indicating that
SNAREs were not stabilized in cis complexes. Kinetic studies
showed that two hours incubation under capacitating conditions
were sufficient for SNAREs assembly in stable complexes. In brief,
our results indicate that capacitation is important for the maturation
of the fusion machinery responsible for acrosome reaction.