INVESTIGADORES
MAYORGA Luis Segundo
congresos y reuniones científicas
Título:
Marcks is phosphorylated during acrosomal exocytosis in living human sperm.
Autor/es:
RODRIGUEZ PEÑA, M; MAYORGA, LS; MICHAUT, M.A.
Lugar:
Mendoza
Reunión:
Congreso; 48º SAIB; 2012
Institución organizadora:
SAIB
Resumen:
To fertilize the egg, human sperm must secrete the acrosomal
content, a process known as acrosomal exocytosis (AE). Different
pathways are activated during AE and protein phosphorylation is
one of the mechanisms involved in this secretory event. It is known
that MARCKS sequesters PIP2 against membranes and when it is
phosphorylated, the protein is released to cytosol increasing the
availability of PIP2. We previously showed that MARCKS is
expressed in human sperm, it participates in AE and regulates PIP2
availability and Ca2+ mobilization during AE in human sperm. In
this study, we hypothesized that, to allow AE, MARCKS must be
phosphorylated during AE stimulated by physiological and nonphysiological stimulators. To test this we performed Western blot
analysis using a specific anti-phospho-MARCKS antibody, which
only recognizes the phosphorylated form of MARCKS. Human
sperm were incubated with 2-ABP to prevent membrane loss and
AE was stimulated by different activators in living sperm. The
results showed that the phosphorylated form of MARCKS
increased an 50%, 60% and 40% when AE was stimulated by
calcium ionophore A23187, PMA, and progesterone, respectively,
when compared to control conditions. The fact that MARCKS is
phosphorylated duringAE is compatible with the idea that in human
sperm MARCKS might be released from membranes increasing the
availability of PIP2.