INVESTIGADORES
MAYORGA Luis Segundo
artículos
Título:
Acrosomal swelling is triggered by cAMP downstream the opening of store-operated calcium channels during acrosomal exocytosis in human sperm
Autor/es:
SOSA CM; ZANETTI, MN; POCOGNONI CA; MAYORGA, LS
Revista:
BIOLOGY OF REPRODUCTION
Editorial:
SOC STUDY REPRODUCTION
Referencias:
Lugar: Madison; Año: 2016 vol. 93
ISSN:
0006-3363
Resumen:
Acrosomal exocytosis in mammalian sperm is a regulatedsecretion with unusual characteristics. One of its most strikingfeatures is the postfusion loss of the outer acrosomal membraneand the overlying plasma membrane as hybrid vesicles. We havepreviously reported in human sperm that, by preventing therelease of calcium from the acrosome, the exocytic process canbe arrested at a stage where the acrosomes are profuselyswollen, with invaginations of the outer acrosomal membrane.In this report, we show by transmission electron microcopyswelling with similar characteristics without arresting theexocytic process. Acrosomal swelling was observed whensecretion was promoted by pharmacological and physiologicalinducers of the acrosome reaction that trigger exocytosis by?4 different mechanisms. We show that progesterone- and thapsigargin-induced swelling depended on a calcium influx from theextracellular medium through store-operated calcium channels.However, calcium was dispensable when sperm were stimulatedwith cAMP analogs. KH7, an inhibitor of the soluble adenylylcyclase, blocked progesterone-induced swelling. Our resultsindicate that swelling is a required process for acrosomalexocytosis triggered by activation of an adenylyl cyclasedownstream of the opening of store-operated calcium channels.