Premium
GABA, progesterone and zona pellucida activation of PLA 2 and regulation by MEK‐ERK1/2 during acrosomal exocytosis in guinea pig spermatozoa
Author(s) -
Chen Wen-Ying,
Ni Ya,
Pan Yong-Miao,
Shi Qi-Xian,
Yuan Yu-Ying,
Chen Ai-Jun,
Mao Li-Zhen,
Yu Shu-Qing,
Roldan Eduardo R.S.
Publication year - 2005
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2005.06.090
Subject(s) - exocytosis , arachidonic acid , protein kinase c , zona pellucida , microbiology and biotechnology , staurosporine , chemistry , phospholipase a2 , biology , biochemistry , kinase , enzyme , secretion , oocyte , embryo
We investigated whether GABA activates phospholipase A 2 (PLA 2 ) during acrosomal exocytosis, and if the MEK‐ERK1/2 pathway modulates PLA 2 activation initiated by GABA, progesterone or zona pellucida (ZP). In guinea pig spermatozoa prelabelled with [ 14 C]arachidonic acid or [ 14 C]choline chloride, GABA stimulated a decrease in phosphatidylcholine (PC), and release of arachidonic acid and lysoPC, during exocytosis. These lipid changes are indicative of PLA 2 activation and appear essential for exocytosis since inclusion of aristolochic acid (a PLA 2 inhibitor) abrogated them, along with exocytosis. GABA activation of PLA 2 seems to be mediated, at least in part, by diacylglycerol (DAG) and protein kinase C since inclusion of the DAG kinase inhibitor R59022 enhanced PLA 2 activity and exocytosis stimulated by GABA, whereas exposure to staurosporine decreased both. GABA‐, progesterone‐ and ZP‐induced release of arachidonic acid and exocytosis were prevented by U0126 and PD98059 (MEK inhibitors). Taken together, our results suggest that PLA 2 plays a fundamental role in agonist‐stimulated exocytosis and that MEK‐ERK1/2 are involved in PLA 2 regulation during this process.