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rab3‐Peptide stimulates exocytosis of the ram sperm acrosome via interaction with cyclic AMP and phospholipase A 2 metabolites
Author(s) -
Garde J.,
Roldan E.R.S.
Publication year - 1996
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 - 10.1016/0014-5793(96)00749-1
Subject(s) - exocytosis , lysophosphatidylcholine , acrosome reaction , acrosome , microbiology and biotechnology , sperm , protein kinase c , phospholipase a2 , protein kinase a , chemistry , phospholipase d , mastoparan , biology , biochemistry , g protein , signal transduction , kinase , membrane , enzyme , phosphatidylcholine , phospholipid , botany
Acrosomal exocytosis triggered with A23187/Ca 2+ was enhanced by rab3AL, a synthetic peptide corresponding to the effector domain of the small GTP‐binding protein rab3. Exocytosis was further enhanced when spermatozoa were also exposed to dibutyryl‐cAMP, but was prevented when H‐89, a protein kinase A (PKA) inhibitor, was included. The action of rab3AL was not on, or upstream of, phospholipase A 2 (PLA 2 ). Inhibition of exocytosis by the PLA 2 inhibitor aristolochic acid was overcome by rab3AL when it was included together with lysophosphatidylcholine; this effect was prevented by H‐89. These results suggest a functional coupling between rab3 protein, metabolites generated by PLA 3 , and cAMP‐activated PKA, in the final steps leading to membrane fusion during acrosomal exocytosis.