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Probable participation of phospholipase A 2 reaction in the process of fertilization‐induced activation of sea urchin eggs
Author(s) -
Kamata Yasuyuki,
Mita Masatoshi,
Fujiwara Akiko,
Tojo Tadashi,
Takano Jiro,
Ide Akira,
Yasumasu Ikuo
Publication year - 1997
Publication title -
development, growth and differentiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 66
eISSN - 1440-169X
pISSN - 0012-1592
DOI - 10.1046/j.1440-169x.1997.t01-3-00002.x
Subject(s) - melittin , chemistry , phospholipase , sea urchin , biochemistry , activator (genetics) , phospholipase a2 , phospholipase a , respiration , phospholipase c , sperm , biophysics , biology , microbiology and biotechnology , enzyme , botany , membrane , gene
In sea urchin eggs activated by sperm, A23187 or melittin, BPB (4‐bromophenacyl bromide, a phospholipase A 2 inhibitor) blocked fertilization envelope formation and transient CN − ‐insensitive respiration in a concentration‐dependent manner. BPB had virtually no effect on the increase in [Ca 2+ ] i , (cytosolic Ca 2+ level), the activity of phosphorylase a and the rate of protein synthesis, as well as acid production and augmentation of CN − ‐sensitive respiration. BPB also inhibited fertilization envelope formation and augmentation of CN − ‐insensitive respiration induced by melittin. Melittin, known to be an activator of phospholipase A 2 , induced the envelope formation, acid production, augmentation of CN − ‐insensitive and sensitive respiration, but did not cause any increase in [Ca 2+ ] i , the phosphorylase a activity and the rate of protein synthesis. An activation of phospholipase A 2 induced by Ca 2+ or melittin seems to result in cortical vesicle discharge and production of fatty acids, which are to be utilized in CN − ‐insensitive lipid peroxidase reactions. Activation of other examined cell functions in eggs activated by sperm or A23187, probably results from Ca 2+ ‐triggered sequential reactions other than Ca 2+ ‐caused activation of phospholipase A 2 .