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Involvement of Wheat Germ Agglutinin (WGA)‐Binding Protein in the Induction of the Acrosome Reaction of the Sea Urchin, Strongylocentrotus intermedius . II. Antibody against WGA‐Binding Protein Induces the Acrosome Reaction
Author(s) -
Sendai Yutaka,
Aketa Kenji
Publication year - 1989
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 - 10.1111/j.1440-169x.1989.00467.x
Subject(s) - wheat germ agglutinin , sea urchin , extracellular , sperm , polyclonal antibodies , acrosome reaction , antibody , intracellular , chemistry , agglutinin , microbiology and biotechnology , verapamil , biology , acrosome , biochemistry , lectin , calcium , immunology , botany , organic chemistry
We obtained a polyclonal antibody against the WGA‐binding protein (WGAbp) of Strongylocentrotus intermedius sperm, which is a membrane glycoprotein of 260 kD under non‐reducing condition. Anti‐WGAbp antibody induced increases in both intracellular Ca 2+ ([Ca 2+ ]i) and intracellular pH (pHi), resulting in the onset of the AR. The increases in [Ca 2+ ]i and pHi required extracellular Ca 2+ and Na + , respectively, and were suppressed by the pretreatment with WGA, resulting in the inhibition of the AR. Anti‐WGAbp antibody‐induced AR was inhibited also by lowered extracellular pH. elevated K + , removal of Na + from seawater and the treatment with verapamil, a Ca 2+ channel inhibitor. These inhibitory conditions are identical with those of the egg jelly‐induced AR. Monovalent Fab fragments from anti‐WGAbp antibody also induced the AR at relatively high concentration. These results suggest that the WGAbp on the sperm plasma membrane is involved in the regulation of Ca 2+ influx and Na + /H + exchange associated with the AR of S. intermedius sperm. It is a strong candidate for the receptor of the AR‐inducing substance in the egg jelly.