Dev Growth Differ 1989 Oct 01;315:467-473. doi: 10.1111/j.1440-169X.1989.00467.x.

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: (WGA-binding protein/sea urchin/sperm/acrosome reaction).

Abstract
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 Ca2+ ([Ca2+ ]i) and intracellular pH (pHi), resulting in the onset of the AR. The increases in [Ca2+ ]i and pHi required extracellular Ca2+ 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 Ca2+ 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 Ca2+ 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.

PubMed ID: 37282132
Article link: Dev Growth Differ