A highly glycosylated protein, which has unique, novel features in localization, structure, and potentia function, is found in pig sperm, and named WGA-gp due to its high binding property with wheat germ agglutinin (WGA). WGA-gp is localized mainly in flagella and enriched in membrane microdomains or lipid rafts. It is not detected by ordinary protein staining methods due to a high content of both N and O-glycans consisting of neutral monosaccharides. Interestingly,WGA-gp may be involved in intracellular Ca2+ regulation. Treatment of sperm with anti-WGA-gp antibody enhances the amplitude of Ca2+ oscillation without changing the basal intracellular Ca2+ concentrations. All these features of WGA-gp except for different carbohydrate structures occupying most part of the molecules, are similar to those of flagellasialin in sea urchin sperm, which regulates the intracellular Ca2+ concentration. Presence of carbohydrate-enriched flagellar proteins involved in intracellular Ca2+ regulation may be a common feature among animal sperm.