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Updated: Jul 1, 2026

Medium-throughput Screening Assays for Assessment of Effects on Ca2+-Signaling and Acrosome Reaction in Human Sperm
Published on: March 1, 2019
Ascidian sperm activating and attracting factor: importance of sulfate groups for the activities and implication of
Manabu Yoshida1, Kogiku Shiba, Kaoru Yoshida
1Misaki Marine Biological Station, Graduate School of Science, University of Tokyo, 1024 Koajiro, Misaki, Miura 238-0225, Japan. yoshida@mmbs.s.u-tokyo.ac.jp
Abstract:
The sperm activating and attracting factor (SAAF) from the eggs of the ascidian Cionaintestinalis was identified as the sulfated polyhydroxysterol,3alpha,4beta,7alpha,26-tetrahydroxy-5alpha-cholestane-3,26-disulfate. We present a functional analysis of SAAF derivatives that reveals the roles of the various SAAF functional groups. Optical isomerism does not affect SAAF activities. Hydrolysis on one side, i.e. at the sulfate groups of SAAF, decreases the sperm-activating and sperm-attracting activities, while hydrolysis on both sides resulted in the loss of both activities. Biotinylated-SAAF lost its sperm-activating ability, but retained sperm-binding and chemotactic abilities. Thus, the sulfate groups of SAAF are responsible for these activities.
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