Mechanism regulating the swimming behavior of sperm by calcium- A role of actin

2016 Fiscal Year Final Research Report

• Project/Area Number: 25291072
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Animal physiology/Animal behavior
• Research Institution: The University of Tokyo
• Principal Investigator: Shingyoji Chikako 東京大学, 理学(系)研究科(研究院), 准教授 (80125997)
• Co-Investigator(Kenkyū-buntansha): 北島 健 名古屋大学, 生物機能開発利用研究センター, 教授 (80192558)
• Project Period (FY): 2013-04-01 – 2017-03-31
• Keywords: 生体膜 / ラフト / カルシウム / 精子 / ウニ / 生体分子

Outline of Final Research Achievements

A mechanism regulating the sperm swimming has not clearly been understood. In sea urchin sperm, calcium plays an important role for this regulation. At pH6-7, sperm does not show swimming and is immotile. Calcium dynamics of influx and efflux through flagellar membrane is known to be necessary for normal swimming and an inhibition of this dynamics brings about the inhibition of swimming movement.By using this characteristics of sperm at pH7 and 8 we compared the differences such as raft formation and behavior of membrane fluorescent probes. We found that the function of calcium efflux protein in the flagellar membrane, PMCA, requires formation of a so-called lipid raft with cooperative existence of flagellasialin. Actin was detected in the raft fraction of the sperm membrane obtained at pH8, but the role of actin has not been elucidated. Furthermore, we observed that a fluorescent probe detecting rafts moves along the flagella at pH8, suggesting a certain dynamic factor of the raft.

Free Research Field

細胞生物学、細胞生理学