Regulation of sperm flagellar motility by Ca2+ and cAMP

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K06592
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 43040:Biophysics-related
• Research Institution: University of Tsukuba
• Principal Investigator: Shiba Kogiku 筑波大学, 生命環境系, 助教 (70533561)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 精子運動 / 繊毛 / イオンチャネル

Outline of Final Research Achievements

Using caged compounds, we analyzed in detail the behavior of cAMP-induced flagellar waveform change process and intracellular calcium concentration, and found that cAMP induces different waveform changes in ascidian spermatozoa under two conditions: calcium-dependent and calcium-independent. The effects of CNG channel inhibitors on sperm chemotaxis were also examined, suggesting that HCN channels, a type of CNG channel activated by cAMP and hyperpolarization, may act on calcium efflux during sperm chemotaxis and regulate the appropriate waveform changes. Our findings provide new insights into the signaling pathways and molecular mechanisms of flagellar wave regulation to induce the correct timing of swimming direction change during sperm　chemotaxis.

Free Research Field

細胞生物学

Academic Significance and Societal Importance of the Research Achievements

真核生物の鞭毛・繊毛は、精子運動・体内の水流制御など細胞運動やシグナル受容において非常に重要な器官であり、その構造・機能は進化を通して高度に保存されている。本申請課題では、材料として扱いやすく反応が顕著に観察できる海産生物精子を用いて、「鞭毛波形制御におけるカルシウムイオンとcAMPの役割」に着目し、研究を実施した。その結果精子鞭毛波形を制御するためのシグナル因子とその役割を明らかにした。本研究成果は、不妊治療や繁殖分野への応用へとつながるものである。