Analysis of the involvment of TPC3 channel for polyspermy

2019 Fiscal Year Final Research Report

• Project/Area Number: 18K15019
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 48020:Physiology-related
• Research Institution: National Institute for Physiological Sciences
• Principal Investigator: Shimomura Takushi 生理学研究所, 分子細胞生理研究領域, 助教 (50635464)
• Project Period (FY): 2018-04-01 – 2020-03-31
• Keywords: two-pore channel / TPC / 電位依存性Na+チャネル / イオンチャネル / 電気生理学 / 受精

Outline of Final Research Achievements

Two-pore channel 3 (TPC3) is a voltage-gated Na+ channel thought to be expressed in oocytes. We analyzed TPC3 for the involvement in fertilization and polyspermy, using Xenopus oocytes as an expression system and two-electrode voltage clamp technique. The functional analyses with pharmacological treatment and exogenous mutant protein expression suggested that TPC3 is regulated by the factors involved in polyspermy. We also found that the Na+ current endogenous in Xenopus oocytes, which shows a TPC3-like activation mode, is phosphoinositide-sensitive, as well as TPC3. Furthermore, we analyzed the molecular basis of the phosphoinositide sensitivity of TPC3 and proposed a hypothesis that explains it at the atomic level.

Free Research Field

電気生理学

Academic Significance and Societal Importance of the Research Achievements

TPC3はヒトデ卵母細胞などでの発現と生理的役割が示唆されていたが、その詳細、特に制御分子に関する知見はほとんど得られていなかった。本研究では、TPC3が生理的に実際に機能する場である卵母細胞を用い、多精拒否に関わる分子などの関与を示す結果を得ることができた。また、PI感受性についての詳細な解析の結果は、TPC3も含めてすべてのサブタイプがPI感受性を持つというTPCファミリーの理解に重要な知見を提供するとともに、一般的なPI認識メカニズムの理解を深めることに寄与すると期待される。