Physiological importance of autophosphorylation of NtCDPK1 involved in gibberellin signal transduction

• Project/Area Number: 15K18555
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Plant molecular biology/Plant physiology
• Research Institution: Hiroshima University
• Principal Investigator: Takeshi Ito 広島大学, 理学研究科, 助教 (30636139)
• Project Period (FY): 2015-04-01 – 2017-03-31
• Project Status: Completed (Fiscal Year 2016)
• Budget Amount: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2016: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000); Fiscal Year 2015: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
• Keywords: 自己リン酸化 / キナーゼ / カルシウム / ジベレリン / 基質認識 / 基質特異性 / タンパク質リン酸化酵素 / 植物ホルモン / CDPK / 信号伝達 / 活性制御

Outline of Final Research Achievements

The tobacco calcium-dependent protein kinase, NtCDPK1, was previously shown to be autophosphorylated in a calcium-dependent manner. Here, we investigated the functional importance of autophosphorylation in NtCDPK1. Autophosphorylation sites of NtCDPK1 were shown to be located in the variable N-terminal domain. The autophosphorylation reduced the binding affinity of NtCDPK1 for RSG. Furthermore, the autophosphorylation decreased the phosphorylation efficiency of RSG, yet increased that of myelin basic protein. Autophosphorylation sites of NtCDPK1 were phosphorylated in response to GAs in plants. The substitution of these autophosphorylation sites with Ala enhanced the NtCDPK1 overexpression-induced sensitization of seeds to a GA biosynthetic inhibitor during germination. These results suggest new functions of autophosphorylation in CDPKs, namely, the autophosphorylation can prevent the excessive phosphorylation of substrates and alter the substrate preference of CDPKs.

Research Products

• [Journal Article] Binding of GID1 to DELLAs Promotes Dissociation of GAF1 from DELLA in GA Dependent Manner (2015)
  • Author(s): Fukazawa, J., Ito, T., Yoshida, M., Kamiya, Y., Yamaguchi, S., and Takahashi, Y.
  • Journal Title: Plant Signaling and Behavior Volume: 10 Issue: 10 Pages: e1052923-e1052923
  • DOI: 10.1080/15592324.2015.1052923
  • Peer Reviewed / Open Access / Acknowledgement Compliant
• [Journal Article] Phosphatase protection assay: 14-3-3 binding protects the phosphate group of RSG from λ protein phosphatase. (2015)
  • Author(s): Ito, T., Takahashi, Y.
  • Journal Title: Bio-protocol Volume: 5
  • Peer Reviewed / Open Access
• [Presentation] DELLA-GAF1/IDD2 complex regulates gibberellin homeostasis and signaling (2016)
  • Author(s): Fukazawa, J., Ito, T., and Takahashi Y.
  • Organizer: 22nd The International Conference on Plant Growth Substances
  • Place of Presentation: Toronto, Canada
  • Year and Date: 2016-06-21
  • Int'l Joint Research
• [Presentation] GAF1複合体によるGA生合成酵素遺伝子の転写抑制機構の解析 (2016)
  • Author(s): 勝部隆義, 伊藤岳, 深澤壽太郎, 高橋陽介
  • Organizer: 第73回 中国四国植物学会（鳥取大会）
  • Place of Presentation: 米子市コンベンションセンタービッグシップ
  • Year and Date: 2016-05-14
• [Presentation] ジベレリンとオーキシンによる茎部の伸長制御機構の解析 (2016)
  • Author(s): 伊東裕太, 伊藤岳, 高橋陽介
  • Organizer: 第73回 中国四国植物学会（鳥取大会）
  • Place of Presentation: 米子市コンベンションセンタービッグシップ
  • Year and Date: 2016-05-14
• [Presentation] カルシウム依存性タンパク質リン酸化酵素NtCDPK1の自己リン酸化による機能制御の解析 (2016)
  • Author(s): 伊藤岳, 石田さらみ, 高橋陽介
  • Organizer: 日本植物生理学会
  • Place of Presentation: 岩手
  • Year and Date: 2016-03-18
• [Presentation] EPR1の新規転写抑制モチーフの機能解析 (2015)
  • Author(s): 伊藤岳, 岡村僚太, 佐久間哲史, 山本卓, 高橋陽介
  • Organizer: 日本分子生物学会
  • Place of Presentation: 神戸
  • Year and Date: 2015-12-01