Structural basis for ubiquitin recognition and catalytic mechanism of ubiquitin ligase Triad3

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K15084
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 44010:Cell biology-related
• Research Institution: Kyoto University
• Principal Investigator: Kei Okatsu 京都大学, 理学研究科, 助教 (00739641)
• Project Period (FY): 2021-04-01 – 2023-03-31
• Keywords: ユビキチン / 炎症 / 細胞内シグナル伝達 / X線結晶構造解析

Outline of Final Research Achievements

Triad3 is a ubiquitin ligase composed of a Cue domain and an RBR domain. The Cue domain is involved in ubiquitin chain recognition and the RBR domain is involved in ubiquitin ligase activity. In this study, we determined the minimum domain required for ubiquitin recognition in Triad3. We also determined the ubiquitin chain selectivity of the Cue domain. Furthermore, we optimized the purification and crystallization conditions of the Cue domain and the ubiquitin chain complex and obtained data at 2.79angstrom. For the RBR domain, we increased the molecular weight by fusing a scaffold protein and obtained images of protein particles by cryo-EM.

Free Research Field

生命科学

Academic Significance and Societal Importance of the Research Achievements

Triad3は、Gordon Holmes 症候群（GHS）と呼ばれる性腺機能低下症をきたす小脳失調症との関連が示唆されている。Triad3の機能としては炎症抑制やシナプス可塑性への関与が知られている。しかし、Triad3による炎症や自然免疫の細胞内シグナリングの認識機構は未解明であった。本研究で、Traid3のCueドメインのユビキチン鎖選択性を明らかにしたことで、特定の細胞内シグナリングへの応答の理解が進むと期待される。