Structural analysis of the complex of F-actin and DNGR-1 by CryoEM.

• Project/Area Number: 25711010
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Partial Multi-year Fund
• Research Field: Biophysics
• Research Institution: Osaka University (2015); Institute of Physical and Chemical Research
• Principal Investigator: FUJII Takashi 大阪大学, 生命機能研究科, 招へい研究員 (10582611)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Project Status: Completed (Fiscal Year 2015)
• Budget Amount: ¥26,910,000 (Direct Cost: ¥20,700,000、Indirect Cost: ¥6,210,000); Fiscal Year 2015: ¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000); Fiscal Year 2014: ¥10,270,000 (Direct Cost: ¥7,900,000、Indirect Cost: ¥2,370,000); Fiscal Year 2013: ¥12,610,000 (Direct Cost: ¥9,700,000、Indirect Cost: ¥2,910,000)
• Keywords: クライオ電子顕微鏡 / アクチン繊維 / DNGR-1 / 自然免疫 / クライオ電顕 / アクチン / ＤＮＧＲ１ / 低温電子顕微鏡法 / 単粒子解析法

Outline of Final Research Achievements

DNGR-1 is a C-type lectin receptor that binds F-actin exposed by dying cells and facilitates cross-presentation of dead cell-associated antigens by dendritic cells. We revealed the structure of DNGR-1 bound to F-actin at 7.7 angstrom resolution by CryoEM. The DNGR-1 ligand binding domain contacts three actin subunits helically arranged in the actin filament, bridging over two protofilaments. Mutation of residues predicted to mediate ligand binding led to loss of DNGR-1-dependent cross-presentation of dead cell-associated antigens, formally demonstrating that the latter depends on F-actin recognition. DNGR-1 has relatively modest affinity for F-actin but multivalent interactions allow a marked increase in binding strength. Our findings shed light on modes of actin binding by cellular proteins and reveal how extracellular detection of cytoskeletal components by dedicated receptors allows immune monitoring of loss of cellular integrity.

Research Products

• [Int'l Joint Research] フランシスクリック研究所(英国)
• [Journal Article] Immune recognition of cell death revealed by the structure od DNGR-1 in complex with F-actin. Immunity in press. (2015)
  • Author(s): Pavel Hanc*，Takashi Fujii*，Salvador Iborra, Yurika Yamada, Jatta Huotari, Oliver Schulz, Susan Ahrens, Svend Kjr, Michael Way, David Sancho, Keiichi Namba, Caetano Reis e Sousa.
  • Journal Title: Immunity Volume: 42 Issue: 5 Pages: 1-11
  • DOI: 10.1016/j.immuni.2015.04.009
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] A repeat unit of Vibrio diarrheal T3S effector subverts cytoskeletal actin homeostasis via binding to interstrand region of actin filaments. (2015)
  • Author(s): Nishimura M, Fujii T, Hiyoshi H, Makino F, Inoue H, Motooka D, Kodama T, Ohkubo T, Kobayashi Y, Nakamura S, Namba K, Iida T.
  • Journal Title: Sci Rep. Volume: 5 Issue: 1 Pages: 10870-10870
  • DOI: 10.1038/srep10870
  • Peer Reviewed / Open Access
• [Presentation] 低温電顕単粒子像解析法による筋収縮制御機構の構造生物学的基盤. (2016)
  • Author(s): 藤井高志
  • Organizer: 第93回日本生理学会大会
  • Place of Presentation: 札幌コンベンションセンター
  • Year and Date: 2016-03-24
  • Invited
• [Presentation] 低温電子顕微鏡法によるタンパク質複合体の高分解能構造解析 (2014)
  • Author(s): 藤井高志
  • Organizer: 第２回Neutrons in Biology 研究会
  • Place of Presentation: 日本原子力研究開発機構
  • Invited
• [Presentation] 低温電子顕微鏡法による赤痢菌ニードル繊維の高分解能構造解析 (2013)
  • Author(s): 藤井高志
  • Organizer: 第86回日本生化学会大会
  • Place of Presentation: パシフィコ横浜
  • Invited
• [Presentation] 低温電子顕微鏡法による蛋白質繊維状複合体の高分解能構造解析 (2013)
  • Author(s): 藤井高志
  • Organizer: 日本顕微鏡学会第57回シンポジウム
  • Place of Presentation: 愛知県産業労働センター
  • Invited