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  • The EMBO Journal (2001) 20, 3947 - 3956
  • doi:10.1093/emboj/20.15.3947

Structure and ligand recognition of the PB1 domain: a novel protein module binding to the PC motif

Hiroaki Terasawa1,2, Yukiko Noda3,4, Takashi Ito5, Hideki Hatanaka1, Saori Ichikawa6, Kenji Ogura1,2,7, Hideki Sumimoto3,4 and Fuyuhiko Inagaki1,2,7,8

  1. Tokyo Metropolitan Institute of Medical Science, 3-18-22 Honkomagome, Bunkyo-ku, Tokyo 113-8613, Japan
  2. CREST, Japan Science and Technology, Kyushu University Graduate School of Medical Science, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
  3. Department of Molecular and Structural Biology, Kyushu University Graduate School of Medical Science, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
  4. Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
  5. Division of Genome Biology, Cancer Research Institute, Kanazawa University, 13-1 Takaramachi, Kanazawa 920-0934, Japan
  6. Department of Material and Biological Science, Faculty of Science, Japan Women's University, 2-8-1 Mejirodai, Bunkyo-ku, Tokyo 112-8681, Japan
  7. Department of Structural Biology, Hokkaido University Graduate School of Pharmaceutical Sciences, Kita 12, Nishi 6, Kita-ku, Sapporo 060-0812, Japan
  8. Department of Structural Biology, Hokkaido University Graduate School of Pharmaceutical Sciences, N12, W6, Kita-ku, Sapporo 060-0812, Japan

Correspondence to:

Fuyuhiko Inagaki, E-mail: finagaki@pharm.hokudai.ac.jp

Received 31 October 2000; Accepted 5 June 2001; Revised 27 April 2001

PB1 domains are novel protein modules capable of binding to target proteins that contain PC motifs. We report here the NMR structure and ligand-binding site of the PB1 domain of the cell polarity establishment protein, Bem1p. In addition, we identify the topology of the PC motif-containing region of Cdc24p by NMR, another cell polarity establishment protein that interacts with Bem1p. The PC motif-containing region is a structural domain offering a scaffold to the PC motif. The chemical shift perturbation experiment and the mutagenesis study show that the PC motif is a major structural element that binds to the PB1 domain. A structural database search reveals close similarity between the Bem1p PB1 domain and the c-Raf1 Ras-binding domain. However, these domains are functionally distinct from each other.

  • Keywords:

    • Bem1p,
    • Cdc24p,
    • NADPH oxidase,
    • p67phox,
    • p40phox