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  • The EMBO Journal (2006) 25, 4020 - 4032
  • doi:10.1038/sj.emboj.7601285

Published online: 17 August 2006

Mitogen-activated protein kinases interacting kinases are autoinhibited by a reprogrammed activation segment

Ralf Jauch1,2, Min-Kyu Cho3, Stefan Jäkel4, Catharina Netter5, Kay Schreiter4, Babette Aicher4, Markus Zweckstetter3, Herbert Jäckle1 and Markus C Wahl5

  1. Max-Planck-Institut für Biophysikalische Chemie, Abteilung Molekulare Entwicklungsbiologie, Göttingen, Germany
  2. Genome Institute of Singapore, Laboratory for Structural Biochemistry, Singapore
  3. Max-Planck-Institut für Biophysikalische Chemie, NMR-basierte Strukturbiologie, Göttingen, Germany
  4. DeveloGen AG, Göttingen, Germany
  5. Max-Planck-Institut für Biophysikalische Chemie, Abteilung Zelluläre Biochemie/Röntgenkristallographie, Göttingen, Germany

Correspondence to:

Ralf Jauch, Genome Institute of Singapore, 60 Biopolis Street, #02-01, Genome, Singapore 138672. Tel.: +65 6478 8653; E-mail: jauchr@gis.a-star.edu.sg

Markus C Wahl, Max-Planck-Institut für Biophysikalische Chemie, Abteilung Zelluläre Biochemie/Röntgenkristallographie, Am Fas zligberg 11, 37077 Göttingen, Germany. Tel.: +49 551 201 1046; Fax: +49 551 201 1197; E-mail: mwahl@gwdg.de

Received 20 March 2006; Accepted 25 July 2006

Autoinhibition is a recurring mode of protein kinase regulation and can be based on diverse molecular mechanisms. Here, we show by crystal structure analysis, nuclear magnetic resonance (NMR)-based nucleotide affinity studies and rational mutagenesis that nonphosphorylated mitogen-activated protein (MAP) kinases interacting kinase (Mnk) 1 is autoinhibited by conversion of the activation segment into an autoinhibitory module. In a Mnk1 crystal structure, the activation segment is repositioned via a Mnk-specific sequence insertion at the N-terminal lobe with the following consequences: (i) the peptide substrate binding site is deconstructed, (ii) the interlobal cleft is narrowed, (iii) an essential Lys–Glu pair is disrupted and (iv) the magnesium-binding loop is locked into an ATP-competitive conformation. Consistently, deletion of the Mnk-specific insertion or removal of a conserved phenylalanine side chain, which induces a blockade of the ATP pocket, increase the ATP affinity of Mnk1. Structural rearrangements required for the activation of Mnks are apparent from the cocrystal structure of a Mnk2D228G–staurosporine complex and can be modeled on the basis of crystal packing interactions. Our data suggest a novel regulatory mechanism specific for the Mnk subfamily.

  • Keywords:

    • autoinhibition,
    • drug design,
    • mitogen-activated protein kinases interacting kinase,
    • Mnk1 and Mnk2,
    • protein kinase regulation