Mitogen-activated protein kinases interacting kinases are autoinhibited by a reprogrammed activation segment.
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 Mnk2 D228G -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.
Jauch
Ralf
R
Max-Planck-Institut für Biophysikalische Chemie, Abteilung Molekulare Entwicklungsbiologie, Göttingen, Germany. jauchr@gis.a-star.edu.sg
Cho
Min-Kyu
MK
Jäkel
Stefan
S
Netter
Catharina
C
Schreiter
Kay
K
Aicher
Babette
B
Zweckstetter
Markus
M
Jäckle
Herbert
H
Wahl
Markus C
MC
D000255:Adenosine Triphosphate / Q000737:chemistry; D000595:Amino Acid Sequence; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics; D008274:Magnesium / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D019906:Nuclear Magnetic Resonance, Biomolecular; D010649:Phenylalanine / Q000737:chemistry; D010766:Phosphorylation; D011487:Protein Conformation; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics; D019311:Staurosporine / Q000737:chemistry
D047908:Intracellular Signaling Peptides and Proteins; D010649:Phenylalanine; D000255:Adenosine Triphosphate; C491395:MKNK1 protein, human; C486342:MKNK2 protein, human; D017346:Protein Serine-Threonine Kinases; D019311:Staurosporine; D008274:Magnesium