Crystal structure of the human protein kinase CK2 regulatory subunit reveals its zinc finger-mediated dimerization

Authors

  • Laurent Chantalat,

    1. Laboratoire de Cristallographie Macromoléculaire, Institut de Biologie Structurale Jean-Pierre Ebel, CNRS/CEA, 41, rue Jules Horowitz, Grenoble, Cedex 1, France
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  • Didier Leroy,

    1. Laboratoire de Biochimie des Régulations Cellulaires Endocrines, Unité INSERM 244,Département de Biologie Moléculaire et Structurale, CEA Grenoble,17, rue Jules Horowitz, Grenoble, Cedex 9, France
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  • Odile Filhol,

    1. Laboratoire de Biochimie des Régulations Cellulaires Endocrines, Unité INSERM 244,Département de Biologie Moléculaire et Structurale, CEA Grenoble,17, rue Jules Horowitz, Grenoble, Cedex 9, France
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  • Arsenio Nueda,

    1. Laboratoire de Biochimie des Régulations Cellulaires Endocrines, Unité INSERM 244,Département de Biologie Moléculaire et Structurale, CEA Grenoble,17, rue Jules Horowitz, Grenoble, Cedex 9, France
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  • Maria Jose Benitez,

    1. Laboratoire de Biochimie des Régulations Cellulaires Endocrines, Unité INSERM 244,Département de Biologie Moléculaire et Structurale, CEA Grenoble,17, rue Jules Horowitz, Grenoble, Cedex 9, France
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  • Edmond M. Chambaz,

    1. Laboratoire de Biochimie des Régulations Cellulaires Endocrines, Unité INSERM 244,Département de Biologie Moléculaire et Structurale, CEA Grenoble,17, rue Jules Horowitz, Grenoble, Cedex 9, France
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  • Claude Cochet,

    Corresponding author
    1. Laboratoire de Biochimie des Régulations Cellulaires Endocrines, Unité INSERM 244,Département de Biologie Moléculaire et Structurale, CEA Grenoble,17, rue Jules Horowitz, Grenoble, Cedex 9, France
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  • Otto Dideberg

    Corresponding author
    1. Laboratoire de Cristallographie Macromoléculaire, Institut de Biologie Structurale Jean-Pierre Ebel, CNRS/CEA, 41, rue Jules Horowitz, Grenoble, Cedex 1, France
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Abstract

Protein kinase CK2 is a tetramer composed of two α catalytic subunits and two β regulatory subunits. The structure of a C-terminal truncated form of the human β subunit has been determined by X-ray crystallography to 1.7 Å resolution. One dimer is observed in the asymmetric unit of the crystal. The most striking feature of the structure is the presence of a zinc finger mediating the dimerization. The monomer structure consists of two domains, one entirely α-helical and one including the zinc finger. The dimer has a crescent shape holding a highly acidic region at both ends. We propose that this acidic region is involved in the interactions with the polyamines and/or catalytic subunits. Interestingly, conserved amino acid residues among β subunit sequences are clustered along one linear ridge that wraps around the entire dimer. This feature suggests that protein partners may interact with the dimer through a stretch of residues in an extended conformation.

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