Generation of mutants of CK2α which are dependent on the β-subunit for catalytic activity

  • Stefania Sarno
  • Paola Ghisellini
  • Luca Cesaro
  • Roberto Battistutta
  • Lorenzo A. Pinna
Part of the Molecular and Cellular Biochemistry book series (DMCB, volume 35)


To shed light on the structural features underlying high constitutive activity of protein kinase CK2 a number of mutants of the human CK2α-subunit altered in the interactions between the β-terminal segment and the activation loop have been generated and shown to be defective in catalytic activity. In particular the truncated mutant A2-12 displays under standard conditions an almost complete loss of catalytic activity accounted for by a dramatic rise in its Km for ATP (from 10 to 206[1M) and a reduced Kcat. Such a drop in efficiency is paralleled by conformational disorganization, as judged from Superdex 75 gel filtration profile. Both catalytic properties and gel filtration behaviour similar to those of wild type CK2α were restored upon association with the regulatory (3-subunit, suggesting that constitutive activity is conferred to CK2α and to CK2 holoenzyme through different molecular mechanisms. In the holoenzyme an assumable release of tension at the backbone of Ala-193 (as seems to be indicated by a comparison of the crystal structures of maize CK2α alone vs. a CK2α-β peptide complex) may result in the ability of the activation loop to adopt its proper conformation independently of interactions with the N-terminal segment. (Mol Cell Biochem 227: 13–19, 2001)

Key words

protein kinase CK2 α catalytic subunit N-terminal domain casein kinase 2 CK2α mutants 


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  1. 1.
    Hanks SK, Hunter T: Protein kinases 6. The eukaryotic protein kinase superfamily: Kinase (catalytic) domain structure and classification. FASEB J 9: 576–596, 1995PubMedGoogle Scholar
  2. 2.
    Niefind K, Guerra B, Pinna LA, Issinger O-G, Schomburg D: Crystal structure of the catalytic subunit of protein kinase CK2 from Zea mays at 2.1 A resolution. EMBO J 17: 2451–2462, 1998PubMedCrossRefGoogle Scholar
  3. 3.
    Jeffrey PD, Russo AA, Polyak K, Gibbs E, Hurwitz J, Massague J, Pavletich NP: Mechanism of CDK activation revealed by the structure of a cyclin A-CDK2 complex. Nature 376: 313–320,1995PubMedCrossRefGoogle Scholar
  4. 4.
    Sarno S, Marin O, Ghisellini P, Meggio F, Pinna LA: Biochemical evidence that the N-terminal segments of the a subunit and the 13 subunit play interchangeable roles in the activation of protein kinase CK2. FEBS Letters 441: 29–33, 1998PubMedCrossRefGoogle Scholar
  5. 5.
    Sarno S, Vaglio P, Meggio F, Issinger O-G, Pinna LA: Protein kinase CK2 mutants defective in substrate recognition. Purification and kinetic analysis. J Biol Chem 271: 10595–10601, 1996PubMedCrossRefGoogle Scholar
  6. 6.
    Ruzzene M, Pinna LA: Assay of protein kinases and phosphatases using specific peptide substrates. In: D.G. Hardie (ed). Protein Phosphorylation. A Practical Approach. Oxford University Press, Oxford, UK, 1999, pp 221–253Google Scholar
  7. 7.
    Laemmli UK: Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature (London) 227: 680–685, 1970CrossRefGoogle Scholar
  8. 8.
    Battistutta R, Sarno S, De Moliner E, Marin O, Issinger, O-G, Zanotti G, Pinna LA: The crystal structure of the complex of Zea mays alpha subunit with a fragment of human beta subunit provides the clue to the architecture of protein kinase CK2 holoenzyme. Eur J Biochem 267: 5184–5190,2000PubMedCrossRefGoogle Scholar
  9. 9.
    Niefind K, Putter M, Guerra B, Issinger O-G, Schomburg D: GTP plus water mimic ATP in the active site of protein kinase CK2. Nat Struct Biol 6: 1100–1103, 1999PubMedCrossRefGoogle Scholar
  10. 10.
    Merritt EA, Bacon DJ: Raster3D - photorealistic molecular graphics. Meth Enzymol 277: 505–524, 1997PubMedCrossRefGoogle Scholar
  11. 11.
    Kraulis J: MOLSCRIPT: Aprogram to produce both detailed and schematic plots of protein structures. J Appl Crystallogr 24: 946–950, 1991CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2001

Authors and Affiliations

  • Stefania Sarno
    • 1
  • Paola Ghisellini
    • 2
  • Luca Cesaro
    • 1
  • Roberto Battistutta
    • 3
  • Lorenzo A. Pinna
    • 1
  1. 1.Dipartimento di Chimica Biologica and Centro per lo Studio delle Biomembrane del CNRUniversita’ di PadovaPadovaItaly
  2. 2.Istituto di BiofisicaUniversita’ di GenovaGenovaItaly
  3. 3.Dipartimento di Chimica Organica e Centro di Ricerca Biopolimeri del CNRUniversita’ di PadovaPadovaItaly

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