Open AccessStructure-based design of small peptide inhibitors of protein kinase CK2 subunit interaction
Author(s) -
Béatrice Laudet,
Caroline Barette,
Vincent Duléry,
Olivier Renaudet,
Pascal Dumy,
Alexandra Metz,
Renaud Prudent,
Alexandre Deshière,
Otto Dideberg,
Odile Filhol,
Claude Cochet
Publication year - 2007
Publication title -
biochemical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.706
H-Index - 265
eISSN - 1470-8728
pISSN - 0264-6021
DOI - 10.1042/bj20070825
Subject(s) - protein subunit , peptide , biochemistry , mutagenesis , in vitro , amino acid , protein–protein interaction , kinase , small molecule , protein kinase a , chemistry , casein kinase 2 , plasma protein binding , biology , microbiology and biotechnology , biophysics , mutation , mitogen activated protein kinase kinase , gene
X-ray crystallography studies, as well as live-cell fluorescent imaging, have recently challenged the traditional view of protein kinase CK2. Unbalanced expression of catalytic and regulatory CK2 subunits has been observed in a variety of tissues and tumours. Thus the potential intersubunit flexibility suggested by these studies raises the likely prospect that the CK2 holoenzyme complex is subject to disassembly and reassembly. In the present paper, we show evidence for the reversible multimeric organization of the CK2 holoenzyme complex in vitro. We used a combination of site-directed mutagenesis, binding experiments and functional assays to show that, both in vitro and in vivo, only a small set of primary hydrophobic residues of CK2beta which contacts at the centre of the CK2alpha/CK2beta interface dominates affinity. The results indicate that a double mutation in CK2beta of amino acids Tyr188 and Phe190, which are complementary and fill up a hydrophobic pocket of CK2alpha, is the most disruptive to CK2alpha binding both in vitro and in living cells. Further characterization of hotspots in a cluster of hydrophobic amino acids centred around Tyr188-Phe190 led us to the structure-based design of small-peptide inhibitors. One conformationally constrained 11-mer peptide (Pc) represents a unique CK2beta-based small molecule that was particularly efficient (i) to antagonize the interaction between the CK2 subunits, (ii) to inhibit the assembly of the CK2 holoenzyme complex, and (iii) to strongly affect its substrate preference.