Interactions of protein kinase CK2β subunit within the holoenzyme and with other proteins

Protein kinase CK2 is a ubiquitous, highly conserved protein kinase with a tetrameric alpha(2)beta(2) structure. For the formation of this tetrameric complex a beta-beta dimer seems to be a prerequisite. Using the two-hybrid system and a series of CK2 beta deletion mutants, we mapped domains involved in alpha-beta and beta-beta interactions. We also detected an intramolecular beta interaction within the amino acid stretch 132-165. Using CK2 beta as a bait in a two-hybrid library screening several new putative cellular partners have been identified, among them the S6 kinase p90(rsk), the putative tumor suppressor protein Doc-1, the Pas-associated protein FAF1, the mitochondrial translational initiation factor 2 and propionyl CoA carboxylase beta subunit.