STRUCTURE OF PROTEIN-KINASE CK2 - DIMERIZATION OF THE HUMAN BETA-SUBUNIT

Protein kinase CK2 has been shown to be elevated in all so far investi gated solid tumors and its catalytic subunit has been shown to serve a s an oncogene product. CK2 is a heterotetrameric serine-threonine kina se composed of two catalytic (alpha and/or alpha') and two regulatory beta-subunits. Using the two-hybrid system we could show that the (alp ha- or alpha'-subunits of CK2 can interact with the beta-subunits of C K2, but not with other alpha- or alpha'-subunits. By comparison, the b eta-subunit of CK2 can interact with another beta-subunit. Important a mino acids for successful dimerization of the beta-subunit were locali zed between amino acid residues 156 and 165. Furthermore, we identifie d residues between amino acid 170 and 180 which antagonize the dimeriz ation.