Regulation of the DNA binding of p53 by its interaction with protein kinase CK2.

Some of the numerous functions of the growth suppressor protein p53 are regulated by its interaction with viral and cellular proteins. C-terminal sequences of p53 are implicated in binding to the regulatory beta-subunit of protein kinase CK2. Using a p53-specific DNA binding element we found that the beta-subunit of CK2 inhibited the DNA binding of p53 whereas the alpha-subunit had no influence. The CK2 holoenzyme consisting of two alpha- and two beta-subunits led to a supershift in DNA binding of p53 similar to the p53-specific monoclonal antibody PAb421 as well as the C-terminus of p53. Thus, our results showed an individual role of the free beta-subunit of CK2 on the DNA binding activity of p53.