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 ar e regulated by its interaction with viral and cellular proteins. C-ter minal sequences of p53 are implicated in binding to the regulatory bet a-subunit of protein kinase CK2. Using a p53-specific DNA binding elem ent we found that the beta-subunit of CK2 inhibited the DNA binding of p53 whereas the alpha-subunit had no influence. The CK2 holoenzyme co nsisting of two alpha- and two beta-subunits led to a supershift in DN A binding of p53 similar to the p53-specific monoclonal antibody PAb42 1 as web as the C-terminus of p53. Thus, our results showed an individ ual role of the free beta-subunit of CK2 on the DNA binding activity o f p53. (C) 1997 Federation of European Biochemical Societies.