After incubation of high mobility group (HMG) proteins 1 and 2 with DNA-dependent protein kinase (DNA-PK) and [γ-32P]ATP in the presence of double-stranded DNA, not only phosphorylation of HMG proteins but also enhancement of autophosphorylation of the catalytic of 350 kDa in DNA-PK was observed. DNA-PK activity with a synthetic peptide and α-casein as substrates was stimulated several-fold by HMG1, HMG2, and the DNA-binding domains. The stimulation was decreased at higher concentrations of HMG proteins, and DNA-PK activity was inhibited by histone H1. Electrophoretic mobility shift analysis suggests that HMG proteins facilitate the binding of DNA-PK to DNA.
|Number of pages
|Biochemical and Biophysical Research Communications
|Published - 1994 Jul 29