FIGURE 1.

p68 is acetylated by p300. A, activation of the TORU luciferase reporter by p68. Where indicated, CV-1 cells were transfected with p68 expression vector and treated with sodium butyrate. B, 293T cells were untreated or either treated with sodium butyrate or transfected with a p300 expression vector. Immunoprecipitation (IP) was performed with two different acetyllysine antibodies (AcK1, AcK2) or control GAL4 antibodies. Immunoprecipitated p68 was then revealed by blotting with a p68 antibody. The bottom panel shows that comparable amounts of total p68 were present in each immunoprecipitation experiment. C, indicated GST fusion proteins were incubated with recombinant p300, P/CAF or ACTR in the presence of [¹⁴C]acetyl coenzyme A. Acetylation was revealed by determining the incorporation of radioactivity through autoradiography. D, p300-HA and HER2/Neu-V664E, Ras-G12V, or Raf-BXB were coexpressed as indicated in 293T cells. Anti-HA immunoprecipitates were then employed in an in vitro acetylation assay with [¹⁴C]acetyl coenzyme A. Shown is the incorporation of radioactivity into GST-p68. E, 293T cells were transfected with 6Myc-p68 and the indicated oncogenic mutants of Ras or Raf. Immunoprecipitations were preformed with control (GAL4) or acetyllysine (AcK1) antibodies. Shown are anti-Myc blots of the immunoprecipitates and the corresponding inputs. F, analogous, impact of HER2/Neu on the in vivo acetylation of p68.