Figure 3. DBC1 acts as an inhibitor of SIRT1 in human cells.
a, DBC1 represses SIRT1 deacetylation activity in vivo. Transfected H1299 cell extracts were analysed by western blot using antibodies as shown. b, DBC1 inhibits SIRT1-mediated co-immunoprecipitation of p53 in vivo. H1299 cells were transfected as indicated and Flag–SIRT1 immunoprecipitations were analysed by western blot as shown. c, DBC1 expression rescues SIRT1-mediated repression of p53 transcriptional activation. H1299 cells were transfected with the PUMA-luciferase promoter construct and p53, SIRT1 and DBC1 as indicated. Lysates were assayed for the dual-luciferase activity. Error bars represent s.d., n = 3. d, Model showing DBC1 acting as an inhibitor of SIRT1-mediated repression of p53.