Fig. 1

Transcriptional and post-transcriptional regulatory mechanisms of SIRT1. Four transcription factors (HIC1, p53, E2F1, and cMYC) have been identified to modulate SIRT1 expression under oxidative stress/DNA-damage conditions and/or nutrient deprivation. Post-transcriptional control of SIRT1: upon oxidative stress, SIRT1 mRNA is degraded due to a checkpoint-kinase-2-mediated dissociation of the RNA binding protein HuR. Via a feedback loop, SIRT1 regulates the activity of promoter-bound transcription factors through deacetylation. Green boxes: activating factors; red boxes: inactivating factors; green arrow: activation/increase; red line: inactivation/inhibition