NAD + -dependent Class III histone deacetylase SIRT1 is a multiple function protein critically involved in stress responses, cellular metabolism and aging through deacetylating a variety of substrates including p53, forkhead-box transcription factors, PGC-1α, NF-κB, Ku70 and histones. The first discovered non-histone target of SIRT1, p53, is suggested to play a central role in SIRT1-mediated functions in tumorigenesis and senescence. SIRT1 was originally considered to be a potential tumor promoter since it negatively regulates the tumor suppressor p53 and other tumor suppressors. There is new evidence that SIRT1 acts as a tumor suppressor based on its role in negatively regulating β-catenin and survivin. This review provides an overview of current knowledge of SIRT1-p53 signaling and controversies regarding the functions of SIRT1 in tumorigenesis.

Background: TIP60 can be regulated by autoacetylation and deacetylated by SIRT1. Results: Novel lysine residues of TIP60 autoacetylation were identified, and TIP60 can be functionally regulated by HDAC3 through deacetylation. Conclusion: HDAC3 promotes TIP60 ubiquitination and cytoplasmic localization and protects cells from apoptosis after DNA damage. Significance: Our findings provide a better understanding of TIP60 regulatory mechanisms and its cellular functions.

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