The Multifunctional Sorting Protein PACS-2 Regulates SIRT1-Mediated Deacetylation of p53 to Modulate p21-Dependent Cell-Cycle Arrest
Katelyn M. Atkins,
Laura L. Thomas,
Jonathan Barroso-González,
Laurel Thomas,
Sylvain Auclair,
Jun Yin,
Hyeog Kang,
Jay H. Chung,
Jimmy D. Dikeakos,
Gary Thomas
Affiliations
Katelyn M. Atkins
Department of Cell and Developmental Biology, Oregon Health & Science University, Portland, OR 97239, USA
Laura L. Thomas
Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
Jonathan Barroso-González
Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
Laurel Thomas
Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
Sylvain Auclair
Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
Jun Yin
Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
Hyeog Kang
Laboratory of Obesity and Aging Research, Genetics and Development Biology Center, National Heart Lung and Blood Institute, NIH, Bethesda, MD 20892, USA
Jay H. Chung
Laboratory of Obesity and Aging Research, Genetics and Development Biology Center, National Heart Lung and Blood Institute, NIH, Bethesda, MD 20892, USA
Jimmy D. Dikeakos
Schulich School of Medicine and Dentistry, University of Western Ontario, London ON N6A 5C1, Canada
Gary Thomas
Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
SIRT1 regulates the DNA damage response by deacetylating p53, thereby repressing p53 transcriptional output. Here, we demonstrate that the sorting protein PACS-2 regulates SIRT1-mediated deacetylation of p53 to modulate the DNA damage response. PACS-2 knockdown cells failed to efficiently undergo p53-induced cell-cycle arrest in response to DNA damage. Accordingly, p53 acetylation was reduced both in PACS-2 knockdown cells and thymocytes from Pacs-2−/− mice, thereby blunting induction of the cyclin-dependent kinase inhibitor p21 (CDKN1A). The SIRT1 inhibitor EX-527 or SIRT1 knockdown restored p53 acetylation and p21 induction as well as p21-dependent cell-cycle arrest in PACS-2 knockdown cells. Trafficking studies revealed that cytoplasmic PACS-2 shuttled to the nucleus, where it interacted with SIRT1 and repressed SIRT1-mediated p53 deacetylation. Correspondingly, in vitro assays demonstrated that PACS-2 directly inhibited SIRT1-catalyzed p53 deacetylation. Together, these findings identify PACS-2 as an in vivo mediator of the SIRT1-p53-p21 axis that modulates the DNA damage response.
