The nucleolar SUMO-specific protease SMT3IP1/SENP3 attenuates Mdm2-mediated p53 ubiquitination and degradation.

SUMO (small ubiquitin-like modifier) modification plays multiple roles in several cellular processes. Sumoylation is reversibly regulated by SUMO-specific proteases. SUMO-specific proteases have recently been implicated in cell proliferation and early embryogenesis, but the underlying mechanisms remain unknown. Here, we show that a nucleolar SUMO-specific protease, SMT3IP1/SENP3, controls the p53-Mdm2 pathway. We found that SMT3IP1 interacts with p53 and Mdm2, and desumoylates both proteins. Overexpression of SMT3IP1 in cells resulted in the accumulation of Mdm2 in the nucleolus and increased stability of the p53 protein. In addition, SMT3IP1 bound to the acidic domain of Mdm2, which also mediates the p53 interaction, and competed with p53 for binding. Increasing expression of SMT3IP1 suppressed Mdm2-mediated p53 ubiquitination and subsequent proteasomal degradation. Interestingly, the desumoylation activity of SMT3IP1 was not necessary for p53 stabilization. These results suggest that SMT3IP1 is a new regulator of the p53-Mdm2 pathway.

[1]  A. Levine,et al.  The p53 pathway: positive and negative feedback loops , 2005, Oncogene.

[2]  D. Lane,et al.  p53, guardian of the genome , 1992, Nature.

[3]  E. Appella,et al.  Post-translational modifications and activation of p53 by genotoxic stresses. , 2001, European journal of biochemistry.

[4]  R. Hay,et al.  SUMO: a history of modification. , 2005, Molecular cell.

[5]  Hirofumi Tanaka,et al.  Oncoprotein MDM2 is a ubiquitin ligase E3 for tumor suppressor p53 , 1997, FEBS letters.

[6]  Ronald T. Hay,et al.  An additional role for SUMO in ubiquitin-mediated proteolysis , 2009, Nature Reviews Molecular Cell Biology.

[7]  Wei Hsu,et al.  SUMO-Specific Protease 2 Is Essential for Modulating p53-Mdm2 in Development of Trophoblast Stem Cell Niches and Lineages , 2008, PLoS biology.

[8]  M. Jiang,et al.  SUMO-specific protease 2 in Mdm2-mediated regulation of p53 , 2011, Cell Death and Differentiation.

[9]  A. Levine.  p53, the Cellular Gatekeeper for Growth and Division , 1997, Cell.

[10]  F. Boisvert,et al.  The multifunctional nucleolus , 2007, Nature Reviews Molecular Cell Biology.

[11]  H. O’Hagan,et al.  Accumulation of soluble and nucleolar-associated p53 proteins following cellular stress. , 2001, Journal of cell science.

[12]  L. Hengst,et al.  SUMO-1 and p53 , 2002, Cell cycle.

[13]  Pier Paolo Pandolfi,et al.  Nucleophosmin and cancer , 2006, Nature Reviews Cancer.

[14]  A. Yergey,et al.  Nucleolar protein B23/nucleophosmin regulates the vertebrate SUMO pathway through SENP3 and SENP5 proteases , 2008, The Journal of cell biology.

[15]  C. Lehner,et al.  Major nucleolar proteins shuttle between nucleus and cytoplasm , 1989, Cell.

[16]  R. Honda,et al.  Sumoylation of Mdm2 by Protein Inhibitor of Activated STAT (PIAS) and RanBP2 Enzymes* , 2002, The Journal of Biological Chemistry.

[17]  Ruiwen Zhang,et al.  p53-independent activities of MDM2 and their relevance to cancer therapy. , 2005, Current cancer drug targets.

[18]  J. Chen,et al.  Sumoylation of nucleophosmin/B23 regulates its subcellular localization, mediating cell proliferation and survival , 2007, Proceedings of the National Academy of Sciences.

[19]  Hirofumi Tanaka,et al.  A novel mammalian Smt3-specific isopeptidase 1 (SMT3IP1) localized in the nucleolus at interphase. , 2000, European journal of biochemistry.

[20]  E. J. Lee,et al.  SUMO-specific protease SUSP4 positively regulates p53 by promoting Mdm2 self-ubiquitination , 2006, Nature Cell Biology.

[21]  Yoshiji Yamada,et al.  SMT3IP1, a nucleolar SUMO-specific protease, deconjugates SUMO-2 from nucleolar and cytoplasmic nucleophosmin. , 2008, Biochemical and biophysical research communications.

[22]  K. Fukami,et al.  PIASy controls ubiquitination-dependent proteasomal degradation of Ets-1. , 2007, The Biochemical journal.

[23]  M. Dasso,et al.  Modification in reverse: the SUMO proteases. , 2007, Trends in biochemical sciences.

[24]  C. Sherr,et al.  Arf-induced turnover of the nucleolar nucleophosmin-associated SUMO-2/3 protease Senp3 , 2008, Cell cycle.

[25]  Pier Giuseppe Pelicci,et al.  Nucleophosmin regulates the stability and transcriptional activity of p53 , 2002, Nature Cell Biology.

[26]  Leena Latonen,et al.  Nucleolar protein NPM interacts with HDM2 and protects tumor suppressor protein p53 from HDM2-mediated degradation. , 2004, Cancer cell.

[27]  D. Eick,et al.  The nucleolar SUMO‐specific protease SENP3 reverses SUMO modification of nucleophosmin and is required for rRNA processing , 2008, EMBO reports.

[28]  C. Sherr,et al.  Sumoylation induced by the Arf tumor suppressor: a p53-independent function. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[29]  A. Levine,et al.  Nucleo‐cytoplasmic shuttling of the hdm2 oncoprotein regulates the levels of the p53 protein via a pathway used by the human immunodeficiency virus rev protein , 1998, The EMBO journal.

[30]  R. Hay,et al.  SUMO-specific proteases: a twist in the tail. , 2007, Trends in cell biology.

[31]  L. Latonen,et al.  p53 and MDM2 are regulated by PI-3-kinases on multiple levels under stress induced by UV radiation and proteasome dysfunction. , 2003, Cellular signalling.

[32]  R. Copeland,et al.  A second p53 binding site in the central domain of Mdm2 is essential for p53 ubiquitination. , 2006, Biochemistry.