Jab1 Induces the Cytoplasmic Localization and Degradation of p53 in Coordination with Hdm2*

The biological mechanisms for maintaining the basal level of p53 in normal cells require nuclear exclusion and cytoplasmic degradation. Here, we showed that Jab1 facilitates p53 nuclear exclusion and its subsequent degradation in coordination with Hdm2. p53 was excluded from the nucleus in the presence of Jab1; this exclusion was prevented by leptomycin B treatment. Nuclear export of p53 was accompanied by a decrease in the levels of p53, as well as of its target proteins, which include p21 and Bax. Domain analyses of Jab1 showed that the N-terminal domain, 1-110, was capable of inducing cytoplasmic translocation of p53. Furthermore, 110-191 was required to facilitate the degradation of p53. Neither of these mutants incorporated into the CSN complex, indicating that Jab1 could affect the levels of p53 independent of intact CSN complex. Conversely, Jab1 was incapable of translocating and degrading two p53 mutants, W23S and 6KR, neither of which could be modified by Hdm2. Moreover, Jab1 did not affect the cellular localization or protein levels of p53 in p53 and Hdm2 double-null mouse embryo fibroblasts. We further observed that the ablation of endogenous Jab1 by small interfering RNA prevented Hdm2-mediated p53 nuclear exclusion. Under stressed conditions, which could sequester Hdm2 in its inactive state, Jab1 did not affect p53. Our studies implicate that Jab1 is required to remove post-translationally modified p53 and provide a novel target for p53-related cancer therapies.

[1]  Yili Yang,et al.  Regulating the p53 system through ubiquitination , 2004, Oncogene.

[2]  Rosa Bernardi,et al.  PML regulates p53 stability by sequestering Mdm2 to the nucleolus , 2004, Nature Cell Biology.

[3]  K. Nakashiro,et al.  Skp2 and Jab1 Expression Are Associated with Inverse Expression of p27KIP1 and Poor Prognosis in Oral Squamous Cell Carcinomas , 2003, Oncology.

[4]  Guillermina Lozano,et al.  Pirh2, a p53-Induced Ubiquitin-Protein Ligase, Promotes p53 Degradation , 2003, Cell.

[5]  C. Maki,et al.  The MDM2 RING-finger domain is required to promote p53 nuclear export , 2000, Nature Cell Biology.

[6]  J. Rodriguez,et al.  Identification of a Functional Nuclear Export Sequence in BRCA1* , 2000, The Journal of Biological Chemistry.

[7]  J. Kato,et al.  Prognostic significance of localized p27Kip1 and potential role of Jab1/CSN5 in pancreatic cancer. , 2004, Oncology reports.

[8]  S. Beckendorf,et al.  The COP9 signalosome promotes degradation of Cyclin E during early Drosophila oogenesis. , 2003, Developmental cell.

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

[10]  D. Livingston,et al.  Polyubiquitination of p53 by a Ubiquitin Ligase Activity of p300 , 2003, Science.

[11]  H. Richard-Foy,et al.  CSN5/Jab1 Is Involved in Ligand-Dependent Degradation of Estrogen Receptor α by the Proteasome , 2005, Molecular and Cellular Biology.

[12]  L. Aravind,et al.  Role of Predicted Metalloprotease Motif of Jab1/Csn5 in Cleavage of Nedd8 from Cul1 , 2002, Science.

[13]  S. Yamanaka,et al.  Multiple Functions of Jab1 Are Required for Early Embryonic Development and Growth Potential in Mice* , 2004, Journal of Biological Chemistry.

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

[15]  C. Maki,et al.  MDM2 Can Promote the Ubiquitination, Nuclear Export, and Degradation of p53 in the Absence of Direct Binding* , 2001, The Journal of Biological Chemistry.

[16]  S. Park,et al.  Jab1/CSN5, a Component of the COP9 Signalosome, Regulates Transforming Growth Factor β Signaling by Binding to Smad7 and Promoting Its Degradation , 2004, Molecular and Cellular Biology.

[17]  R. Kraft,et al.  COP9 signalosome‐specific phosphorylation targets p53 to degradation by the ubiquitin system , 2001, The EMBO journal.

[18]  Patrick Dowd,et al.  The ubiquitin ligase COP1 is a critical negative regulator of p53 , 2004, Nature.

[19]  T. Toda,et al.  A new group of conserved coactivators that increase the specificity of AP-1 transcription factors , 1996, Nature.

[20]  Charles J. Sherr,et al.  Nucleolar Arf sequesters Mdm2 and activates p53 , 1999, Nature Cell Biology.

[21]  D. Lane,et al.  Mdm2-Mediated NEDD8 Conjugation of p53 Inhibits Its Transcriptional Activity , 2004, Cell.

[22]  T. Niki,et al.  Immunohistochemical study of Skp2 and Jab1, two key molecules in the degradation of P27, in lung adenocarcinoma , 2004, Pathology international.

[23]  L. Aravind,et al.  Role of Rpn11 Metalloprotease in Deubiquitination and Degradation by the 26S Proteasome , 2002, Science.

[24]  K. Tsai,et al.  An intact HDM2 RING-finger domain is required for nuclear exclusion of p53 , 2000, Nature Cell Biology.

[25]  J. Kato,et al.  Degradation of the cyclin-dependent-kinase inhibitor p27Kip1 is instigated by Jab1 , 1999, Nature.

[26]  Xin Lu,et al.  Live or let die: the cell's response to p53 , 2002, Nature Reviews Cancer.

[27]  C. Kittas,et al.  Jun activation domain-binding protein 1 expression in breast cancer inversely correlates with the cell cycle inhibitor p27(Kip1). , 2003, Cancer research.

[28]  Xuesong Cao,et al.  Jab1 antagonizes TGF‐β signaling by inducing Smad4 degradation , 2002 .

[29]  Y. Dong,et al.  Jab1 expression is associated with inverse expression of p27(kip1) and poor prognosis in epithelial ovarian tumors. , 2001, Clinical cancer research : an official journal of the American Association for Cancer Research.

[30]  A. Levine,et al.  Nuclear Export Is Required for Degradation of Endogenous p53 by MDM2 and Human Papillomavirus E6 , 1998, Molecular and Cellular Biology.

[31]  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.

[32]  Muyang Li,et al.  Mono- Versus Polyubiquitination: Differential Control of p53 Fate by Mdm2 , 2003, Science.

[33]  Minoru Yoshida,et al.  The Cytoplasmic Shuttling and Subsequent Degradation of p27Kip1 Mediated by Jab1/CSN5 and the COP9 Signalosome Complex* , 2002, The Journal of Biological Chemistry.

[34]  P. Giannakakou,et al.  The importance of p53 location: nuclear or cytoplasmic zip code? , 2003, Drug resistance updates : reviews and commentaries in antimicrobial and anticancer chemotherapy.

[35]  M. Oren.  Regulation of the p53 Tumor Suppressor Protein* , 1999, The Journal of Biological Chemistry.

[36]  H. Nakamine,et al.  Jun activation domain-binding protein 1 expression in malignant lymphoma of the thyroid: its linkage to degree of malignancy and p27 expression. , 2003, Anticancer research.

[37]  Guillermina Lozano,et al.  Rescue of early embryonic lethality in mdm2-deficient mice by deletion of p53 , 1995, Nature.

[38]  L. Latonen,et al.  Cellular stress and DNA damage invoke temporally distinct Mdm2, p53 and PML complexes and damage-specific nuclear relocalization , 2003, Journal of Cell Science.

[39]  W. Kaelin,et al.  Degradation of p53 by adenovirus E4orf6 and E1B55K proteins occurs via a novel mechanism involving a Cullin-containing complex. , 2001, Genes & development.

[40]  G. Wahl,et al.  A leucine‐rich nuclear export signal in the p53 tetramerization domain: regulation of subcellular localization and p53 activity by NES masking , 1999, The EMBO journal.