title: Acetylation-dependent regulation of MDM2 E3 ligase activity dictates its oncogenic function.
abstract: Abnormal activation of the oncogenic E3 ubiquitin ligase murine double minute 2 (MDM2) is frequently observed in human cancers. By ubiquitinating the tumor suppressor p53 protein, which leads to its proteasome-mediated destruction, MDM2 limits the tumor-suppressing activity of p53. On the other hand, by ubiquitinating itself, MDM2 targets itself for destruction and promotes the p53 tumor suppressor pathway, a process that can be antagonized by the deubiquitinase herpesvirus-associated ubiquitin-specific protease (HAUSP). We investigated the regulation of MDM2 substrate specificity and found that acetyltransferase p300-mediated acetylation and stabilization of MDM2 are molecular switches that block self-ubiquitination, thereby shifting its E3 ligase activity toward p53. In vitro and in cancer cell lines, p300-mediated acetylation of MDM2 on Lys182and Lys185enabled HAUSP to bind, presumably deubiquitinate, and stabilize MDM2. This acetylation within the nuclear localization signal domain decreased its interaction with the acidic domain, subsequently increased the interaction between the acidic domain and RING domain in MDM2, enabled the binding of HAUSP to the acidic domain in MDM2, and shifted MDM2 activity from autoubiquitination to p53 ubiquitination. However, upon genotoxic stress through exposure to etoposide, the deacetylase sirtuin 1 (SIRT1) deacetylated MDM2 at Lys182and Lys185, thereby promoting self-ubiquitination and less ubiquitination and subsequent degradation of p53, thus increasing p53-dependent apoptosis. Therefore, this study indicates that dynamic acetylation is a molecular switch in the regulation of MDM2 substrate specificity, revealing further insight into the posttranslational regulation of the MDM2/p53 cell survival axis.
authors.affiliation: Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Naoe T
authors.identifier: 0000-0001-5618-7538
authors.initials: NT
authors.lastname: Nihira
authors.affiliation: Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA.|Department of Infectious Diseases, National Center for Global Health and Medicine, Tokyo 162-8655, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Ogura
authors.affiliation: Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA.|Center for Advanced Stem Cell and Regenerative Research, Tohoku University Graduate School of Dentistry, Sendai 980-8575, Japan.
authors.forename: Kouhei
authors.identifier: 0000-0001-9523-4296
authors.initials: K
authors.lastname: Shimizu
authors.affiliation: Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Brian J
authors.identifier: 0000-0003-0463-7028
authors.initials: BJ
authors.lastname: North
authors.affiliation: Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Jinfang
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA.|Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue-yang Road, Shanghai 200031, China.
authors.forename: Daming
authors.initials: D
authors.lastname: Gao
authors.affiliation: Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA. wwei2@bidmc.harvard.edu hinuzuka@bidmc.harvard.edu.|Center for Advanced Stem Cell and Regenerative Research, Tohoku University Graduate School of Dentistry, Sendai 980-8575, Japan.
authors.forename: Hiroyuki
authors.identifier: 0000-0002-4892-0047
authors.initials: H
authors.lastname: Inuzuka
authors.affiliation: Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA. wwei2@bidmc.harvard.edu hinuzuka@bidmc.harvard.edu.
authors.forename: Wenyi
authors.identifier: 0000-0003-0512-3811
authors.initials: W
authors.lastname: Wei
mesh_terms: D000072283:A549 Cells; D000107:Acetylation; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000378:metabolism*; D045325:HCT116 Cells; D057809:HEK293 Cells; D006801:Humans; D015151:Immunoblotting; D008239:Lysine / Q000235:genetics / Q000378:metabolism; D061986:MCF-7 Cells; D009857:Oncogenes; D011485:Protein Binding; D051736:Proto-Oncogene Proteins c-mdm2 / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D056564:Sirtuin 1 / Q000235:genetics / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D000076084:Ubiquitin-Specific Peptidase 7 / Q000378:metabolism; D054875:Ubiquitination; D050880:p300-CBP Transcription Factors / Q000235:genetics / Q000378:metabolism*; D000099224:p300-CBP-Associated Factor
chemical_list: D008239:Lysine; D051736:Proto-Oncogene Proteins c-mdm2; D056564:Sirtuin 1; D016159:Tumor Suppressor Protein p53; D000076084:Ubiquitin-Specific Peptidase 7; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor; C447939:SIRT1 protein, human