MDM2-C Functions as an E3 Ubiquitin Ligase.
MDM2 splice variants
breast cancer
mutant p53
wild-type p53
Journal
Cancer management and research
ISSN: 1179-1322
Titre abrégé: Cancer Manag Res
Pays: New Zealand
ID NLM: 101512700
Informations de publication
Date de publication:
2020
2020
Historique:
received:
07
05
2020
accepted:
02
08
2020
entrez:
9
9
2020
pubmed:
10
9
2020
medline:
10
9
2020
Statut:
epublish
Résumé
Mouse double minute 2 (MDM2) is an E3 ubiquitin ligase that is over-expressed in many cancers and regulates target proteins through ubiquitination. Full-length MDM2 (MDM2-FL) is best known for targeting wild-type p53 for degradation by the proteasome, but the functions of the many splice variants of MDM2 are under-explored. The three well-studied alternative MDM2 isoforms are MDM2-A/ALT2, MDM2-B/ALT1, and MDM2-C/ALT3. MDM2-A and MDM2-B are capable of down-regulating MDM2-FL activity and have transforming activity in cancers with mutant p53. The MDM2 isoform MDM2-C is over-expressed in breast cancer and correlates with decreased survival in the context of mutant p53 expression. Therefore, MDM2-C requires further study to determine if it has biochemical activities similar to MDM2-FL. Hypothesis: We hypothesized that like MDM2-FL, the MDM2-C isoform (lacking exons 5-9 and containing a full C-terminal RING finger sequence) would maintain E3 ubiquitin ligase activity. In order to explore the biochemical function of MDM2-C, we used an in vitro ubiquitination assay and a glutaraldehyde cross-linking assay. Here we report, for the first time, that MDM2-C has E3 auto-ubiquitin ligase activity, which can promote ubiquitination of wild-type p53 and mutant p53 R273H, and also can form a protein-protein interaction with p53 proteins. This information strongly positions MDM2-C as a protein with biochemical activities that may explain the varied outcomes observed in patients with high-level expression of MDM2-C in the presence of wild-type p53 versus mutant p53.
Sections du résumé
BACKGROUND
BACKGROUND
Mouse double minute 2 (MDM2) is an E3 ubiquitin ligase that is over-expressed in many cancers and regulates target proteins through ubiquitination. Full-length MDM2 (MDM2-FL) is best known for targeting wild-type p53 for degradation by the proteasome, but the functions of the many splice variants of MDM2 are under-explored. The three well-studied alternative MDM2 isoforms are MDM2-A/ALT2, MDM2-B/ALT1, and MDM2-C/ALT3. MDM2-A and MDM2-B are capable of down-regulating MDM2-FL activity and have transforming activity in cancers with mutant p53. The MDM2 isoform MDM2-C is over-expressed in breast cancer and correlates with decreased survival in the context of mutant p53 expression. Therefore, MDM2-C requires further study to determine if it has biochemical activities similar to MDM2-FL. Hypothesis: We hypothesized that like MDM2-FL, the MDM2-C isoform (lacking exons 5-9 and containing a full C-terminal RING finger sequence) would maintain E3 ubiquitin ligase activity.
MATERIALS AND METHODS
METHODS
In order to explore the biochemical function of MDM2-C, we used an in vitro ubiquitination assay and a glutaraldehyde cross-linking assay.
RESULTS
RESULTS
Here we report, for the first time, that MDM2-C has E3 auto-ubiquitin ligase activity, which can promote ubiquitination of wild-type p53 and mutant p53 R273H, and also can form a protein-protein interaction with p53 proteins.
CONCLUSION
CONCLUSIONS
This information strongly positions MDM2-C as a protein with biochemical activities that may explain the varied outcomes observed in patients with high-level expression of MDM2-C in the presence of wild-type p53 versus mutant p53.
Identifiants
pubmed: 32904724
doi: 10.2147/CMAR.S260943
pii: 260943
pmc: PMC7457725
doi:
Types de publication
Journal Article
Langues
eng
Pagination
7715-7724Subventions
Organisme : NIGMS NIH HHS
ID : R25 GM060665
Pays : United States
Informations de copyright
© 2020 Kim et al.
Déclaration de conflit d'intérêts
The authors report no conflicts of interest in this work.
Références
Cell. 1991 Jun 14;65(6):1083-91
pubmed: 1646078
Cell. 1997 Feb 7;88(3):323-31
pubmed: 9039259
Subcell Biochem. 2014;85:247-61
pubmed: 25201199
Nat Commun. 2013;4:2996
pubmed: 24356649
J Mol Cell Biol. 2019 Jul 19;11(7):605-609
pubmed: 31283823
Mol Cell. 2006 Feb 3;21(3):307-15
pubmed: 16455486
PLoS One. 2013 Oct 11;8(10):e77643
pubmed: 24147044
Nat Struct Mol Biol. 2014 Apr;21(4):301-7
pubmed: 24699078
Mol Cell Biol. 2019 Feb 4;39(4):
pubmed: 30455251
Oncogene. 2014 Aug 28;33(35):4365-76
pubmed: 24096477
Mol Cell Biol. 2007 Dec;27(23):8284-95
pubmed: 17908790
Genes Dev. 2018 Aug 1;32(15-16):1045-1059
pubmed: 30012555
Proc Natl Acad Sci U S A. 1999 Sep 28;96(20):11364-9
pubmed: 10500182
Proc Natl Acad Sci U S A. 1993 Apr 15;90(8):3319-23
pubmed: 8475074
PLoS One. 2014 Aug 08;9(8):e104444
pubmed: 25105592
Breast Cancer Res Treat. 2019 Feb;174(1):257-269
pubmed: 30470976
J Biol Chem. 2011 May 6;286(18):16018-29
pubmed: 21454483
Cancer Res. 2006 Oct 1;66(19):9502-8
pubmed: 17018606
Cell Cycle. 2017 Apr 3;16(7):660-664
pubmed: 28166445
Mol Cancer Res. 2003 Dec;1(14):1001-8
pubmed: 14707283
Nat Commun. 2020 Feb 5;11(1):711
pubmed: 32024829
Genes Cancer. 2012 Mar;3(3-4):311-9
pubmed: 23150764
Mol Cancer Res. 2011 May;9(5):577-88
pubmed: 21478269
EMBO J. 2004 Apr 7;23(7):1547-56
pubmed: 15029243
Annu Rev Biochem. 2009;78:399-434
pubmed: 19489725
J Biol Chem. 2006 Sep 29;281(39):28575-83
pubmed: 16870621
Neoplasia. 2013 Sep;15(9):1049-63
pubmed: 24027430
Nat Struct Mol Biol. 2017 Jul;24(7):578-587
pubmed: 28553961
FEBS Lett. 1999 Mar 19;447(1):5-9
pubmed: 10218570
Nat Struct Mol Biol. 2010 Aug;17(8):982-9
pubmed: 20639885
Nature. 2000 Nov 16;408(6810):307-10
pubmed: 11099028
Cancer Res. 1997 Nov 15;57(22):5013-6
pubmed: 9371494
J Biol Chem. 2000 Mar 24;275(12):8945-51
pubmed: 10722742