5mnj

Structural highlights

Disease

[MDM2_HUMAN] Note=Seems to be amplified in certain tumors (including soft tissue sarcomas, osteosarcomas and gliomas). A higher frequency of splice variants lacking p53 binding domain sequences was found in late-stage and high-grade ovarian and bladder carcinomas. Four of the splice variants show loss of p53 binding.

Function

[MDM4_HUMAN] Inhibits p53/TP53- and TP73/p73-mediated cell cycle arrest and apoptosis by binding its transcriptional activation domain. Inhibits degradation of MDM2. Can reverse MDM2-targeted degradation of TP53 while maintaining suppression of TP53 transactivation and apoptotic functions.^{[1] [2]} [UB2D2_HUMAN] Accepts ubiquitin from the E1 complex and catalyzes its covalent attachment to other proteins. In vitro catalyzes 'Lys-48'-linked polyubiquitination. Mediates the selective degradation of short-lived and abnormal proteins. Functions in the E6/E6-AP-induced ubiquitination of p53/TP53. Mediates ubiquitination of PEX5 and autoubiquitination of STUB1 and TRAF6. Involved in the signal-induced conjugation and subsequent degradation of NFKBIA, FBXW2-mediated GCM1 ubiquitination and degradation, MDM2-dependent degradation of p53/TP53 and the activation of MAVS in the mitochondria by DDX58/RIG-I in response to viral infection. Essential for viral activation of IRF3.^{[3] [4] [5] [6] [7] [8] [9] [10]} [MDM2_HUMAN] E3 ubiquitin-protein ligase that mediates ubiquitination of p53/TP53, leading to its degradation by the proteasome. Inhibits p53/TP53- and p73/TP73-mediated cell cycle arrest and apoptosis by binding its transcriptional activation domain. Also acts as an ubiquitin ligase E3 toward itself and ARRB1. Permits the nuclear export of p53/TP53. Promotes proteasome-dependent ubiquitin-independent degradation of retinoblastoma RB1 protein. Inhibits DAXX-mediated apoptosis by inducing its ubiquitination and degradation. Component of the TRIM28/KAP1-MDM2-p53/TP53 complex involved in stabilizing p53/TP53. Also component of the TRIM28/KAP1-ERBB4-MDM2 complex which links growth factor and DNA damage response pathways. Mediates ubiquitination and subsequent proteasome degradation of DYRK2 in nucleus. Ubiquitinates IGF1R and promotes it to proteasomal degradation.^{[11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21]} [UBB_HUMAN] Ubiquitin exists either covalently attached to another protein, or free (unanchored). When covalently bound, it is conjugated to target proteins via an isopeptide bond either as a monomer (monoubiquitin), a polymer linked via different Lys residues of the ubiquitin (polyubiquitin chains) or a linear polymer linked via the initiator Met of the ubiquitin (linear polyubiquitin chains). Polyubiquitin chains, when attached to a target protein, have different functions depending on the Lys residue of the ubiquitin that is linked: Lys-6-linked may be involved in DNA repair; Lys-11-linked is involved in ERAD (endoplasmic reticulum-associated degradation) and in cell-cycle regulation; Lys-29-linked is involved in lysosomal degradation; Lys-33-linked is involved in kinase modification; Lys-48-linked is involved in protein degradation via the proteasome; Lys-63-linked is involved in endocytosis, DNA-damage responses as well as in signaling processes leading to activation of the transcription factor NF-kappa-B. Linear polymer chains formed via attachment by the initiator Met lead to cell signaling. Ubiquitin is usually conjugated to Lys residues of target proteins, however, in rare cases, conjugation to Cys or Ser residues has been observed. When polyubiquitin is free (unanchored-polyubiquitin), it also has distinct roles, such as in activation of protein kinases, and in signaling.^{[22] [23]}

References

1. ↑ Chen L, Gilkes DM, Pan Y, Lane WS, Chen J. ATM and Chk2-dependent phosphorylation of MDMX contribute to p53 activation after DNA damage. EMBO J. 2005 Oct 5;24(19):3411-22. Epub 2005 Sep 15. PMID:16163388 doi:10.1038/sj.emboj.7600812
2. ↑ Jin Y, Dai MS, Lu SZ, Xu Y, Luo Z, Zhao Y, Lu H. 14-3-3gamma binds to MDMX that is phosphorylated by UV-activated Chk1, resulting in p53 activation. EMBO J. 2006 Mar 22;25(6):1207-18. Epub 2006 Mar 2. PMID:16511572 doi:10.1038/sj.emboj.7601010
3. ↑ Gonen H, Bercovich B, Orian A, Carrano A, Takizawa C, Yamanaka K, Pagano M, Iwai K, Ciechanover A. Identification of the ubiquitin carrier proteins, E2s, involved in signal-induced conjugation and subsequent degradation of IkappaBalpha. J Biol Chem. 1999 May 21;274(21):14823-30. PMID:10329681
4. ↑ Saville MK, Sparks A, Xirodimas DP, Wardrop J, Stevenson LF, Bourdon JC, Woods YL, Lane DP. Regulation of p53 by the ubiquitin-conjugating enzymes UbcH5B/C in vivo. J Biol Chem. 2004 Oct 1;279(40):42169-81. Epub 2004 Jul 26. PMID:15280377 doi:10.1074/jbc.M403362200
5. ↑ Windheim M, Peggie M, Cohen P. Two different classes of E2 ubiquitin-conjugating enzymes are required for the mono-ubiquitination of proteins and elongation by polyubiquitin chains with a specific topology. Biochem J. 2008 Feb 1;409(3):723-9. PMID:18042044 doi:10.1042/BJ20071338
6. ↑ Chiang MH, Chen LF, Chen H. Ubiquitin-conjugating enzyme UBE2D2 is responsible for FBXW2 (F-box and WD repeat domain containing 2)-mediated human GCM1 (glial cell missing homolog 1) ubiquitination and degradation. Biol Reprod. 2008 Nov;79(5):914-20. doi: 10.1095/biolreprod.108.071407. Epub 2008, Aug 13. PMID:18703417 doi:10.1095/biolreprod.108.071407
7. ↑ Grou CP, Carvalho AF, Pinto MP, Wiese S, Piechura H, Meyer HE, Warscheid B, Sa-Miranda C, Azevedo JE. Members of the E2D (UbcH5) family mediate the ubiquitination of the conserved cysteine of Pex5p, the peroxisomal import receptor. J Biol Chem. 2008 May 23;283(21):14190-7. doi: 10.1074/jbc.M800402200. Epub 2008 , Mar 22. PMID:18359941 doi:10.1074/jbc.M800402200
8. ↑ Zeng W, Xu M, Liu S, Sun L, Chen ZJ. Key role of Ubc5 and lysine-63 polyubiquitination in viral activation of IRF3. Mol Cell. 2009 Oct 23;36(2):315-25. doi: 10.1016/j.molcel.2009.09.037. PMID:19854139 doi:10.1016/j.molcel.2009.09.037
9. ↑ Zeng W, Sun L, Jiang X, Chen X, Hou F, Adhikari A, Xu M, Chen ZJ. Reconstitution of the RIG-I pathway reveals a signaling role of unanchored polyubiquitin chains in innate immunity. Cell. 2010 Apr 16;141(2):315-30. doi: 10.1016/j.cell.2010.03.029. PMID:20403326 doi:10.1016/j.cell.2010.03.029
10. ↑ David Y, Ziv T, Admon A, Navon A. The E2 ubiquitin conjugating enzymes direct polyubiquitination to preferred lysines. J Biol Chem. 2010 Jan 8. PMID:20061386 doi:M109.089003
11. ↑ Girnita L, Girnita A, Larsson O. Mdm2-dependent ubiquitination and degradation of the insulin-like growth factor 1 receptor. Proc Natl Acad Sci U S A. 2003 Jul 8;100(14):8247-52. Epub 2003 Jun 23. PMID:12821780 doi:10.1073/pnas.1431613100
12. ↑ Li M, Brooks CL, Kon N, Gu W. A dynamic role of HAUSP in the p53-Mdm2 pathway. Mol Cell. 2004 Mar 26;13(6):879-86. PMID:15053880
13. ↑ Bernardi R, Scaglioni PP, Bergmann S, Horn HF, Vousden KH, Pandolfi PP. PML regulates p53 stability by sequestering Mdm2 to the nucleolus. Nat Cell Biol. 2004 Jul;6(7):665-72. Epub 2004 Jun 13. PMID:15195100 doi:10.1038/ncb1147
14. ↑ Sdek P, Ying H, Chang DL, Qiu W, Zheng H, Touitou R, Allday MJ, Xiao ZX. MDM2 promotes proteasome-dependent ubiquitin-independent degradation of retinoblastoma protein. Mol Cell. 2005 Dec 9;20(5):699-708. PMID:16337594 doi:10.1016/j.molcel.2005.10.017
15. ↑ Brady M, Vlatkovic N, Boyd MT. Regulation of p53 and MDM2 activity by MTBP. Mol Cell Biol. 2005 Jan;25(2):545-53. PMID:15632057 doi:25/2/545
16. ↑ Stevenson LF, Sparks A, Allende-Vega N, Xirodimas DP, Lane DP, Saville MK. The deubiquitinating enzyme USP2a regulates the p53 pathway by targeting Mdm2. EMBO J. 2007 Feb 21;26(4):976-86. Epub 2007 Feb 8. PMID:17290220 doi:10.1038/sj.emboj.7601567
17. ↑ Chen D, Zhang J, Li M, Rayburn ER, Wang H, Zhang R. RYBP stabilizes p53 by modulating MDM2. EMBO Rep. 2009 Feb;10(2):166-72. doi: 10.1038/embor.2008.231. Epub 2008 Dec 19. PMID:19098711 doi:10.1038/embor.2008.231
18. ↑ Busso CS, Iwakuma T, Izumi T. Ubiquitination of mammalian AP endonuclease (APE1) regulated by the p53-MDM2 signaling pathway. Oncogene. 2009 Apr 2;28(13):1616-25. doi: 10.1038/onc.2009.5. Epub 2009 Feb 16. PMID:19219073 doi:10.1038/onc.2009.5
19. ↑ Taira N, Yamamoto H, Yamaguchi T, Miki Y, Yoshida K. ATM augments nuclear stabilization of DYRK2 by inhibiting MDM2 in the apoptotic response to DNA damage. J Biol Chem. 2010 Feb 12;285(7):4909-19. doi: 10.1074/jbc.M109.042341. Epub 2009 , Dec 4. PMID:19965871 doi:10.1074/jbc.M109.042341
20. ↑ Gilmore-Hebert M, Ramabhadran R, Stern DF. Interactions of ErbB4 and Kap1 connect the growth factor and DNA damage response pathways. Mol Cancer Res. 2010 Oct;8(10):1388-98. doi: 10.1158/1541-7786.MCR-10-0042. Epub , 2010 Sep 21. PMID:20858735 doi:10.1158/1541-7786.MCR-10-0042
21. ↑ Fu X, Yucer N, Liu S, Li M, Yi P, Mu JJ, Yang T, Chu J, Jung SY, O'Malley BW, Gu W, Qin J, Wang Y. RFWD3-Mdm2 ubiquitin ligase complex positively regulates p53 stability in response to DNA damage. Proc Natl Acad Sci U S A. 2010 Mar 9;107(10):4579-84. doi:, 10.1073/pnas.0912094107. Epub 2010 Feb 19. PMID:20173098 doi:10.1073/pnas.0912094107
22. ↑ Huang F, Kirkpatrick D, Jiang X, Gygi S, Sorkin A. Differential regulation of EGF receptor internalization and degradation by multiubiquitination within the kinase domain. Mol Cell. 2006 Mar 17;21(6):737-48. PMID:16543144 doi:S1097-2765(06)00120-1
23. ↑ Komander D. The emerging complexity of protein ubiquitination. Biochem Soc Trans. 2009 Oct;37(Pt 5):937-53. doi: 10.1042/BST0370937. PMID:19754430 doi:10.1042/BST0370937
24. ↑ Nomura K, Klejnot M, Kowalczyk D, Hock AK, Sibbet GJ, Vousden KH, Huang DT. Structural analysis of MDM2 RING separates degradation from regulation of p53 transcription activity. Nat Struct Mol Biol. 2017 Jul;24(7):578-587. doi: 10.1038/nsmb.3414. Epub 2017, May 29. PMID:28553961 doi:http://dx.doi.org/10.1038/nsmb.3414