5aiu

Structural highlights

Function

[RNF4_RAT] E3 ubiquitin-protein ligase which binds polysumoylated chains covalently attached to proteins and mediates 'Lys-6'-, 'Lys-11'-, 'Lys-48'- and 'Lys-63'-linked polyubiquitination of those substrates and their subsequent targeting to the proteasome for degradation. Regulates the degradation of several proteins including PML and the transcriptional activator PEA3. Involved in chromosome alignment and spindle assembly, it regulates the kinetochore CENPH-CENPI-CENPK complex by targeting polysumoylated CENPI to proteasomal degradation. Regulates the cellular responses to hypoxia and heat shock through degradation of respectively EPAS1 and PARP1. Alternatively, it may also bind DNA/nucleosomes and have a more direct role in the regulation of transcription for instance enhancing basal transcription and steroid receptor-mediated transcriptional activation.^{[1] [2] [3] [4] [5] [6]} [UBC_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.^{[7] [8]} [UBE2N_HUMAN] The UBE2V1-UBE2N and UBE2V2-UBE2N heterodimers catalyze the synthesis of non-canonical 'Lys-63'-linked polyubiquitin chains. This type of polyubiquitination does not lead to protein degradation by the proteasome. Mediates transcriptional activation of target genes. Plays a role in the control of progress through the cell cycle and differentiation. Plays a role in the error-free DNA repair pathway and contributes to the survival of cells after DNA damage. Acts together with the E3 ligases, HLTF and SHPRH, in the 'Lys-63'-linked poly-ubiquitination of PCNA upon genotoxic stress, which is required for DNA repair. Appears to act together with E3 ligase RNF5 in the 'Lys-63'-linked polyubiquitination of JKAMP thereby regulating JKAMP function by decreasing its association with components of the proteasome and ERAD. Promotes TRIM5 capsid-specific restriction activity and the UBE2V1-UBE2N heterodimer acts in concert with TRIM5 to generate 'Lys-63'-linked polyubiquitin chains which activate the MAP3K7/TAK1 complex which in turn results in the induction and expression of NF-kappa-B and MAPK-responsive inflammatory genes (By similarity).^{[9] [10] [11] [12] [13]}

References

1. ↑ Moilanen AM, Poukka H, Karvonen U, Hakli M, Janne OA, Palvimo JJ. Identification of a novel RING finger protein as a coregulator in steroid receptor-mediated gene transcription. Mol Cell Biol. 1998 Sep;18(9):5128-39. PMID:9710597
2. ↑ Hakli M, Karvonen U, Janne OA, Palvimo JJ. The RING finger protein SNURF is a bifunctional protein possessing DNA binding activity. J Biol Chem. 2001 Jun 29;276(26):23653-60. Epub 2001 Apr 23. PMID:11319220 doi:10.1074/jbc.M009891200
3. ↑ Hakli M, Lorick KL, Weissman AM, Janne OA, Palvimo JJ. Transcriptional coregulator SNURF (RNF4) possesses ubiquitin E3 ligase activity. FEBS Lett. 2004 Feb 27;560(1-3):56-62. PMID:14987998 doi:10.1016/S0014-5793(04)00070-5
4. ↑ Hakli M, Karvonen U, Janne OA, Palvimo JJ. SUMO-1 promotes association of SNURF (RNF4) with PML nuclear bodies. Exp Cell Res. 2005 Mar 10;304(1):224-33. Epub 2004 Nov 23. PMID:15707587 doi:10.1016/j.yexcr.2004.10.029
5. ↑ Tatham MH, Geoffroy MC, Shen L, Plechanovova A, Hattersley N, Jaffray EG, Palvimo JJ, Hay RT. RNF4 is a poly-SUMO-specific E3 ubiquitin ligase required for arsenic-induced PML degradation. Nat Cell Biol. 2008 May;10(5):538-46. doi: 10.1038/ncb1716. Epub 2008 Apr 13. PMID:18408734 doi:10.1038/ncb1716
6. ↑ Geoffroy MC, Jaffray EG, Walker KJ, Hay RT. Arsenic-induced SUMO-dependent recruitment of RNF4 into PML nuclear bodies. Mol Biol Cell. 2010 Dec;21(23):4227-39. doi: 10.1091/mbc.E10-05-0449. Epub 2010, Oct 13. PMID:20943951 doi:10.1091/mbc.E10-05-0449
7. ↑ 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
8. ↑ 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
9. ↑ Hofmann RM, Pickart CM. Noncanonical MMS2-encoded ubiquitin-conjugating enzyme functions in assembly of novel polyubiquitin chains for DNA repair. Cell. 1999 Mar 5;96(5):645-53. PMID:10089880
10. ↑ Bothos J, Summers MK, Venere M, Scolnick DM, Halazonetis TD. The Chfr mitotic checkpoint protein functions with Ubc13-Mms2 to form Lys63-linked polyubiquitin chains. Oncogene. 2003 Oct 16;22(46):7101-7. PMID:14562038 doi:10.1038/sj.onc.1206831
11. ↑ Tcherpakov M, Delaunay A, Toth J, Kadoya T, Petroski MD, Ronai ZA. Regulation of endoplasmic reticulum-associated degradation by RNF5-dependent ubiquitination of JNK-associated membrane protein (JAMP). J Biol Chem. 2009 May 1;284(18):12099-109. doi: 10.1074/jbc.M808222200. Epub 2009, Mar 6. PMID:19269966 doi:10.1074/jbc.M808222200
12. ↑ 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
13. ↑ Pertel T, Hausmann S, Morger D, Zuger S, Guerra J, Lascano J, Reinhard C, Santoni FA, Uchil PD, Chatel L, Bisiaux A, Albert ML, Strambio-De-Castillia C, Mothes W, Pizzato M, Grutter MG, Luban J. TRIM5 is an innate immune sensor for the retrovirus capsid lattice. Nature. 2011 Apr 21;472(7343):361-5. doi: 10.1038/nature09976. PMID:21512573 doi:10.1038/nature09976