| Structural highlights
Warning: this is a large structure, and loading might take a long time or not happen at all.
Function
[H2B1J_HUMAN] Core component of nucleosome. Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries which require DNA as a template. Histones thereby play a central role in transcription regulation, DNA repair, DNA replication and chromosomal stability. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called histone code, and nucleosome remodeling.[1] [2] [3] Has broad antibacterial activity. May contribute to the formation of the functional antimicrobial barrier of the colonic epithelium, and to the bactericidal activity of amniotic fluid.[4] [5] [6] [RN169_HUMAN] Probable E3 ubiquitin-protein ligase that acts as a negative regulator of double-strand breaks (DSBs) repair following DNA damage. Recruited to DSB repair sites by recognizing and binding ubiquitin catalyzed by RNF168 and competes with TP53BP1 and BRCA1 for association with RNF168-modified chromatin, thereby acting as a negative regulator of DSBs repair. E3 ubiquitin-protein ligase activity is not required for regulation of DSBs repair.[7] [8] [9] [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.[10] [11]
Publication Abstract from PubMed
The protein 53BP1 plays a central regulatory role in DNA double-strand break repair. 53BP1 relocates to chromatin by recognizing RNF168-mediated mono-ubiquitylation of histone H2A Lys15 in the nucleosome core particle dimethylated at histone H4 Lys20 (NCP-ubme). 53BP1 relocation is terminated by ubiquitin ligases RNF169 and RAD18 via unknown mechanisms. Using nuclear magnetic resonance (NMR) spectroscopy and biochemistry, we show that RNF169 bridges ubiquitin and histone surfaces, stabilizing a pre-existing ubiquitin orientation in NCP-ubme to form a high-affinity complex. This conformational selection mechanism contrasts with the low-affinity binding mode of 53BP1, and it ensures 53BP1 displacement by RNF169 from NCP-ubme. We also show that RAD18 binds tightly to NCP-ubme through a ubiquitin-binding domain that contacts ubiquitin and nucleosome surfaces accessed by 53BP1. Our work uncovers diverse ubiquitin recognition mechanisms in the nucleosome, explaining how RNF168, RNF169, and RAD18 regulate 53BP1 chromatin recruitment and how specificity can be achieved in the recognition of a ubiquitin-modified substrate.
Mechanisms of Ubiquitin-Nucleosome Recognition and Regulation of 53BP1 Chromatin Recruitment by RNF168/169 and RAD18.,Hu Q, Botuyan MV, Cui G, Zhao D, Mer G Mol Cell. 2017 May 18;66(4):473-487.e9. doi: 10.1016/j.molcel.2017.04.009. Epub, 2017 May 11. PMID:28506460[12]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Kim HS, Cho JH, Park HW, Yoon H, Kim MS, Kim SC. Endotoxin-neutralizing antimicrobial proteins of the human placenta. J Immunol. 2002 Mar 1;168(5):2356-64. PMID:11859126
- ↑ Tollin M, Bergman P, Svenberg T, Jornvall H, Gudmundsson GH, Agerberth B. Antimicrobial peptides in the first line defence of human colon mucosa. Peptides. 2003 Apr;24(4):523-30. PMID:12860195
- ↑ Howell SJ, Wilk D, Yadav SP, Bevins CL. Antimicrobial polypeptides of the human colonic epithelium. Peptides. 2003 Nov;24(11):1763-70. PMID:15019208 doi:10.1016/j.peptides.2003.07.028
- ↑ Kim HS, Cho JH, Park HW, Yoon H, Kim MS, Kim SC. Endotoxin-neutralizing antimicrobial proteins of the human placenta. J Immunol. 2002 Mar 1;168(5):2356-64. PMID:11859126
- ↑ Tollin M, Bergman P, Svenberg T, Jornvall H, Gudmundsson GH, Agerberth B. Antimicrobial peptides in the first line defence of human colon mucosa. Peptides. 2003 Apr;24(4):523-30. PMID:12860195
- ↑ Howell SJ, Wilk D, Yadav SP, Bevins CL. Antimicrobial polypeptides of the human colonic epithelium. Peptides. 2003 Nov;24(11):1763-70. PMID:15019208 doi:10.1016/j.peptides.2003.07.028
- ↑ Poulsen M, Lukas C, Lukas J, Bekker-Jensen S, Mailand N. Human RNF169 is a negative regulator of the ubiquitin-dependent response to DNA double-strand breaks. J Cell Biol. 2012 Apr 16;197(2):189-99. doi: 10.1083/jcb.201109100. Epub 2012 Apr, 9. PMID:22492721 doi:http://dx.doi.org/10.1083/jcb.201109100
- ↑ Chen J, Feng W, Jiang J, Deng Y, Huen MS. Ring finger protein RNF169 antagonizes the ubiquitin-dependent signaling cascade at sites of DNA damage. J Biol Chem. 2012 Aug 10;287(33):27715-22. doi: 10.1074/jbc.M112.373530. Epub, 2012 Jun 25. PMID:22733822 doi:http://dx.doi.org/10.1074/jbc.M112.373530
- ↑ Panier S, Ichijima Y, Fradet-Turcotte A, Leung CC, Kaustov L, Arrowsmith CH, Durocher D. Tandem protein interaction modules organize the ubiquitin-dependent response to DNA double-strand breaks. Mol Cell. 2012 Aug 10;47(3):383-95. doi: 10.1016/j.molcel.2012.05.045. Epub 2012 , Jun 27. PMID:22742833 doi:10.1016/j.molcel.2012.05.045
- ↑ 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
- ↑ 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
- ↑ Hu Q, Botuyan MV, Cui G, Zhao D, Mer G. Mechanisms of Ubiquitin-Nucleosome Recognition and Regulation of 53BP1 Chromatin Recruitment by RNF168/169 and RAD18. Mol Cell. 2017 May 18;66(4):473-487.e9. doi: 10.1016/j.molcel.2017.04.009. Epub, 2017 May 11. PMID:28506460 doi:http://dx.doi.org/10.1016/j.molcel.2017.04.009
|
