| Structural highlights
Function
[TNAP3_HUMAN] Ubiquitin-editing enzyme that contains both ubiquitin ligase and deubiquitinase activities. Involved in immune and inflammatory responses signaled by cytokines, such as TNF-alpha and IL-1 beta, or pathogens via Toll-like receptors (TLRs) through terminating NF-kappa-B activity. Essential component of a ubiquitin-editing protein complex, comprising also RNF11, ITCH and TAX1BP1, that ensures the transient nature of inflammatory signaling pathways. In cooperation with TAX1BP1 promotes disassembly of E2-E3 ubiquitin protein ligase complexes in IL-1R and TNFR-1 pathways; affected are at least E3 ligases TRAF6, TRAF2 and BIRC2, and E2 ubiquitin-conjugating enzymes UBE2N and UBE2D3. In cooperation with TAX1BP1 promotes ubiquitination of UBE2N and proteasomal degradation of UBE2N and UBE2D3. Upon TNF stimulation, deubiquitinates 'Lys-63'-polyubiquitin chains on RIPK1 and catalyzes the formation of 'Lys-48'-polyubiquitin chains. This leads to RIPK1 proteasomal degradation and consequently termination of the TNF- or LPS-mediated activation of NF-kappa-B. Deubiquinates TRAF6 probably acting on 'Lys-63'-linked polyubiquitin. Upon T-cell receptor (TCR)-mediated T-cell activation, deubiquitinates 'Lys-63'-polyubiquitin chains on MALT1 thereby mediating disassociation of the CBM (CARD11:BCL10:MALT1) and IKK complexes and preventing sustained IKK activation. Deubiquinates NEMO/IKBKG; the function is facilitated by TNIP1 and leads to inhibition of NF-kappa-B activation. Upon stimulation by bacterial peptidoglycans, probably deubiquitinates RIPK2. Can also inhibit I-kappa-B-kinase (IKK) through a non-catalytic mechanism which involves polyubiquitin; polyubiquitin promotes association with IKBKG and prevents IKK MAP3K7-mediated phosphorylation. Targets TRAF2 for lysosomal degradation. In vitro able to deubiquitinate both 'Lys-48'- and 'Lys-63' polyubiquitin chains. Inhibitor of programmed cell death. Has a role in the function of the lymphoid system.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Nuclear factor kappaB (NF-kappaB) activation in tumor necrosis factor, interleukin-1, and Toll-like receptor pathways requires Lys63-linked nondegradative polyubiquitination. A20 is a specific feedback inhibitor of NF-kappaB activation in these pathways that possesses dual ubiquitin-editing functions. While the N-terminal domain of A20 is a deubiquitinating enzyme (DUB) for Lys63-linked polyubiquitinated signaling mediators such as TRAF6 and RIP, its C-terminal domain is a ubiquitin ligase (E3) for Lys48-linked degradative polyubiquitination of the same substrates. To elucidate the molecular basis for the DUB activity of A20, we determined its crystal structure and performed a series of biochemical and cell biological studies. The structure reveals the potential catalytic mechanism of A20, which may be significantly different from papain-like cysteine proteases. Ubiquitin can be docked onto a conserved A20 surface; this interaction exhibits charge complementarity and no steric clash. Surprisingly, A20 does not have specificity for Lys63-linked polyubiquitin chains. Instead, it effectively removes Lys63-linked polyubiquitin chains from TRAF6 without dissembling the chains themselves. Our studies suggest that A20 does not act as a general DUB but has the specificity for particular polyubiquitinated substrates to assure its fidelity in regulating NF-kappaB activation in the tumor necrosis factor, interleukin-1, and Toll-like receptor pathways.
Molecular basis for the unique deubiquitinating activity of the NF-kappaB inhibitor A20.,Lin SC, Chung JY, Lamothe B, Rajashankar K, Lu M, Lo YC, Lam AY, Darnay BG, Wu H J Mol Biol. 2008 Feb 15;376(2):526-40. Epub 2007 Dec 4. PMID:18164316[12]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Song HY, Rothe M, Goeddel DV. The tumor necrosis factor-inducible zinc finger protein A20 interacts with TRAF1/TRAF2 and inhibits NF-kappaB activation. Proc Natl Acad Sci U S A. 1996 Jun 25;93(13):6721-5. PMID:8692885
- ↑ De Valck D, Heyninck K, Van Criekinge W, Vandenabeele P, Fiers W, Beyaert R. A20 inhibits NF-kappaB activation independently of binding to 14-3-3 proteins. Biochem Biophys Res Commun. 1997 Sep 18;238(2):590-4. PMID:9299557 doi:10.1006/bbrc.1997.7343
- ↑ Eliopoulos AG, Blake SM, Floettmann JE, Rowe M, Young LS. Epstein-Barr virus-encoded latent membrane protein 1 activates the JNK pathway through its extreme C terminus via a mechanism involving TRADD and TRAF2. J Virol. 1999 Feb;73(2):1023-35. PMID:9882303
- ↑ Evans PC, Ovaa H, Hamon M, Kilshaw PJ, Hamm S, Bauer S, Ploegh HL, Smith TS. Zinc-finger protein A20, a regulator of inflammation and cell survival, has de-ubiquitinating activity. Biochem J. 2004 Mar 15;378(Pt 3):727-34. PMID:14748687 doi:10.1042/BJ20031377
- ↑ Wertz IE, O'Rourke KM, Zhou H, Eby M, Aravind L, Seshagiri S, Wu P, Wiesmann C, Baker R, Boone DL, Ma A, Koonin EV, Dixit VM. De-ubiquitination and ubiquitin ligase domains of A20 downregulate NF-kappaB signalling. Nature. 2004 Aug 5;430(7000):694-9. Epub 2004 Jul 18. PMID:15258597 doi:10.1038/nature02794
- ↑ Mauro C, Pacifico F, Lavorgna A, Mellone S, Iannetti A, Acquaviva R, Formisano S, Vito P, Leonardi A. ABIN-1 binds to NEMO/IKKgamma and co-operates with A20 in inhibiting NF-kappaB. J Biol Chem. 2006 Jul 7;281(27):18482-8. Epub 2006 May 9. PMID:16684768 doi:10.1074/jbc.M601502200
- ↑ Li L, Soetandyo N, Wang Q, Ye Y. The zinc finger protein A20 targets TRAF2 to the lysosomes for degradation. Biochim Biophys Acta. 2009 Feb;1793(2):346-53. doi: 10.1016/j.bbamcr.2008.09.013., Epub 2008 Oct 8. PMID:18952128 doi:10.1016/j.bbamcr.2008.09.013
- ↑ Duwel M, Welteke V, Oeckinghaus A, Baens M, Kloo B, Ferch U, Darnay BG, Ruland J, Marynen P, Krappmann D. A20 negatively regulates T cell receptor signaling to NF-kappaB by cleaving Malt1 ubiquitin chains. J Immunol. 2009 Jun 15;182(12):7718-28. doi: 10.4049/jimmunol.0803313. PMID:19494296 doi:10.4049/jimmunol.0803313
- ↑ Skaug B, Chen J, Du F, He J, Ma A, Chen ZJ. Direct, noncatalytic mechanism of IKK inhibition by A20. Mol Cell. 2011 Nov 18;44(4):559-71. doi: 10.1016/j.molcel.2011.09.015. PMID:22099304 doi:10.1016/j.molcel.2011.09.015
- ↑ Komander D, Barford D. Structure of the A20 OTU domain and mechanistic insights into deubiquitination. Biochem J. 2008 Jan 1;409(1):77-85. PMID:17961127 doi:10.1042/BJ20071399
- ↑ Lin SC, Chung JY, Lamothe B, Rajashankar K, Lu M, Lo YC, Lam AY, Darnay BG, Wu H. Molecular basis for the unique deubiquitinating activity of the NF-kappaB inhibitor A20. J Mol Biol. 2008 Feb 15;376(2):526-40. Epub 2007 Dec 4. PMID:18164316 doi:http://dx.doi.org/10.1016/j.jmb.2007.11.092
- ↑ Lin SC, Chung JY, Lamothe B, Rajashankar K, Lu M, Lo YC, Lam AY, Darnay BG, Wu H. Molecular basis for the unique deubiquitinating activity of the NF-kappaB inhibitor A20. J Mol Biol. 2008 Feb 15;376(2):526-40. Epub 2007 Dec 4. PMID:18164316 doi:http://dx.doi.org/10.1016/j.jmb.2007.11.092
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