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24  structures 762  species 0  interactions 6751  sequences 76  architectures

Family: zf-A20 (PF01754)

Summary: A20-like zinc finger

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This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

A20-like zinc finger Provide feedback

The A20 Zn-finger of bovine/human Rabex5/rabGEF1 is a Ubiquitin Binding Domain [5-6]. The zinc finger mediates self-association in A20. These fingers also mediate IL-1-induced NF-kappa B activation.

Literature references

  1. Heyninck K, Beyaert R; , FEBS Lett 1999;442:147-150.: The cytokine-inducible zinc finger protein A20 inhibits IL-1-induced NF- kappaB activation at the level of TRAF6. PUBMED:9928991 EPMC:9928991

  2. De Valck D, Heyninck K, Van Criekinge W, Contreras R, Beyaert R, Fiers W; , FEBS Lett 1996;384:61-64.: A20, an inhibitor of cell death, self-associates by its zinc finger domain. PUBMED:8797804 EPMC:8797804

  3. Song HY, Rothe M, Goeddel DV; , Proc Natl Acad Sci U S A 1996;93:6721-6725.: The tumor necrosis factor-inducible zinc finger protein A20 interacts with TRAF1/TRAF2 and inhibits NF-kappaB activation. PUBMED:8692885 EPMC:8692885

  4. Opipari AW Jr, Boguski MS, Dixit VM; , J Biol Chem 1990;265:14705-14708.: The A20 cDNA induced by tumor necrosis factor alpha encodes a novel type of zinc finger protein. PUBMED:2118515 EPMC:2118515

  5. Penengo L, Mapelli M, Murachelli AG, Confalonieri S, Magri L, Musacchio A, Di Fiore PP, Polo S, Schneider TR;, Cell. 2006;124:1183-1195.: Crystal structure of the ubiquitin binding domains of rabex-5 reveals two modes of interaction with ubiquitin. PUBMED:16499958 EPMC:16499958

  6. Lee S, Tsai YC, Mattera R, Smith WJ, Kostelansky MS, Weissman AM, Bonifacino JS, Hurley JH;, Nat Struct Mol Biol. 2006;13:264-271.: Structural basis for ubiquitin recognition and autoubiquitination by Rabex-5. PUBMED:16462746 EPMC:16462746

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR002653

Zinc finger (Znf) domains are relatively small protein motifs which contain multiple finger-like protrusions that make tandem contacts with their target molecule. Some of these domains bind zinc, but many do not; instead binding other metals such as iron, or no metal at all. For example, some family members form salt bridges to stabilise the finger-like folds. They were first identified as a DNA-binding motif in transcription factor TFIIIA from Xenopus laevis (African clawed frog), however they are now recognised to bind DNA, RNA, protein and/or lipid substrates [ PUBMED:10529348 , PUBMED:15963892 , PUBMED:15718139 , PUBMED:17210253 , PUBMED:12665246 ]. Their binding properties depend on the amino acid sequence of the finger domains and of the linker between fingers, as well as on the higher-order structures and the number of fingers. Znf domains are often found in clusters, where fingers can have different binding specificities. There are many superfamilies of Znf motifs, varying in both sequence and structure. They display considerable versatility in binding modes, even between members of the same class (e.g. some bind DNA, others protein), suggesting that Znf motifs are stable scaffolds that have evolved specialised functions. For example, Znf-containing proteins function in gene transcription, translation, mRNA trafficking, cytoskeleton organisation, epithelial development, cell adhesion, protein folding, chromatin remodelling and zinc sensing, to name but a few [ PUBMED:11179890 ]. Zinc-binding motifs are stable structures, and they rarely undergo conformational changes upon binding their target.

This entry represents the zinc finger domain found in A20. A20 is an inhibitor of cell death that inhibits NF-kappaB activation via the tumour necrosis factor receptor associated factor pathway [ PUBMED:17449604 ]. The zinc finger domains appear to mediate self-association in A20. These fingers also mediate IL-1-induced NF-kappa B activation.

Gene Ontology

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database (reference proteomes) using the family HMM. We also generate alignments using four representative proteomes (RP) sets and the UniProtKB sequence database. More...

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We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.

Representative proteomes UniProt
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Representative proteomes UniProt

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We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.

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You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

HMM logo

HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...


This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

Note: You can also download the data file for the tree.

Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation View help on the curation process

Seed source: SMART
Previous IDs: none
Type: Family
Sequence Ontology: SO:0100021
Author: SMART
Number in seed: 117
Number in full: 6751
Average length of the domain: 24.1 aa
Average identity of full alignment: 44 %
Average coverage of the sequence by the domain: 8.28 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 61295632 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 21.6 21.6
Trusted cut-off 21.6 21.6
Noise cut-off 21.5 21.5
Model length: 24
Family (HMM) version: 19
Download: download the raw HMM for this family

Species distribution

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Colour assignments

Archea Archea Eukaryota Eukaryota
Bacteria Bacteria Other sequences Other sequences
Viruses Viruses Unclassified Unclassified
Viroids Viroids Unclassified sequence Unclassified sequence


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This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the adjacent tab. More...

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For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the zf-A20 domain has been found. There are 24 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein sequence.

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AlphaFold Structure Predictions

The list of proteins below match this family and have AlphaFold predicted structures. Click on the protein accession to view the predicted structure.

Protein Predicted structure External Information
A0A044S4Z8 View 3D Structure Click here
A0A044V0B5 View 3D Structure Click here
A0A077Z3J5 View 3D Structure Click here
A0A077ZBX2 View 3D Structure Click here
A0A0K0DW21 View 3D Structure Click here
A0A0K0DW27 View 3D Structure Click here
A0A0N4UCW4 View 3D Structure Click here
A0A0P0XNG8 View 3D Structure Click here
A0A0R0ENC6 View 3D Structure Click here
A0A0R0F4E8 View 3D Structure Click here
A0A0R4J5B8 View 3D Structure Click here
A0A1D6P4W8 View 3D Structure Click here
A0A1P6BYS8 View 3D Structure Click here
A0A3P7SQX6 View 3D Structure Click here
A0A3Q0KK37 View 3D Structure Click here
A0A3Q0KNZ0 View 3D Structure Click here
A0A486WY48 View 3D Structure Click here
A2BFW0 View 3D Structure Click here
A2YEZ6 View 3D Structure Click here
A2Z2J6 View 3D Structure Click here
A3BDI8 View 3D Structure Click here
A3C039 View 3D Structure Click here
A8QZ73 View 3D Structure Click here
B2RUR8 View 3D Structure Click here
B4F8R6 View 3D Structure Click here
B4FQ77 View 3D Structure Click here
B5DF11 View 3D Structure Click here
B6UIJ0 View 3D Structure Click here
C6SXF9 View 3D Structure Click here
D3ZH40 View 3D Structure Click here
D4ABZ4 View 3D Structure Click here
E0A2W1 View 3D Structure Click here
E7F165 View 3D Structure Click here
F1QJ69 View 3D Structure Click here
F1R8D3 View 3D Structure Click here
G3V631 View 3D Structure Click here
G4LXY5 View 3D Structure Click here
G4VCZ9 View 3D Structure Click here
I1JNG1 View 3D Structure Click here
I1JQ03 View 3D Structure Click here