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11  structures 198  species 2  interactions 235  sequences 2  architectures

Family: Med20 (PF08612)

Summary: TATA-binding related factor (TRF) of subunit 20 of Mediator complex

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TATA-binding related factor (TRF) of subunit 20 of Mediator complex Provide feedback

This family of proteins is related to TATA-binding protein (TBP). TBP is a highly conserved RNA polymerase II general transcription factor that binds to the core promoter and initiates assembly of the preinitiation complex. Human TRF has been shown to associate with an RNA polymerase II-SRB complex [1]. This Med20 subunit of Mediator is found in the non-essential part of the head [2].

Literature references

  1. Xiao H, Tao Y, Roeder RG; , J Biol Chem. 1999;274:3937-3940.: The human homologue of Drosophila TRF-proximal protein is associated with an RNA polymerase II-SRB complex. PUBMED:9933582 EPMC:9933582

  2. Bourbon HM, Aguilera A, Ansari AZ, Asturias FJ, Berk AJ, Bjorklund S, Blackwell TK, Borggrefe T, Carey M, Carlson M, Conaway JW, Conaway RC, Emmons SW, Fondell JD, Freedman LP, Fukasawa T, Gustafsson CM, Han M, He X, Herman PK, Hinnebusch AG, Holmberg S, , Mol Cell. 2004;14:553-557.: A unified nomenclature for protein subunits of mediator complexes linking transcriptional regulators to RNA polymerase II. PUBMED:15175151 EPMC:15175151


External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR013921

The Mediator complex is a coactivator involved in the regulated transcription of nearly all RNA polymerase II-dependent genes. Mediator functions as a bridge to convey information from gene-specific regulatory proteins to the basal RNA polymerase II transcription machinery. The Mediator complex, having a compact conformation in its free form, is recruited to promoters by direct interactions with regulatory proteins and serves for the assembly of a functional preinitiation complex with RNA polymerase II and the general transcription factors. On recruitment the Mediator complex unfolds to an extended conformation and partially surrounds RNA polymerase II, specifically interacting with the unphosphorylated form of the C-terminal domain (CTD) of RNA polymerase II. The Mediator complex dissociates from the RNA polymerase II holoenzyme and stays at the promoter when transcriptional elongation begins.

The Mediator complex is composed of at least 31 subunits: MED1, MED4, MED6, MED7, MED8, MED9, MED10, MED11, MED12, MED13, MED13L, MED14, MED15, MED16, MED17, MED18, MED19, MED20, MED21, MED22, MED23, MED24, MED25, MED26, MED27, MED29, MED30, MED31, CCNC, CDK8 and CDC2L6/CDK11.

The subunits form at least three structurally distinct submodules. The head and the middle modules interact directly with RNA polymerase II, whereas the elongated tail module interacts with gene-specific regulatory proteins. Mediator containing the CDK8 module is less active than Mediator lacking this module in supporting transcriptional activation.

  • The head module contains: MED6, MED8, MED11, SRB4/MED17, SRB5/MED18, ROX3/MED19, SRB2/MED20 and SRB6/MED22.
  • The middle module contains: MED1, MED4, NUT1/MED5, MED7, CSE2/MED9, NUT2/MED10, SRB7/MED21 and SOH1/MED31. CSE2/MED9 interacts directly with MED4.
  • The tail module contains: MED2, PGD1/MED3, RGR1/MED14, GAL11/MED15 and SIN4/MED16.
  • The CDK8 module contains: MED12, MED13, CCNC and CDK8.

Individual preparations of the Mediator complex lacking one or more distinct subunits have been variously termed ARC, CRSP, DRIP, PC2, SMCC and TRAP.

Proteins in this entry are subunit Med20 of the Mediator complex, and is found in the non-essential part of the head [PUBMED:15175151]. and related to the TATA-binding protein (TBP). TBP is a highly conserved RNA polymerase II general transcription factor that binds to the core promoter and initiates assembly of the pre-initiation complex. Human TRF has been shown to associate with an RNA polymerase II-SRB complex [PUBMED:9933582].

Gene Ontology

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Domain organisation

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Alignments

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Representative proteomes NCBI
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RP35
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RP55
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RP75
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Format an alignment

  Seed
(32)
Full
(235)
Representative proteomes NCBI
(239)
Meta
(0)
RP15
(45)
RP35
(76)
RP55
(127)
RP75
(160)
Alignment:
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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.

  Seed
(32)
Full
(235)
Representative proteomes NCBI
(239)
Meta
(0)
RP15
(45)
RP35
(76)
RP55
(127)
RP75
(160)
Raw Stockholm Download   Download   Download   Download   Download   Download   Download    
Gzipped Download   Download   Download   Download   Download   Download   Download    

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

External links

MyHits provides a collection of tools to handle multiple sequence alignments. For example, one can refine a seed alignment (sequence addition or removal, re-alignment or manual edition) and then search databases for remote homologs using HMMER3.

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...

Trees

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.

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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: manual
Previous IDs: TATA_RF;
Type: Family
Author: Mistry J, Wood V
Number in seed: 32
Number in full: 235
Average length of the domain: 213.80 aa
Average identity of full alignment: 26 %
Average coverage of the sequence by the domain: 92.51 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 25.0 25.0
Trusted cut-off 25.0 28.1
Noise cut-off 24.5 24.8
Model length: 225
Family (HMM) version: 6
Download: download the raw HMM for this family

Species distribution

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Interactions

There are 2 interactions for this family. More...

Med20 Med18

Structures

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 Med20 domain has been found. There are 11 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 seqence.

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