P34162 (MED20_YEAST) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Mediator of RNA polymerase II transcription subunit 20

Alternative name(s):
Hyper-recombination suppressor protein 2
Mediator complex subunit 20
Suppressor of RNA polymerase B 2

Gene names

Name:	SRB2
Synonyms:	HRS2, MED20
Ordered Locus Names:	YHR041C

Organism

Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast) [Reference proteome]

Taxonomic identifier

559292 [NCBI]

Taxonomic lineage

cellular organisms › Eukaryota › Opisthokonta › Fungi › Dikarya › Ascomycota › saccharomyceta › Saccharomycotina › Saccharomycetes › Saccharomycetales › Saccharomycetaceae › Saccharomyces › Saccharomyces cerevisiae

Protein attributes

Sequence length	210 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Component of the Mediator complex, 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. 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. Ref.12 Ref.13 Ref.14 Ref.17
Subunit structure	Component of the Mediator complex, which is composed of at least 21 subunits that form three structurally distinct submodules. The Mediator 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, and the tail module contains MED2, PGD1/MED3, RGR1/MED14, GAL11/MED15 and SIN4/MED16. The head and the middle modules interact directly with RNA polymerase II, whereas the elongated tail module interacts with gene-specific regulatory proteins. MED1 interacts directly with MED4 and MED7. SRB2/MED20 interacts directly with SRB4/MED17 and SRB5/MED18. Ref.6 Ref.15 Ref.17
Subcellular location	Nucleus Ref.7.
Miscellaneous	Present with 1720 molecules/cell in log phase SD medium.
Sequence similarities	Belongs to the Mediator complex subunit 20 family.

Ontologies

Keywords
Biological process	Transcription Transcription regulation
Cellular component	Nucleus
Molecular function	Activator
Technical term	3D-structure Complete proteome Reference proteome
Gene Ontology (GO)
Biological_process	negative regulation of ribosomal protein gene transcription from RNA polymerase II promoter in response to chemical stimulus Inferred from mutant phenotype PubMed 18604275. Source: SGD negative regulation of ribosomal protein gene transcription from RNA polymerase II promoter in response to nutrient levels Inferred from mutant phenotype PubMed 18604275. Source: SGD
Cellular_component	core mediator complex Inferred from direct assay PubMed 9891034. Source: SGD mediator complex Inferred from electronic annotation. Source: InterPro
Molecular_function	RNA polymerase II transcription coactivator activity involved in preinitiation complex assembly Inferred from direct assay Ref.1. Source: SGD RNA polymerase II transcription factor recruiting transcription factor activity Inferred from mutant phenotype PubMed 15831453. Source: SGD TBP-class protein binding RNA polymerase II transcription factor activity involved in preinitiation complex assembly Inferred from direct assay Ref.1. Source: SGD core RNA polymerase II binding transcription factor activity Inferred from direct assay PubMed 20154708. Source: SGD protein domain specific binding Inferred from genetic interaction PubMed 2693207. Source: SGD
Complete GO annotation...

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Chain

1 – 210

210

Mediator of RNA polymerase II transcription subunit 20

PRO_0000096374

Regions

Compositional bias

1 – 210

210

Ser/Thr/Tyr-rich

Experimental info

Mutagenesis

14

1

P → H in SRB2-1; suppresses the phenotypic defects of a RNA polymerase II CTD truncation. Ref.1

Secondary structure

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210

Helix Strand Turn

Details...

Beta strand

4 – 9

6

Helix

16 – 24

9

Helix

25 – 27

3

Beta strand

30 – 32

3

Beta strand

35 – 44

10

Beta strand

51 – 53

3

Beta strand

56 – 73

18

Beta strand

76 – 81

6

Helix

84 – 86

3

Helix

89 – 93

5

Helix

104 – 111

8

Turn

113 – 115

3

Beta strand

116 – 132

17

Beta strand

135 – 144

10

Beta strand

147 – 158

12

Helix

160 – 162

3

Helix

163 – 176

14

Beta strand

183 – 185

3

Helix

196 – 208

13

Sequences

	Sequence		Length	Mass (Da)
	P34162 [UniParc]. Last modified February 1, 1994. Version 1. Checksum: C30BF309D43AFB2A	FASTA	210	22,894
	10 20 30 40 50 60 MGKSAVIFVE RATPATLTEL KDALSNSILS VRDPWSIDFR TYRCSIKNLP ADVSKLMYSI 70 80 90 100 110 120 TFHHHGRQTV LIKDNSAMVT TAAAADIPPA LVFNGSSTGV PESIDTILSS KLSNIWMQRQ 130 140 150 160 170 180 LIKGDAGETL ILDGLTVRLV NLFSSTGFKG LLIELQADEA GEFETKIAGI EGHLAEIRAK 190 200 210 EYKTSSDSLG PDTSNEICDL AYQYVRALEL

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"A novel transcription factor reveals a functional link between the RNA polymerase II CTD and TFIID." Koleske A.J., Buratowski S., Nonet M., Young R.A. Cell 69:883-894(1992) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA], MUTAGENESIS OF PRO-14.
[2]	"Complete nucleotide sequence of Saccharomyces cerevisiae chromosome VIII." Johnston M., Andrews S., Brinkman R., Cooper J., Ding H., Dover J., Du Z., Favello A., Fulton L., Gattung S., Geisel C., Kirsten J., Kucaba T., Hillier L.W., Jier M., Johnston L., Langston Y., Latreille P. , Louis E.J., Macri C., Mardis E., Menezes S., Mouser L., Nhan M., Rifkin L., Riles L., St Peter H., Trevaskis E., Vaughan K., Vignati D., Wilcox L., Wohldman P., Waterston R., Wilson R., Vaudin M. Science 265:2077-2082(1994) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: ATCC 204511 / S288c / AB972.
[3]	Saccharomyces Genome Database Submitted (DEC-2009) to the EMBL/GenBank/DDBJ databases Cited for: GENOME REANNOTATION. Strain: ATCC 204508 / S288c.
[4]	"A multisubunit complex associated with the RNA polymerase II CTD and TATA-binding protein in yeast." Thompson C.M., Koleske A.J., Chao D.M., Young R.A. Cell 73:1361-1375(1993) [PubMed] [Europe PMC] [Abstract] Cited for: CHARACTERIZATION.
[5]	"A multiprotein mediator of transcriptional activation and its interaction with the C-terminal repeat domain of RNA polymerase II." Kim Y.-J., Bjoerklund S., Li Y., Sayre M.H., Kornberg R.D. Cell 77:599-608(1994) [PubMed] [Europe PMC] [Abstract] Cited for: COMPONENT OF MEDIATOR COMPLEX.
[6]	"An activator target in the RNA polymerase II holoenzyme." Koh S.S., Ansari A.Z., Ptashne M., Young R.A. Mol. Cell 1:895-904(1998) [PubMed] [Europe PMC] [Abstract] Cited for: INTERACTION WITH SRB4 AND SRB5.
[7]	"Global analysis of protein localization in budding yeast." Huh W.-K., Falvo J.V., Gerke L.C., Carroll A.S., Howson R.W., Weissman J.S., O'Shea E.K. Nature 425:686-691(2003) [PubMed] [Europe PMC] [Abstract] Cited for: SUBCELLULAR LOCATION [LARGE SCALE ANALYSIS].
[8]	"Global analysis of protein expression in yeast." Ghaemmaghami S., Huh W.-K., Bower K., Howson R.W., Belle A., Dephoure N., O'Shea E.K., Weissman J.S. Nature 425:737-741(2003) [PubMed] [Europe PMC] [Abstract] Cited for: LEVEL OF PROTEIN EXPRESSION [LARGE SCALE ANALYSIS].
[9]	"A unified nomenclature for protein subunits of mediator complexes linking transcriptional regulators to RNA polymerase II." Bourbon H.-M., Aguilera A., Ansari A.Z., Asturias F.J., Berk A.J., Bjoerklund S., Blackwell T.K., Borggrefe T., Carey M., Carlson M., Conaway J.W., Conaway R.C., Emmons S.W., Fondell J.D., Freedman L.P., Fukasawa T., Gustafsson C.M., Han M. , He X., Herman P.K., Hinnebusch A.G., Holmberg S., Holstege F.C.P., Jaehning J.A., Kim Y.-J., Kuras L., Leutz A., Lis J.T., Meisterernest M., Naeaer A.M., Nasmyth K., Parvin J.D., Ptashne M., Reinberg D., Ronne H., Sadowski I., Sakurai H., Sipiczki M., Sternberg P.W., Stillman D.J., Strich R., Struhl K., Svejstrup J.Q., Tuck S., Winston F., Roeder R.G., Kornberg R.D. Mol. Cell 14:553-557(2004) [PubMed] [Europe PMC] [Abstract] Cited for: NOMENCLATURE.
[10]	"A high resolution protein interaction map of the yeast Mediator complex." Guglielmi B., van Berkum N.L., Klapholz B., Bijma T., Boube M., Boschiero C., Bourbon H.-M., Holstege F.C.P., Werner M. Nucleic Acids Res. 32:5379-5391(2004) [PubMed] [Europe PMC] [Abstract] Cited for: TOPOLOGY OF THE MEDIATOR COMPLEX.
[11]	"Preponderance of free mediator in the yeast Saccharomyces cerevisiae." Takagi Y., Chadick J.Z., Davis J.A., Asturias F.J. J. Biol. Chem. 280:31200-31207(2005) [PubMed] [Europe PMC] [Abstract] Cited for: CHARACTERIZATION OF THE MEDIATOR COMPLEX.
[12]	"Mediator and TFIIH govern carboxyl-terminal domain-dependent transcription in yeast extracts." Nair D., Kim Y., Myers L.C. J. Biol. Chem. 280:33739-33748(2005) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION OF THE MEDIATOR COMPLEX.
[13]	"Mediator expression profiling epistasis reveals a signal transduction pathway with antagonistic submodules and highly specific downstream targets." van de Peppel J., Kettelarij N., van Bakel H., Kockelkorn T.T.J.P., van Leenen D., Holstege F.C.P. Mol. Cell 19:511-522(2005) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION.
[14]	"Mediator as a general transcription factor." Takagi Y., Kornberg R.D. J. Biol. Chem. 281:80-89(2006) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION OF THE MEDIATOR COMPLEX.
[15]	"Med19(Rox3) regulates intermodule interactions in the Saccharomyces cerevisiae mediator complex." Baidoobonso S.M., Guidi B.W., Myers L.C. J. Biol. Chem. 282:5551-5559(2007) [PubMed] [Europe PMC] [Abstract] Cited for: CHARACTERIZATION OF THE MEDIATOR COMPLEX, INTERACTION OF THE MEDIATOR COMPLEX WITH RNA POLYMERASE II.
[16]	"Structure of the yeast RNA polymerase II holoenzyme: mediator conformation and polymerase interaction." Davis J.A., Takagi Y., Kornberg R.D., Asturias F.J. Mol. Cell 10:409-415(2002) [PubMed] [Europe PMC] [Abstract] Cited for: ELECTRON MICROSCOPY OF MEDIATOR COMPLEX IN COMPLEX WITH RNA POLYMERASE II.
[17]	"Head module control of mediator interactions." Takagi Y., Calero G., Komori H., Brown J.A., Ehrensberger A.H., Hudmon A., Asturias F.J., Kornberg R.D. Mol. Cell 23:355-364(2006) [PubMed] [Europe PMC] [Abstract] Cited for: ELECTRON MICROSCOPY OF THE MEDIATOR COMPLEX HEAD MODULE, FUNCTION OF THE MEDIATOR COMPLEX HEAD MODULE, INTERACTION OF THE MEDIATOR COMPLEX HEAD MODULE WITH RNA POLYMERASE II AND TFIIF, INTERACTION WITH MED8; SRB4 AND SRB5.
[18]	"Structure and TBP binding of the Mediator head subcomplex Med8-Med18-Med20." Lariviere L., Geiger S., Hoeppner S., Roether S., Straesser K., Cramer P. Nat. Struct. Mol. Biol. 13:895-901(2006) [PubMed] [Europe PMC] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (2.7 ANGSTROMS) OF 2-210 IN COMPLEX WITH MED8 AND SRB5, X-RAY CRYSTALLOGRAPHY (2.4 ANGSTROMS) IN COMPLEX WITH SRB5.
+	Additional computationally mapped references.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ

S36754 Genomic DNA. Translation: AAB22223.1.
U00062 Genomic DNA. Translation: AAB68920.1.
BK006934 Genomic DNA. Translation: DAA06733.1.

PIR

A38105.

RefSeq

NP_011907.1. NM_001179171.1.

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
2HZM	X-ray	2.40	A/C/E/G	1-210	[»]
2HZS	X-ray	2.70	A/C/E/G	2-210	[»]
3J1O	electron microscopy	16.00	M	1-210	[»]
3RJ1	X-ray	4.30	F/M/T	1-210	[»]
4GWP	X-ray	4.20	F	1-210	[»]
4GWQ	X-ray	4.50	F	1-210	[»]

ProteinModelPortal

P34162.

SMR

P34162. Positions 2-210.

ModBase

Search...

Protein-protein interaction databases

DIP

DIP-107N.

IntAct

P34162. 18 interactions.

MINT

MINT-473266.

STRING

4932.YHR041C.

Proteomic databases

PaxDb

P34162.

PeptideAtlas

P34162.

Protocols and materials databases

StructuralBiologyKnowledgebase

Search...

Genome annotation databases

EnsemblFungi

YHR041C; YHR041C; YHR041C.

GeneID

856437.

KEGG

sce:YHR041C.

Organism-specific databases

CYGD

YHR041c.

SGD

S000001083. SRB2.

Phylogenomic databases

eggNOG

NOG41765.

HOGENOM

HOG000113535.

OMA

FKIFRNN.

OrthoDB

EOG43R6X7.

Gene expression databases

Genevestigator

P34162.

GermOnline

YHR041C. Saccharomyces cerevisiae.

Family and domain databases

InterPro

IPR013921. Mediator_Med20.
IPR016532. Mediator_Med20_fun.
[Graphical view]

Pfam

PF08612. Med20. 1 hit.
[Graphical view]

PIRSF

PIRSF007945. SRB2. 1 hit.

ProtoNet

Search...

Other

EvolutionaryTrace

P34162.

NextBio

982039.

Entry information

Entry name

MED20_YEAST

Accession

Primary (citable) accession number: P34162
Secondary accession number(s): D3DKY9

Entry history

Integrated into UniProtKB/Swiss-Prot:	February 1, 1994
Last sequence update:	February 1, 1994
Last modified:	May 1, 2013
This is version 113 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Fungal Protein Annotation Program