ID   MED20_YEAST             Reviewed;         210 AA.
AC   P34162; D3DKY9;
DT   01-FEB-1994, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1994, sequence version 1.
DT   02-SEP-2026, entry version 191.
DE   RecName: Full=Mediator of RNA polymerase II transcription subunit 20;
DE   AltName: Full=Hyper-recombination suppressor protein 2;
DE   AltName: Full=Mediator complex subunit 20;
DE   AltName: Full=Suppressor of RNA polymerase B 2;
GN   Name=SRB2; Synonyms=HRS2, MED20; OrderedLocusNames=YHR041C;
OS   Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast).
OC   Eukaryota; Fungi; Dikarya; Ascomycota; Saccharomycotina; Saccharomycetes;
OC   Saccharomycetales; Saccharomycetaceae; Saccharomyces.
OX   NCBI_TaxID=559292;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA], AND MUTAGENESIS OF PRO-14.
RX   PubMed=1591782; DOI=10.1016/0092-8674(92)90298-q;
RA   Koleske A.J., Buratowski S., Nonet M., Young R.A.;
RT   "A novel transcription factor reveals a functional link between the RNA
RT   polymerase II CTD and TFIID.";
RL   Cell 69:883-894(1992).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 204508 / S288c;
RX   PubMed=8091229; DOI=10.1126/science.8091229;
RA   Johnston M., Andrews S., Brinkman R., Cooper J., Ding H., Dover J., Du Z.,
RA   Favello A., Fulton L., Gattung S., Geisel C., Kirsten J., Kucaba T.,
RA   Hillier L.W., Jier M., Johnston L., Langston Y., Latreille P., Louis E.J.,
RA   Macri C., Mardis E., Menezes S., Mouser L., Nhan M., Rifkin L., Riles L.,
RA   St Peter H., Trevaskis E., Vaughan K., Vignati D., Wilcox L., Wohldman P.,
RA   Waterston R., Wilson R., Vaudin M.;
RT   "Complete nucleotide sequence of Saccharomyces cerevisiae chromosome
RT   VIII.";
RL   Science 265:2077-2082(1994).
RN   [3]
RP   GENOME REANNOTATION.
RC   STRAIN=ATCC 204508 / S288c;
RX   PubMed=24374639; DOI=10.1534/g3.113.008995;
RA   Engel S.R., Dietrich F.S., Fisk D.G., Binkley G., Balakrishnan R.,
RA   Costanzo M.C., Dwight S.S., Hitz B.C., Karra K., Nash R.S., Weng S.,
RA   Wong E.D., Lloyd P., Skrzypek M.S., Miyasato S.R., Simison M., Cherry J.M.;
RT   "The reference genome sequence of Saccharomyces cerevisiae: Then and now.";
RL   G3 (Bethesda) 4:389-398(2014).
RN   [4]
RP   CHARACTERIZATION.
RX   PubMed=8324825; DOI=10.1016/0092-8674(93)90362-t;
RA   Thompson C.M., Koleske A.J., Chao D.M., Young R.A.;
RT   "A multisubunit complex associated with the RNA polymerase II CTD and TATA-
RT   binding protein in yeast.";
RL   Cell 73:1361-1375(1993).
RN   [5]
RP   COMPONENT OF MEDIATOR COMPLEX.
RX   PubMed=8187178; DOI=10.1016/0092-8674(94)90221-6;
RA   Kim Y.-J., Bjoerklund S., Li Y., Sayre M.H., Kornberg R.D.;
RT   "A multiprotein mediator of transcriptional activation and its interaction
RT   with the C-terminal repeat domain of RNA polymerase II.";
RL   Cell 77:599-608(1994).
RN   [6]
RP   INTERACTION WITH SRB4 AND SRB5.
RX   PubMed=9660972; DOI=10.1016/s1097-2765(00)80088-x;
RA   Koh S.S., Ansari A.Z., Ptashne M., Young R.A.;
RT   "An activator target in the RNA polymerase II holoenzyme.";
RL   Mol. Cell 1:895-904(1998).
RN   [7]
RP   SUBCELLULAR LOCATION [LARGE SCALE ANALYSIS].
RX   PubMed=14562095; DOI=10.1038/nature02026;
RA   Huh W.-K., Falvo J.V., Gerke L.C., Carroll A.S., Howson R.W.,
RA   Weissman J.S., O'Shea E.K.;
RT   "Global analysis of protein localization in budding yeast.";
RL   Nature 425:686-691(2003).
RN   [8]
RP   LEVEL OF PROTEIN EXPRESSION [LARGE SCALE ANALYSIS].
RX   PubMed=14562106; DOI=10.1038/nature02046;
RA   Ghaemmaghami S., Huh W.-K., Bower K., Howson R.W., Belle A., Dephoure N.,
RA   O'Shea E.K., Weissman J.S.;
RT   "Global analysis of protein expression in yeast.";
RL   Nature 425:737-741(2003).
RN   [9]
RP   NOMENCLATURE.
RX   PubMed=15175151; DOI=10.1016/j.molcel.2004.05.011;
RA   Bourbon H.-M., Aguilera A., Ansari A.Z., Asturias F.J., Berk A.J.,
RA   Bjoerklund S., Blackwell T.K., Borggrefe T., Carey M., Carlson M.,
RA   Conaway J.W., Conaway R.C., Emmons S.W., Fondell J.D., Freedman L.P.,
RA   Fukasawa T., Gustafsson C.M., Han M., He X., Herman P.K., Hinnebusch A.G.,
RA   Holmberg S., Holstege F.C.P., Jaehning J.A., Kim Y.-J., Kuras L., Leutz A.,
RA   Lis J.T., Meisterernest M., Naeaer A.M., Nasmyth K., Parvin J.D.,
RA   Ptashne M., Reinberg D., Ronne H., Sadowski I., Sakurai H., Sipiczki M.,
RA   Sternberg P.W., Stillman D.J., Strich R., Struhl K., Svejstrup J.Q.,
RA   Tuck S., Winston F., Roeder R.G., Kornberg R.D.;
RT   "A unified nomenclature for protein subunits of mediator complexes linking
RT   transcriptional regulators to RNA polymerase II.";
RL   Mol. Cell 14:553-557(2004).
RN   [10]
RP   TOPOLOGY OF THE MEDIATOR COMPLEX.
RX   PubMed=15477388; DOI=10.1093/nar/gkh878;
RA   Guglielmi B., van Berkum N.L., Klapholz B., Bijma T., Boube M.,
RA   Boschiero C., Bourbon H.-M., Holstege F.C.P., Werner M.;
RT   "A high resolution protein interaction map of the yeast Mediator complex.";
RL   Nucleic Acids Res. 32:5379-5391(2004).
RN   [11]
RP   CHARACTERIZATION OF THE MEDIATOR COMPLEX.
RX   PubMed=16002404; DOI=10.1074/jbc.c500150200;
RA   Takagi Y., Chadick J.Z., Davis J.A., Asturias F.J.;
RT   "Preponderance of free mediator in the yeast Saccharomyces cerevisiae.";
RL   J. Biol. Chem. 280:31200-31207(2005).
RN   [12]
RP   FUNCTION OF THE MEDIATOR COMPLEX.
RX   PubMed=16076843; DOI=10.1074/jbc.m506067200;
RA   Nair D., Kim Y., Myers L.C.;
RT   "Mediator and TFIIH govern carboxyl-terminal domain-dependent transcription
RT   in yeast extracts.";
RL   J. Biol. Chem. 280:33739-33748(2005).
RN   [13]
RP   FUNCTION.
RX   PubMed=16109375; DOI=10.1016/j.molcel.2005.06.033;
RA   van de Peppel J., Kettelarij N., van Bakel H., Kockelkorn T.T.J.P.,
RA   van Leenen D., Holstege F.C.P.;
RT   "Mediator expression profiling epistasis reveals a signal transduction
RT   pathway with antagonistic submodules and highly specific downstream
RT   targets.";
RL   Mol. Cell 19:511-522(2005).
RN   [14]
RP   FUNCTION OF THE MEDIATOR COMPLEX.
RX   PubMed=16263706; DOI=10.1074/jbc.m508253200;
RA   Takagi Y., Kornberg R.D.;
RT   "Mediator as a general transcription factor.";
RL   J. Biol. Chem. 281:80-89(2006).
RN   [15]
RP   CHARACTERIZATION OF THE MEDIATOR COMPLEX, AND INTERACTION OF THE MEDIATOR
RP   COMPLEX WITH RNA POLYMERASE II.
RX   PubMed=17192271; DOI=10.1074/jbc.m609484200;
RA   Baidoobonso S.M., Guidi B.W., Myers L.C.;
RT   "Med19(Rox3) regulates intermodule interactions in the Saccharomyces
RT   cerevisiae mediator complex.";
RL   J. Biol. Chem. 282:5551-5559(2007).
RN   [16]
RP   IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
RX   PubMed=22814378; DOI=10.1073/pnas.1210303109;
RA   Van Damme P., Lasa M., Polevoda B., Gazquez C., Elosegui-Artola A.,
RA   Kim D.S., De Juan-Pardo E., Demeyer K., Hole K., Larrea E., Timmerman E.,
RA   Prieto J., Arnesen T., Sherman F., Gevaert K., Aldabe R.;
RT   "N-terminal acetylome analyses and functional insights of the N-terminal
RT   acetyltransferase NatB.";
RL   Proc. Natl. Acad. Sci. U.S.A. 109:12449-12454(2012).
RN   [17]
RP   ELECTRON MICROSCOPY OF MEDIATOR COMPLEX IN COMPLEX WITH RNA POLYMERASE II.
RX   PubMed=12191485; DOI=10.1016/s1097-2765(02)00598-1;
RA   Davis J.A., Takagi Y., Kornberg R.D., Asturias F.J.;
RT   "Structure of the yeast RNA polymerase II holoenzyme: mediator conformation
RT   and polymerase interaction.";
RL   Mol. Cell 10:409-415(2002).
RN   [18]
RP   ELECTRON MICROSCOPY OF THE MEDIATOR COMPLEX HEAD MODULE, FUNCTION OF THE
RP   MEDIATOR COMPLEX HEAD MODULE, INTERACTION OF THE MEDIATOR COMPLEX HEAD
RP   MODULE WITH RNA POLYMERASE II AND TFIIF, AND INTERACTION WITH MED8; SRB4
RP   AND SRB5.
RX   PubMed=16885025; DOI=10.1016/j.molcel.2006.06.007;
RA   Takagi Y., Calero G., Komori H., Brown J.A., Ehrensberger A.H., Hudmon A.,
RA   Asturias F.J., Kornberg R.D.;
RT   "Head module control of mediator interactions.";
RL   Mol. Cell 23:355-364(2006).
RN   [19]
RP   X-RAY CRYSTALLOGRAPHY (2.7 ANGSTROMS) OF 2-210 IN COMPLEX WITH MED8 AND
RP   SRB5, AND X-RAY CRYSTALLOGRAPHY (2.4 ANGSTROMS) IN COMPLEX WITH SRB5.
RX   PubMed=16964259; DOI=10.1038/nsmb1143;
RA   Lariviere L., Geiger S., Hoeppner S., Roether S., Straesser K., Cramer P.;
RT   "Structure and TBP binding of the Mediator head subcomplex Med8-Med18-
RT   Med20.";
RL   Nat. Struct. Mol. Biol. 13:895-901(2006).
CC   -!- FUNCTION: Component of the Mediator complex, a coactivator involved in
CC       the regulated transcription of nearly all RNA polymerase II-dependent
CC       genes. Mediator functions as a bridge to convey information from gene-
CC       specific regulatory proteins to the basal RNA polymerase II
CC       transcription machinery. The Mediator complex, having a compact
CC       conformation in its free form, is recruited to promoters by direct
CC       interactions with regulatory proteins and serves for the assembly of a
CC       functional preinitiation complex with RNA polymerase II and the general
CC       transcription factors. The Mediator complex unfolds to an extended
CC       conformation and partially surrounds RNA polymerase II, specifically
CC       interacting with the unphosphorylated form of the C-terminal domain
CC       (CTD) of RNA polymerase II. The Mediator complex dissociates from the
CC       RNA polymerase II holoenzyme and stays at the promoter when
CC       transcriptional elongation begins. {ECO:0000269|PubMed:16076843,
CC       ECO:0000269|PubMed:16109375, ECO:0000269|PubMed:16263706,
CC       ECO:0000269|PubMed:16885025}.
CC   -!- SUBUNIT: Component of the Mediator complex, which is composed of at
CC       least 21 subunits that form three structurally distinct submodules. The
CC       Mediator head module contains MED6, MED8, MED11, SRB4/MED17,
CC       SRB5/MED18, ROX3/MED19, SRB2/MED20 and SRB6/MED22, the middle module
CC       contains MED1, MED4, NUT1/MED5, MED7, CSE2/MED9, NUT2/MED10, SRB7/MED21
CC       and SOH1/MED31, and the tail module contains MED2, PGD1/MED3,
CC       RGR1/MED14, GAL11/MED15 and SIN4/MED16. The head and the middle modules
CC       interact directly with RNA polymerase II, whereas the elongated tail
CC       module interacts with gene-specific regulatory proteins. MED1 interacts
CC       directly with MED4 and MED7. SRB2/MED20 interacts directly with
CC       SRB4/MED17 and SRB5/MED18. {ECO:0000269|PubMed:16885025,
CC       ECO:0000269|PubMed:16964259, ECO:0000269|PubMed:17192271,
CC       ECO:0000269|PubMed:9660972}.
CC   -!- INTERACTION:
CC       P34162; P38304: MED8; NbExp=3; IntAct=EBI-18018, EBI-20932;
CC       P34162; P32585: SRB5; NbExp=7; IntAct=EBI-18018, EBI-18032;
CC   -!- SUBCELLULAR LOCATION: Nucleus {ECO:0000269|PubMed:14562095}.
CC   -!- MISCELLANEOUS: Present with 1720 molecules/cell in log phase SD medium.
CC       {ECO:0000269|PubMed:14562106}.
CC   -!- SIMILARITY: Belongs to the Mediator complex subunit 20 family.
CC       {ECO:0000305}.
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DR   EMBL; S36754; AAB22223.1; -; Genomic_DNA.
DR   EMBL; U00062; AAB68920.1; -; Genomic_DNA.
DR   EMBL; BK006934; DAA06733.1; -; Genomic_DNA.
DR   PIR; A38105; A38105.
DR   RefSeq; NP_011907.1; NM_001179171.1.
DR   PDB; 2HZM; X-ray; 2.40 A; A/C/E/G=1-210.
DR   PDB; 2HZS; X-ray; 2.70 A; A/C/E/G=2-210.
DR   PDB; 3J1O; EM; 16.00 A; M=1-210.
DR   PDB; 3RJ1; X-ray; 4.30 A; F/M/T=1-210.
DR   PDB; 4GWP; X-ray; 4.20 A; F=1-210.
DR   PDB; 4GWQ; X-ray; 4.50 A; F=1-210.
DR   PDB; 4V1O; EM; 9.70 A; Y=2-210.
DR   PDB; 5OQM; EM; 5.80 A; f=1-210.
DR   PDB; 5SVA; EM; 15.30 A; R=1-210.
DR   PDB; 7UI9; EM; 3.30 A; t=1-210.
DR   PDB; 7UIF; EM; 4.60 A; t=1-210.
DR   PDB; 7UIG; EM; 4.30 A; t=1-210.
DR   PDB; 7UIO; EM; 3.30 A; At/Bt=1-210.
DR   PDB; 8CEN; EM; 3.00 A; f=1-210.
DR   PDB; 8CEO; EM; 3.60 A; f=1-210.
DR   AlphaFoldDB; P34162; -.
DR   EMDB; EMD-16610; -.
DR   EMDB; EMD-16611; -.
DR   EMDB; EMD-26542; -.
DR   EMDB; EMD-26544; -.
DR   EMDB; EMD-26545; -.
DR   EMDB; EMD-26551; -.
DR   EMDB; EMD-2786; -.
DR   EMDB; EMD-3850; -.
DR   EMDB; EMD-8305; -.
DR   SMR; P34162; -.
DR   BioGRID; 36473; 677.
DR   ComplexPortal; CPX-3226; Core mediator complex.
DR   DIP; DIP-107N; -.
DR   FunCoup; P34162; 298.
DR   IntAct; P34162; 32.
DR   MINT; P34162; -.
DR   STRING; 4932.YHR041C; -.
DR   PaxDb; 4932-YHR041C; -.
DR   PeptideAtlas; P34162; -.
DR   EnsemblFungi; YHR041C_mRNA; YHR041C; YHR041C.
DR   GeneID; 856437; -.
DR   KEGG; sce:YHR041C; -.
DR   AGR; SGD:S000001083; -.
DR   SGD; S000001083; SRB2.
DR   VEuPathDB; FungiDB:YHR041C; -.
DR   eggNOG; ENOG502RXMU; Eukaryota.
DR   HOGENOM; CLU_065844_1_0_1; -.
DR   InParanoid; P34162; -.
DR   OMA; WTQRQSI; -.
DR   OrthoDB; 1854899at2759; -.
DR   BioCyc; YEAST:G3O-31100-MONOMER; -.
DR   BioGRID-ORCS; 856437; 1 hit in 10 CRISPR screens.
DR   EvolutionaryTrace; P34162; -.
DR   PRO; PR:P34162; -.
DR   Proteomes; UP000002311; Chromosome VIII.
DR   RNAct; P34162; protein.
DR   GO; GO:0070847; C:core mediator complex; IDA:SGD.
DR   GO; GO:0016592; C:mediator complex; IEA:InterPro.
DR   GO; GO:0005634; C:nucleus; IDA:ComplexPortal.
DR   GO; GO:0019904; F:protein domain specific binding; IGI:SGD.
DR   GO; GO:0001094; F:TFIID-class transcription factor complex binding; IDA:SGD.
DR   GO; GO:0003713; F:transcription coactivator activity; IDA:SGD.
DR   GO; GO:0031669; P:cellular response to nutrient levels; IMP:SGD.
DR   GO; GO:0010688; P:negative regulation of ribosomal protein gene transcription by RNA polymerase II; IMP:SGD.
DR   GO; GO:0045944; P:positive regulation of transcription by RNA polymerase II; IDA:SGD.
DR   GO; GO:0032968; P:positive regulation of transcription elongation by RNA polymerase II; IDA:ComplexPortal.
DR   GO; GO:0060261; P:positive regulation of transcription initiation by RNA polymerase II; IDA:ComplexPortal.
DR   GO; GO:0051123; P:RNA polymerase II preinitiation complex assembly; IDA:SGD.
DR   FunFam; 3.30.310.180:FF:000001; Mediator of RNA polymerase II transcription subunit 20; 1.
DR   Gene3D; 3.30.310.180; -; 2.
DR   InterPro; IPR016532; Med20.
DR   InterPro; IPR013921; Mediator_Med20.
DR   Pfam; PF08612; Med20; 1.
DR   PIRSF; PIRSF007945; SRB2; 1.
DR   PDBsum; 2HZM; -.
DR   PDBsum; 2HZS; -.
DR   PDBsum; 3J1O; -.
DR   PDBsum; 3RJ1; -.
DR   PDBsum; 4GWP; -.
DR   PDBsum; 4GWQ; -.
DR   PDBsum; 4V1O; -.
DR   PDBsum; 5OQM; -.
DR   PDBsum; 5SVA; -.
DR   PDBsum; 7UI9; -.
DR   PDBsum; 7UIF; -.
DR   PDBsum; 7UIG; -.
DR   PDBsum; 7UIO; -.
DR   PDBsum; 8CEN; -.
DR   PDBsum; 8CEO; -.
PE   1: Evidence at protein level;
KW   3D-structure; Activator; Nucleus; Reference proteome; Transcription;
KW   Transcription regulation.
FT   CHAIN           1..210
FT                   /note="Mediator of RNA polymerase II transcription subunit
FT                   20"
FT                   /id="PRO_0000096374"
FT   MUTAGEN         14
FT                   /note="P->H: In SRB2-1; suppresses the phenotypic defects
FT                   of an RNA polymerase IICTD truncation."
FT                   /evidence="ECO:0000269|PubMed:1591782"
FT   STRAND          4..9
FT                   /evidence="ECO:0007829|PDB:2HZM"
FT   HELIX           16..24
FT                   /evidence="ECO:0007829|PDB:2HZM"
FT   HELIX           25..27
FT                   /evidence="ECO:0007829|PDB:2HZM"
FT   STRAND          30..32
FT                   /evidence="ECO:0007829|PDB:2HZS"
FT   STRAND          35..44
FT                   /evidence="ECO:0007829|PDB:2HZM"
FT   STRAND          51..53
FT                   /evidence="ECO:0007829|PDB:2HZS"
FT   STRAND          56..73
FT                   /evidence="ECO:0007829|PDB:2HZM"
FT   STRAND          76..81
FT                   /evidence="ECO:0007829|PDB:2HZM"
FT   HELIX           84..86
FT                   /evidence="ECO:0007829|PDB:2HZM"
FT   HELIX           89..93
FT                   /evidence="ECO:0007829|PDB:2HZM"
FT   HELIX           104..111
FT                   /evidence="ECO:0007829|PDB:2HZM"
FT   TURN            113..115
FT                   /evidence="ECO:0007829|PDB:2HZM"
FT   STRAND          116..132
FT                   /evidence="ECO:0007829|PDB:2HZM"
FT   STRAND          135..144
FT                   /evidence="ECO:0007829|PDB:2HZM"
FT   STRAND          147..158
FT                   /evidence="ECO:0007829|PDB:2HZM"
FT   HELIX           160..162
FT                   /evidence="ECO:0007829|PDB:2HZM"
FT   HELIX           163..176
FT                   /evidence="ECO:0007829|PDB:2HZM"
FT   STRAND          183..185
FT                   /evidence="ECO:0007829|PDB:2HZM"
FT   HELIX           196..208
FT                   /evidence="ECO:0007829|PDB:2HZM"
SQ   SEQUENCE   210 AA;  22894 MW;  C30BF309D43AFB2A CRC64;
     MGKSAVIFVE RATPATLTEL KDALSNSILS VRDPWSIDFR TYRCSIKNLP ADVSKLMYSI
     TFHHHGRQTV LIKDNSAMVT TAAAADIPPA LVFNGSSTGV PESIDTILSS KLSNIWMQRQ
     LIKGDAGETL ILDGLTVRLV NLFSSTGFKG LLIELQADEA GEFETKIAGI EGHLAEIRAK
     EYKTSSDSLG PDTSNEICDL AYQYVRALEL
//