Skip Header

You are using a version of browser that may not display all the features of this website. Please consider upgrading your browser.
Protein

C-terminal-binding protein 1

Gene

CTBP1

Organism
Homo sapiens (Human)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

Corepressor targeting diverse transcription regulators such as GLIS2 or BCL6. Has dehydrogenase activity. Involved in controlling the equilibrium between tubular and stacked structures in the Golgi complex. Functions in brown adipose tissue (BAT) differentiation.5 Publications

Cofactori

NAD+1 PublicationNote: NAD is required for efficient interaction with E1A. Cofactor binding induces a conformation change.1 Publication

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Binding sitei100NADBy similarity1
Binding sitei204NADBy similarity1
Active sitei266By similarity1
Binding sitei290NADBy similarity1
Active sitei295By similarity1
Active sitei315Proton donorBy similarity1

Regions

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Nucleotide bindingi180 – 185NADBy similarity6
Nucleotide bindingi237 – 243NADBy similarity7
Nucleotide bindingi264 – 266NADBy similarity3
Nucleotide bindingi315 – 318NADBy similarity4

GO - Molecular functioni

  • NAD binding Source: UniProtKB
  • oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor Source: InterPro
  • protein C-terminus binding Source: ProtInc
  • protein domain specific binding Source: UniProtKB
  • protein homodimerization activity Source: GO_Central
  • repressing transcription factor binding Source: BHF-UCL
  • RNA polymerase II transcription corepressor activity Source: BHF-UCL
  • transcription factor activity, sequence-specific DNA binding Source: Ensembl
  • transcription factor binding Source: UniProtKB

GO - Biological processi

  • negative regulation of cell proliferation Source: ProtInc
  • negative regulation of histone acetylation Source: BHF-UCL
  • negative regulation of histone H4 acetylation Source: BHF-UCL
  • negative regulation of transcription, DNA-templated Source: UniProtKB
  • negative regulation of transcription from RNA polymerase II promoter Source: BHF-UCL
  • negative regulation of transcription from RNA polymerase II promoter by histone modification Source: BHF-UCL
  • positive regulation of histone deacetylation Source: BHF-UCL
  • protein phosphorylation Source: ProtInc
  • regulation of cell cycle Source: BHF-UCL
  • transcription, DNA-templated Source: UniProtKB-KW
  • viral genome replication Source: ProtInc
  • white fat cell differentiation Source: UniProtKB
Complete GO annotation...

Keywords - Molecular functioni

Oxidoreductase, Repressor

Keywords - Biological processi

Differentiation, Host-virus interaction, Transcription, Transcription regulation

Keywords - Ligandi

NAD

Enzyme and pathway databases

ReactomeiR-HSA-3769402. Deactivation of the beta-catenin transactivating complex.
R-HSA-4641265. Repression of WNT target genes.
R-HSA-5339700. TCF7L2 mutants don't bind CTBP.
SignaLinkiQ13363.
SIGNORiQ13363.

Names & Taxonomyi

Protein namesi
Recommended name:
C-terminal-binding protein 1 (EC:1.1.1.-)
Short name:
CtBP1
Gene namesi
Name:CTBP1
Synonyms:CTBP
OrganismiHomo sapiens (Human)
Taxonomic identifieri9606 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo
Proteomesi
  • UP000005640 Componenti: Chromosome 4

Organism-specific databases

HGNCiHGNC:2494. CTBP1.

Subcellular locationi

GO - Cellular componenti

Complete GO annotation...

Keywords - Cellular componenti

Cytoplasm, Nucleus

Pathology & Biotechi

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi134C → A: Strongly reduces E1A binding; when associated with A-138; A-141 and A-150. 1 Publication1
Mutagenesisi138N → A: Strongly reduces E1A binding; when associated with A-134; A-141 and A-150. 1 Publication1
Mutagenesisi141 – 142RR → AA: Strongly reduces E1A binding; when associated with A-163 and A-171. 1 Publication2
Mutagenesisi141R → A: Strongly reduces E1A binding; when associated with A-134; A-138 and A-150. 1 Publication1
Mutagenesisi150L → A: Strongly reduces E1A binding; when associated with A-134; A-138 and A-141. 1 Publication1
Mutagenesisi163R → A: Strongly reduces E1A binding; when associated with A-141; A-142 and A-171. 1 Publication1
Mutagenesisi171R → A: Strongly reduces E1A binding; when associated with A-141; A-142 and A-163. 1 Publication1
Mutagenesisi181G → V: Strongly reduces E1A binding; when associated with V-183 and A-204. 1 Publication1
Mutagenesisi183G → V: Strongly reduces E1A binding; when associated with V-181 and A-204. 1 Publication1
Mutagenesisi204D → A: Strongly reduces E1A binding; when associated with V-181 and V-183. 1 Publication1
Mutagenesisi266R → A: Strongly reduces E1A binding; when associated with A-290; A-295 and A-315. 1 Publication1
Mutagenesisi290D → A: Strongly reduces E1A binding; when associated with A-266; A-295 and A-315. 1 Publication1
Mutagenesisi295E → A: Strongly reduces E1A binding; when associated with A-266; A-290 and A-315. 1 Publication1
Mutagenesisi315H → A: Strongly reduces E1A binding; when associated with A-266; A-290 and A-295. 1 Publication1
Mutagenesisi422S → A: Abolishes phosphorylation by HIPK2 and prevents UV-induced clearance. 1 Publication1

Organism-specific databases

DisGeNETi1487.
OpenTargetsiENSG00000159692.
PharmGKBiPA26995.

Polymorphism and mutation databases

BioMutaiCTBP1.
DMDMi6014741.

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00000760411 – 440C-terminal-binding protein 1Add BLAST440

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Modified residuei300PhosphoserineCombined sources1
Modified residuei422Phosphoserine; by HIPK21 Publication1
Cross-linki428Glycyl lysine isopeptide (Lys-Gly) (interchain with G-Cter in SUMO)1 Publication

Post-translational modificationi

The level of phosphorylation appears to be regulated during the cell cycle. Phosphorylation by HIPK2 on Ser-422 induces proteasomal degradation.2 Publications
ADP-ribosylated; when cells are exposed to brefeldin A.By similarity
Sumoylation on Lys-428 is promoted by the E3 SUMO-protein ligase CBX4.1 Publication

Keywords - PTMi

ADP-ribosylation, Isopeptide bond, Phosphoprotein, Ubl conjugation

Proteomic databases

EPDiQ13363.
PaxDbiQ13363.
PeptideAtlasiQ13363.
PRIDEiQ13363.

PTM databases

iPTMnetiQ13363.
PhosphoSitePlusiQ13363.
SwissPalmiQ13363.

Expressioni

Tissue specificityi

Expressed in germinal center B-cells.1 Publication

Gene expression databases

BgeeiENSG00000159692.
CleanExiHS_CTBP1.
ExpressionAtlasiQ13363. baseline and differential.
GenevisibleiQ13363. HS.

Organism-specific databases

HPAiCAB004217.
HPA018987.
HPA044971.

Interactioni

Subunit structurei

Homo- or heterodimer. Heterodimer with CTBP2. Interacts with PRDM16; the interaction represses white adipose tissue (WAT)-specific genes expression. Interacts with GLIS2, FOXP2, HDAC4, HDAC5, HDAC9 and ZNF217. Interacts with adenovirus E1A protein (via its C-terminus); the interaction disrupts the interaction of CTBP1 with RBBP8. Interacts with Epstein-Barr virus EBNA3 and EBNA6. Interacts with ELK3 (via its PXDLS motif). Interacts with RBBP8 (via its PXDLS motif); the interaction is disrupted by binding to adenovirus E1A. Interacts with FOXP1, HIPK2, PNN, NRIP1, MECOM, ZNF366, ZFHX1B and WIZ. Interaction with SATB1 (non-acetylated form); the interaction stabilizes its attachment to DNA and promotes transcription repression. Interacts with BCL6; the interaction is required for BCL6 transcriptional autoinhibition and inhibition of some BCL6 target genes. Interacts with IKZF4 (By similarity). Interacts with human adenovirus 5 E1A protein; this interaction seems to potentiate viral replication (PubMed:23747199). Interacts with MCRIP1 (unphosphorylated form, via the PXDLS motif); competitively inhibiting CTBP-ZEB1 interaction (PubMed:25728771).By similarity19 Publications

Binary interactionsi

WithEntry#Exp.IntActNotes
BCAS3Q9H6U63EBI-10171858,EBI-6083685
CDKN2DP552733EBI-10171858,EBI-745859
CEP68Q76N323EBI-10171858,EBI-9051024
CRY2Q49AN03EBI-10171858,EBI-2212355
CTBP2P565453EBI-10171858,EBI-741533
CTBP2Q8IY443EBI-10171858,EBI-10171902
DMRTB1I6L9A03EBI-10171858,EBI-10178554
FOXP2O154095EBI-10171858,EBI-983612
HEMGNQ9BXL52EBI-908846,EBI-3916399
HIC1Q145264EBI-908846,EBI-2507362
HOXB5P090673EBI-10171858,EBI-3893317
IKZF1Q134223EBI-10171858,EBI-745305
IKZF1Q13422-74EBI-10171858,EBI-11522367
KLF12Q9Y4X45EBI-10171858,EBI-750750
KLF4O434744EBI-908846,EBI-7232405
MAPK9P459843EBI-10171858,EBI-713568
NOL4O94818-23EBI-10171858,EBI-10190763
NOL4LQ96MY13EBI-10171858,EBI-6660790
PLCB1Q9NQ663EBI-10171858,EBI-3396023
PRKAA1Q131313EBI-10171858,EBI-1181405
TERF2IPQ9NYB02EBI-908846,EBI-750109
TGIF1Q155833EBI-10171858,EBI-714215
THAP11Q96EK42EBI-908846,EBI-1790529
TSHZ3A1L0U73EBI-10171858,EBI-10171826
Zbp1A2APF72EBI-908846,EBI-6115394From a different organism.
ZNF366Q8N8955EBI-908846,EBI-2813661

GO - Molecular functioni

  • protein C-terminus binding Source: ProtInc
  • protein domain specific binding Source: UniProtKB
  • protein homodimerization activity Source: GO_Central
  • repressing transcription factor binding Source: BHF-UCL
  • transcription factor binding Source: UniProtKB

Protein-protein interaction databases

BioGridi107869. 153 interactors.
DIPiDIP-24245N.
IntActiQ13363. 54 interactors.
MINTiMINT-94454.
STRINGi9606.ENSP00000290921.

Chemistry databases

BindingDBiQ13363.

Structurei

Secondary structure

1440
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Beta strandi29 – 34Combined sources6
Turni39 – 41Combined sources3
Helixi42 – 45Combined sources4
Turni46 – 48Combined sources3
Beta strandi50 – 53Combined sources4
Helixi59 – 61Combined sources3
Helixi64 – 69Combined sources6
Beta strandi70 – 75Combined sources6
Beta strandi77 – 79Combined sources3
Helixi83 – 86Combined sources4
Beta strandi94 – 100Combined sources7
Helixi107 – 112Combined sources6
Beta strandi116 – 118Combined sources3
Turni121 – 124Combined sources4
Helixi125 – 141Combined sources17
Helixi143 – 151Combined sources9
Helixi159 – 165Combined sources7
Turni166 – 168Combined sources3
Beta strandi176 – 180Combined sources5
Helixi184 – 194Combined sources11
Turni195 – 197Combined sources3
Beta strandi199 – 203Combined sources5
Helixi211 – 215Combined sources5
Helixi223 – 229Combined sources7
Beta strandi231 – 235Combined sources5
Beta strandi246 – 248Combined sources3
Helixi249 – 252Combined sources4
Beta strandi259 – 263Combined sources5
Helixi267 – 269Combined sources3
Helixi272 – 280Combined sources9
Beta strandi283 – 290Combined sources8
Beta strandi293 – 296Combined sources4
Turni303 – 306Combined sources4
Beta strandi308 – 312Combined sources5
Helixi321 – 340Combined sources20
Turni343 – 346Combined sources4
Beta strandi348 – 350Combined sources3

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1MX3X-ray1.95A28-353[»]
4LCEX-ray2.38A28-353[»]
4U6QX-ray2.30A28-353[»]
4U6SX-ray2.10A28-353[»]
ProteinModelPortaliQ13363.
SMRiQ13363.
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiQ13363.

Family & Domainsi

Region

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Regioni1 – 70Interaction with GLIS2 1By similarityAdd BLAST70
Regioni288 – 360Interaction with GLIS2 2By similarityAdd BLAST73

Sequence similaritiesi

Phylogenomic databases

eggNOGiKOG0067. Eukaryota.
COG0111. LUCA.
GeneTreeiENSGT00530000063021.
HOGENOMiHOG000136701.
HOVERGENiHBG001898.
InParanoidiQ13363.
KOiK04496.
OMAiDRDHPSD.
OrthoDBiEOG091G08GS.
PhylomeDBiQ13363.
TreeFamiTF313593.

Family and domain databases

Gene3Di3.40.50.720. 2 hits.
InterProiIPR006139. D-isomer_2_OHA_DH_cat_dom.
IPR029753. D-isomer_DH_CS.
IPR029752. D-isomer_DH_CS1.
IPR006140. D-isomer_DH_NAD-bd.
IPR016040. NAD(P)-bd_dom.
[Graphical view]
PfamiPF00389. 2-Hacid_dh. 1 hit.
PF02826. 2-Hacid_dh_C. 1 hit.
[Graphical view]
SUPFAMiSSF51735. SSF51735. 1 hit.
PROSITEiPS00065. D_2_HYDROXYACID_DH_1. 1 hit.
PS00671. D_2_HYDROXYACID_DH_3. 1 hit.
[Graphical view]

Sequences (2)i

Sequence statusi: Complete.

This entry describes 2 isoformsi produced by alternative splicing. AlignAdd to basket

Isoform 1 (identifier: Q13363-1) [UniParc]FASTAAdd to basket

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.

« Hide

        10         20         30         40         50
MGSSHLLNKG LPLGVRPPIM NGPLHPRPLV ALLDGRDCTV EMPILKDVAT
60 70 80 90 100
VAFCDAQSTQ EIHEKVLNEA VGALMYHTIT LTREDLEKFK ALRIIVRIGS
110 120 130 140 150
GFDNIDIKSA GDLGIAVCNV PAASVEETAD STLCHILNLY RRATWLHQAL
160 170 180 190 200
REGTRVQSVE QIREVASGAA RIRGETLGII GLGRVGQAVA LRAKAFGFNV
210 220 230 240 250
LFYDPYLSDG VERALGLQRV STLQDLLFHS DCVTLHCGLN EHNHHLINDF
260 270 280 290 300
TVKQMRQGAF LVNTARGGLV DEKALAQALK EGRIRGAALD VHESEPFSFS
310 320 330 340 350
QGPLKDAPNL ICTPHAAWYS EQASIEMREE AAREIRRAIT GRIPDSLKNC
360 370 380 390 400
VNKDHLTAAT HWASMDPAVV HPELNGAAYR YPPGVVGVAP TGIPAAVEGI
410 420 430 440
VPSAMSLSHG LPPVAHPPHA PSPGQTVKPE ADRDHASDQL
Length:440
Mass (Da):47,535
Last modified:July 15, 1999 - v2
Checksum:iF071DD30B385603F
GO
Isoform 2 (identifier: Q13363-2) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     1-13: MGSSHLLNKGLPL → MS

Note: No experimental confirmation available.
Show »
Length:429
Mass (Da):46,405
Checksum:i0366A6370016910B
GO

Alternative sequence

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Alternative sequenceiVSP_0433051 – 13MGSSH…KGLPL → MS in isoform 2. 1 PublicationAdd BLAST13

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U37408 mRNA. Translation: AAC62822.1.
AF091555 mRNA. Translation: AAD14597.1.
AC092535 Genomic DNA. Translation: AAY40989.1.
CH471131 Genomic DNA. Translation: EAW82599.1.
CH471131 Genomic DNA. Translation: EAW82600.1.
CH471131 Genomic DNA. Translation: EAW82601.1.
BC011655 mRNA. Translation: AAH11655.1.
BC053320 mRNA. Translation: AAH53320.1.
CCDSiCCDS3348.1. [Q13363-1]
CCDS43203.1. [Q13363-2]
RefSeqiNP_001012632.1. NM_001012614.1. [Q13363-2]
NP_001319.1. NM_001328.2. [Q13363-1]
XP_016863253.1. XM_017007764.1. [Q13363-2]
XP_016863254.1. XM_017007765.1. [Q13363-2]
XP_016863255.1. XM_017007766.1. [Q13363-2]
XP_016863256.1. XM_017007767.1. [Q13363-2]
UniGeneiHs.208597.

Genome annotation databases

EnsembliENST00000290921; ENSP00000290921; ENSG00000159692. [Q13363-1]
ENST00000382952; ENSP00000372411; ENSG00000159692. [Q13363-2]
GeneIDi1487.
KEGGihsa:1487.
UCSCiuc003gcu.2. human. [Q13363-1]

Keywords - Coding sequence diversityi

Alternative splicing

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U37408 mRNA. Translation: AAC62822.1.
AF091555 mRNA. Translation: AAD14597.1.
AC092535 Genomic DNA. Translation: AAY40989.1.
CH471131 Genomic DNA. Translation: EAW82599.1.
CH471131 Genomic DNA. Translation: EAW82600.1.
CH471131 Genomic DNA. Translation: EAW82601.1.
BC011655 mRNA. Translation: AAH11655.1.
BC053320 mRNA. Translation: AAH53320.1.
CCDSiCCDS3348.1. [Q13363-1]
CCDS43203.1. [Q13363-2]
RefSeqiNP_001012632.1. NM_001012614.1. [Q13363-2]
NP_001319.1. NM_001328.2. [Q13363-1]
XP_016863253.1. XM_017007764.1. [Q13363-2]
XP_016863254.1. XM_017007765.1. [Q13363-2]
XP_016863255.1. XM_017007766.1. [Q13363-2]
XP_016863256.1. XM_017007767.1. [Q13363-2]
UniGeneiHs.208597.

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1MX3X-ray1.95A28-353[»]
4LCEX-ray2.38A28-353[»]
4U6QX-ray2.30A28-353[»]
4U6SX-ray2.10A28-353[»]
ProteinModelPortaliQ13363.
SMRiQ13363.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi107869. 153 interactors.
DIPiDIP-24245N.
IntActiQ13363. 54 interactors.
MINTiMINT-94454.
STRINGi9606.ENSP00000290921.

Chemistry databases

BindingDBiQ13363.

PTM databases

iPTMnetiQ13363.
PhosphoSitePlusiQ13363.
SwissPalmiQ13363.

Polymorphism and mutation databases

BioMutaiCTBP1.
DMDMi6014741.

Proteomic databases

EPDiQ13363.
PaxDbiQ13363.
PeptideAtlasiQ13363.
PRIDEiQ13363.

Protocols and materials databases

DNASUi1487.
Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsembliENST00000290921; ENSP00000290921; ENSG00000159692. [Q13363-1]
ENST00000382952; ENSP00000372411; ENSG00000159692. [Q13363-2]
GeneIDi1487.
KEGGihsa:1487.
UCSCiuc003gcu.2. human. [Q13363-1]

Organism-specific databases

CTDi1487.
DisGeNETi1487.
GeneCardsiCTBP1.
HGNCiHGNC:2494. CTBP1.
HPAiCAB004217.
HPA018987.
HPA044971.
MIMi602618. gene.
neXtProtiNX_Q13363.
OpenTargetsiENSG00000159692.
PharmGKBiPA26995.
GenAtlasiSearch...

Phylogenomic databases

eggNOGiKOG0067. Eukaryota.
COG0111. LUCA.
GeneTreeiENSGT00530000063021.
HOGENOMiHOG000136701.
HOVERGENiHBG001898.
InParanoidiQ13363.
KOiK04496.
OMAiDRDHPSD.
OrthoDBiEOG091G08GS.
PhylomeDBiQ13363.
TreeFamiTF313593.

Enzyme and pathway databases

ReactomeiR-HSA-3769402. Deactivation of the beta-catenin transactivating complex.
R-HSA-4641265. Repression of WNT target genes.
R-HSA-5339700. TCF7L2 mutants don't bind CTBP.
SignaLinkiQ13363.
SIGNORiQ13363.

Miscellaneous databases

ChiTaRSiCTBP1. human.
EvolutionaryTraceiQ13363.
GeneWikiiCTBP1.
GenomeRNAii1487.
PROiQ13363.
SOURCEiSearch...

Gene expression databases

BgeeiENSG00000159692.
CleanExiHS_CTBP1.
ExpressionAtlasiQ13363. baseline and differential.
GenevisibleiQ13363. HS.

Family and domain databases

Gene3Di3.40.50.720. 2 hits.
InterProiIPR006139. D-isomer_2_OHA_DH_cat_dom.
IPR029753. D-isomer_DH_CS.
IPR029752. D-isomer_DH_CS1.
IPR006140. D-isomer_DH_NAD-bd.
IPR016040. NAD(P)-bd_dom.
[Graphical view]
PfamiPF00389. 2-Hacid_dh. 1 hit.
PF02826. 2-Hacid_dh_C. 1 hit.
[Graphical view]
SUPFAMiSSF51735. SSF51735. 1 hit.
PROSITEiPS00065. D_2_HYDROXYACID_DH_1. 1 hit.
PS00671. D_2_HYDROXYACID_DH_3. 1 hit.
[Graphical view]
ProtoNetiSearch...

Entry informationi

Entry nameiCTBP1_HUMAN
AccessioniPrimary (citable) accession number: Q13363
Secondary accession number(s): Q4W5N3, Q7Z2Q5
Entry historyi
Integrated into UniProtKB/Swiss-Prot: July 15, 1998
Last sequence update: July 15, 1999
Last modified: November 30, 2016
This is version 185 of the entry and version 2 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programChordata Protein Annotation Program
DisclaimerAny medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care.

Miscellaneousi

Keywords - Technical termi

3D-structure, Complete proteome, Direct protein sequencing, Reference proteome

Documents

  1. Human chromosome 4
    Human chromosome 4: entries, gene names and cross-references to MIM
  2. MIM cross-references
    Online Mendelian Inheritance in Man (MIM) cross-references in UniProtKB/Swiss-Prot
  3. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  4. SIMILARITY comments
    Index of protein domains and families

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.