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Protein

Cyclic AMP-dependent transcription factor ATF-7

Gene

ATF7

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

Functioni

Plays important functions in early cell signaling. Binds the cAMP response element (CRE) (consensus: 5'-GTGACGT[AG][AG]-3'), a sequence present in many viral and cellular promoters. Activator of the NF-ELAM1/delta-A site of the E-selectin promoter. Has no intrinsic transcriptional activity, but activates transcription on formation of JUN or FOS heterodimers. Also can bind TRE promoter sequences when heterodimerized with members of the JUN family.
Isoform 4 acts as a dominant repressor of the E-selectin/NF-ELAM1/delta-A promoter.
Isoform 5 acts as a negative regulator, inhibiting both ATF2 and ATF7 transcriptional activities. It may exert these effects by sequestrating in the cytoplasm the Thr-53 phosphorylating kinase, preventing activation.

Regions

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Zinc fingeri7 – 31C2H2-typePROSITE-ProRule annotationAdd BLAST25

GO - Molecular functioni

  • enzyme binding Source: UniProtKB
  • metal ion binding Source: UniProtKB-KW
  • mitogen-activated protein kinase binding Source: UniProtKB
  • RNA polymerase II core promoter proximal region sequence-specific DNA binding Source: NTNU_SB
  • sequence-specific DNA binding Source: InterPro
  • transcriptional repressor activity, RNA polymerase II core promoter proximal region sequence-specific binding Source: NTNU_SB
  • transcription factor activity, sequence-specific DNA binding Source: ProtInc
  • transcription factor binding Source: UniProtKB

GO - Biological processi

Complete GO annotation...

Keywords - Molecular functioni

Activator

Keywords - Biological processi

Host-virus interaction, Transcription, Transcription regulation

Keywords - Ligandi

DNA-binding, Metal-binding, Zinc

Enzyme and pathway databases

BioCyciZFISH:ENSG00000170653-MONOMER.
SIGNORiP17544.

Names & Taxonomyi

Protein namesi
Recommended name:
Cyclic AMP-dependent transcription factor ATF-7
Short name:
cAMP-dependent transcription factor ATF-7
Alternative name(s):
Activating transcription factor 7
Transcription factor ATF-A
Gene namesi
Name:ATF7
Synonyms:ATFA
OrganismiHomo sapiens (Human)
Taxonomic identifieri9606 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo
Proteomesi
  • UP000005640 Componenti: Chromosome 12

Organism-specific databases

HGNCiHGNC:792. ATF7.

Subcellular locationi

Isoform 5 :

GO - Cellular componenti

  • cytoplasm Source: UniProtKB-SubCell
  • nuclear periphery Source: UniProtKB
  • nucleoplasm Source: UniProtKB-SubCell
  • nucleus Source: UniProtKB
Complete GO annotation...

Keywords - Cellular componenti

Cytoplasm, Nucleus

Pathology & Biotechi

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi9C → A: Severely reduced TAF12-mediated enhancement of transcriptional activity. 1 Publication1
Mutagenesisi14C → A: Greatly reduced JNK2- or adenovirus E1A-mediated transactivation. Abolishes adenovirus 2 E1A-mediated transactivation; when associated with A-51; A-53 and G-112. 1 Publication1
Mutagenesisi22D → K: No effect on binding adenovirus 2 E1A. Abolishes ATF7-mediated E1A responsiveness. 1 Publication1
Mutagenesisi27H → N: No effect on binding adenovirus 2 E1A. Abolishes ATF7-mediated E1A responsiveness. 1 Publication1
Mutagenesisi33M → D: Severely reduced TAF12-induced transcriptional activity; when associated with S-35. 1 Publication1
Mutagenesisi35L → S: Severely reduced TAF12-induced transcriptional activity; when associated with D-33. 1 Publication1
Mutagenesisi51T → A: Severely reduced TAF12-induced transcriptional activity. No effect on MAPK9-mediated phosphorylation; when associated with A-53. Greatly reduces MAPK9- and adenovirus E1A-mediated transactivation; when associated with A-53 and G-112. Abolishes adenovirus 2 E1A-mediated transactivation; when associated with A-14; A-53 and G-112. 3 Publications1
Mutagenesisi51T → D: Completely abolishes MAPK9- and adenovirus E1A-mediated transactivation; when associated with D-53. 3 Publications1
Mutagenesisi53T → A: Severely reduced TAF12-induced transcriptional activity. No effect on MAPK9-mediated phosphorylation; when associated with A-51. Greatly reduces MAPK9- and adenovirus E1A-mediated transactivation; when associated with A-51 and G-112. Abolishes adenovirus 2 E1A-mediated transactivation; when associated with A-14; A-51 and G-112. 3 Publications1
Mutagenesisi53T → D: Completely abolishes MAPK9- and adenovirus E1A-mediated transactivation; when associated with D-51. 3 Publications1
Mutagenesisi112T → G: Some reduction in transactivation but, completely abolishes MAPK9-mediated activation. Abolishes MAPK9-mediated and greatly reduces adenovirus E1A-mediated transactivation; when associated with A-51 and A-53. Abolishes adenovirus 2 E1A-mediated transactivation; when associated with A-14; A-51 and A-53. 2 Publications1
Mutagenesisi118K → R: Abolishes sumoylation. Exclusive nucleoplasmic location. Increase in binding the E-selectin promoter. 1 Publication1
Mutagenesisi156T → A: No effect on transactivation; when associated with A-158. 1 Publication1
Mutagenesisi158T → A: No effect on transactivation; when associated with A-156. 1 Publication1

Organism-specific databases

DisGeNETi11016.
OpenTargetsiENSG00000170653.
PharmGKBiPA25092.

Chemistry databases

DrugBankiDB00852. Pseudoephedrine.

Polymorphism and mutation databases

BioMutaiATF7.
DMDMi12643393.

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00000765921 – 494Cyclic AMP-dependent transcription factor ATF-7Add BLAST494

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Modified residuei51Phosphothreonine; by MAPK111 Publication1
Modified residuei53Phosphothreonine1 Publication1
Modified residuei112Phosphothreonine1 Publication1
Cross-linki118Glycyl lysine isopeptide (Lys-Gly) (interchain with G-Cter in SUMO1)2 Publications
Modified residuei424PhosphoserineCombined sources1
Modified residuei434PhosphoserineCombined sources1

Post-translational modificationi

On EGF stimulation, phosphorylated first on Thr-53 allowing subsequent phosphorylation on Thr-51. This latter phosphorylation prevents sumoylation, increases binding to TAF12 and enhances transcriptional activity.1 Publication
Sumoylation delays nuclear localization and inhibits transactivation activity through preventing binding to TAF12. RANBP2 appears to be the specific E3 ligase.

Keywords - PTMi

Isopeptide bond, Phosphoprotein, Ubl conjugation

Proteomic databases

EPDiP17544.
MaxQBiP17544.
PaxDbiP17544.
PeptideAtlasiP17544.
PRIDEiP17544.

PTM databases

iPTMnetiP17544.
PhosphoSitePlusiP17544.

Expressioni

Tissue specificityi

Expressed in heart, lung and skeletal muscle. Isoform 4 is expressed in various tissues including heart, brain, placenta, lung and skeletal muscle. Highest levels in skeletal muscle. Lowest in lung and placenta.1 Publication

Gene expression databases

BgeeiENSG00000170653.
CleanExiHS_ATF7.
ExpressionAtlasiP17544. baseline and differential.
GenevisibleiP17544. HS.

Organism-specific databases

HPAiHPA003384.

Interactioni

Subunit structurei

Homodimer; binds DNA as homodimer. Heterodimer; heterodimerizes with other members of ATF family and with JUN family members. Interacts with JNK2; the interaction does not phosphorylate ATF7 but acts as a docking site for other ATF-associated partners such as JUN family members. Interacts (via its transactivation domain) with TAF12 (isoforms TAFII15 and TAFII20); the interaction potentiates the transactivation activity (isoform TAFII20 only) and is inhibited by ATF7 sumoylation. Interacts with TAF4; the interaction inhibits the TAF12-dependent transactivation. Interacts with adenovirus 2 E1A; the interaction enhances the ATF7-mediated viral transactivation activity which requires the zinc-binding domains of both E1A and ATF7. Interacts with MAPK9; the interaction does not phosphorylate ATF7 but acts as a docking site for ATF7-associated partners such as JUN.7 Publications

Binary interactionsi

WithEntry#Exp.IntActNotes
ATF3P188472EBI-765623,EBI-712767
CCDC155Q8N6L03EBI-765623,EBI-749265
FAM9BQ8IZU03EBI-765623,EBI-10175124
FCER2P067343EBI-765623,EBI-10199985
FOSP011004EBI-765623,EBI-852851
FOSL2P154082EBI-765623,EBI-3893419
HBZP0C7462EBI-765623,EBI-10890294From a different organism.
JUNP054126EBI-765623,EBI-852823
JUNBP172752EBI-765623,EBI-748062
JUNDP175352EBI-765623,EBI-2682803
MDV005Q9DGW52EBI-765623,EBI-10889526From a different organism.
OCIAD1Q9NX402EBI-765623,EBI-2683029
TMEM239Q8WW343EBI-765623,EBI-9675724

GO - Molecular functioni

  • enzyme binding Source: UniProtKB
  • mitogen-activated protein kinase binding Source: UniProtKB
  • transcription factor binding Source: UniProtKB

Protein-protein interaction databases

BioGridi116206. 34 interactors.
IntActiP17544. 30 interactors.
MINTiMINT-194321.
STRINGi9606.ENSP00000329212.

Structurei

3D structure databases

ProteinModelPortaliP17544.
SMRiP17544.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Domains and Repeats

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Domaini343 – 406bZIPPROSITE-ProRule annotationAdd BLAST64

Region

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Regioni1 – 296Transactivation domainAdd BLAST296
Regioni336 – 494Essential for binding adenovirus 2 E1AAdd BLAST159
Regioni345 – 365Basic motifPROSITE-ProRule annotationAdd BLAST21
Regioni371 – 399Leucine-zipperPROSITE-ProRule annotationAdd BLAST29

Sequence similaritiesi

Belongs to the bZIP family.Curated
Contains 1 bZIP (basic-leucine zipper) domain.PROSITE-ProRule annotation
Contains 1 C2H2-type zinc finger.PROSITE-ProRule annotation

Zinc finger

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Zinc fingeri7 – 31C2H2-typePROSITE-ProRule annotationAdd BLAST25

Keywords - Domaini

Zinc-finger

Phylogenomic databases

eggNOGiKOG1414. Eukaryota.
ENOG4111CH5. LUCA.
GeneTreeiENSGT00390000020106.
HOGENOMiHOG000220894.
HOVERGENiHBG004300.
InParanoidiP17544.
KOiK09045.
OMAiVIQHSSV.
OrthoDBiEOG091G0AO8.
PhylomeDBiP17544.

Family and domain databases

Gene3Di3.30.160.60. 1 hit.
InterProiIPR004827. bZIP.
IPR016378. TF_CRE-BP1-typ.
IPR007087. Znf_C2H2.
IPR015880. Znf_C2H2-like.
IPR013087. Znf_C2H2/integrase_DNA-bd.
[Graphical view]
PfamiPF00170. bZIP_1. 1 hit.
[Graphical view]
PIRSFiPIRSF003153. ATF2_CRE-BP1. 1 hit.
SMARTiSM00338. BRLZ. 1 hit.
SM00355. ZnF_C2H2. 1 hit.
[Graphical view]
PROSITEiPS50217. BZIP. 1 hit.
PS00036. BZIP_BASIC. 1 hit.
PS00028. ZINC_FINGER_C2H2_1. 1 hit.
PS50157. ZINC_FINGER_C2H2_2. 1 hit.
[Graphical view]

Sequences (6)i

Sequence statusi: Complete.

This entry describes 6 isoformsi produced by alternative splicing. AlignAdd to basket

Isoform 3 (identifier: P17544-1) [UniParc]FASTAAdd to basket
Also known as: ATF-A1

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
MGDDRPFVCN APGCGQRFTN EDHLAVHKHK HEMTLKFGPA RTDSVIIADQ
60 70 80 90 100
TPTPTRFLKN CEEVGLFNEL ASSFEHEFKK AADEDEKKAR SRTVAKKLVA
110 120 130 140 150
AAGPLDMSLP STPDIKIKEE EPVEVDSSPP DSPASSPCSP PLKEKEVTPK
160 170 180 190 200
PVLISTPTPT IVRPGSLPLH LGYDPLHPTL PSPTSVITQA PPSNRQMGSP
210 220 230 240 250
TGSLPLVMHL ANGQTMPVLP GPPVQMPSVI SLARPVSMVP NIPGIPGPPV
260 270 280 290 300
NSSGSISPSG HPIPSEAKMR LKATLTHQVS SINGGCGMVV GTASTMVTAR
310 320 330 340 350
PEQSQILIQH PDAPSPAQPQ VSPAQPTPST GGRRRRTVDE DPDERRQRFL
360 370 380 390 400
ERNRAAASRC RQKRKLWVSS LEKKAEELTS QNIQLSNEVT LLRNEVAQLK
410 420 430 440 450
QLLLAHKDCP VTALQKKTQG YLESPKESSE PTGSPAPVIQ HSSATAPSNG
460 470 480 490
LSVRSAAEAV ATSVLTQMAS QRTELSMPIQ SHVIMTPQSQ SAGR
Length:494
Mass (Da):52,967
Last modified:January 24, 2001 - v2
Checksum:i511EAF79C6503300
GO
Isoform 1 (identifier: P17544-2) [UniParc]FASTAAdd to basket
Also known as: ATF-A

The sequence of this isoform differs from the canonical sequence as follows:
     89-99: Missing.
     125-145: Missing.

Show »
Length:462
Mass (Da):49,650
Checksum:i92AB6DF8D2A954CD
GO
Isoform 2 (identifier: P17544-3) [UniParc]FASTAAdd to basket
Also known as: ATF-A-delta

The sequence of this isoform differs from the canonical sequence as follows:
     125-145: Missing.

Show »
Length:473
Mass (Da):50,860
Checksum:i6CB9C4D7A0128AA9
GO
Isoform 4 (identifier: P17544-4) [UniParc]FASTAAdd to basket
Also known as: ATF-A0

The sequence of this isoform differs from the canonical sequence as follows:
     89-99: Missing.
     146-321: Missing.

Show »
Length:307
Mass (Da):33,681
Checksum:i01665BFA649C6CA1
GO
Isoform 5 (identifier: P17544-5) [UniParc]FASTAAdd to basket
Also known as: ATF-4

The sequence of this isoform differs from the canonical sequence as follows:
     100-494: AAAGPLDMSL...MTPQSQSAGR → VFRPRLFLLCFGIIFLIG

Show »
Length:117
Mass (Da):13,278
Checksum:i15298D193695ACED
GO
Isoform 6 (identifier: P17544-6) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     89-99: Missing.

Note: No experimental confirmation available.
Show »
Length:483
Mass (Da):51,757
Checksum:i07080BC24FED635B
GO

Experimental Info

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sequence conflicti12P → T in AAH42363 (PubMed:15489334).Curated1

Alternative sequence

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Alternative sequenceiVSP_00059489 – 99Missing in isoform 1, isoform 4 and isoform 6. 3 PublicationsAdd BLAST11
Alternative sequenceiVSP_042469100 – 494AAAGP…QSAGR → VFRPRLFLLCFGIIFLIG in isoform 5. 1 PublicationAdd BLAST395
Alternative sequenceiVSP_000595125 – 145Missing in isoform 1 and isoform 2. 1 PublicationAdd BLAST21
Alternative sequenceiVSP_034543146 – 321Missing in isoform 4. 1 PublicationAdd BLAST176

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
X52943 mRNA. Translation: CAA37118.1.
X57197 mRNA. Translation: CAA40483.1.
AK298853 mRNA. Translation: BAG60976.1.
AC023509 Genomic DNA. No translation available.
AC073594 Genomic DNA. No translation available.
CH471054 Genomic DNA. Translation: EAW96723.1.
CH471054 Genomic DNA. Translation: EAW96724.1.
BC042363 mRNA. Translation: AAH42363.1.
BC136302 mRNA. Translation: AAI36303.1.
BC140006 mRNA. Translation: AAI40007.1.
CCDSiCCDS44906.1. [P17544-6]
CCDS58238.1. [P17544-5]
PIRiS12741.
RefSeqiNP_001123532.1. NM_001130060.1. [P17544-2]
NP_001193611.1. NM_001206682.1. [P17544-5]
NP_001193612.1. NM_001206683.1. [P17544-5]
NP_006847.1. NM_006856.2. [P17544-6]
XP_005268644.1. XM_005268587.3. [P17544-6]
XP_016874211.1. XM_017018722.1. [P17544-6]
UniGeneiHs.12286.
Hs.633602.

Genome annotation databases

EnsembliENST00000420353; ENSP00000399465; ENSG00000170653. [P17544-6]
ENST00000456903; ENSP00000387406; ENSG00000170653. [P17544-6]
ENST00000548118; ENSP00000456858; ENSG00000170653. [P17544-5]
ENST00000548446; ENSP00000449938; ENSG00000170653. [P17544-1]
ENST00000591397; ENSP00000465192; ENSG00000170653. [P17544-5]
GeneIDi11016.
KEGGihsa:11016.
UCSCiuc001sdz.4. human. [P17544-1]

Keywords - Coding sequence diversityi

Alternative splicing

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
X52943 mRNA. Translation: CAA37118.1.
X57197 mRNA. Translation: CAA40483.1.
AK298853 mRNA. Translation: BAG60976.1.
AC023509 Genomic DNA. No translation available.
AC073594 Genomic DNA. No translation available.
CH471054 Genomic DNA. Translation: EAW96723.1.
CH471054 Genomic DNA. Translation: EAW96724.1.
BC042363 mRNA. Translation: AAH42363.1.
BC136302 mRNA. Translation: AAI36303.1.
BC140006 mRNA. Translation: AAI40007.1.
CCDSiCCDS44906.1. [P17544-6]
CCDS58238.1. [P17544-5]
PIRiS12741.
RefSeqiNP_001123532.1. NM_001130060.1. [P17544-2]
NP_001193611.1. NM_001206682.1. [P17544-5]
NP_001193612.1. NM_001206683.1. [P17544-5]
NP_006847.1. NM_006856.2. [P17544-6]
XP_005268644.1. XM_005268587.3. [P17544-6]
XP_016874211.1. XM_017018722.1. [P17544-6]
UniGeneiHs.12286.
Hs.633602.

3D structure databases

ProteinModelPortaliP17544.
SMRiP17544.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi116206. 34 interactors.
IntActiP17544. 30 interactors.
MINTiMINT-194321.
STRINGi9606.ENSP00000329212.

Chemistry databases

DrugBankiDB00852. Pseudoephedrine.

PTM databases

iPTMnetiP17544.
PhosphoSitePlusiP17544.

Polymorphism and mutation databases

BioMutaiATF7.
DMDMi12643393.

Proteomic databases

EPDiP17544.
MaxQBiP17544.
PaxDbiP17544.
PeptideAtlasiP17544.
PRIDEiP17544.

Protocols and materials databases

DNASUi11016.
Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsembliENST00000420353; ENSP00000399465; ENSG00000170653. [P17544-6]
ENST00000456903; ENSP00000387406; ENSG00000170653. [P17544-6]
ENST00000548118; ENSP00000456858; ENSG00000170653. [P17544-5]
ENST00000548446; ENSP00000449938; ENSG00000170653. [P17544-1]
ENST00000591397; ENSP00000465192; ENSG00000170653. [P17544-5]
GeneIDi11016.
KEGGihsa:11016.
UCSCiuc001sdz.4. human. [P17544-1]

Organism-specific databases

CTDi11016.
DisGeNETi11016.
GeneCardsiATF7.
H-InvDBHIX0201838.
HGNCiHGNC:792. ATF7.
HPAiHPA003384.
MIMi606371. gene.
neXtProtiNX_P17544.
OpenTargetsiENSG00000170653.
PharmGKBiPA25092.
GenAtlasiSearch...

Phylogenomic databases

eggNOGiKOG1414. Eukaryota.
ENOG4111CH5. LUCA.
GeneTreeiENSGT00390000020106.
HOGENOMiHOG000220894.
HOVERGENiHBG004300.
InParanoidiP17544.
KOiK09045.
OMAiVIQHSSV.
OrthoDBiEOG091G0AO8.
PhylomeDBiP17544.

Enzyme and pathway databases

BioCyciZFISH:ENSG00000170653-MONOMER.
SIGNORiP17544.

Miscellaneous databases

ChiTaRSiATF7. human.
GeneWikiiATF7.
GenomeRNAii11016.
PROiP17544.
SOURCEiSearch...

Gene expression databases

BgeeiENSG00000170653.
CleanExiHS_ATF7.
ExpressionAtlasiP17544. baseline and differential.
GenevisibleiP17544. HS.

Family and domain databases

Gene3Di3.30.160.60. 1 hit.
InterProiIPR004827. bZIP.
IPR016378. TF_CRE-BP1-typ.
IPR007087. Znf_C2H2.
IPR015880. Znf_C2H2-like.
IPR013087. Znf_C2H2/integrase_DNA-bd.
[Graphical view]
PfamiPF00170. bZIP_1. 1 hit.
[Graphical view]
PIRSFiPIRSF003153. ATF2_CRE-BP1. 1 hit.
SMARTiSM00338. BRLZ. 1 hit.
SM00355. ZnF_C2H2. 1 hit.
[Graphical view]
PROSITEiPS50217. BZIP. 1 hit.
PS00036. BZIP_BASIC. 1 hit.
PS00028. ZINC_FINGER_C2H2_1. 1 hit.
PS50157. ZINC_FINGER_C2H2_2. 1 hit.
[Graphical view]
ProtoNetiSearch...

Entry informationi

Entry nameiATF7_HUMAN
AccessioniPrimary (citable) accession number: P17544
Secondary accession number(s): A5D6Y4
, B2RMP1, B4DQL4, Q13814, Q8IVR8, Q9UD83
Entry historyi
Integrated into UniProtKB/Swiss-Prot: August 1, 1990
Last sequence update: January 24, 2001
Last modified: November 2, 2016
This is version 172 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

Complete proteome, Reference proteome

Documents

  1. Human chromosome 12
    Human chromosome 12: 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. 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.