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Protein

Mesoderm induction early response protein 3

Gene

MIER3

Organism
Homo sapiens (Human)
Status
Reviewed-Annotation score: Annotation score: 3 out of 5-Experimental evidence at protein leveli

Functioni

Transcriptional repressor.By similarity

GO - Molecular functioni

GO - Biological processi

Complete GO annotation...

Keywords - Molecular functioni

Repressor

Keywords - Biological processi

Transcription, Transcription regulation

Names & Taxonomyi

Protein namesi
Recommended name:
Mesoderm induction early response protein 3
Short name:
Mi-er3
Gene namesi
Name:MIER3
OrganismiHomo sapiens (Human)
Taxonomic identifieri9606 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo
Proteomesi
  • UP000005640 Componenti: Chromosome 5

Organism-specific databases

HGNCiHGNC:26678. MIER3.

Subcellular locationi

  • Nucleus PROSITE-ProRule annotation

GO - Cellular componenti

Complete GO annotation...

Keywords - Cellular componenti

Nucleus

Pathology & Biotechi

Organism-specific databases

PharmGKBiPA145008088.

Polymorphism and mutation databases

BioMutaiMIER3.
DMDMi166217020.

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Chaini1 – 550550Mesoderm induction early response protein 3PRO_0000313680Add
BLAST

Amino acid modifications

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Modified residuei52 – 521PhosphoserineCombined sources
Modified residuei53 – 531PhosphoserineCombined sources
Modified residuei114 – 1141PhosphoserineBy similarity
Modified residuei156 – 1561PhosphoserineCombined sources
Modified residuei163 – 1631PhosphothreonineBy similarity
Modified residuei165 – 1651PhosphoserineBy similarity
Modified residuei168 – 1681PhosphoserineBy similarity

Keywords - PTMi

Phosphoprotein

Proteomic databases

EPDiQ7Z3K6.
MaxQBiQ7Z3K6.
PaxDbiQ7Z3K6.
PRIDEiQ7Z3K6.

PTM databases

iPTMnetiQ7Z3K6.
PhosphoSiteiQ7Z3K6.

Expressioni

Gene expression databases

BgeeiQ7Z3K6.
CleanExiHS_MIER3.
ExpressionAtlasiQ7Z3K6. baseline and differential.
GenevisibleiQ7Z3K6. HS.

Organism-specific databases

HPAiHPA065946.

Interactioni

Protein-protein interaction databases

BioGridi127939. 6 interactions.
IntActiQ7Z3K6. 3 interactions.
MINTiMINT-4720437.
STRINGi9606.ENSP00000370611.

Structurei

3D structure databases

ProteinModelPortaliQ7Z3K6.
SMRiQ7Z3K6. Positions 175-340.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Domains and Repeats

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Domaini174 – 27299ELM2PROSITE-ProRule annotationAdd
BLAST
Domaini277 – 32953SANTPROSITE-ProRule annotationAdd
BLAST

Sequence similaritiesi

Contains 1 ELM2 domain.PROSITE-ProRule annotation
Contains 1 SANT domain.PROSITE-ProRule annotation

Phylogenomic databases

eggNOGiKOG4329. Eukaryota.
ENOG410Y9DJ. LUCA.
GeneTreeiENSGT00510000046482.
HOVERGENiHBG052923.
InParanoidiQ7Z3K6.
OMAiHTLHQHA.
OrthoDBiEOG7HQN7T.
PhylomeDBiQ7Z3K6.
TreeFamiTF106453.

Family and domain databases

InterProiIPR000949. ELM2_dom.
IPR009057. Homeodomain-like.
IPR031156. MIER3.
IPR001005. SANT/Myb.
IPR017884. SANT_dom.
[Graphical view]
PANTHERiPTHR10865:SF22. PTHR10865:SF22. 1 hit.
PfamiPF01448. ELM2. 1 hit.
PF00249. Myb_DNA-binding. 1 hit.
[Graphical view]
SMARTiSM01189. ELM2. 1 hit.
SM00717. SANT. 1 hit.
[Graphical view]
SUPFAMiSSF46689. SSF46689. 1 hit.
PROSITEiPS51156. ELM2. 1 hit.
PS51293. SANT. 1 hit.
[Graphical view]

Sequences (5)i

Sequence statusi: Complete.

This entry describes 5 isoformsi produced by alternative splicing. AlignAdd to basket

Isoform 1 (identifier: Q7Z3K6-1) [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
MAEASFGSSS PVGSLSSEDH DFDPTAEMLV HDYDDERTLE EEEMMDEGKN
60 70 80 90 100
FSSEIEDLEK EGTMPLEDLL AFYGYEPTIP AVANSSANSS PSELADELPD
110 120 130 140 150
MTLDKEEIAK DLLSGDDEET QSSADDLTPS VTSHETSDFF PRPLRSNTAC
160 170 180 190 200
DGDKESEVED VETDSGNSPE DLRKEIMIGL QYQAEIPPYL GEYDGNEKVY
210 220 230 240 250
ENEDQLLWCP DVVLESKVKE YLVETSLRTG SEKIMDRISA GTHTRDNEQA
260 270 280 290 300
LYELLKCNHN IKEAIERYCC NGKASQEGMT AWTEEECRSF EHALMLFGKD
310 320 330 340 350
FHLIQKNKVR TRTVAECVAF YYMWKKSERY DYFAQQTRFG KKRYNHHPGV
360 370 380 390 400
TDYMDRLVDE TEALGGTVNA SALTSNRPEP IPDQQLNILN SFTASDLTAL
410 420 430 440 450
TNSVATVCDP TDVNCLDDSF PPLGNTPRGQ VNHVPVVTEE LLTLPSNGES
460 470 480 490 500
DCFNLFETGF YHSELNPMNM CSEESERPAK RLKMGIAVPE SFMNEVSVNN
510 520 530 540 550
LGVDFENHTH HITSAKMAVS VADFGSLSAN ETNGFISAHA LHQHAALHSE
Length:550
Mass (Da):61,437
Last modified:January 15, 2008 - v2
Checksum:iF2A75EC59477C54F
GO
Isoform 2 (identifier: Q7Z3K6-2) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     11-11: P → PVCFIP

Note: No experimental confirmation available.
Show »
Length:555
Mass (Da):61,996
Checksum:i0F50BD18BD9FCCD4
GO
Isoform 3 (identifier: Q7Z3K6-3) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     277-277: Missing.

Show »
Length:549
Mass (Da):61,307
Checksum:i80185C6D704A08B6
GO
Isoform 4 (identifier: Q7Z3K6-4) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     1-63: Missing.

Show »
Length:487
Mass (Da):54,420
Checksum:i28698EF2661C2ED4
GO
Isoform 5 (identifier: Q7Z3K6-5) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     106-119: EEIAKDLLSGDDEE → ISGRERNPHLGTSS
     120-550: Missing.

Show »
Length:119
Mass (Da):13,023
Checksum:iC51B62C7EB93B020
GO

Sequence cautioni

The sequence AAH41348.2 differs from that shown. Reason: Erroneous initiation. Curated
The sequence BAC04117.1 differs from that shown. Reason: Frameshift at positions 9, 46, 49 and 466. Curated
The sequence CAD97846.1 differs from that shown. Reason: Erroneous initiation. Curated
The sequence CAE45951.2 differs from that shown. Reason: Erroneous initiation. Curated
The sequence CAI56710.1 differs from that shown. Reason: Frameshift at position 4. Curated

Experimental Info

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Sequence conflicti5 – 51S → L in CAI56710 (PubMed:17974005).Curated

Natural variant

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Natural varianti126 – 1261D → G.1 Publication
Corresponds to variant rs17854108 [ dbSNP | Ensembl ].
VAR_037699
Natural varianti414 – 4141N → K.
Corresponds to variant rs13177917 [ dbSNP | Ensembl ].
VAR_037700
Natural varianti432 – 4321N → D.
Corresponds to variant rs13181823 [ dbSNP | Ensembl ].
VAR_037701
Natural varianti530 – 5301N → S.
Corresponds to variant rs36017815 [ dbSNP | Ensembl ].
VAR_037702

Alternative sequence

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Alternative sequencei1 – 6363Missing in isoform 4. 1 PublicationVSP_030099Add
BLAST
Alternative sequencei11 – 111P → PVCFIP in isoform 2. 1 PublicationVSP_030100
Alternative sequencei106 – 11914EEIAK…GDDEE → ISGRERNPHLGTSS in isoform 5. 1 PublicationVSP_030101Add
BLAST
Alternative sequencei120 – 550431Missing in isoform 5. 1 PublicationVSP_030102Add
BLAST
Alternative sequencei277 – 2771Missing in isoform 3. 2 PublicationsVSP_030103

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AK093273 mRNA. Translation: BAC04117.1. Frameshift.
AK299285 mRNA. Translation: BAG61301.1.
BX537798 mRNA. Translation: CAD97846.1. Different initiation.
AC008937 Genomic DNA. No translation available.
AC016644 Genomic DNA. No translation available.
BX640907 mRNA. Translation: CAE45951.2. Different initiation.
BX648294 mRNA. Translation: CAI56710.1. Frameshift.
CR749246 mRNA. Translation: CAH18102.1.
CR749805 mRNA. Translation: CAH18665.1.
BC041348 mRNA. Translation: AAH41348.2. Different initiation.
CCDSiCCDS3973.2. [Q7Z3K6-3]
CCDS75248.1. [Q7Z3K6-1]
CCDS78011.1. [Q7Z3K6-2]
RefSeqiNP_001284527.1. NM_001297598.1. [Q7Z3K6-2]
NP_001284528.1. NM_001297599.1. [Q7Z3K6-1]
NP_689835.3. NM_152622.4. [Q7Z3K6-3]
UniGeneiHs.657594.

Genome annotation databases

EnsembliENST00000381199; ENSP00000370596; ENSG00000155545. [Q7Z3K6-1]
ENST00000381213; ENSP00000370611; ENSG00000155545. [Q7Z3K6-3]
ENST00000381226; ENSP00000370624; ENSG00000155545. [Q7Z3K6-2]
ENST00000409421; ENSP00000386584; ENSG00000155545. [Q7Z3K6-4]
ENST00000452157; ENSP00000408076; ENSG00000155545. [Q7Z3K6-5]
GeneIDi166968.
KEGGihsa:166968.
UCSCiuc003jqz.2. human. [Q7Z3K6-1]

Keywords - Coding sequence diversityi

Alternative splicing, Polymorphism

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AK093273 mRNA. Translation: BAC04117.1. Frameshift.
AK299285 mRNA. Translation: BAG61301.1.
BX537798 mRNA. Translation: CAD97846.1. Different initiation.
AC008937 Genomic DNA. No translation available.
AC016644 Genomic DNA. No translation available.
BX640907 mRNA. Translation: CAE45951.2. Different initiation.
BX648294 mRNA. Translation: CAI56710.1. Frameshift.
CR749246 mRNA. Translation: CAH18102.1.
CR749805 mRNA. Translation: CAH18665.1.
BC041348 mRNA. Translation: AAH41348.2. Different initiation.
CCDSiCCDS3973.2. [Q7Z3K6-3]
CCDS75248.1. [Q7Z3K6-1]
CCDS78011.1. [Q7Z3K6-2]
RefSeqiNP_001284527.1. NM_001297598.1. [Q7Z3K6-2]
NP_001284528.1. NM_001297599.1. [Q7Z3K6-1]
NP_689835.3. NM_152622.4. [Q7Z3K6-3]
UniGeneiHs.657594.

3D structure databases

ProteinModelPortaliQ7Z3K6.
SMRiQ7Z3K6. Positions 175-340.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi127939. 6 interactions.
IntActiQ7Z3K6. 3 interactions.
MINTiMINT-4720437.
STRINGi9606.ENSP00000370611.

PTM databases

iPTMnetiQ7Z3K6.
PhosphoSiteiQ7Z3K6.

Polymorphism and mutation databases

BioMutaiMIER3.
DMDMi166217020.

Proteomic databases

EPDiQ7Z3K6.
MaxQBiQ7Z3K6.
PaxDbiQ7Z3K6.
PRIDEiQ7Z3K6.

Protocols and materials databases

DNASUi166968.
Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsembliENST00000381199; ENSP00000370596; ENSG00000155545. [Q7Z3K6-1]
ENST00000381213; ENSP00000370611; ENSG00000155545. [Q7Z3K6-3]
ENST00000381226; ENSP00000370624; ENSG00000155545. [Q7Z3K6-2]
ENST00000409421; ENSP00000386584; ENSG00000155545. [Q7Z3K6-4]
ENST00000452157; ENSP00000408076; ENSG00000155545. [Q7Z3K6-5]
GeneIDi166968.
KEGGihsa:166968.
UCSCiuc003jqz.2. human. [Q7Z3K6-1]

Organism-specific databases

CTDi166968.
GeneCardsiMIER3.
HGNCiHGNC:26678. MIER3.
HPAiHPA065946.
neXtProtiNX_Q7Z3K6.
PharmGKBiPA145008088.
GenAtlasiSearch...

Phylogenomic databases

eggNOGiKOG4329. Eukaryota.
ENOG410Y9DJ. LUCA.
GeneTreeiENSGT00510000046482.
HOVERGENiHBG052923.
InParanoidiQ7Z3K6.
OMAiHTLHQHA.
OrthoDBiEOG7HQN7T.
PhylomeDBiQ7Z3K6.
TreeFamiTF106453.

Miscellaneous databases

GenomeRNAii166968.
PROiQ7Z3K6.

Gene expression databases

BgeeiQ7Z3K6.
CleanExiHS_MIER3.
ExpressionAtlasiQ7Z3K6. baseline and differential.
GenevisibleiQ7Z3K6. HS.

Family and domain databases

InterProiIPR000949. ELM2_dom.
IPR009057. Homeodomain-like.
IPR031156. MIER3.
IPR001005. SANT/Myb.
IPR017884. SANT_dom.
[Graphical view]
PANTHERiPTHR10865:SF22. PTHR10865:SF22. 1 hit.
PfamiPF01448. ELM2. 1 hit.
PF00249. Myb_DNA-binding. 1 hit.
[Graphical view]
SMARTiSM01189. ELM2. 1 hit.
SM00717. SANT. 1 hit.
[Graphical view]
SUPFAMiSSF46689. SSF46689. 1 hit.
PROSITEiPS51156. ELM2. 1 hit.
PS51293. SANT. 1 hit.
[Graphical view]
ProtoNetiSearch...

Publicationsi

  1. "Complete sequencing and characterization of 21,243 full-length human cDNAs."
    Ota T., Suzuki Y., Nishikawa T., Otsuki T., Sugiyama T., Irie R., Wakamatsu A., Hayashi K., Sato H., Nagai K., Kimura K., Makita H., Sekine M., Obayashi M., Nishi T., Shibahara T., Tanaka T., Ishii S.
    , Yamamoto J., Saito K., Kawai Y., Isono Y., Nakamura Y., Nagahari K., Murakami K., Yasuda T., Iwayanagi T., Wagatsuma M., Shiratori A., Sudo H., Hosoiri T., Kaku Y., Kodaira H., Kondo H., Sugawara M., Takahashi M., Kanda K., Yokoi T., Furuya T., Kikkawa E., Omura Y., Abe K., Kamihara K., Katsuta N., Sato K., Tanikawa M., Yamazaki M., Ninomiya K., Ishibashi T., Yamashita H., Murakawa K., Fujimori K., Tanai H., Kimata M., Watanabe M., Hiraoka S., Chiba Y., Ishida S., Ono Y., Takiguchi S., Watanabe S., Yosida M., Hotuta T., Kusano J., Kanehori K., Takahashi-Fujii A., Hara H., Tanase T.-O., Nomura Y., Togiya S., Komai F., Hara R., Takeuchi K., Arita M., Imose N., Musashino K., Yuuki H., Oshima A., Sasaki N., Aotsuka S., Yoshikawa Y., Matsunawa H., Ichihara T., Shiohata N., Sano S., Moriya S., Momiyama H., Satoh N., Takami S., Terashima Y., Suzuki O., Nakagawa S., Senoh A., Mizoguchi H., Goto Y., Shimizu F., Wakebe H., Hishigaki H., Watanabe T., Sugiyama A., Takemoto M., Kawakami B., Yamazaki M., Watanabe K., Kumagai A., Itakura S., Fukuzumi Y., Fujimori Y., Komiyama M., Tashiro H., Tanigami A., Fujiwara T., Ono T., Yamada K., Fujii Y., Ozaki K., Hirao M., Ohmori Y., Kawabata A., Hikiji T., Kobatake N., Inagaki H., Ikema Y., Okamoto S., Okitani R., Kawakami T., Noguchi S., Itoh T., Shigeta K., Senba T., Matsumura K., Nakajima Y., Mizuno T., Morinaga M., Sasaki M., Togashi T., Oyama M., Hata H., Watanabe M., Komatsu T., Mizushima-Sugano J., Satoh T., Shirai Y., Takahashi Y., Nakagawa K., Okumura K., Nagase T., Nomura N., Kikuchi H., Masuho Y., Yamashita R., Nakai K., Yada T., Nakamura Y., Ohara O., Isogai T., Sugano S.
    Nat. Genet. 36:40-45(2004) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORMS 1 AND 4).
    Tissue: Testis.
  2. Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORMS 1; 2; 3 AND 5).
    Tissue: Fetal kidney and Uterus.
  3. "The DNA sequence and comparative analysis of human chromosome 5."
    Schmutz J., Martin J., Terry A., Couronne O., Grimwood J., Lowry S., Gordon L.A., Scott D., Xie G., Huang W., Hellsten U., Tran-Gyamfi M., She X., Prabhakar S., Aerts A., Altherr M., Bajorek E., Black S.
    , Branscomb E., Caoile C., Challacombe J.F., Chan Y.M., Denys M., Detter J.C., Escobar J., Flowers D., Fotopulos D., Glavina T., Gomez M., Gonzales E., Goodstein D., Grigoriev I., Groza M., Hammon N., Hawkins T., Haydu L., Israni S., Jett J., Kadner K., Kimball H., Kobayashi A., Lopez F., Lou Y., Martinez D., Medina C., Morgan J., Nandkeshwar R., Noonan J.P., Pitluck S., Pollard M., Predki P., Priest J., Ramirez L., Retterer J., Rodriguez A., Rogers S., Salamov A., Salazar A., Thayer N., Tice H., Tsai M., Ustaszewska A., Vo N., Wheeler J., Wu K., Yang J., Dickson M., Cheng J.-F., Eichler E.E., Olsen A., Pennacchio L.A., Rokhsar D.S., Richardson P., Lucas S.M., Myers R.M., Rubin E.M.
    Nature 431:268-274(2004) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
  4. "The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC)."
    The MGC Project Team
    Genome Res. 14:2121-2127(2004) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA] (ISOFORM 3), VARIANT GLY-126.
    Tissue: Testis.
  5. Cited for: PHOSPHORYLATION [LARGE SCALE ANALYSIS] AT SER-156, IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
    Tissue: Cervix carcinoma.
  6. "Quantitative phosphoproteomic analysis of T cell receptor signaling reveals system-wide modulation of protein-protein interactions."
    Mayya V., Lundgren D.H., Hwang S.-I., Rezaul K., Wu L., Eng J.K., Rodionov V., Han D.K.
    Sci. Signal. 2:RA46-RA46(2009) [PubMed] [Europe PMC] [Abstract]
    Cited for: PHOSPHORYLATION [LARGE SCALE ANALYSIS] AT SER-53, IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
    Tissue: Leukemic T-cell.
  7. "Quantitative phosphoproteomics reveals widespread full phosphorylation site occupancy during mitosis."
    Olsen J.V., Vermeulen M., Santamaria A., Kumar C., Miller M.L., Jensen L.J., Gnad F., Cox J., Jensen T.S., Nigg E.A., Brunak S., Mann M.
    Sci. Signal. 3:RA3-RA3(2010) [PubMed] [Europe PMC] [Abstract]
    Cited for: PHOSPHORYLATION [LARGE SCALE ANALYSIS] AT SER-52 AND SER-53, IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
    Tissue: Cervix carcinoma.
  8. "System-wide temporal characterization of the proteome and phosphoproteome of human embryonic stem cell differentiation."
    Rigbolt K.T., Prokhorova T.A., Akimov V., Henningsen J., Johansen P.T., Kratchmarova I., Kassem M., Mann M., Olsen J.V., Blagoev B.
    Sci. Signal. 4:RS3-RS3(2011) [PubMed] [Europe PMC] [Abstract]
    Cited for: PHOSPHORYLATION [LARGE SCALE ANALYSIS] AT SER-52 AND SER-53, IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].

Entry informationi

Entry nameiMIER3_HUMAN
AccessioniPrimary (citable) accession number: Q7Z3K6
Secondary accession number(s): B4DRI9
, B8ZZQ0, Q5CZI0, Q68CS3, Q6MZS7, Q86YG8, Q8NA13
Entry historyi
Integrated into UniProtKB/Swiss-Prot: January 15, 2008
Last sequence update: January 15, 2008
Last modified: June 8, 2016
This is version 108 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 5
    Human chromosome 5: entries, gene names and cross-references to MIM
  2. Human entries with polymorphisms or disease mutations
    List of human entries with polymorphisms or disease mutations
  3. Human polymorphisms and disease mutations
    Index of human polymorphisms and disease mutations
  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.