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

Endoplasmic reticulum resident protein 44

Gene

ERP44

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

Functioni

Mediates thiol-dependent retention in the early secretory pathway, forming mixed disulfides with substrate proteins through its conserved CRFS motif. Inhibits the calcium channel activity of ITPR1. May have a role in the control of oxidative protein folding in the endoplasmic reticulum. Required to retain ERO1L and ERO1LB in the endoplasmic reticulum.2 Publications

GO - Molecular functioni

  1. protein disulfide isomerase activity Source: UniProtKB

GO - Biological processi

  1. cell redox homeostasis Source: UniProtKB
  2. glycoprotein metabolic process Source: UniProtKB
  3. protein folding Source: UniProtKB
  4. response to endoplasmic reticulum stress Source: UniProtKB
  5. response to unfolded protein Source: UniProtKB
Complete GO annotation...

Keywords - Molecular functioni

Chaperone

Keywords - Biological processi

Stress response

Names & Taxonomyi

Protein namesi
Recommended name:
Endoplasmic reticulum resident protein 44
Short name:
ER protein 44
Short name:
ERp44
Alternative name(s):
Thioredoxin domain-containing protein 4
Gene namesi
Name:ERP44
Synonyms:KIAA0573, TXNDC4
ORF Names:UNQ532/PRO1075
OrganismiHomo sapiens (Human)
Taxonomic identifieri9606 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo
ProteomesiUP000005640 Componenti: Chromosome 9

Organism-specific databases

HGNCiHGNC:18311. ERP44.

Subcellular locationi

GO - Cellular componenti

  1. cell surface Source: MGI
  2. endoplasmic reticulum-Golgi intermediate compartment Source: UniProtKB
  3. endoplasmic reticulum lumen Source: UniProtKB
  4. endoplasmic reticulum membrane Source: UniProtKB
  5. extracellular vesicular exosome Source: UniProtKB
Complete GO annotation...

Keywords - Cellular componenti

Endoplasmic reticulum

Pathology & Biotechi

Organism-specific databases

PharmGKBiPA164719295.

Polymorphism and mutation databases

BioMutaiERP44.
DMDMi31077035.

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Signal peptidei1 – 2929Add
BLAST
Chaini30 – 406377Endoplasmic reticulum resident protein 44PRO_0000034180Add
BLAST

Amino acid modifications

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Disulfide bondi58 – 58Interchain (with ERO1L)1 Publication
Disulfide bondi189 ↔ 2411 Publication
Disulfide bondi301 ↔ 3181 Publication

Keywords - PTMi

Disulfide bond

Proteomic databases

MaxQBiQ9BS26.
PaxDbiQ9BS26.
PeptideAtlasiQ9BS26.
PRIDEiQ9BS26.

2D gel databases

REPRODUCTION-2DPAGEIPI00401264.

Expressioni

Inductioni

Up-regulated by inducers of the unfolded protein response (UPR), including tunicamycin and dithiothreitol.1 Publication

Gene expression databases

BgeeiQ9BS26.
CleanExiHS_TXNDC4.
GenevestigatoriQ9BS26.

Organism-specific databases

HPAiHPA001318.

Interactioni

Subunit structurei

Forms mixed disulfides with both ERO1L and ERO1LB and cargo folding intermediates. Directly interacts with ITPR1 in a pH-, redox state- and calcium-dependent manner, but not with ITPR2 or ITPR3. The strength of this interaction inversely correlates with calcium concentration (By similarity).By similarity

Binary interactionsi

WithEntry#Exp.IntActNotes
LMAN1P492573EBI-541644,EBI-1057738

Protein-protein interaction databases

BioGridi116704. 32 interactions.
IntActiQ9BS26. 14 interactions.
MINTiMINT-2816102.
STRINGi9606.ENSP00000262455.

Structurei

Secondary structure

1
406
Legend: HelixTurnBeta strand
Show more details
Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Turni36 – 383Combined sources
Helixi39 – 457Combined sources
Beta strandi47 – 548Combined sources
Helixi59 – 7517Combined sources
Beta strandi85 – 917Combined sources
Turni92 – 943Combined sources
Helixi96 – 1016Combined sources
Beta strandi106 – 1149Combined sources
Beta strandi117 – 1226Combined sources
Helixi129 – 14012Combined sources
Beta strandi145 – 1473Combined sources
Beta strandi162 – 1687Combined sources
Beta strandi170 – 1723Combined sources
Helixi173 – 18513Combined sources
Turni186 – 1883Combined sources
Beta strandi190 – 1967Combined sources
Beta strandi208 – 2125Combined sources
Beta strandi214 – 2185Combined sources
Helixi230 – 24112Combined sources
Beta strandi244 – 2474Combined sources
Helixi250 – 2578Combined sources
Beta strandi263 – 2686Combined sources
Helixi274 – 28613Combined sources
Helixi288 – 2903Combined sources
Turni291 – 2933Combined sources
Beta strandi294 – 3007Combined sources
Turni301 – 3044Combined sources
Helixi305 – 3106Combined sources
Helixi315 – 3173Combined sources
Beta strandi319 – 3246Combined sources
Beta strandi329 – 3313Combined sources
Helixi336 – 3394Combined sources
Helixi343 – 35311Combined sources
Helixi387 – 3904Combined sources
Turni394 – 3963Combined sources

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
2R2JX-ray2.60A30-406[»]
ProteinModelPortaliQ9BS26.
SMRiQ9BS26. Positions 32-401.
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiQ9BS26.

Family & Domainsi

Domains and Repeats

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Domaini30 – 138109ThioredoxinPROSITE-ProRule annotationAdd
BLAST

Region

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Regioni236 – 28550Interaction with ITPR1By similarityAdd
BLAST

Motif

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Motifi403 – 4064Prevents secretion from ERPROSITE-ProRule annotation

Sequence similaritiesi

Contains 1 thioredoxin domain.PROSITE-ProRule annotation

Keywords - Domaini

Signal

Phylogenomic databases

eggNOGiCOG0526.
GeneTreeiENSGT00760000119201.
HOGENOMiHOG000007707.
InParanoidiQ9BS26.
KOiK17264.
OMAiRHMYLFP.
OrthoDBiEOG718KCX.
PhylomeDBiQ9BS26.
TreeFamiTF106378.

Family and domain databases

Gene3Di3.40.30.10. 2 hits.
InterProiIPR012336. Thioredoxin-like_fold.
IPR013766. Thioredoxin_domain.
[Graphical view]
PfamiPF00085. Thioredoxin. 1 hit.
[Graphical view]
SUPFAMiSSF52833. SSF52833. 3 hits.
PROSITEiPS00014. ER_TARGET. 1 hit.
PS51352. THIOREDOXIN_2. 1 hit.
[Graphical view]

Sequencei

Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

Q9BS26-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MHPAVFLSLP DLRCSLLLLV TWVFTPVTTE ITSLDTENID EILNNADVAL
60 70 80 90 100
VNFYADWCRF SQMLHPIFEE ASDVIKEEFP NENQVVFARV DCDQHSDIAQ
110 120 130 140 150
RYRISKYPTL KLFRNGMMMK REYRGQRSVK ALADYIRQQK SDPIQEIRDL
160 170 180 190 200
AEITTLDRSK RNIIGYFEQK DSDNYRVFER VANILHDDCA FLSAFGDVSK
210 220 230 240 250
PERYSGDNII YKPPGHSAPD MVYLGAMTNF DVTYNWIQDK CVPLVREITF
260 270 280 290 300
ENGEELTEEG LPFLILFHMK EDTESLEIFQ NEVARQLISE KGTINFLHAD
310 320 330 340 350
CDKFRHPLLH IQKTPADCPV IAIDSFRHMY VFGDFKDVLI PGKLKQFVFD
360 370 380 390 400
LHSGKLHREF HHGPDPTDTA PGEQAQDVAS SPPESSFQKL APSEYRYTLL

RDRDEL
Length:406
Mass (Da):46,971
Last modified:June 1, 2001 - v1
Checksum:i3865DCF3811BC263
GO

Sequence cautioni

The sequence BAA25499.1 differs from that shown. Reason: Erroneous initiation. Curated

Experimental Info

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Sequence conflicti35 – 351D → A in AAQ89407 (PubMed:12975309).Curated

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AJ344330 mRNA. Translation: CAC87611.1.
AB011145 mRNA. Translation: BAA25499.1. Different initiation.
AY359048 mRNA. Translation: AAQ89407.1.
AK075024 mRNA. Translation: BAG52054.1.
AL360084, AL137072, AL358937 Genomic DNA. Translation: CAH70308.1.
AL137072, AL358937, AL360084 Genomic DNA. Translation: CAH72172.1.
AL358937, AL137072, AL360084 Genomic DNA. Translation: CAI95319.1.
BC005374 mRNA. Translation: AAH05374.1.
CCDSiCCDS35082.1.
RefSeqiNP_055866.1. NM_015051.2.
UniGeneiHs.154023.

Genome annotation databases

EnsembliENST00000262455; ENSP00000262455; ENSG00000023318.
GeneIDi23071.
KEGGihsa:23071.
UCSCiuc004bam.3. human.

Polymorphism and mutation databases

BioMutaiERP44.

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AJ344330 mRNA. Translation: CAC87611.1.
AB011145 mRNA. Translation: BAA25499.1. Different initiation.
AY359048 mRNA. Translation: AAQ89407.1.
AK075024 mRNA. Translation: BAG52054.1.
AL360084, AL137072, AL358937 Genomic DNA. Translation: CAH70308.1.
AL137072, AL358937, AL360084 Genomic DNA. Translation: CAH72172.1.
AL358937, AL137072, AL360084 Genomic DNA. Translation: CAI95319.1.
BC005374 mRNA. Translation: AAH05374.1.
CCDSiCCDS35082.1.
RefSeqiNP_055866.1. NM_015051.2.
UniGeneiHs.154023.

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
2R2JX-ray2.60A30-406[»]
ProteinModelPortaliQ9BS26.
SMRiQ9BS26. Positions 32-401.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi116704. 32 interactions.
IntActiQ9BS26. 14 interactions.
MINTiMINT-2816102.
STRINGi9606.ENSP00000262455.

Polymorphism and mutation databases

BioMutaiERP44.
DMDMi31077035.

2D gel databases

REPRODUCTION-2DPAGEIPI00401264.

Proteomic databases

MaxQBiQ9BS26.
PaxDbiQ9BS26.
PeptideAtlasiQ9BS26.
PRIDEiQ9BS26.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsembliENST00000262455; ENSP00000262455; ENSG00000023318.
GeneIDi23071.
KEGGihsa:23071.
UCSCiuc004bam.3. human.

Organism-specific databases

CTDi23071.
GeneCardsiGC09M102742.
HGNCiHGNC:18311. ERP44.
HPAiHPA001318.
MIMi609170. gene.
neXtProtiNX_Q9BS26.
PharmGKBiPA164719295.
HUGEiSearch...
GenAtlasiSearch...

Phylogenomic databases

eggNOGiCOG0526.
GeneTreeiENSGT00760000119201.
HOGENOMiHOG000007707.
InParanoidiQ9BS26.
KOiK17264.
OMAiRHMYLFP.
OrthoDBiEOG718KCX.
PhylomeDBiQ9BS26.
TreeFamiTF106378.

Miscellaneous databases

ChiTaRSiERP44. human.
EvolutionaryTraceiQ9BS26.
GeneWikiiERP44.
GenomeRNAii23071.
NextBioi44171.
PROiQ9BS26.
SOURCEiSearch...

Gene expression databases

BgeeiQ9BS26.
CleanExiHS_TXNDC4.
GenevestigatoriQ9BS26.

Family and domain databases

Gene3Di3.40.30.10. 2 hits.
InterProiIPR012336. Thioredoxin-like_fold.
IPR013766. Thioredoxin_domain.
[Graphical view]
PfamiPF00085. Thioredoxin. 1 hit.
[Graphical view]
SUPFAMiSSF52833. SSF52833. 3 hits.
PROSITEiPS00014. ER_TARGET. 1 hit.
PS51352. THIOREDOXIN_2. 1 hit.
[Graphical view]
ProtoNetiSearch...

Publicationsi

« Hide 'large scale' publications
  1. "ERp44, a novel endoplasmic reticulum folding assistant of the thioredoxin family."
    Anelli T., Alessio M., Mezghrani A., Simmen T., Talamo F., Bachi A., Sitia R.
    EMBO J. 21:835-844(2002) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 149-158 AND 314-327, FUNCTION, INTERACTION WITH ERO1L AND ERO1LB, MIXED DISULFIDE BOND FORMATION, INDUCTION.
    Tissue: Cervix.
  2. "Prediction of the coding sequences of unidentified human genes. IX. The complete sequences of 100 new cDNA clones from brain which can code for large proteins in vitro."
    Nagase T., Ishikawa K., Miyajima N., Tanaka A., Kotani H., Nomura N., Ohara O.
    DNA Res. 5:31-39(1998) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
    Tissue: Brain.
  3. Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
  4. "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].
  5. "DNA sequence and analysis of human chromosome 9."
    Humphray S.J., Oliver K., Hunt A.R., Plumb R.W., Loveland J.E., Howe K.L., Andrews T.D., Searle S., Hunt S.E., Scott C.E., Jones M.C., Ainscough R., Almeida J.P., Ambrose K.D., Ashwell R.I.S., Babbage A.K., Babbage S., Bagguley C.L.
    , Bailey J., Banerjee R., Barker D.J., Barlow K.F., Bates K., Beasley H., Beasley O., Bird C.P., Bray-Allen S., Brown A.J., Brown J.Y., Burford D., Burrill W., Burton J., Carder C., Carter N.P., Chapman J.C., Chen Y., Clarke G., Clark S.Y., Clee C.M., Clegg S., Collier R.E., Corby N., Crosier M., Cummings A.T., Davies J., Dhami P., Dunn M., Dutta I., Dyer L.W., Earthrowl M.E., Faulkner L., Fleming C.J., Frankish A., Frankland J.A., French L., Fricker D.G., Garner P., Garnett J., Ghori J., Gilbert J.G.R., Glison C., Grafham D.V., Gribble S., Griffiths C., Griffiths-Jones S., Grocock R., Guy J., Hall R.E., Hammond S., Harley J.L., Harrison E.S.I., Hart E.A., Heath P.D., Henderson C.D., Hopkins B.L., Howard P.J., Howden P.J., Huckle E., Johnson C., Johnson D., Joy A.A., Kay M., Keenan S., Kershaw J.K., Kimberley A.M., King A., Knights A., Laird G.K., Langford C., Lawlor S., Leongamornlert D.A., Leversha M., Lloyd C., Lloyd D.M., Lovell J., Martin S., Mashreghi-Mohammadi M., Matthews L., McLaren S., McLay K.E., McMurray A., Milne S., Nickerson T., Nisbett J., Nordsiek G., Pearce A.V., Peck A.I., Porter K.M., Pandian R., Pelan S., Phillimore B., Povey S., Ramsey Y., Rand V., Scharfe M., Sehra H.K., Shownkeen R., Sims S.K., Skuce C.D., Smith M., Steward C.A., Swarbreck D., Sycamore N., Tester J., Thorpe A., Tracey A., Tromans A., Thomas D.W., Wall M., Wallis J.M., West A.P., Whitehead S.L., Willey D.L., Williams S.A., Wilming L., Wray P.W., Young L., Ashurst J.L., Coulson A., Blocker H., Durbin R.M., Sulston J.E., Hubbard T., Jackson M.J., Bentley D.R., Beck S., Rogers J., Dunham I.
    Nature 429:369-374(2004) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
  6. "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].
    Tissue: Liver.
  7. "Thiol-mediated protein retention in the endoplasmic reticulum: the role of ERp44."
    Anelli T., Alessio M., Bachi A., Bergamelli L., Bertoli G., Camerini S., Mezghrani A., Ruffato E., Simmen T., Sitia R.
    EMBO J. 22:5015-5022(2003) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION.
  8. Cited for: IDENTIFICATION BY MASS SPECTROMETRY.
    Tissue: Platelet.
  9. "Subtype-specific and ER lumenal environment-dependent regulation of inositol 1,4,5-trisphosphate receptor type 1 by ERp44."
    Higo T., Hattori M., Nakamura T., Natsume T., Michikawa T., Mikoshiba K.
    Cell 120:85-98(2005) [PubMed] [Europe PMC] [Abstract]
    Cited for: INTERACTION WITH ITPR1.
  10. Cited for: IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
  11. "An enzyme assisted RP-RPLC approach for in-depth analysis of human liver phosphoproteome."
    Bian Y., Song C., Cheng K., Dong M., Wang F., Huang J., Sun D., Wang L., Ye M., Zou H.
    J. Proteomics 96:253-262(2014) [PubMed] [Europe PMC] [Abstract]
    Cited for: IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
    Tissue: Liver.
  12. "Crystal structure of human ERp44 shows a dynamic functional modulation by its carboxy-terminal tail."
    Wang L., Wang L., Vavassori S., Li S., Ke H., Anelli T., Degano M., Ronzoni R., Sitia R., Sun F., Wang C.-C.
    EMBO Rep. 9:642-647(2008) [PubMed] [Europe PMC] [Abstract]
    Cited for: X-RAY CRYSTALLOGRAPHY (2.6 ANGSTROMS) OF 25-406, DISULFIDE BONDS.

Entry informationi

Entry nameiERP44_HUMAN
AccessioniPrimary (citable) accession number: Q9BS26
Secondary accession number(s): O60319
, Q4VXC1, Q5VWZ7, Q6UW14, Q8WX67
Entry historyi
Integrated into UniProtKB/Swiss-Prot: May 23, 2003
Last sequence update: June 1, 2001
Last modified: April 29, 2015
This is version 132 of the entry and version 1 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 9
    Human chromosome 9: 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

External Data

Dasty 3

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 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.