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

Inhibin beta A chain

Gene

INHBA

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

Functioni

Inhibins and activins inhibit and activate, respectively, the secretion of follitropin by the pituitary gland. Inhibins/activins are involved in regulating a number of diverse functions such as hypothalamic and pituitary hormone secretion, gonadal hormone secretion, germ cell development and maturation, erythroid differentiation, insulin secretion, nerve cell survival, embryonic axial development or bone growth, depending on their subunit composition. Inhibins appear to oppose the functions of activins.

GO - Molecular functioni

  1. cytokine activity Source: HGNC
  2. growth factor activity Source: UniProtKB
  3. hormone activity Source: UniProtKB
  4. identical protein binding Source: UniProtKB
  5. peptide hormone binding Source: UniProtKB
  6. transforming growth factor beta receptor binding Source: GO_Central
  7. type II activin receptor binding Source: BHF-UCL

GO - Biological processi

  1. activin receptor signaling pathway Source: BHF-UCL
  2. cell-cell signaling Source: UniProtKB
  3. cell cycle arrest Source: HGNC
  4. cell development Source: GO_Central
  5. cell differentiation Source: UniProtKB
  6. cell surface receptor signaling pathway Source: UniProtKB
  7. cellular response to cholesterol Source: Ensembl
  8. cellular response to follicle-stimulating hormone stimulus Source: Ensembl
  9. defense response Source: UniProtKB
  10. endodermal cell differentiation Source: BHF-UCL
  11. erythrocyte differentiation Source: UniProtKB
  12. extrinsic apoptotic signaling pathway Source: BHF-UCL
  13. eyelid development in camera-type eye Source: UniProtKB
  14. G1/S transition of mitotic cell cycle Source: HGNC
  15. growth Source: InterPro
  16. hair follicle development Source: UniProtKB
  17. hematopoietic progenitor cell differentiation Source: UniProtKB
  18. hemoglobin biosynthetic process Source: UniProtKB
  19. male gonad development Source: UniProtKB
  20. mesodermal cell differentiation Source: Ensembl
  21. negative regulation of B cell differentiation Source: UniProtKB
  22. negative regulation of cell cycle Source: HGNC
  23. negative regulation of cell growth Source: UniProtKB
  24. negative regulation of cell proliferation Source: UniProtKB
  25. negative regulation of follicle-stimulating hormone secretion Source: UniProtKB
  26. negative regulation of interferon-gamma biosynthetic process Source: UniProtKB
  27. negative regulation of macrophage differentiation Source: UniProtKB
  28. negative regulation of phosphorylation Source: UniProtKB
  29. nervous system development Source: UniProtKB
  30. odontogenesis Source: UniProtKB
  31. ovarian follicle development Source: UniProtKB
  32. palate development Source: UniProtKB
  33. positive regulation of cellular protein metabolic process Source: BHF-UCL
  34. positive regulation of erythrocyte differentiation Source: HGNC
  35. positive regulation of extrinsic apoptotic signaling pathway in absence of ligand Source: UniProtKB
  36. positive regulation of follicle-stimulating hormone secretion Source: UniProtKB
  37. positive regulation of ovulation Source: UniProtKB
  38. positive regulation of pathway-restricted SMAD protein phosphorylation Source: BHF-UCL
  39. positive regulation of transcription, DNA-templated Source: UniProtKB
  40. positive regulation of transcription from RNA polymerase II promoter Source: UniProtKB
  41. progesterone secretion Source: UniProtKB
  42. regulation of follicle-stimulating hormone secretion Source: UniProtKB
  43. regulation of MAPK cascade Source: GO_Central
  44. regulation of transcription from RNA polymerase II promoter Source: UniProtKB
  45. response to drug Source: UniProtKB
  46. SMAD protein signal transduction Source: GO_Central
Complete GO annotation...

Keywords - Molecular functioni

Growth factor, Hormone

Enzyme and pathway databases

ReactomeiREACT_150238. Signaling by Activin.
REACT_150276. Antagonism of Activin by Follistatin.
REACT_15398. Glycoprotein hormones.
SignaLinkiP08476.

Names & Taxonomyi

Protein namesi
Recommended name:
Inhibin beta A chain
Alternative name(s):
Activin beta-A chain
Erythroid differentiation protein
Short name:
EDF
Gene namesi
Name:INHBA
OrganismiHomo sapiens (Human)
Taxonomic identifieri9606 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo
ProteomesiUP000005640 Componenti: Chromosome 7

Organism-specific databases

HGNCiHGNC:6066. INHBA.

Subcellular locationi

GO - Cellular componenti

  1. activin A complex Source: HGNC
  2. extracellular region Source: UniProtKB
  3. inhibin A complex Source: HGNC
Complete GO annotation...

Keywords - Cellular componenti

Secreted

Pathology & Biotechi

Organism-specific databases

Orphaneti213504. Adenocarcinoma of ovary.
PharmGKBiPA29877.

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Signal peptidei1 – 2020By similarityAdd
BLAST
Propeptidei21 – 310290PRO_0000033708Add
BLAST
Chaini311 – 426116Inhibin beta A chainPRO_0000033709Add
BLAST

Amino acid modifications

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Glycosylationi165 – 1651N-linked (GlcNAc...)Sequence Analysis
Disulfide bondi314 ↔ 3221 Publication
Disulfide bondi321 ↔ 3911 Publication
Disulfide bondi350 ↔ 4231 Publication
Disulfide bondi354 ↔ 4251 Publication
Disulfide bondi390 – 390Interchain1 Publication

Keywords - PTMi

Cleavage on pair of basic residues, Disulfide bond, Glycoprotein

Proteomic databases

MaxQBiP08476.
PaxDbiP08476.
PRIDEiP08476.

PTM databases

PhosphoSiteiP08476.

Expressioni

Gene expression databases

BgeeiP08476.
CleanExiHS_INHBA.
ExpressionAtlasiP08476. baseline and differential.
GenevestigatoriP08476.

Organism-specific databases

HPAiHPA020031.

Interactioni

Subunit structurei

Dimeric, linked by one or more disulfide bonds. Inhibin A is a dimer of alpha and beta-A. Inhibin B is a dimer of alpha and beta-B. Activin A is a homodimer of beta-A. Activin B is a homodimer of beta-B. Activin AB is a dimer of beta-A and beta-B. Interacts with FST and FSTL3.3 Publications

Binary interactionsi

WithEntry#Exp.IntActNotes
FstP216742EBI-8077140,EBI-5746973From a different organism.

Protein-protein interaction databases

BioGridi109836. 8 interactions.
DIPiDIP-5824N.
IntActiP08476. 1 interaction.
MINTiMINT-1786936.
STRINGi9606.ENSP00000242208.

Structurei

Secondary structure

1
426
Legend: HelixTurnBeta strand
Show more details
Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Beta strandi321 – 3244Combined sources
Beta strandi327 – 3293Combined sources
Helixi330 – 3334Combined sources
Turni336 – 3383Combined sources
Beta strandi339 – 3413Combined sources
Beta strandi343 – 3464Combined sources
Beta strandi349 – 3524Combined sources
Helixi356 – 3583Combined sources
Beta strandi362 – 3643Combined sources
Helixi368 – 3758Combined sources
Turni378 – 3803Combined sources
Turni382 – 3865Combined sources
Beta strandi391 – 40414Combined sources
Turni406 – 4083Combined sources
Beta strandi410 – 42516Combined sources

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
1NYSX-ray3.05B/D311-426[»]
1NYUX-ray3.10B/D311-426[»]
1S4YX-ray2.30B/D311-426[»]
2ARPX-ray2.00A311-426[»]
2ARVX-ray2.00A/B311-426[»]
2B0UX-ray2.80A/B311-426[»]
2P6AX-ray3.40A/B311-426[»]
3B4VX-ray2.48A/B/E/F311-426[»]
4MIDX-ray2.14A360-426[»]
ProteinModelPortaliP08476.
SMRiP08476. Positions 289-426.
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiP08476.

Family & Domainsi

Sequence similaritiesi

Belongs to the TGF-beta family.Curated

Keywords - Domaini

Signal

Phylogenomic databases

eggNOGiNOG312557.
GeneTreeiENSGT00760000119112.
HOGENOMiHOG000220890.
HOVERGENiHBG105613.
InParanoidiP08476.
KOiK04667.
OMAiNITRPVP.
OrthoDBiEOG7NSB2Q.
PhylomeDBiP08476.
TreeFamiTF351791.

Family and domain databases

Gene3Di2.10.90.10. 1 hit.
InterProiIPR029034. Cystine-knot_cytokine.
IPR000491. Inhibin_betaA.
IPR001839. TGF-b_C.
IPR001111. TGF-b_N.
IPR015615. TGF-beta-rel.
IPR017948. TGFb_CS.
[Graphical view]
PANTHERiPTHR11848. PTHR11848. 1 hit.
PfamiPF00019. TGF_beta. 1 hit.
PF00688. TGFb_propeptide. 1 hit.
[Graphical view]
PRINTSiPR00670. INHIBINBA.
SMARTiSM00204. TGFB. 1 hit.
[Graphical view]
SUPFAMiSSF57501. SSF57501. 1 hit.
PROSITEiPS00250. TGF_BETA_1. 1 hit.
PS51362. TGF_BETA_2. 1 hit.
[Graphical view]

Sequencei

Sequence statusi: Complete.

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

P08476-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MPLLWLRGFL LASCWIIVRS SPTPGSEGHS AAPDCPSCAL AALPKDVPNS
60 70 80 90 100
QPEMVEAVKK HILNMLHLKK RPDVTQPVPK AALLNAIRKL HVGKVGENGY
110 120 130 140 150
VEIEDDIGRR AEMNELMEQT SEIITFAESG TARKTLHFEI SKEGSDLSVV
160 170 180 190 200
ERAEVWLFLK VPKANRTRTK VTIRLFQQQK HPQGSLDTGE EAEEVGLKGE
210 220 230 240 250
RSELLLSEKV VDARKSTWHV FPVSSSIQRL LDQGKSSLDV RIACEQCQES
260 270 280 290 300
GASLVLLGKK KKKEEEGEGK KKGGGEGGAG ADEEKEQSHR PFLMLQARQS
310 320 330 340 350
EDHPHRRRRR GLECDGKVNI CCKKQFFVSF KDIGWNDWII APSGYHANYC
360 370 380 390 400
EGECPSHIAG TSGSSLSFHS TVINHYRMRG HSPFANLKSC CVPTKLRPMS
410 420
MLYYDDGQNI IKKDIQNMIV EECGCS
Length:426
Mass (Da):47,442
Last modified:June 30, 1989 - v2
Checksum:i201CDEDF99CB6919
GO

Experimental Info

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Sequence conflicti377 – 3793RMR → AC in CAA51163 (Ref. 7) Curated

Natural variant

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Natural varianti280 – 2801G → E Found in a patient with early-onset epithelial ovarian tumor; uncertain pathological significance. 1 Publication
VAR_072640
Natural varianti299 – 2991Q → P.
Corresponds to variant rs41294833 [ dbSNP | Ensembl ].
VAR_052566
Natural varianti386 – 3861N → S Found in a patient with early-onset epithelial ovarian tumor; alters the ratio of secreted activins and ihibins; uncertain pathological significance. 1 Publication
VAR_072641

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
M13436 mRNA. Translation: AAA59168.1.
X04447 Genomic DNA. Translation: CAA28041.1.
X57578, X57579 Genomic DNA. Translation: CAA40805.1.
X57579 Genomic DNA. Translation: CAA40806.1.
AC005027 Genomic DNA. Translation: AAQ96861.1.
BC007858 mRNA. Translation: AAH07858.1.
J03634 mRNA. Translation: AAA35787.1.
X72498 mRNA. Translation: CAA51163.1.
CCDSiCCDS5464.1.
PIRiS30488. B24248.
RefSeqiNP_002183.1. NM_002192.2.
UniGeneiHs.583348.

Genome annotation databases

EnsembliENST00000242208; ENSP00000242208; ENSG00000122641.
ENST00000442711; ENSP00000397197; ENSG00000122641.
GeneIDi3624.
KEGGihsa:3624.
UCSCiuc003thq.3. human.

Polymorphism databases

DMDMi124279.

Keywords - Coding sequence diversityi

Polymorphism

Cross-referencesi

Web resourcesi

Wikipedia

Activin entry

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
M13436 mRNA. Translation: AAA59168.1.
X04447 Genomic DNA. Translation: CAA28041.1.
X57578, X57579 Genomic DNA. Translation: CAA40805.1.
X57579 Genomic DNA. Translation: CAA40806.1.
AC005027 Genomic DNA. Translation: AAQ96861.1.
BC007858 mRNA. Translation: AAH07858.1.
J03634 mRNA. Translation: AAA35787.1.
X72498 mRNA. Translation: CAA51163.1.
CCDSiCCDS5464.1.
PIRiS30488. B24248.
RefSeqiNP_002183.1. NM_002192.2.
UniGeneiHs.583348.

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
1NYSX-ray3.05B/D311-426[»]
1NYUX-ray3.10B/D311-426[»]
1S4YX-ray2.30B/D311-426[»]
2ARPX-ray2.00A311-426[»]
2ARVX-ray2.00A/B311-426[»]
2B0UX-ray2.80A/B311-426[»]
2P6AX-ray3.40A/B311-426[»]
3B4VX-ray2.48A/B/E/F311-426[»]
4MIDX-ray2.14A360-426[»]
ProteinModelPortaliP08476.
SMRiP08476. Positions 289-426.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi109836. 8 interactions.
DIPiDIP-5824N.
IntActiP08476. 1 interaction.
MINTiMINT-1786936.
STRINGi9606.ENSP00000242208.

PTM databases

PhosphoSiteiP08476.

Polymorphism databases

DMDMi124279.

Proteomic databases

MaxQBiP08476.
PaxDbiP08476.
PRIDEiP08476.

Protocols and materials databases

DNASUi3624.
Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsembliENST00000242208; ENSP00000242208; ENSG00000122641.
ENST00000442711; ENSP00000397197; ENSG00000122641.
GeneIDi3624.
KEGGihsa:3624.
UCSCiuc003thq.3. human.

Organism-specific databases

CTDi3624.
GeneCardsiGC07M041724.
HGNCiHGNC:6066. INHBA.
HPAiHPA020031.
MIMi147290. gene.
neXtProtiNX_P08476.
Orphaneti213504. Adenocarcinoma of ovary.
PharmGKBiPA29877.
GenAtlasiSearch...

Phylogenomic databases

eggNOGiNOG312557.
GeneTreeiENSGT00760000119112.
HOGENOMiHOG000220890.
HOVERGENiHBG105613.
InParanoidiP08476.
KOiK04667.
OMAiNITRPVP.
OrthoDBiEOG7NSB2Q.
PhylomeDBiP08476.
TreeFamiTF351791.

Enzyme and pathway databases

ReactomeiREACT_150238. Signaling by Activin.
REACT_150276. Antagonism of Activin by Follistatin.
REACT_15398. Glycoprotein hormones.
SignaLinkiP08476.

Miscellaneous databases

EvolutionaryTraceiP08476.
GenomeRNAii3624.
NextBioi14181.
PROiP08476.
SOURCEiSearch...

Gene expression databases

BgeeiP08476.
CleanExiHS_INHBA.
ExpressionAtlasiP08476. baseline and differential.
GenevestigatoriP08476.

Family and domain databases

Gene3Di2.10.90.10. 1 hit.
InterProiIPR029034. Cystine-knot_cytokine.
IPR000491. Inhibin_betaA.
IPR001839. TGF-b_C.
IPR001111. TGF-b_N.
IPR015615. TGF-beta-rel.
IPR017948. TGFb_CS.
[Graphical view]
PANTHERiPTHR11848. PTHR11848. 1 hit.
PfamiPF00019. TGF_beta. 1 hit.
PF00688. TGFb_propeptide. 1 hit.
[Graphical view]
PRINTSiPR00670. INHIBINBA.
SMARTiSM00204. TGFB. 1 hit.
[Graphical view]
SUPFAMiSSF57501. SSF57501. 1 hit.
PROSITEiPS00250. TGF_BETA_1. 1 hit.
PS51362. TGF_BETA_2. 1 hit.
[Graphical view]
ProtoNetiSearch...

Publicationsi

« Hide 'large scale' publications
  1. Cited for: NUCLEOTIDE SEQUENCE [MRNA].
  2. "Erythroid differentiation factor is encoded by the same mRNA as that of the inhibin beta A chain."
    Murata M., Eto Y., Shibai H., Sakai M., Muramatsu M.
    Proc. Natl. Acad. Sci. U.S.A. 85:2434-2438(1987) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [MRNA].
  3. "Structure and sequence analysis of the human activin beta A subunit gene."
    Tanimoto K., Handa S.I., Ueno N., Murakami K., Fukamizu A.
    DNA Seq. 2:103-110(1990) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
  4. "The DNA sequence of human chromosome 7."
    Hillier L.W., Fulton R.S., Fulton L.A., Graves T.A., Pepin K.H., Wagner-McPherson C., Layman D., Maas J., Jaeger S., Walker R., Wylie K., Sekhon M., Becker M.C., O'Laughlin M.D., Schaller M.E., Fewell G.A., Delehaunty K.D., Miner T.L.
    , Nash W.E., Cordes M., Du H., Sun H., Edwards J., Bradshaw-Cordum H., Ali J., Andrews S., Isak A., Vanbrunt A., Nguyen C., Du F., Lamar B., Courtney L., Kalicki J., Ozersky P., Bielicki L., Scott K., Holmes A., Harkins R., Harris A., Strong C.M., Hou S., Tomlinson C., Dauphin-Kohlberg S., Kozlowicz-Reilly A., Leonard S., Rohlfing T., Rock S.M., Tin-Wollam A.-M., Abbott A., Minx P., Maupin R., Strowmatt C., Latreille P., Miller N., Johnson D., Murray J., Woessner J.P., Wendl M.C., Yang S.-P., Schultz B.R., Wallis J.W., Spieth J., Bieri T.A., Nelson J.O., Berkowicz N., Wohldmann P.E., Cook L.L., Hickenbotham M.T., Eldred J., Williams D., Bedell J.A., Mardis E.R., Clifton S.W., Chissoe S.L., Marra M.A., Raymond C., Haugen E., Gillett W., Zhou Y., James R., Phelps K., Iadanoto S., Bubb K., Simms E., Levy R., Clendenning J., Kaul R., Kent W.J., Furey T.S., Baertsch R.A., Brent M.R., Keibler E., Flicek P., Bork P., Suyama M., Bailey J.A., Portnoy M.E., Torrents D., Chinwalla A.T., Gish W.R., Eddy S.R., McPherson J.D., Olson M.V., Eichler E.E., Green E.D., Waterston R.H., Wilson R.K.
    Nature 424:157-164(2002) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
  5. "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(2003) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
    Tissue: Eye.
  6. "Human inhibin genes. Genomic characterisation and sequencing."
    Stewart A.G., Milborrow H.M., Ring J.M., Crowther C.E., Forage R.G.
    FEBS Lett. 206:329-334(1985) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 311-426.
  7. Berg H., Walter M., Northemann W.
    Submitted (APR-1993) to the EMBL/GenBank/DDBJ databases
    Cited for: NUCLEOTIDE SEQUENCE OF 311-426.
    Tissue: Testis.
  8. "Differential binding and neutralization of activins A and B by follistatin and follistatin like-3 (FSTL-3/FSRP/FLRG)."
    Schneyer A., Schoen A., Quigg A., Sidis Y.
    Endocrinology 144:1671-1674(2002) [PubMed] [Europe PMC] [Abstract]
    Cited for: INTERACTION WITH FST AND FSTL3.
  9. "Structures of an ActRIIB:activin A complex reveal a novel binding mode for TGF-beta ligand:receptor interactions."
    Thompson T.B., Woodruff T.K., Jardetzky T.S.
    EMBO J. 22:1555-1566(2002) [PubMed] [Europe PMC] [Abstract]
    Cited for: X-RAY CRYSTALLOGRAPHY (3.05 ANGSTROMS) IN COMPLEX WITH RAT ACTRIIB EXTRACELLULAR DOMAIN.
  10. "The structure of FSTL3.activin A complex. Differential binding of N-terminal domains influences follistatin-type antagonist specificity."
    Stamler R., Keutmann H.T., Sidis Y., Kattamuri C., Schneyer A., Thompson T.B.
    J. Biol. Chem. 283:32831-32838(2007) [PubMed] [Europe PMC] [Abstract]
    Cited for: X-RAY CRYSTALLOGRAPHY (2.48 ANGSTROMS) OF 311-426 IN COMPLEX WITH FSTL3, DISULFIDE BONDS.
  11. Cited for: VARIANTS GLU-280 AND SER-386, CHARACTERIZATION OF VARIANT SER-386.

Entry informationi

Entry nameiINHBA_HUMAN
AccessioniPrimary (citable) accession number: P08476
Secondary accession number(s): Q14599
Entry historyi
Integrated into UniProtKB/Swiss-Prot: July 31, 1988
Last sequence update: June 30, 1989
Last modified: March 31, 2015
This is version 174 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, Reference proteome

Documents

  1. Human chromosome 7
    Human chromosome 7: 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. MIM cross-references
    Online Mendelian Inheritance in Man (MIM) cross-references in UniProtKB/Swiss-Prot
  5. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  6. 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.