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Protein

Suppressor of kinetochore protein 1

Gene

SKP1

Organism
Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

Essential component of the E3 ubiquitin ligase complex SCF (SKP1-CUL1-F-box protein) ubiquitin ligase complex, which mediates the ubiquitination and subsequent proteasomal degradation of target proteins like phosphorylated SIC1. Participates in the attachment of chromosomes to the spindle. Acts as a regulatory component of the centromere DNA-binding protein complex CBF3, which is essential for chromosome segregation and movement of centromeres along microtubules. CBF3 is required for the recruitment of other kinetochore complexes to CEN DNA. It plays a role in the attachment of chromosomes to the spindle and binds selectively to a highly conserved DNA sequence called CDEIII, found in centromeres and in several promoters. The association of CBF3C with CBF3D and SGT1 is required for CBF3C activation and CBF3 assembly. SKP1/CBF3D could retrieve cyclins or cyclin-CDK-like proteins into the kinetochore thus providing cell cycle-regulated kinetochore activity. Involved in the regulation of methionine biosynthesis genes. Facilitates association of CDC53 with CDC4 and of ROY1 with YPT52.7 Publications

Pathwayi: protein ubiquitination

This protein is involved in the pathway protein ubiquitination, which is part of Protein modification.
View all proteins of this organism that are known to be involved in the pathway protein ubiquitination and in Protein modification.

GO - Molecular functioni

  • DNA replication origin binding Source: SGD

GO - Biological processi

  • exit from mitosis Source: SGD
  • G1/S transition of mitotic cell cycle Source: SGD
  • G2/M transition of mitotic cell cycle Source: SGD
  • kinetochore assembly Source: SGD
  • negative regulation of cytoplasmic translation Source: SGD
  • protein complex assembly Source: SGD
  • protein neddylation Source: SGD
  • protein ubiquitination involved in ubiquitin-dependent protein catabolic process Source: SGD
  • regulation of exit from mitosis Source: SGD
  • regulation of protein complex assembly Source: SGD
  • SCF-dependent proteasomal ubiquitin-dependent protein catabolic process Source: SGD
  • septin ring assembly Source: SGD
  • vacuolar acidification Source: SGD
Complete GO annotation...

Keywords - Biological processi

Ubl conjugation pathway

Keywords - Ligandi

DNA-binding

Enzyme and pathway databases

BioCyciYEAST:G3O-29884-MONOMER.
ReactomeiR-SCE-174113. SCF-beta-TrCP mediated degradation of Emi1.
UniPathwayiUPA00143.

Names & Taxonomyi

Protein namesi
Recommended name:
Suppressor of kinetochore protein 1
Alternative name(s):
Centromere DNA-binding protein complex CBF3 subunit D
E3 ubiquitin ligase complex SCF subunit SKP1
Gene namesi
Name:SKP1
Synonyms:CBF3D
Ordered Locus Names:YDR328C
ORF Names:D9798.14
OrganismiSaccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast)
Taxonomic identifieri559292 [NCBI]
Taxonomic lineageiEukaryotaFungiDikaryaAscomycotaSaccharomycotinaSaccharomycetesSaccharomycetalesSaccharomycetaceaeSaccharomyces
Proteomesi
  • UP000002311 Componenti: Chromosome IV

Organism-specific databases

EuPathDBiFungiDB:YDR328C.
SGDiS000002736. SKP1.

Subcellular locationi

GO - Cellular componenti

  • CBF3 complex Source: SGD
  • condensed chromosome kinetochore Source: UniProtKB-SubCell
  • cytoplasm Source: SGD
  • kinetochore Source: SGD
  • nucleus Source: SGD
  • RAVE complex Source: SGD
  • SCF ubiquitin ligase complex Source: SGD
Complete GO annotation...

Keywords - Cellular componenti

Centromere, Chromosome, Cytoplasm, Kinetochore, Nucleus

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Initiator methionineiRemoved1 Publication
Chaini2 – 194193Suppressor of kinetochore protein 1PRO_0000187257Add
BLAST

Amino acid modifications

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Modified residuei177 – 1771PhosphothreonineCombined sources

Keywords - PTMi

Phosphoprotein

Proteomic databases

MaxQBiP52286.
PeptideAtlasiP52286.
PRIDEiP52286.

PTM databases

iPTMnetiP52286.

Interactioni

Subunit structurei

Component of the E3 ubiquitin ligase complexes SCF with HRT1, some cullins like CDC53, and some F-box proteins like MET30 CDC4 and SAF1. Interacts with CDC53 and MET30 to form the E3 ubiquitin ligase complex SCF(Met30) which also contains MET4. Forms complex SCF(Cdc4) together with CDC4 and CDC53. Component of the CBF3 complex, which is formed of CBF3A/CBF2, CBF3B/CEP3, CBF3C/CTF13 and CBF3D. Component of the RAVE complex composed of RAV1, RAV2 and SKP1/CBF3D. Interacts with RCY1, ROY1, CBF3D and SGT1.11 Publications

Binary interactionsi

WithEntry#Exp.IntActNotes
CDC4P0783410EBI-4090,EBI-4434
CDC53Q1201813EBI-4090,EBI-4321
CTF13P352035EBI-4090,EBI-4085
EFT2P323242EBI-4090,EBI-6333
GRR1P248146EBI-4090,EBI-7898
HRT3Q123472EBI-4090,EBI-30029
MDM30Q059303EBI-4090,EBI-31799
MET30P3901413EBI-4090,EBI-11507
RAV1P471045EBI-4090,EBI-25471
ROY1Q048474EBI-4090,EBI-27556
SAF1P383524EBI-4090,EBI-21172
SGT1Q084466EBI-4090,EBI-17070
YLR224WQ059472EBI-4090,EBI-33647

Protein-protein interaction databases

BioGridi32385. 145 interactions.
DIPiDIP-1236N.
IntActiP52286. 74 interactions.
MINTiMINT-384072.

Structurei

Secondary structure

1
194
Legend: HelixTurnBeta strand
Show more details
Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Beta strandi5 – 95Combined sources
Beta strandi15 – 195Combined sources
Helixi20 – 234Combined sources
Helixi27 – 348Combined sources
Beta strandi76 – 783Combined sources
Helixi84 – 9613Combined sources
Turni97 – 993Combined sources
Helixi118 – 1236Combined sources
Helixi128 – 14013Combined sources
Helixi144 – 15815Combined sources
Helixi163 – 1708Combined sources
Helixi178 – 1858Combined sources

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
1NEXX-ray2.70A/C1-194[»]
3MKSX-ray2.60A/C2-194[»]
3V7DX-ray2.31A/C1-194[»]
ProteinModelPortaliP52286.
SMRiP52286. Positions 4-188.
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiP52286.

Family & Domainsi

Region

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Regioni135 – 19460Interaction with the F-box domain of F-box proteinsBy similarityAdd
BLAST

Compositional bias

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Compositional biasi66 – 749Asp/Glu-rich (highly acidic)

Sequence similaritiesi

Belongs to the SKP1 family.Curated

Phylogenomic databases

GeneTreeiENSGT00390000012652.
HOGENOMiHOG000172184.
InParanoidiP52286.
KOiK03094.
OMAiKENSWCE.
OrthoDBiEOG7N37RH.

Family and domain databases

InterProiIPR016897. SKP1.
IPR001232. SKP1-like.
IPR011333. SKP1/BTB/POZ.
IPR016072. Skp1_comp_dimer.
IPR016073. Skp1_comp_POZ.
[Graphical view]
PfamiPF01466. Skp1. 1 hit.
PF03931. Skp1_POZ. 2 hits.
[Graphical view]
PIRSFiPIRSF028729. E3_ubiquit_lig_SCF_Skp. 1 hit.
SMARTiSM00512. Skp1. 1 hit.
[Graphical view]
SUPFAMiSSF54695. SSF54695. 2 hits.
SSF81382. SSF81382. 1 hit.

Sequencei

Sequence statusi: Complete.

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

P52286-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MVTSNVVLVS GEGERFTVDK KIAERSLLLK NYLNDMHDSN LQNNSDSESD
60 70 80 90 100
SDSETNHKSK DNNNGDDDDE DDDEIVMPVP NVRSSVLQKV IEWAEHHRDS
110 120 130 140 150
NFPDEDDDDS RKSAPVDSWD REFLKVDQEM LYEIILAANY LNIKPLLDAG
160 170 180 190
CKVVAEMIRG RSPEEIRRTF NIVNDFTPEE EAAIRRENEW AEDR
Length:194
Mass (Da):22,330
Last modified:January 23, 2007 - v2
Checksum:i746DDE6470A69432
GO

Experimental Info

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Sequence conflicti48 – 481E → D in AAC49492 (PubMed:8706131).Curated

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U43179 Genomic DNA. Translation: AAB17500.1.
U61764 mRNA. Translation: AAC49492.1.
U32517 Genomic DNA. Translation: AAB64763.1.
AY557730 Genomic DNA. Translation: AAS56056.1.
BK006938 Genomic DNA. Translation: DAA12170.1.
PIRiS59793.
RefSeqiNP_010615.3. NM_001180636.3.

Genome annotation databases

EnsemblFungiiYDR328C; YDR328C; YDR328C.
GeneIDi851928.
KEGGisce:YDR328C.

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
U43179 Genomic DNA. Translation: AAB17500.1.
U61764 mRNA. Translation: AAC49492.1.
U32517 Genomic DNA. Translation: AAB64763.1.
AY557730 Genomic DNA. Translation: AAS56056.1.
BK006938 Genomic DNA. Translation: DAA12170.1.
PIRiS59793.
RefSeqiNP_010615.3. NM_001180636.3.

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
EntryMethodResolution (Å)ChainPositionsPDBsum
1NEXX-ray2.70A/C1-194[»]
3MKSX-ray2.60A/C2-194[»]
3V7DX-ray2.31A/C1-194[»]
ProteinModelPortaliP52286.
SMRiP52286. Positions 4-188.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi32385. 145 interactions.
DIPiDIP-1236N.
IntActiP52286. 74 interactions.
MINTiMINT-384072.

PTM databases

iPTMnetiP52286.

Proteomic databases

MaxQBiP52286.
PeptideAtlasiP52286.
PRIDEiP52286.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsemblFungiiYDR328C; YDR328C; YDR328C.
GeneIDi851928.
KEGGisce:YDR328C.

Organism-specific databases

EuPathDBiFungiDB:YDR328C.
SGDiS000002736. SKP1.

Phylogenomic databases

GeneTreeiENSGT00390000012652.
HOGENOMiHOG000172184.
InParanoidiP52286.
KOiK03094.
OMAiKENSWCE.
OrthoDBiEOG7N37RH.

Enzyme and pathway databases

UniPathwayiUPA00143.
BioCyciYEAST:G3O-29884-MONOMER.
ReactomeiR-SCE-174113. SCF-beta-TrCP mediated degradation of Emi1.

Miscellaneous databases

EvolutionaryTraceiP52286.
NextBioi969983.
PROiP52286.

Family and domain databases

InterProiIPR016897. SKP1.
IPR001232. SKP1-like.
IPR011333. SKP1/BTB/POZ.
IPR016072. Skp1_comp_dimer.
IPR016073. Skp1_comp_POZ.
[Graphical view]
PfamiPF01466. Skp1. 1 hit.
PF03931. Skp1_POZ. 2 hits.
[Graphical view]
PIRSFiPIRSF028729. E3_ubiquit_lig_SCF_Skp. 1 hit.
SMARTiSM00512. Skp1. 1 hit.
[Graphical view]
SUPFAMiSSF54695. SSF54695. 2 hits.
SSF81382. SSF81382. 1 hit.
ProtoNetiSearch...

Publicationsi

« Hide 'large scale' publications
  1. "Budding yeast SKP1 encodes an evolutionarily conserved kinetochore protein required for cell cycle progression."
    Connelly C., Hieter P.
    Cell 86:275-285(1996) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA], FUNCTION.
    Strain: ATCC 204508 / S288c.
  2. "SKP1 connects cell cycle regulators to the ubiquitin proteolysis machinery through a novel motif, the F-box."
    Bai C., Sen P., Hofmann K., Ma L., Goebl M., Harper J.W., Elledge S.J.
    Cell 86:263-274(1996) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, INTERACTION WITH CDC4.
    Strain: ATCC 204508 / S288c.
  3. "The nucleotide sequence of Saccharomyces cerevisiae chromosome IV."
    Jacq C., Alt-Moerbe J., Andre B., Arnold W., Bahr A., Ballesta J.P.G., Bargues M., Baron L., Becker A., Biteau N., Bloecker H., Blugeon C., Boskovic J., Brandt P., Brueckner M., Buitrago M.J., Coster F., Delaveau T.
    , del Rey F., Dujon B., Eide L.G., Garcia-Cantalejo J.M., Goffeau A., Gomez-Peris A., Granotier C., Hanemann V., Hankeln T., Hoheisel J.D., Jaeger W., Jimenez A., Jonniaux J.-L., Kraemer C., Kuester H., Laamanen P., Legros Y., Louis E.J., Moeller-Rieker S., Monnet A., Moro M., Mueller-Auer S., Nussbaumer B., Paricio N., Paulin L., Perea J., Perez-Alonso M., Perez-Ortin J.E., Pohl T.M., Prydz H., Purnelle B., Rasmussen S.W., Remacha M.A., Revuelta J.L., Rieger M., Salom D., Saluz H.P., Saiz J.E., Saren A.-M., Schaefer M., Scharfe M., Schmidt E.R., Schneider C., Scholler P., Schwarz S., Soler-Mira A., Urrestarazu L.A., Verhasselt P., Vissers S., Voet M., Volckaert G., Wagner G., Wambutt R., Wedler E., Wedler H., Woelfl S., Harris D.E., Bowman S., Brown D., Churcher C.M., Connor R., Dedman K., Gentles S., Hamlin N., Hunt S., Jones L., McDonald S., Murphy L.D., Niblett D., Odell C., Oliver K., Rajandream M.A., Richards C., Shore L., Walsh S.V., Barrell B.G., Dietrich F.S., Mulligan J.T., Allen E., Araujo R., Aviles E., Berno A., Carpenter J., Chen E., Cherry J.M., Chung E., Duncan M., Hunicke-Smith S., Hyman R.W., Komp C., Lashkari D., Lew H., Lin D., Mosedale D., Nakahara K., Namath A., Oefner P., Oh C., Petel F.X., Roberts D., Schramm S., Schroeder M., Shogren T., Shroff N., Winant A., Yelton M.A., Botstein D., Davis R.W., Johnston M., Andrews S., Brinkman R., Cooper J., Ding H., Du Z., Favello A., Fulton L., Gattung S., Greco T., Hallsworth K., Hawkins J., Hillier L.W., Jier M., Johnson D., Johnston L., Kirsten J., Kucaba T., Langston Y., Latreille P., Le T., Mardis E., Menezes S., Miller N., Nhan M., Pauley A., Peluso D., Rifkin L., Riles L., Taich A., Trevaskis E., Vignati D., Wilcox L., Wohldman P., Vaudin M., Wilson R., Waterston R., Albermann K., Hani J., Heumann K., Kleine K., Mewes H.-W., Zollner A., Zaccaria P.
    Nature 387:75-78(1997) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
    Strain: ATCC 204508 / S288c.
  4. Cited for: GENOME REANNOTATION.
    Strain: ATCC 204508 / S288c.
  5. Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
    Strain: ATCC 204508 / S288c.
  6. "The Saccharomyces cerevisiae kinetochore contains a cyclin-CDK complexing homologue, as identified by in vitro reconstitution."
    Stemmann O., Lechner J.
    EMBO J. 15:3611-3620(1996) [PubMed] [Europe PMC] [Abstract]
    Cited for: PROTEIN SEQUENCE OF 2-24, CHARACTERIZATION.
  7. "F-box proteins are receptors that recruit phosphorylated substrates to the SCF ubiquitin-ligase complex."
    Skowyra D., Craig K.L., Tyers M., Elledge S.J., Harper J.W.
    Cell 91:209-219(1997) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION, SUBUNIT.
  8. "A complex of Cdc4p, Skp1p, and Cdc53p/cullin catalyzes ubiquitination of the phosphorylated CDK inhibitor Sic1p."
    Feldman R.M., Correll C.C., Kaplan K.B., Deshaies R.J.
    Cell 91:221-230(1997) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION, SUBUNIT.
  9. "A multidimensional chromatography technology for in-depth phosphoproteome analysis."
    Albuquerque C.P., Smolka M.B., Payne S.H., Bafna V., Eng J., Zhou H.
    Mol. Cell. Proteomics 7:1389-1396(2008) [PubMed] [Europe PMC] [Abstract]
    Cited for: PHOSPHORYLATION [LARGE SCALE ANALYSIS] AT THR-177, IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
  10. "Global analysis of Cdk1 substrate phosphorylation sites provides insights into evolution."
    Holt L.J., Tuch B.B., Villen J., Johnson A.D., Gygi S.P., Morgan D.O.
    Science 325:1682-1686(2009) [PubMed] [Europe PMC] [Abstract]
    Cited for: PHOSPHORYLATION [LARGE SCALE ANALYSIS] AT THR-177, IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
  11. "Non-SCF-type F-box protein Roy1/Ymr258c interacts with a Rab5-like GTPase Ypt52 and inhibits Ypt52 function."
    Liu Y., Nakatsukasa K., Kotera M., Kanada A., Nishimura T., Kishi T., Mimura S., Kamura T.
    Mol. Biol. Cell 22:1575-1584(2011) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION, INTERACTION WITH ROY1.
  12. "Cdc53 is a scaffold protein for multiple Cdc34/Skp1/F-box protein complexes that regulate cell division and methionine biosynthesis in yeast."
    Patton E.E., Willems A.R., Sa D., Kuras L., Thomas D., Craig K.L., Tyers M.
    Genes Dev. 12:692-705(1998) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION, INTERACTION WITH MET30 AND CDC53.
  13. "Feedback-regulated degradation of the transcriptional activator Met4 is triggered by the SCF(Met30) complex."
    Rouillon A., Barbey R., Patton E.E., Tyers M., Thomas D.
    EMBO J. 19:282-294(2000) [PubMed] [Europe PMC] [Abstract]
    Cited for: SUBUNIT.
  14. "Skp1p and the F-box protein Rcy1p form a non-SCF complex involved in recycling of the SNARE Snc1p in yeast."
    Galan J.M., Wiederkehr A., Seol J.H., Haguenauer-Tsapis R., Deshaies R.J., Riezman H., Peter M.
    Mol. Cell. Biol. 21:3105-3117(2001) [PubMed] [Europe PMC] [Abstract]
    Cited for: INTERACTION WITH RCY1.
  15. "Skp1 forms multiple protein complexes, including RAVE, a regulator of V-ATPase assembly."
    Seol J.H., Shevchenko A., Shevchenko A., Deshaies R.J.
    Nat. Cell Biol. 3:384-391(2001) [PubMed] [Europe PMC] [Abstract]
    Cited for: IDENTIFICATION IN THE RAVE COMPLEX WITH RAV1 AND RAV2.
  16. Cited for: IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
  17. "Structural basis for phosphodependent substrate selection and orientation by the SCFCdc4 ubiquitin ligase."
    Orlicky S., Tang X., Willems A., Tyers M., Sicheri F.
    Cell 112:243-256(2003) [PubMed] [Europe PMC] [Abstract]
    Cited for: X-RAY CRYSTALLOGRAPHY (2.7 ANGSTROMS) OF 7-166.
  18. Cited for: SUBCELLULAR LOCATION [LARGE SCALE ANALYSIS].
  19. "The amino-terminal portion of the F-box protein Met30p mediates its nuclear import and assimilation into an SCF complex."
    Brunson L.E., Dixon C., Kozubowski L., Mathias N.
    J. Biol. Chem. 279:6674-6682(2004) [PubMed] [Europe PMC] [Abstract]
    Cited for: INTERACTION WITH MET30.
  20. "Sgt1p and Skp1p modulate the assembly and turnover of CBF3 complexes required for proper kinetochore function."
    Rodrigo-Brenni M.C., Thomas S., Bouck D.C., Kaplan K.B.
    Mol. Biol. Cell 15:3366-3378(2004) [PubMed] [Europe PMC] [Abstract]
    Cited for: ASSEMBLY OF THE CBF3 COMPLEX, INTERACTION WITH CBF3C AND SGT1.
  21. "Skp1-Cullin-F-box-dependent degradation of Aah1p requires its interaction with the F-box protein Saf1p."
    Escusa S., Laporte D., Massoni A., Boucherie H., Dautant A., Daignan-Fornier B.
    J. Biol. Chem. 282:20097-20103(2007) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION, IDENTIFICATION IN THE SCF(SAF1) COMPLEX.

Entry informationi

Entry nameiSKP1_YEAST
AccessioniPrimary (citable) accession number: P52286
Secondary accession number(s): D6VSW0, Q07186
Entry historyi
Integrated into UniProtKB/Swiss-Prot: October 1, 1996
Last sequence update: January 23, 2007
Last modified: May 11, 2016
This is version 158 of the entry and version 2 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programFungal Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

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

Documents

  1. PATHWAY comments
    Index of metabolic and biosynthesis pathways
  2. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  3. SIMILARITY comments
    Index of protein domains and families
  4. Yeast
    Yeast (Saccharomyces cerevisiae): entries, gene names and cross-references to SGD
  5. Yeast chromosome IV
    Yeast (Saccharomyces cerevisiae) chromosome IV: entries and gene names

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.