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

Polyphosphatidylinositol phosphatase INP53

Gene

INP53

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

Dephosphorylates a number of phosphatidylinositols (PIs) like phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2), but also phosphatidylinositol 3-phosphate (PtdIns3P), phosphatidylinositol 4-phosphate (PtdIns4P), and phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P2). Controls the cellular levels and subcellular distribution of phosphatidylinositol 3-phosphate and phosphatidylinositol 4,5-bisphosphate. Plays an essential role in a TGN (trans Golgi network)-to-early endosome pathway. Involved in clathrin-mediated protein sorting at the TGN.12 Publications

Catalytic activityi

1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate + H2O = 1-phosphatidyl-1D-myo-inositol 4-phosphate + phosphate.

GO - Molecular functioni

  • phosphatidylinositol-3,5-bisphosphate 5-phosphatase activity Source: SGD
  • phosphatidylinositol-3-phosphatase activity Source: SGD
  • phosphatidylinositol-4,5-bisphosphate 5-phosphatase activity Source: SGD
  • phosphatidylinositol-4-phosphate phosphatase activity Source: SGD

GO - Biological processi

  • endocytosis Source: UniProtKB-KW
  • phosphatidylinositol dephosphorylation Source: SGD
  • protein transport Source: UniProtKB-KW
Complete GO annotation...

Keywords - Molecular functioni

Hydrolase

Keywords - Biological processi

Endocytosis, Protein transport, Transport

Enzyme and pathway databases

BioCyciYEAST:MONOMER3O-72.
YEAST:YOR109W-MONOMER.
ReactomeiR-SCE-1660499. Synthesis of PIPs at the plasma membrane.
R-SCE-1660514. Synthesis of PIPs at the Golgi membrane.
R-SCE-1855183. Synthesis of IP2, IP, and Ins in the cytosol.
R-SCE-1855204. Synthesis of IP3 and IP4 in the cytosol.
R-SCE-194840. Rho GTPase cycle.
R-SCE-202424. Downstream TCR signaling.

Names & Taxonomyi

Protein namesi
Recommended name:
Polyphosphatidylinositol phosphatase INP53
Alternative name(s):
Suppressor of PMA1 protein 2
Synaptojanin-like protein 3
Including the following 2 domains:
SAC1-like phosphoinositide phosphatase (EC:3.1.3.-)
Phosphatidylinositol 4,5-bisphosphate 5-phosphatase (EC:3.1.3.36)
Gene namesi
Name:INP53
Synonyms:SJL3, SOP2
Ordered Locus Names:YOR109W
ORF Names:YOR3231w
OrganismiSaccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast)
Taxonomic identifieri559292 [NCBI]
Taxonomic lineageiEukaryotaFungiDikaryaAscomycotaSaccharomycotinaSaccharomycetesSaccharomycetalesSaccharomycetaceaeSaccharomyces
Proteomesi
  • UP000002311 Componenti: Chromosome XV

Organism-specific databases

EuPathDBiFungiDB:YOR109W.
SGDiS000005635. INP53.

Subcellular locationi

GO - Cellular componenti

  • actin cortical patch Source: SGD
  • cytoplasm Source: SGD
  • membrane Source: SGD
Complete GO annotation...

Keywords - Cellular componenti

Cytoplasm

Pathology & Biotechi

Mutagenesis

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Mutagenesisi421 – 4211C → A: Reduces hydrolysis of PtdIns(4)P; when associated with A-424 and A-427. 1 Publication
Mutagenesisi424 – 4241C → A: Reduces hydrolysis of PtdIns(4)P; when associated with A-421 and A-427. 1 Publication
Mutagenesisi427 – 4271R → A: Reduces hydrolysis of PtdIns(4)P; when associated with A-421 and A-424. 1 Publication
Mutagenesisi746 – 7461D → A: Abolishes hydrolysis of PtdIns(4,5)P2; when associated with A-748. 1 Publication
Mutagenesisi748 – 7481N → A: Abolishes hydrolysis of PtdIns(4,5)P2; when associated with A-746. 1 Publication

PTM / Processingi

Molecule processing

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Chaini1 – 11071107Polyphosphatidylinositol phosphatase INP53PRO_0000268681Add
BLAST

Amino acid modifications

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Modified residuei497 – 4971PhosphoserineBy similarity
Modified residuei986 – 9861PhosphoserineCombined sources
Modified residuei1035 – 10351PhosphoserineCombined sources
Modified residuei1105 – 11051PhosphothreonineCombined sources

Keywords - PTMi

Phosphoprotein

Proteomic databases

MaxQBiQ12271.

PTM databases

iPTMnetiQ12271.

Interactioni

Subunit structurei

Interacts with BSP1 and CHC1.2 Publications

Protein-protein interaction databases

BioGridi34505. 189 interactions.
DIPiDIP-2555N.
IntActiQ12271. 14 interactions.
MINTiMINT-4502837.

Structurei

3D structure databases

ProteinModelPortaliQ12271.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Domains and Repeats

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Domaini142 – 482341SACPROSITE-ProRule annotationAdd
BLAST

Compositional bias

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifierActions
Compositional biasi957 – 98933Pro-richAdd
BLAST

Domaini

The SAC1 domain is capable of hydrolyzing phosphatidylinositol 3-phosphate (PtdIns3P), phosphatidylinositol 4-phosphate (PtdIns4P), and phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P2).
The 5-phosphatase domain (residues 568 to 856) selectively removes the phosphate group at the 5' position of inositol of phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2).
The C-terminal proline-rich domain is required for the function and associates with clathrin heavy chain CHC1.

Sequence similaritiesi

Belongs to the synaptojanin family.Curated
In the central section; belongs to the inositol 1,4,5-trisphosphate 5-phosphatase family.Curated
Contains 1 SAC domain.PROSITE-ProRule annotation

Phylogenomic databases

GeneTreeiENSGT00760000119075.
HOGENOMiHOG000179717.
InParanoidiQ12271.
KOiK01106.
OMAiNINDCRI.
OrthoDBiEOG7DRJBN.

Family and domain databases

Gene3Di3.60.10.10. 1 hit.
InterProiIPR005135. Endo/exonuclease/phosphatase.
IPR000300. IPPc.
IPR002013. SAC_dom.
[Graphical view]
PfamiPF03372. Exo_endo_phos. 1 hit.
PF02383. Syja_N. 1 hit.
[Graphical view]
SMARTiSM00128. IPPc. 1 hit.
[Graphical view]
SUPFAMiSSF56219. SSF56219. 1 hit.
PROSITEiPS50275. SAC. 1 hit.
[Graphical view]

Sequencei

Sequence statusi: Complete.

Q12271-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MIIFVSEEPE RRLAIVSNLY ALVLKPVGKK PSDKPLCAIE LLQKNDLKKY
60 70 80 90 100
GFKRLTSHEI FGVIGLIEVN GLLFVGAITG KSKVAQPCPG ETVNKIFAVD
110 120 130 140 150
FFCLNDNSWD FIEIDSSGYP VLPETASTEY QDALPKHPCY ELKKLLSNGS
160 170 180 190 200
FYYSSDFDLT STLQHRGYGQ HSLSTDTYEE EYMWNSFLMQ EMITYRDHLD
210 220 230 240 250
TNLKQILDDE GFLTTVIRGF AETFVSYVKK LKVALTIISK QSWKRAGTRF
260 270 280 290 300
NARGVDDEAN VANFVETEFI MYSSQYCYAF TQIRGSIPVF WEQGTSLINP
310 320 330 340 350
RVQITRSFEA TQPVFDKHIM KSVEKYGPVH VVNLLSTKSS EIELSKRYKE
360 370 380 390 400
HLTHSKKLNF NKDIFLTEFD FHKETSQEGF SGVRKLIPLI LDSLLSSGYY
410 420 430 440 450
SYDVREKKNI SEQHGIFRTN CLDCLDRTNL AQQIISLAAF RTFLEDFRLI
460 470 480 490 500
SSNSFIDDDD FVSKHNTLWA DHGDQISQIY TGTNALKSSF SRKGKMSLAG
510 520 530 540 550
ALSDATKSVS RIYINNFMDK EKQQNIDTLL GRLPYQKAVQ LYDPVNEYVS
560 570 580 590 600
TKLQSMSDKF TSTSNINLLI GSFNVNGATK KVDLSKWLFP IGEKFKPDIV
610 620 630 640 650
VLGLQEVIEL SAGSILNADY SKSSFWENLV GDCLNQYDDK YLLLRVEQMT
660 670 680 690 700
SLLILFFVKA DKAKYVKQVE GATKKTGFRG MAGNKGAVSI RFEYGATSFC
710 720 730 740 750
FVNSHLAAGA TNVEERRSDY ESIVRGITFT RTKMIPHHDS IFWLGDMNYR
760 770 780 790 800
INLPNEDVRR ELLNQEEGYI DKLLHFDQLT LGINSGSVFE GFKEPTLKFR
810 820 830 840 850
PTYKYDPGTG TYDSSEKERT PSWTDRIIYK GENLLPLSYS DAPIMISDHR
860 870 880 890 900
PVYAAYRAKI TFVDDKERLS LKKRLFTEYK QEHPEEPGSL ISDLLSLDLD
910 920 930 940 950
NKSTDGFKSS SESSLLDIDP IMAQPTASSV ASSSPVSSAS ASLQPVRTQN
960 970 980 990 1000
SSQSRTPIKK PVLRPPPPPA HKSVSAPAPS TSKEKSPTPQ TSTASLSSVT
1010 1020 1030 1040 1050
KNIQENKPLA QNRRIPPPGF SQNILTPKST SNLASPMSSK VDLYNSASES
1060 1070 1080 1090 1100
TRSAQDARQQ TPTAFAASRD VNGQPEALLG DENPIEPEEK AKLNHMTLDS

WQPLTPK
Length:1,107
Mass (Da):124,577
Last modified:November 1, 1996 - v1
Checksum:i1E024F15085261EA
GO

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
X94335 Genomic DNA. Translation: CAA64029.1.
Z75017 Genomic DNA. Translation: CAA99307.1.
BK006948 Genomic DNA. Translation: DAA10884.1.
PIRiS61667.
RefSeqiNP_014752.3. NM_001183528.3.

Genome annotation databases

EnsemblFungiiYOR109W; YOR109W; YOR109W.
GeneIDi854276.
KEGGisce:YOR109W.

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
X94335 Genomic DNA. Translation: CAA64029.1.
Z75017 Genomic DNA. Translation: CAA99307.1.
BK006948 Genomic DNA. Translation: DAA10884.1.
PIRiS61667.
RefSeqiNP_014752.3. NM_001183528.3.

3D structure databases

ProteinModelPortaliQ12271.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi34505. 189 interactions.
DIPiDIP-2555N.
IntActiQ12271. 14 interactions.
MINTiMINT-4502837.

PTM databases

iPTMnetiQ12271.

Proteomic databases

MaxQBiQ12271.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsemblFungiiYOR109W; YOR109W; YOR109W.
GeneIDi854276.
KEGGisce:YOR109W.

Organism-specific databases

EuPathDBiFungiDB:YOR109W.
SGDiS000005635. INP53.

Phylogenomic databases

GeneTreeiENSGT00760000119075.
HOGENOMiHOG000179717.
InParanoidiQ12271.
KOiK01106.
OMAiNINDCRI.
OrthoDBiEOG7DRJBN.

Enzyme and pathway databases

BioCyciYEAST:MONOMER3O-72.
YEAST:YOR109W-MONOMER.
ReactomeiR-SCE-1660499. Synthesis of PIPs at the plasma membrane.
R-SCE-1660514. Synthesis of PIPs at the Golgi membrane.
R-SCE-1855183. Synthesis of IP2, IP, and Ins in the cytosol.
R-SCE-1855204. Synthesis of IP3 and IP4 in the cytosol.
R-SCE-194840. Rho GTPase cycle.
R-SCE-202424. Downstream TCR signaling.

Miscellaneous databases

PROiQ12271.

Family and domain databases

Gene3Di3.60.10.10. 1 hit.
InterProiIPR005135. Endo/exonuclease/phosphatase.
IPR000300. IPPc.
IPR002013. SAC_dom.
[Graphical view]
PfamiPF03372. Exo_endo_phos. 1 hit.
PF02383. Syja_N. 1 hit.
[Graphical view]
SMARTiSM00128. IPPc. 1 hit.
[Graphical view]
SUPFAMiSSF56219. SSF56219. 1 hit.
PROSITEiPS50275. SAC. 1 hit.
[Graphical view]
ProtoNetiSearch...

Publicationsi

« Hide 'large scale' publications
  1. Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
  2. "The nucleotide sequence of Saccharomyces cerevisiae chromosome XV."
    Dujon B., Albermann K., Aldea M., Alexandraki D., Ansorge W., Arino J., Benes V., Bohn C., Bolotin-Fukuhara M., Bordonne R., Boyer J., Camasses A., Casamayor A., Casas C., Cheret G., Cziepluch C., Daignan-Fornier B., Dang V.-D.
    , de Haan M., Delius H., Durand P., Fairhead C., Feldmann H., Gaillon L., Galisson F., Gamo F.-J., Gancedo C., Goffeau A., Goulding S.E., Grivell L.A., Habbig B., Hand N.J., Hani J., Hattenhorst U., Hebling U., Hernando Y., Herrero E., Heumann K., Hiesel R., Hilger F., Hofmann B., Hollenberg C.P., Hughes B., Jauniaux J.-C., Kalogeropoulos A., Katsoulou C., Kordes E., Lafuente M.J., Landt O., Louis E.J., Maarse A.C., Madania A., Mannhaupt G., Marck C., Martin R.P., Mewes H.-W., Michaux G., Paces V., Parle-McDermott A.G., Pearson B.M., Perrin A., Pettersson B., Poch O., Pohl T.M., Poirey R., Portetelle D., Pujol A., Purnelle B., Ramezani Rad M., Rechmann S., Schwager C., Schweizer M., Sor F., Sterky F., Tarassov I.A., Teodoru C., Tettelin H., Thierry A., Tobiasch E., Tzermia M., Uhlen M., Unseld M., Valens M., Vandenbol M., Vetter I., Vlcek C., Voet M., Volckaert G., Voss H., Wambutt R., Wedler H., Wiemann S., Winsor B., Wolfe K.H., Zollner A., Zumstein E., Kleine K.
    Nature 387:98-102(1997) [PubMed] [Europe PMC] [Abstract]
    Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
    Strain: ATCC 204508 / S288c.
  3. Cited for: GENOME REANNOTATION.
    Strain: ATCC 204508 / S288c.
  4. "Novel genes involved in endosomal traffic in yeast revealed by suppression of a targeting-defective plasma membrane ATPase mutant."
    Luo W.-J., Chang A.
    J. Cell Biol. 138:731-746(1997) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION.
  5. "Identification and characterization of an essential family of inositol polyphosphate 5-phosphatases (INP51, INP52 and INP53 gene products) in the yeast Saccharomyces cerevisiae."
    Stolz L.E., Huynh C.V., Thorner J., York J.D.
    Genetics 148:1715-1729(1998) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION.
  6. "Synaptojanin family members are implicated in endocytic membrane traffic in yeast."
    Singer-Krueger B., Nemoto Y., Daniell L., Ferro-Novick S., De Camilli P.
    J. Cell Sci. 111:3347-3356(1998) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION.
  7. "SAC1-like domains of yeast SAC1, INP52, and INP53 and of human synaptojanin encode polyphosphoinositide phosphatases."
    Guo S., Stolz L.E., Lemrow S.M., York J.D.
    J. Biol. Chem. 274:12990-12995(1999) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION, DOMAIN.
  8. "Disruption of six unknown open reading frames from Saccharomyces cerevisiae reveals two genes involved in vacuolar morphogenesis and one gene required for sporulation."
    Saiz J.E., de Los Angeles Santos M., Vazquez de Aldana C.R., Revuelta J.L.
    Yeast 15:155-164(1999) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION.
  9. "Synthetic genetic interactions with temperature-sensitive clathrin in Saccharomyces cerevisiae. Roles for synaptojanin-like Inp53p and dynamin-related Vps1p in clathrin-dependent protein sorting at the trans-Golgi network."
    Bensen E.S., Costaguta G., Payne G.S.
    Genetics 154:83-97(2000) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION.
  10. "SAC1 encodes a regulated lipid phosphoinositide phosphatase, defects in which can be suppressed by the homologous Inp52p and Inp53p phosphatases."
    Hughes W.E., Woscholski R., Cooke F.T., Patrick R.S., Dove S.K., McDonald N.Q., Parker P.J.
    J. Biol. Chem. 275:801-808(2000) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION.
  11. "The yeast inositol polyphosphate 5-phosphatases inp52p and inp53p translocate to actin patches following hyperosmotic stress: mechanism for regulating phosphatidylinositol 4,5-bisphosphate at plasma membrane invaginations."
    Ooms L.M., McColl B.K., Wiradjaja F., Wijayaratnam A.P.W., Gleeson P., Gething M.J., Sambrook J.F., Mitchell C.A.
    Mol. Cell. Biol. 20:9376-9390(2000) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION, DOMAIN, SUBCELLULAR LOCATION.
  12. "A novel mechanism for localizing membrane proteins to yeast trans-Golgi network requires function of synaptojanin-like protein."
    Ha S.-A., Bunch J.T., Hama H., DeWald D.B., Nothwehr S.F.
    Mol. Biol. Cell 12:3175-3190(2001) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION.
  13. "Bsp1p/Ypr171p is an adapter that directly links some synaptojanin family members to the cortical actin cytoskeleton in yeast."
    Wicky S., Frischmuth S., Singer-Krueger B.
    FEBS Lett. 537:35-41(2003) [PubMed] [Europe PMC] [Abstract]
    Cited for: INTERACTION WITH BSP1.
  14. "The synaptojanin-like protein Inp53/Sjl3 functions with clathrin in a yeast TGN-to-endosome pathway distinct from the GGA protein-dependent pathway."
    Ha S.-A., Torabinejad J., DeWald D.B., Wenk M.R., Lucast L., De Camilli P., Newitt R.A., Aebersold R., Nothwehr S.F.
    Mol. Biol. Cell 14:1319-1333(2003) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION, DOMAINS, MUTAGENESIS OF CYS-421; CYS-424; ARG-427; ASP-746 AND ASN-748, INTERACTION WITH CHC1.
  15. Cited for: SUBCELLULAR LOCATION [LARGE SCALE ANALYSIS].
  16. Cited for: LEVEL OF PROTEIN EXPRESSION [LARGE SCALE ANALYSIS].
  17. "Essential role for the myotubularin-related phosphatase Ymr1p and the synaptojanin-like phosphatases Sjl2p and Sjl3p in regulation of phosphatidylinositol 3-phosphate in yeast."
    Parrish W.R., Stefan C.J., Emr S.D.
    Mol. Biol. Cell 15:3567-3579(2004) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION.
  18. "Interaction of Pik1p and Sjl proteins in membrane trafficking."
    Nguyen P.H., Hasek J., Kohlwein S.D., Romero C., Choi J.H., Vancura A.
    FEMS Yeast Res. 5:363-371(2005) [PubMed] [Europe PMC] [Abstract]
    Cited for: FUNCTION.
  19. "Large-scale phosphorylation analysis of alpha-factor-arrested Saccharomyces cerevisiae."
    Li X., Gerber S.A., Rudner A.D., Beausoleil S.A., Haas W., Villen J., Elias J.E., Gygi S.P.
    J. Proteome Res. 6:1190-1197(2007) [PubMed] [Europe PMC] [Abstract]
    Cited for: PHOSPHORYLATION [LARGE SCALE ANALYSIS] AT THR-1105, IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
    Strain: ADR376.
  20. "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 SER-1035, IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
  21. "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 SER-986 AND THR-1105, IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].
  22. Cited for: IDENTIFICATION BY MASS SPECTROMETRY [LARGE SCALE ANALYSIS].

Entry informationi

Entry nameiINP53_YEAST
AccessioniPrimary (citable) accession number: Q12271
Secondary accession number(s): D6W2G8
Entry historyi
Integrated into UniProtKB/Swiss-Prot: December 12, 2006
Last sequence update: November 1, 1996
Last modified: July 6, 2016
This is version 125 of the entry and version 1 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programFungal Protein Annotation Program

Miscellaneousi

Miscellaneous

Present with 1520 molecules/cell in log phase SD medium.1 Publication

Keywords - Technical termi

Complete proteome, Reference proteome

Documents

  1. SIMILARITY comments
    Index of protein domains and families
  2. Yeast
    Yeast (Saccharomyces cerevisiae): entries, gene names and cross-references to SGD
  3. Yeast chromosome XV
    Yeast (Saccharomyces cerevisiae) chromosome XV: 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.