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Protein

Voltage-dependent P/Q-type calcium channel subunit alpha-1A

Gene

Cacna1a

Organism
Rattus norvegicus (Rat)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

Voltage-sensitive calcium channels (VSCC) mediate the entry of calcium ions into excitable cells and are also involved in a variety of calcium-dependent processes, including muscle contraction, hormone or neurotransmitter release, gene expression, cell motility, cell division and cell death. The isoform alpha-1A gives rise to P and/or Q-type calcium currents. P/Q-type calcium channels belong to the 'high-voltage activated' (HVA) group and are blocked by the funnel toxin (Ftx) and by the omega-agatoxin-IVA (omega-Aga-IVA). They are however insensitive to dihydropyridines (DHP), and omega-conotoxin-GVIA (omega-CTx-GVIA).

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sitei320Calcium ion selectivity and permeabilityBy similarity1
Sitei670Calcium ion selectivity and permeabilityBy similarity1
Sitei1411Calcium ion selectivity and permeabilityBy similarity1
Sitei1600Binds to omega-Aga-IVABy similarity1
Sitei1707Calcium ion selectivity and permeabilityBy similarity1

Regions

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Calcium bindingi1791 – 1802By similarityAdd BLAST12

GO - Molecular functioni

  • calmodulin binding Source: UniProtKB
  • high voltage-gated calcium channel activity Source: RGD
  • metal ion binding Source: UniProtKB-KW
  • voltage-gated calcium channel activity Source: UniProtKB

GO - Biological processi

  • calcium ion import Source: RGD
  • calcium ion transport Source: RGD
  • chemical synaptic transmission Source: RGD
  • membrane depolarization during action potential Source: GO_Central
  • positive regulation of cytosolic calcium ion concentration Source: UniProtKB
  • sensory perception of pain Source: RGD
Complete GO annotation...

Keywords - Molecular functioni

Calcium channel, Ion channel, Voltage-gated channel

Keywords - Biological processi

Calcium transport, Ion transport, Transport

Keywords - Ligandi

Calcium, Metal-binding

Protein family/group databases

TCDBi1.A.1.11.8. the voltage-gated ion channel (vic) superfamily.

Names & Taxonomyi

Protein namesi
Recommended name:
Voltage-dependent P/Q-type calcium channel subunit alpha-1A
Alternative name(s):
Brain calcium channel I
Short name:
BI
Calcium channel, L type, alpha-1 polypeptide, isoform 4
Rat brain class A
Short name:
RBA-I
Voltage-gated calcium channel subunit alpha Cav2.1
Gene namesi
Name:Cacna1a
Synonyms:Cach4, Cacn3, Cacnl1a4
OrganismiRattus norvegicus (Rat)
Taxonomic identifieri10116 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresGliresRodentiaSciurognathiMuroideaMuridaeMurinaeRattus
Proteomesi
  • UP000002494 Componenti: Unplaced

Organism-specific databases

RGDi2244. Cacna1a.

Subcellular locationi

Topology

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Topological domaini1 – 100CytoplasmicSequence analysisAdd BLAST100
Transmembranei101 – 119Helical; Name=S1 of repeat ISequence analysisAdd BLAST19
Topological domaini120 – 138ExtracellularSequence analysisAdd BLAST19
Transmembranei139 – 156Helical; Name=S2 of repeat ISequence analysisAdd BLAST18
Topological domaini157 – 168CytoplasmicSequence analysisAdd BLAST12
Transmembranei169 – 184Helical; Name=S3 of repeat ISequence analysisAdd BLAST16
Topological domaini185 – 192ExtracellularSequence analysis8
Transmembranei193 – 211Helical; Name=S4 of repeat ISequence analysisAdd BLAST19
Topological domaini212 – 230CytoplasmicSequence analysisAdd BLAST19
Transmembranei231 – 250Helical; Name=S5 of repeat ISequence analysisAdd BLAST20
Topological domaini251 – 337ExtracellularSequence analysisAdd BLAST87
Transmembranei338 – 362Helical; Name=S6 of repeat ISequence analysisAdd BLAST25
Topological domaini363 – 489CytoplasmicSequence analysisAdd BLAST127
Transmembranei490 – 509Helical; Name=S1 of repeat IISequence analysisAdd BLAST20
Topological domaini510 – 523ExtracellularSequence analysisAdd BLAST14
Transmembranei524 – 543Helical; Name=S2 of repeat IISequence analysisAdd BLAST20
Topological domaini544 – 551CytoplasmicSequence analysis8
Transmembranei552 – 570Helical; Name=S3 of repeat IISequence analysisAdd BLAST19
Topological domaini571 – 580ExtracellularSequence analysis10
Transmembranei581 – 599Helical; Name=S4 of repeat IISequence analysisAdd BLAST19
Topological domaini600 – 618CytoplasmicSequence analysisAdd BLAST19
Transmembranei619 – 638Helical; Name=S5 of repeat IISequence analysisAdd BLAST20
Topological domaini639 – 691ExtracellularSequence analysisAdd BLAST53
Transmembranei692 – 716Helical; Name=S6 of repeat IISequence analysisAdd BLAST25
Topological domaini717 – 1190CytoplasmicSequence analysisAdd BLAST474
Transmembranei1191 – 1214Helical; Name=S1 of repeat IIISequence analysisAdd BLAST24
Topological domaini1215 – 1231ExtracellularSequence analysisAdd BLAST17
Transmembranei1232 – 1251Helical; Name=S2 of repeat IIISequence analysisAdd BLAST20
Topological domaini1252 – 1258CytoplasmicSequence analysis7
Transmembranei1259 – 1282Helical; Name=S3 of repeat IIISequence analysisAdd BLAST24
Topological domaini1283 – 1293ExtracellularSequence analysisAdd BLAST11
Transmembranei1294 – 1311Helical; Name=S4 of repeat IIISequence analysisAdd BLAST18
Topological domaini1312 – 1330CytoplasmicSequence analysisAdd BLAST19
Transmembranei1331 – 1350Helical; Name=S5 of repeat IIISequence analysisAdd BLAST20
Topological domaini1351 – 1437ExtracellularSequence analysisAdd BLAST87
Transmembranei1438 – 1462Helical; Name=S6 of repeat IIISequence analysisAdd BLAST25
Topological domaini1463 – 1518CytoplasmicSequence analysisAdd BLAST56
Transmembranei1519 – 1537Helical; Name=S1 of repeat IVSequence analysisAdd BLAST19
Topological domaini1538 – 1551ExtracellularSequence analysisAdd BLAST14
Transmembranei1552 – 1573Helical; Name=S2 of repeat IVSequence analysisAdd BLAST22
Topological domaini1574 – 1580CytoplasmicSequence analysis7
Transmembranei1581 – 1600Helical; Name=S3 of repeat IVSequence analysisAdd BLAST20
Topological domaini1601 – 1607ExtracellularSequence analysis7
Transmembranei1608 – 1626Helical; Name=S4 of repeat IVSequence analysisAdd BLAST19
Topological domaini1627 – 1645CytoplasmicSequence analysisAdd BLAST19
Transmembranei1646 – 1665Helical; Name=S5 of repeat IVSequence analysisAdd BLAST20
Topological domaini1666 – 1737ExtracellularSequence analysisAdd BLAST72
Transmembranei1738 – 1763Helical; Name=S6 of repeat IVSequence analysisAdd BLAST26
Topological domaini1764 – 2212CytoplasmicSequence analysisAdd BLAST449

GO - Cellular componenti

  • perikaryon Source: RGD
  • plasma membrane Source: RGD
  • protein complex Source: RGD
  • voltage-gated calcium channel complex Source: RGD
Complete GO annotation...

Keywords - Cellular componenti

Membrane

Pathology & Biotechi

Chemistry databases

GuidetoPHARMACOLOGYi532.

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
ChainiPRO_00000539191 – 2212Voltage-dependent P/Q-type calcium channel subunit alpha-1AAdd BLAST2212

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Glycosylationi285N-linked (GlcNAc...)Sequence analysis1
Modified residuei411PhosphothreonineBy similarity1
Modified residuei450PhosphoserineBy similarity1
Modified residuei453PhosphoserineCombined sources1
Modified residuei752PhosphoserineCombined sources1
Modified residuei755PhosphoserineCombined sources1
Modified residuei792PhosphoserineBy similarity1
Modified residuei1038PhosphoserineBy similarity1
Modified residuei1042PhosphoserineBy similarity1
Modified residuei1051PhosphoserineBy similarity1
Glycosylationi1607N-linked (GlcNAc...)Sequence analysis1
Modified residuei1773Phosphoserine; by PKASequence analysis1
Modified residuei1935PhosphothreonineBy similarity1
Modified residuei1998PhosphoserineCombined sources1
Modified residuei2016PhosphoserineBy similarity1
Modified residuei2028PhosphoserineCombined sources1
Modified residuei2030PhosphoserineCombined sources1
Modified residuei2071PhosphoserineCombined sources1
Modified residuei2091PhosphoserineCombined sources1

Keywords - PTMi

Disulfide bond, Glycoprotein, Phosphoprotein

Proteomic databases

PaxDbiP54282.
PRIDEiP54282.

PTM databases

iPTMnetiP54282.
PhosphoSitePlusiP54282.

Expressioni

Tissue specificityi

Brain specific. Purkinje cells contain predominantly P-type VSCC, the Q-type being a prominent calcium current in cerebellar granule cells. Also found in heart, in kidney distal convoluted tubule (DCT), and in pituitary.

Interactioni

Subunit structurei

Voltage-dependent calcium channels are multisubunit complexes, consisting of alpha-1, alpha-2, beta and delta subunits in a 1:1:1:1 ratio. The channel activity is directed by the pore-forming and voltage-sensitive alpha-1 subunit. In many cases, this subunit is sufficient to generate voltage-sensitive calcium channel activity. The auxiliary subunits beta and alpha-2/delta linked by a disulfide bridge regulate the channel activity. Interact (via C-terminal CDB motif) with CABP1 in the pre- and postsynaptic membranes.

Binary interactionsi

WithEntry#Exp.IntActNotes
Rims1Q9JIR44EBI-3507416,EBI-3507436

GO - Molecular functioni

  • calmodulin binding Source: UniProtKB

Protein-protein interaction databases

BioGridi247433. 3 interactors.
DIPiDIP-29638N.
IntActiP54282. 2 interactors.
STRINGi10116.ENSRNOP00000059641.

Structurei

3D structure databases

ProteinModelPortaliP54282.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Domains and Repeats

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Repeati87 – 365IAdd BLAST279
Repeati475 – 719IIAdd BLAST245
Repeati1182 – 1465IIIAdd BLAST284
Repeati1502 – 1765IVAdd BLAST264

Region

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Regioni385 – 402Binding to the beta subunitBy similarityAdd BLAST18

Compositional bias

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Compositional biasi13 – 20Poly-Gly8
Compositional biasi729 – 734Poly-Glu6
Compositional biasi1155 – 1158Poly-Glu4
Compositional biasi2162 – 2171Poly-His10

Domaini

Each of the four internal repeats contains five hydrophobic transmembrane segments (S1, S2, S3, S5, S6) and one positively charged transmembrane segment (S4). S4 segments probably represent the voltage-sensor and are characterized by a series of positively charged amino acids at every third position.

Sequence similaritiesi

Keywords - Domaini

Repeat, Transmembrane, Transmembrane helix

Phylogenomic databases

eggNOGiKOG2301. Eukaryota.
ENOG410XNP6. LUCA.
HOGENOMiHOG000231530.
HOVERGENiHBG050763.
InParanoidiP54282.
KOiK04344.
PhylomeDBiP54282.

Family and domain databases

Gene3Di1.20.120.350. 4 hits.
InterProiIPR005448. CACNA1A.
IPR027359. Channel_four-helix_dom.
IPR031649. GPHH_dom.
IPR005821. Ion_trans_dom.
IPR014873. VDCC_a1su_IQ.
IPR002077. VDCCAlpha1.
[Graphical view]
PANTHERiPTHR10037:SF59. PTHR10037:SF59. 3 hits.
PfamiPF08763. Ca_chan_IQ. 1 hit.
PF16905. GPHH. 1 hit.
PF00520. Ion_trans. 4 hits.
[Graphical view]
PRINTSiPR00167. CACHANNEL.
PR01632. PQVDCCALPHA1.
SMARTiSM01062. Ca_chan_IQ. 1 hit.
[Graphical view]

Sequences (4)i

Sequence statusi: Complete.

This entry describes 4 isoformsi produced by alternative splicing. AlignAdd to basket

Note: Additional isoforms seem to exist.
Isoform 1 (identifier: P54282-1) [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
MARFGDEMPG RYGAGGGGSG PAAGVVVGAA GGRGAGGSRQ GGQPGAQRMY
60 70 80 90 100
KQSMAQRART MALYNPIPVR QNCLTVNRSL FLFSEDNVVR KYAKKITEWP
110 120 130 140 150
PFEYMILATI IANCIVLALE QHLPDDDKTP MSERLDDTEP YFIGIFCFEA
160 170 180 190 200
GIKIVALGFA FHKGSYLRNG WNVMDFVVVL TGILATVGTE FDLRTLRAVR
210 220 230 240 250
VLRPLKLVSG IPSLQVVLKS IMKAMIPLLQ IGLLLFFAIL IFAIIGLEFY
260 270 280 290 300
MGKFHTTCFE EGTDDIQGES PAPCGTEEPA RTCPNGTKCQ PYWEGPNNGI
310 320 330 340 350
TQFDNILFAV LTVFQCITME GWTDLLYNSN DASGNTWNWL YFIPLIIIGS
360 370 380 390 400
FFMLNLVLGV LSGEFAKERE RVENRRAFLK LRRQQQIERE LNGYMEWISK
410 420 430 440 450
AEEVILAEDE TDVEQRHPFD GALRRATLKK SKTDLLNPEE AEDQLADIAS
460 470 480 490 500
VGSPFARASI KSAKLENSTF FHKKERRMRF YIRRMVKTQA FYWTVLSLVA
510 520 530 540 550
LNTLWLAIVH YNQPEWLSDF LYYAEFIFLG LFMSEMFIKM YGLGTRPYFH
560 570 580 590 600
SSFNCFDCGV IIGSIFEVIW AVIKPGTSFG ISVLRALRLL RIFKVTKYWA
610 620 630 640 650
SLRNLVVSLL NSMKSIISLL FLLFLFIVVF ALLGMQLFGG QFNFDEGTPP
660 670 680 690 700
TNFDTFPAAI MTVFQILTGE DWNEVMYDEI KSQGGVQGGM VFSIYFIVLT
710 720 730 740 750
LFGNYTLLNV FLAIAVDNLA NAQELTKDEQ EEEEAANQKL ALQKAKEVAE
760 770 780 790 800
VSPLSAANMS IAVKEQQKNQ KPAKSVWEQR TSEMRKQNLL ASREALYGDA
810 820 830 840 850
AERWPTTYAR PLRPDVKTHL DRPLVVDPQE NRNNNTNKSR APEALRQTAR
860 870 880 890 900
PRESARDPDA RRAWPSSPER APGREGPYGR ESEPQQREHA PPREHVPWDA
910 920 930 940 950
DPERAKAGDA PRRHTHRPVA EGEPRRHRAR RRPGDEPDDR PERRPRPRDA
960 970 980 990 1000
TRPARAADGE GDDGERKRRH RHGPPAHDDR ERRHRRRKES QGSGVPMSGP
1010 1020 1030 1040 1050
NLSTTRPIQQ DLGRQDLPLA EDLDNMKNNK LATGEPASPH DSLGHSGLPP
1060 1070 1080 1090 1100
SPAKIGNSTN PGPALATNPQ NAASRRTPNN PGNPSNPGPP KTPENSLIVT
1110 1120 1130 1140 1150
NPSSTQPNSA KTARKPEHMA VEIPPACPPL NHTVVQVNKN ANPDPLPKKE
1160 1170 1180 1190 1200
EEKKEEEEAD PGEDGPKPMP PYSSMFILST TNPLRRLCHY ILNLRYFEMC
1210 1220 1230 1240 1250
ILMVIAMSSI ALAAEDPVQP NAPRNNVLRY FDYVFTGVFT FEMVIKMIDL
1260 1270 1280 1290 1300
GLVLHQGAYF RDLWNILDFI VVSGALVAFA FTGNSKGKDI NTIKSLRVLR
1310 1320 1330 1340 1350
VLRPLKTIKR LPKLKAVFDC VVNSLKNVFN ILIVYMLFMF IFAVVAVQLF
1360 1370 1380 1390 1400
KGKFFHCTDE SKEFERDCRG KYLLYEKNEV KARDREWKKY DFHYDNVLWA
1410 1420 1430 1440 1450
LLTLFTVSTG EGWPQVLKHS VDATFENQGP SPGYRMEMSI FYVVYFVVFP
1460 1470 1480 1490 1500
FFFVNIFVAL IIITFQEQGD KMMEEYSLEK NERACIDFAI SAKPLTRHMP
1510 1520 1530 1540 1550
QNKQSFQYRM WQFVVSPPFE YTIMAMIALN TIVLMMKFYG ASVAYENALR
1560 1570 1580 1590 1600
VFNIVFTSLF SLECVLKVMA FGILNYFRDA WNIFDFVTVL GSITDILVTE
1610 1620 1630 1640 1650
FGNNFINLSF LRLFRAARLI KLLRQGYTIR ILLWTFVQSF KALPYVCLLI
1660 1670 1680 1690 1700
AMLFFIYAII GMQVFGNIGI DGEDEDSDED EFQITEHNNF RTFFQALMLL
1710 1720 1730 1740 1750
FRSATGEAWH NIMLSCLSGK PCDKNSGIQK PECGNEFAYF YFVSFIFLCS
1760 1770 1780 1790 1800
FLMLNLFVAV IMDNFEYLTR DSSILGPHHL DEYVRVWAEY DPAACGRIHY
1810 1820 1830 1840 1850
KDMYSLLRVI SPPLGLGKKC PHRVACKRLL RMDLPVADDN TVHFNSTLMA
1860 1870 1880 1890 1900
LIRTALDIKI AKGGADKQQM DAELRKEMMA IWPNLSQKTL DLLVTPHKST
1910 1920 1930 1940 1950
DLTVGKIYAA MMIMEYYRQS KAKKLQAMRE EQNRTPLMFQ RMEPPSPTQE
1960 1970 1980 1990 2000
GGPSQNALPS TQLDPGGGLM AQESSMKESP SWVTQRAQEM FQKTGTWSPE
2010 2020 2030 2040 2050
RGPPIDMPNS QPNSQSVEMR EMGTDGYSDS EHYLPMEGQT RAASMPRLPA
2060 2070 2080 2090 2100
ENQRRRGRPR GNNLSTISDT SPMKRSASVL GPKARRLDDY SLERVPPEEN
2110 2120 2130 2140 2150
QRYHQRRRDR GHRTSERSLG RYTDVDTGLG TDLSMTTQSG DLPSKDRDQD
2160 2170 2180 2190 2200
RGRPKDRKHR PHHHHHHHHH HPPAPDRERY AQERPDTGRA RAREQRWSRS
2210
PSEGREHATH RQ
Length:2,212
Mass (Da):251,527
Last modified:October 1, 1996 - v1
Checksum:iDFBD7A0F553AFA52
GO
Isoform 2 (identifier: P54282-2) [UniParc]FASTAAdd to basket
Also known as: RKC8

The sequence of this isoform differs from the canonical sequence as follows:
     1602-1602: G → GNP

Show »
Length:2,214
Mass (Da):251,739
Checksum:iD2ED9869D22AF77F
GO
Isoform 3 (identifier: P54282-3)
Also known as: RBA-65
Sequence is not available
Length:
Mass (Da):
Isoform 4 (identifier: P54282-4)
Sequence is not available
Length:
Mass (Da):

Alternative sequence

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Alternative sequenceiVSP_0008811602G → GNP in isoform 2. 1 Publication1

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
M64373 mRNA. Translation: AAA40806.1.
M99222 mRNA. Translation: AAA40896.1.
PIRiA41098.
RefSeqiNP_037050.2. NM_012918.3.
UniGeneiRn.87769.

Genome annotation databases

GeneIDi25398.
KEGGirno:25398.

Keywords - Coding sequence diversityi

Alternative splicing

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
M64373 mRNA. Translation: AAA40806.1.
M99222 mRNA. Translation: AAA40896.1.
PIRiA41098.
RefSeqiNP_037050.2. NM_012918.3.
UniGeneiRn.87769.

3D structure databases

ProteinModelPortaliP54282.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi247433. 3 interactors.
DIPiDIP-29638N.
IntActiP54282. 2 interactors.
STRINGi10116.ENSRNOP00000059641.

Chemistry databases

GuidetoPHARMACOLOGYi532.

Protein family/group databases

TCDBi1.A.1.11.8. the voltage-gated ion channel (vic) superfamily.

PTM databases

iPTMnetiP54282.
PhosphoSitePlusiP54282.

Proteomic databases

PaxDbiP54282.
PRIDEiP54282.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

GeneIDi25398.
KEGGirno:25398.

Organism-specific databases

CTDi773.
RGDi2244. Cacna1a.

Phylogenomic databases

eggNOGiKOG2301. Eukaryota.
ENOG410XNP6. LUCA.
HOGENOMiHOG000231530.
HOVERGENiHBG050763.
InParanoidiP54282.
KOiK04344.
PhylomeDBiP54282.

Miscellaneous databases

PROiP54282.

Family and domain databases

Gene3Di1.20.120.350. 4 hits.
InterProiIPR005448. CACNA1A.
IPR027359. Channel_four-helix_dom.
IPR031649. GPHH_dom.
IPR005821. Ion_trans_dom.
IPR014873. VDCC_a1su_IQ.
IPR002077. VDCCAlpha1.
[Graphical view]
PANTHERiPTHR10037:SF59. PTHR10037:SF59. 3 hits.
PfamiPF08763. Ca_chan_IQ. 1 hit.
PF16905. GPHH. 1 hit.
PF00520. Ion_trans. 4 hits.
[Graphical view]
PRINTSiPR00167. CACHANNEL.
PR01632. PQVDCCALPHA1.
SMARTiSM01062. Ca_chan_IQ. 1 hit.
[Graphical view]
ProtoNetiSearch...

Entry informationi

Entry nameiCAC1A_RAT
AccessioniPrimary (citable) accession number: P54282
Secondary accession number(s): Q01541
Entry historyi
Integrated into UniProtKB/Swiss-Prot: October 1, 1996
Last sequence update: October 1, 1996
Last modified: November 2, 2016
This is version 138 of the entry and version 1 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programChordata Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

Complete proteome, Reference proteome

Documents

  1. 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.