ID   ACTP3_ACTEQ             Reviewed;          20 AA.
AC   P0C1H2;
DT   27-JUN-2006, integrated into UniProtKB/Swiss-Prot.
DT   27-JUN-2006, sequence version 1.
DT   25-MAY-2022, entry version 42.
DE   RecName: Full=Equinatoxin-3 {ECO:0000305};
DE   AltName: Full=DELTA-actitoxin {ECO:0000305};
DE   AltName: Full=Equinatoxin III {ECO:0000303|PubMed:10414864};
DE            Short=EqT III {ECO:0000303|PubMed:10414864};
DE            Short=EqT-III;
DE            Short=EqTIII {ECO:0000303|PubMed:10414864};
DE   Flags: Fragment;
OS   Actinia equina (Beadlet anemone).
OC   Eukaryota; Metazoa; Cnidaria; Anthozoa; Hexacorallia; Actiniaria;
OC   Actiniidae; Actinia.
OX   NCBI_TaxID=6106;
RN   [1]
RP   PROTEIN SEQUENCE.
RX   PubMed=10414864; DOI=10.1016/s0041-0101(99)00082-3;
RA   Anderluh G., Krizaj I., Strukelj B., Gubensek F., Macek P., Pungercar J.;
RT   "Equinatoxins, pore-forming proteins from the sea anemone Actinia equina,
RT   belong to a multigene family.";
RL   Toxicon 37:1391-1401(1999).
RN   [2]
RP   AMINO-ACID COMPOSITION, AND TOXIC DOSE.
RX   PubMed=2903587; DOI=10.1016/0041-0101(88)90183-3;
RA   Macek P., Lebez D.;
RT   "Isolation and characterization of three lethal and hemolytic toxins from
RT   the sea anemone Actinia equina L.";
RL   Toxicon 26:441-451(1988).
RN   [3]
RP   REVIEW.
RX   PubMed=19268680; DOI=10.1016/j.toxicon.2009.02.026;
RA   Kristan K.C., Viero G., Dalla Serra M., Macek P., Anderluh G.;
RT   "Molecular mechanism of pore formation by actinoporins.";
RL   Toxicon 54:1125-1134(2009).
CC   -!- FUNCTION: Pore-forming protein that forms cations-selective hydrophilic
CC       pores of around 1 nm and causes cardiac stimulation and hemolysis. Pore
CC       formation is a multi-step process that involves specific recognition of
CC       membrane sphingomyelin (but neither cholesterol nor
CC       phosphatidylcholine) using aromatic rich region and adjacent
CC       phosphocholine (POC) binding site, firm binding to the membrane (mainly
CC       driven by hydrophobic interactions) accompanied by the transfer of the
CC       N-terminal region to the lipid-water interface and finally pore
CC       formation after oligomerization of monomers. Cytolytic effects include
CC       red blood cells hemolysis, platelet aggregation and lysis, cytotoxic
CC       and cytostatic effects on fibroblasts. Lethality in mammals has been
CC       ascribed to severe vasospasm of coronary vessels, cardiac arrhythmia,
CC       and inotropic effects. {ECO:0000250}.
CC   -!- SUBUNIT: Tetramer in the presence of a lipidic interface. Monomer, in
CC       soluble state. {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305}. Nematocyst {ECO:0000305}.
CC       Target cell membrane {ECO:0000250}. Note=Forms an alpha-helical
CC       membrane channel in the prey. {ECO:0000250}.
CC   -!- DOMAIN: The N-terminal region, before the pore is formed, is bound to
CC       the lipid membrane. It partitions into the lipid-water interface and
CC       stabilizes the monomeric molecule on the membrane. Finally, it
CC       traverses the bilayer, thus forming the transmembrane pore.
CC       {ECO:0000250|UniProtKB:P61914}.
CC   -!- TOXIC DOSE: LD(50) is 83 ug/kg by intravenous injection into mice.
CC       {ECO:0000269|PubMed:2903587}.
CC   -!- SIMILARITY: Belongs to the actinoporin family. Sea anemone subfamily.
CC       {ECO:0000305}.
CC   ---------------------------------------------------------------------------
CC   Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms
CC   Distributed under the Creative Commons Attribution (CC BY 4.0) License
CC   ---------------------------------------------------------------------------
DR   AlphaFoldDB; P0C1H2; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR   GO; GO:0042151; C:nematocyst; IEA:UniProtKB-SubCell.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   GO; GO:0044179; P:hemolysis in another organism; IEA:UniProtKB-KW.
DR   GO; GO:0006811; P:ion transport; IEA:UniProtKB-KW.
PE   1: Evidence at protein level;
KW   Cytolysis; Direct protein sequencing; Hemolysis; Ion transport; Membrane;
KW   Nematocyst; Secreted; Target cell membrane; Target membrane; Toxin;
KW   Transmembrane; Transport.
FT   PEPTIDE         1..>20
FT                   /note="Equinatoxin-3"
FT                   /id="PRO_0000244625"
FT   REGION          3..12
FT                   /note="Plays an important role in the hemolytic activity"
FT                   /evidence="ECO:0000250|UniProtKB:P07845"
FT   REGION          11..>20
FT                   /note="N-terminal region"
FT                   /evidence="ECO:0000250|UniProtKB:P61914"
FT   NON_TER         20
SQ   SEQUENCE   20 AA;  1943 MW;  BB32B990183CF5E6 CRC64;
     SVAVAGAIIK GAALTFNVLQ