ACTP4_ACTEQ
ID ACTP4_ACTEQ Reviewed; 214 AA.
AC Q9Y1U9;
DT 01-DEC-2000, integrated into UniProtKB/Swiss-Prot.
DT 01-NOV-1999, sequence version 1.
DT 03-AUG-2022, entry version 100.
DE RecName: Full=DELTA-actitoxin-Aeq1c {ECO:0000303|PubMed:22683676};
DE Short=DELTA-AITX-Aeq1c {ECO:0000303|PubMed:22683676};
DE AltName: Full=Equinatoxin IV {ECO:0000303|PubMed:10414864};
DE Short=EqT IV;
DE Short=EqTIV {ECO:0000303|PubMed:10414864};
DE AltName: Full=Equinatoxin-4 {ECO:0000305};
DE Flags: Precursor;
OS Actinia equina (Beadlet anemone).
OC Eukaryota; Metazoa; Cnidaria; Anthozoa; Hexacorallia; Actiniaria;
OC Actiniidae; Actinia.
OX NCBI_TaxID=6106;
RN [1]
RP NUCLEOTIDE SEQUENCE [MRNA].
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 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).
RN [3]
RP NOMENCLATURE.
RX PubMed=22683676; DOI=10.1016/j.toxicon.2012.05.020;
RA Oliveira J.S., Fuentes-Silva D., King G.F.;
RT "Development of a rational nomenclature for naming peptide and protein
RT toxins from sea anemones.";
RL Toxicon 60:539-550(2012).
CC -!- FUNCTION: Pore-forming protein that forms cations-selective hydrophilic
CC pores of around 1 nm and causes hemolysis. Pore formation is a multi-
CC step process that involves specific recognition of membrane
CC sphingomyelin (but neither cholesterol nor phosphatidylcholine) using
CC aromatic rich region and adjacent phosphocholine (POC) binding site,
CC firm binding to the membrane (mainly driven by hydrophobic
CC interactions) accompanied by the transfer of the N-terminal region to
CC the lipid-water interface and finally pore formation after
CC oligomerization of monomers.
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. Note=Forms an alpha-helical membrane channel in
CC the prey.
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 -!- SIMILARITY: Belongs to the actinoporin family. Sea anemone subfamily.
CC {ECO:0000305}.
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DR EMBL; AF057028; AAD39836.1; -; mRNA.
DR AlphaFoldDB; Q9Y1U9; -.
DR SMR; Q9Y1U9; -.
DR EnsemblMetazoa; EGACTEQ4350022204-RA; EGACTEQ4350022204-PA; EGACTEQ4350022204.
DR EnsemblMetazoa; EGACTEQ4350022204-RB; EGACTEQ4350022204-PB; EGACTEQ4350022204.
DR GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR GO; GO:0042151; C:nematocyst; IEA:UniProtKB-SubCell.
DR GO; GO:0046930; C:pore complex; IEA:InterPro.
DR GO; GO:0015267; F:channel activity; IEA:InterPro.
DR GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR GO; GO:0006812; P:cation transport; IEA:InterPro.
DR GO; GO:0044179; P:hemolysis in another organism; IEA:UniProtKB-KW.
DR GO; GO:0046931; P:pore complex assembly; IEA:InterPro.
DR Gene3D; 2.60.270.20; -; 1.
DR InterPro; IPR009104; Anemon_actinoporin-like.
DR InterPro; IPR015926; Cytolysin/lectin.
DR Pfam; PF06369; Anemone_cytotox; 1.
DR SUPFAM; SSF63724; SSF63724; 1.
PE 2: Evidence at transcript level;
KW Cleavage on pair of basic residues; Cytolysis; Hemolysis; Ion transport;
KW Membrane; Nematocyst; Secreted; Signal; Target cell membrane;
KW Target membrane; Toxin; Transmembrane; Transport.
FT SIGNAL 1..19
FT /evidence="ECO:0000255"
FT PROPEP 20..35
FT /evidence="ECO:0000250"
FT /id="PRO_0000034832"
FT CHAIN 36..214
FT /note="DELTA-actitoxin-Aeq1c"
FT /id="PRO_0000034833"
FT REGION 38..47
FT /note="Plays an important role in the hemolytic activity"
FT /evidence="ECO:0000250|UniProtKB:P07845"
FT REGION 46..65
FT /note="N-terminal region"
FT /evidence="ECO:0000250|UniProtKB:P61914"
FT REGION 140..155
FT /note="Trp-rich region, which is important for the binding
FT to lipid membrane"
FT /evidence="ECO:0000250|UniProtKB:P61914"
FT MOTIF 179..181
FT /note="Cell attachment site"
FT /evidence="ECO:0000255"
FT BINDING 89
FT /ligand="phosphocholine"
FT /ligand_id="ChEBI:CHEBI:295975"
FT /evidence="ECO:0000250|UniProtKB:P07845"
FT BINDING 122
FT /ligand="phosphocholine"
FT /ligand_id="ChEBI:CHEBI:295975"
FT /evidence="ECO:0000250|UniProtKB:P07845"
FT BINDING 140
FT /ligand="phosphocholine"
FT /ligand_id="ChEBI:CHEBI:295975"
FT /evidence="ECO:0000250|UniProtKB:P07845"
FT BINDING 142
FT /ligand="phosphocholine"
FT /ligand_id="ChEBI:CHEBI:295975"
FT /evidence="ECO:0000250|UniProtKB:P07845"
FT BINDING 168
FT /ligand="phosphocholine"
FT /ligand_id="ChEBI:CHEBI:295975"
FT /evidence="ECO:0000250|UniProtKB:P07845"
FT BINDING 172
FT /ligand="phosphocholine"
FT /ligand_id="ChEBI:CHEBI:295975"
FT /evidence="ECO:0000250|UniProtKB:P07845"
FT BINDING 173
FT /ligand="phosphocholine"
FT /ligand_id="ChEBI:CHEBI:295975"
FT /evidence="ECO:0000250|UniProtKB:P07845"
FT SITE 147
FT /note="Important in the initial contact with the lipid
FT membrane"
FT /evidence="ECO:0000250|UniProtKB:P61914"
FT SITE 148
FT /note="Important in the initial contact with the lipid
FT membrane"
FT /evidence="ECO:0000250|UniProtKB:P61914"
FT SITE 179
FT /note="Interacts with the lipid membrane"
FT /evidence="ECO:0000250|UniProtKB:P61914"
FT SITE 195
FT /note="Interacts with the lipid membrane"
FT /evidence="ECO:0000250|UniProtKB:P61914"
SQ SEQUENCE 214 AA; 23792 MW; 2FE01464C6525808 CRC64;
MSRLIIVFIV VSMICSATAL PSKKIIDEDE KDEKRSVAVA GAIIKGAALT FNVLQTVLKA
LGDISRKIAV GVDNESGKTW TALNTYFRSG TSDIVLPHKV PHGKALLYNG QKDRGPVATG
AVGVLAYAMS DGNTLAVLFS VPYDYNWYSN WWNVRIFKGR RRADQRMYEQ LYYYLSPFRG
DNGWHERHLG YGLKSRGFMN SGGQAILEIH VTKA
