ACTP_STIME
ID ACTP_STIME Reviewed; 40 AA.
AC P0DMX4;
DT 22-JUL-2015, integrated into UniProtKB/Swiss-Prot.
DT 22-JUL-2015, sequence version 1.
DT 25-MAY-2022, entry version 17.
DE RecName: Full=Cytolysin SmT-1 {ECO:0000303|PubMed:10665806};
DE AltName: Full=DELTA-stichotoxin {ECO:0000305};
DE AltName: Full=SmT-2 {ECO:0000303|PubMed:10665806};
DE Flags: Fragment;
OS Stichodactyla mertensii (Merten's carpet sea anemone).
OC Eukaryota; Metazoa; Cnidaria; Anthozoa; Hexacorallia; Actiniaria;
OC Stichodactylidae; Stichodactyla.
OX NCBI_TaxID=645706;
RN [1]
RP PROTEIN SEQUENCE, AND FUNCTION.
RX PubMed=10665806; DOI=10.1016/s0041-0101(99)00154-3;
RA Samejima Y., Yanagisawa M., Aoki-Tomomatsu Y., Iwasaki E., Ando J.,
RA Mebs D.;
RT "Amino acid sequence studies on cytolytic toxins from sea anemone
RT Heteractis magnifica, Entacmaea quadricolor and Stichodactyla mertensii
RT (Anthozoa).";
RL Toxicon 38:259-264(2000).
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).
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 (By similarity). This toxin
CC shows hemolytic activities (PubMed:10665806).
CC {ECO:0000250|UniProtKB:Q9U6X1, ECO:0000269|PubMed:10665806}.
CC -!- SUBUNIT: Tetramer in the presence of a lipidic interface. Monomer, in
CC soluble state. {ECO:0000250}.
CC -!- SUBCELLULAR LOCATION: Secreted {ECO:0000250|UniProtKB:Q9U6X1}.
CC Nematocyst {ECO:0000250|UniProtKB:Q9U6X1}. Target cell membrane
CC {ECO:0000250|UniProtKB:Q9U6X1}. Note=Forms an alpha-helical membrane
CC channel in the prey. {ECO:0000250|UniProtKB:Q9U6X1}.
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}.
CC -!- CAUTION: A second toxin (SmT-2) has been reported which has been
CC sequenced up to residue 24 and only differs by two residues that are
CC missing (see conflict in the feature table).
CC {ECO:0000305|PubMed:10665806}.
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DR AlphaFoldDB; P0DMX4; -.
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 1: Evidence at protein level;
KW Cleavage on pair of basic residues; Cytolysis; Direct protein sequencing;
KW Hemolysis; Ion transport; Membrane; Nematocyst; Secreted;
KW Target cell membrane; Target membrane; Toxin; Transmembrane; Transport.
FT CHAIN 1..>40
FT /note="Cytolysin SmT-1"
FT /id="PRO_0000433583"
FT REGION 3..12
FT /note="Plays an important role in the hemolytic activity"
FT /evidence="ECO:0000250|UniProtKB:P07845"
FT REGION 11..30
FT /note="N-terminal region"
FT /evidence="ECO:0000250|UniProtKB:P61914"
FT CONFLICT 25
FT /note="Missing (in Ref. 1; AA sequence)"
FT /evidence="ECO:0000305"
FT CONFLICT 27
FT /note="Missing (in Ref. 1; AA sequence)"
FT /evidence="ECO:0000305"
FT NON_TER 40
SQ SEQUENCE 40 AA; 3983 MW; 5F9F10A1FC871E88 CRC64;
SAALAGTIIA GASLGFQILD KVLGELGKVS RKIAVGVDNE
