ID   CTXI4_MESEU             Reviewed;          35 AA.
AC   P60269;
DT   16-JAN-2004, integrated into UniProtKB/Swiss-Prot.
DT   16-JAN-2004, sequence version 1.
DT   03-AUG-2022, entry version 51.
DE   RecName: Full=Insectotoxin-I4 {ECO:0000303|PubMed:9891977};
DE   AltName: Full=BeI4;
OS   Mesobuthus eupeus (Lesser Asian scorpion) (Buthus eupeus).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Buthida; Buthoidea; Buthidae; Mesobuthus.
OX   NCBI_TaxID=34648;
RN   [1]
RP   PROTEIN SEQUENCE, AND SUBCELLULAR LOCATION.
RC   TISSUE=Venom;
RX   PubMed=9891977; DOI=10.1016/s0014-5793(98)01589-0;
RA   Tytgat J., Debont T., Rostoll K., Mueller G.J., Verdonck F., Daenens P.,
RA   van der Walt J.J., Possani L.D.;
RT   "Purification and partial characterization of a 'short' insectotoxin-like
RT   peptide from the venom of the scorpion Parabuthus schlechteri.";
RL   FEBS Lett. 441:387-391(1998).
CC   -!- FUNCTION: Toxin with unknown function in healthy organisms. On glioma
CC       cells, interacts with chloride channels (probably ClC-3/CLCN3) and MMP2
CC       at the surface of glioma cells. This complex is then internalized via
CC       caveolae, thus inhibiting the chloride channels necessary for cell
CC       shrinkage and tumor propagation (By similarity).
CC       {ECO:0000250|UniProtKB:Q9UAD0}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:9891977}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:9891977}.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin.
CC       {ECO:0000250|UniProtKB:P15222}.
CC   -!- MISCELLANEOUS: The protein sequence was deduced by comparison to other
CC       short insectotoxin sequences.
CC   -!- SIMILARITY: Belongs to the short scorpion toxin superfamily. Chloride
CC       channel inhibitor family. {ECO:0000255|PROSITE-ProRule:PRU00545}.
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DR   AlphaFoldDB; P60269; -.
DR   SMR; P60269; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0017081; F:chloride channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   InterPro; IPR036574; Scorpion_toxin-like_sf.
DR   InterPro; IPR007958; Scorpion_toxinS_Cl_inh.
DR   Pfam; PF05294; Toxin_5; 1.
DR   SUPFAM; SSF57095; SSF57095; 1.
DR   PROSITE; PS51200; SHORT_SCORPION_CHLORIDE; 1.
PE   1: Evidence at protein level;
KW   Chloride channel impairing toxin; Direct protein sequencing;
KW   Disulfide bond; Ion channel impairing toxin; Knottin; Secreted; Toxin;
KW   Voltage-gated chloride channel impairing toxin.
FT   PEPTIDE         1..35
FT                   /note="Insectotoxin-I4"
FT                   /evidence="ECO:0000269|PubMed:9891977"
FT                   /id="PRO_0000044937"
FT   DISULFID        2..19
FT                   /evidence="ECO:0000250|UniProtKB:P15222,
FT                   ECO:0000255|PROSITE-ProRule:PRU00545"
FT   DISULFID        5..26
FT                   /evidence="ECO:0000250|UniProtKB:P15222,
FT                   ECO:0000255|PROSITE-ProRule:PRU00545"
FT   DISULFID        16..31
FT                   /evidence="ECO:0000250|UniProtKB:P15222,
FT                   ECO:0000255|PROSITE-ProRule:PRU00545"
FT   DISULFID        20..33
FT                   /evidence="ECO:0000250|UniProtKB:P15222,
FT                   ECO:0000255|PROSITE-ProRule:PRU00545"
SQ   SEQUENCE   35 AA;  3875 MW;  47CBE8190B64318F CRC64;
     MCMPCFTTDH NMAKKCRDCC GGNGKCFGPQ CLCNR