ID   CLKTX_ISOMC             Reviewed;          57 AA.
AC   P0DJL0;
DT   03-APR-2013, integrated into UniProtKB/Swiss-Prot.
DT   03-APR-2013, sequence version 1.
DT   25-MAY-2022, entry version 15.
DE   RecName: Full=Potassium channel toxin KTx1 {ECO:0000303|PubMed:21308893};
DE            Short=ImKTx1 {ECO:0000303|PubMed:21308893};
DE   Flags: Precursor; Fragment;
OS   Isometrus maculatus (Lesser brown scorpion) (Scorpio maculatus).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Buthida; Buthoidea; Buthidae; Isometrus.
OX   NCBI_TaxID=497827;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], SYNTHESIS, AND FUNCTION.
RC   TISSUE=Venom gland;
RX   PubMed=21308893; DOI=10.1002/jbt.20382;
RA   Chen Z., Hu Y., Han S., Yin S., He Y., Wu Y., Cao Z., Li W.;
RT   "ImKTx1, a new Kv1.3 channel blocker with a unique primary structure.";
RL   J. Biochem. Mol. Toxicol. 25:244-251(2011).
CC   -!- FUNCTION: This recombinant peptide inhibits voltage-gated potassium
CC       channels mKv1.3/KCNA3 (IC(50)=1.70 uM), mKv1.1/KCNA1 (10 uM inhibits
CC       40% of currents) and hKv1.2/KCNA2 (10 uM inhibits 42% of currents)
CC       (PubMed:21308893). May also increase intracellular calcium release
CC       through the activation of nuclear inositol 1,4,5-trisphosphate
CC       receptors (ITPR) of cardiomyocytes, thereby causing an increase in the
CC       contraction frequency of these cells (By similarity).
CC       {ECO:0000250|UniProtKB:P0DM29, ECO:0000269|PubMed:21308893}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305|PubMed:21308893}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:21308893}.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin.
CC       {ECO:0000250|UniProtKB:P59868}.
CC   -!- MISCELLANEOUS: Does not show effect on rNav1.2/SCN2A and mNav1.4/SCN4A.
CC       {ECO:0000269|PubMed:21308893}.
CC   -!- SIMILARITY: Belongs to the scorpion calcin-like family. KTX subfamily.
CC       {ECO:0000305}.
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DR   AlphaFoldDB; P0DJL0; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0015459; F:potassium channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
PE   2: Evidence at transcript level;
KW   Disulfide bond; Ion channel impairing toxin; Knottin; Neurotoxin;
KW   Potassium channel impairing toxin; Secreted; Signal; Toxin.
FT   SIGNAL          <1..13
FT                   /evidence="ECO:0000250"
FT   PROPEP          14..18
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000422065"
FT   CHAIN           19..57
FT                   /note="Potassium channel toxin KTx1"
FT                   /id="PRO_0000422066"
FT   DISULFID        24..37
FT                   /evidence="ECO:0000250|UniProtKB:P59868"
FT   DISULFID        30..42
FT                   /evidence="ECO:0000250|UniProtKB:P59868"
FT   DISULFID        36..51
FT                   /evidence="ECO:0000250|UniProtKB:P59868"
FT   NON_TER         1
SQ   SEQUENCE   57 AA;  6486 MW;  E93D5DEDFDEA0967 CRC64;
     FLVLLLVSLM CYAEIAEGSQ PTECKYGRPC NSDRDCCWEY RCLSSGREYT CKQDPGP