InterPro : IPR003582

Name  ShKT domain Short Name  ShKT_dom
Type  Domain Description  BgK, a 37-residue peptide toxin from the sea anemone Bunodosoma granulifera, and ShK, a 35-residue peptide toxin from the sea anemone Stichodactyla helianthus, are potent inhibitors of K(+) channels. There is a large superfamily of proteins that contains domains (referred to as ShKT domains) ressembling these two toxins. Many of these proteins are metallopeptidases, whereas others are prolyl-4-hydroxylases, tyrosinases, peroxidases, oxidoreductases, or proteins containing epidermal growth factor-like domains, thrombospondin-type repeats, or trypsin-like serine protease domains []. The ShKT domain has also been called NC6 (nematode six-cysteine) domain [], SXC (six-cysteine) domain [, , , ]and ICR (ion channel regulator) [, ]. The ShKT domain is short (36 to 42 amino acids), with six conserved cysteines and a number of other conserved residues. The fold adopted by the ShKT domain contains two nearly perpendicular stretches of helices, with no additional canonical secondary structures []. The globular architecture of the ShKT domain is stabilised by three disulfides, one of them linking the two helices. In venomous creatures, the ShKT domain may have been modified to give rise to potent ion channel blockers, whereas the incorporation of this domain into plant oxidoreductases and prolyl hydroxylases and into worm astacin-like metalloproteases and trypsin-like serines protaeses produced enzymes with potential channel-modulatory activity.Some proteins known to contain a ShKT domain are listed below:Caribbean sea anemone ShK, a potassium channel toxin []. Sea anemone BgK, a potassium channel toxin [].Toxocara canis family of secreted mucins Tc-MUC-1 to -5, which are implicated in immune evasion. They combine two evolutionarily distinct modules, the mucin and ShkT domains [, ].Some Caenorhabditis elegans astacin-like proteins (nematode astacins, NAS), metalloproteases [].Vertebrate cysteine-rich secretory proteins (Crisp) []. Mammalian microfibrillar-associated protein 2 (MFAP2 or MAGP1), a matrix protein.Plant prolyl 4-hydroxylase.

Sequence Features

GO Displayer


InterPro protein domain ID --> Contigs



0 Child Features

0 Contains

2 Found In

Id Name Short Name Type
IPR017367 Peptidase M12A, nematode astacin 7/8 Peptidase_M12A_astacin-7/8 Family
IPR017368 Peptidase M12A, nematode astacin 9/10/11 Peptidase_M12A_astacin-9/10/11 Family

0 Parent Features

8 Publications

First Author Title Year Journal Volume Pages
Gibbs GM The cysteine-rich secretory protein domain of Tpx-1 is related to ion channel toxins and regulates ryanodine receptor Ca2+ signaling. 2006 J Biol Chem 281 4156-63
Castañeda O Characterization of a potassium channel toxin from the Caribbean Sea anemone Stichodactyla helianthus. 1995 Toxicon 33 603-13
Dauplais M On the convergent evolution of animal toxins. Conservation of a diad of functional residues in potassium channel-blocking toxins with unrelated structures. 1997 J Biol Chem 272 4302-9
Möhrlen F The astacin protein family in Caenorhabditis elegans. 2003 Eur J Biochem 270 4909-20
Rangaraju S Potassium channel modulation by a toxin domain in matrix metalloprotease 23. 2010 J Biol Chem 285 9124-36
Loukas A A family of secreted mucins from the parasitic nematode Toxocara canis bears diverse mucin domains but shares similar flanking six-cysteine repeat motifs. 2000 J Biol Chem 275 39600-7
Doedens A A cDNA encoding Tc-MUC-5, a mucin from Toxocara canis larvae identified by expression screening. 2001 Acta Trop 79 211-7
Blaxter M Caenorhabditis elegans is a nematode. 1998 Science 282 2041-6

To cite PlanMine, please refer to the following publication:

Rozanski, A., Moon, H., Brandl, H., Martín-Durán, J. M., Grohme, M., Hüttner, K., Bartscherer, K., Henry, I., & Rink, J. C.
PlanMine 3.0—improvements to a mineable resource of flatworm biology and biodiversity
Nucleic Acids Research, gky1070. doi:10.1093/nar/gky1070 (2018)