Family

Conotoxin, mu-type (IPR008036)

Short name: Conotoxin_mu-typ

Family relationships

None.

Description

This entry represents Mu-type conotoxins. Cone snail toxins, conotoxins, are small peptides with disulphide connectivity, that target ion-channels or G-protein coupled receptors. Based on the number and pattern of disulphide bonds and biological activities, conotoxins can be classified into several families [PMID: 11478951]. Omega, delta and kappa families of conotoxins have a knottin or inhibitor cystine knot scaffold. The knottin scaffold is a very special disulphide through disulphide knot, in which the III-VI disulphide bond crosses the macrocycle formed by two other disulphide bonds (I-IV and II-V) and the interconnecting backbone segments, where I-VI indicates the six cysteine residues starting from the N terminus.

The disulphide bonding network as well as specific amino acids in inter-cysteine loops provide specificity of conotoxin [PMID: 10988292]. The cysteine arrangement is the same for omega, delta and kappa families, but omega conotoxins are calcium channel blockers, whereas delta conotoxins delay the inactivation of sodium channels and kappa conotoxins are potassium channel blockers [PMID: 11478951]. Mu conotoxins have two types of cysteine arrangement, but the knottin scaffold is not observed. Conotoxin gm9a, a putative 27-residue polypeptide encoded by Conus gloriamaris, has been shown to adopt an inhibitory cystine knot motif constrained by three disulphide bonds [PMID: 12006587, PMID: 12193600].Mu conotoxins target the voltage-gated sodium channels, preferential skeletal muscle [PMID: 11478951], and are useful probes for investigating voltage-dependent sodium channels of excitable tissues [PMID: 2410412]. Alpha conotoxins have two types of cysteine arrangement [PMID: 1390774] and are competitive nicotinic acetylcholine receptor antagonists.

GO terms

Biological Process

GO:0009405 pathogenesis

Molecular Function

GO:0019871 sodium channel inhibitor activity

Cellular Component

GO:0005576 extracellular region

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns
Pfam