Mu-conotoxin KIIIB

UniProtKB accession:  P0C195

Grouped By:  Matching UniProtKB accession

UniProtKB description:  Mu-conotoxin KIIIA-P1: mu-conotoxins block voltage-gated sodium channels (Nav). This toxin potently blocks Nav1.2/SCN2A (IC(50)5-124 nM), Nav1.4/SCN4A (IC(50)=20-90 nM), and Nav1.7/SCN9A (IC(50)=290-413 nM) (PubMed:17724025, PubMed:19221510, PubMed:21652775, PubMed:21709136, PubMed:21781281, PubMed:23146020, PubMed:25658507, PubMed:35167877). It moderately blocks Nav1.1/SCN1A, and mNav1.6/SCN8A (PubMed:17724025, PubMed:21652775, PubMed:21709136, PubMed:21781281, PubMed:23146020, PubMed:25658507, PubMed:35167877). It also shows a very low activity on Nav1.3/SCN3A (PubMed:17724025, PubMed:21781281). This toxin binds a microsite within the pore different from the tetrodotoxin binding site 1 (tested on Nav1.2) (PubMed:19221510). The block is partial, with a residual current that can be completely blocked by TTX (PubMed:19221510). The toxin probably docks at a more superficial site in the outer vestibule of the channel than does TTX (PubMed:19221510). On rNav1.2/SCN2A, it produces a block that is only partially reversible. The block of Nav1.7 is modified when beta-subunits are coexpressed with the alpha subunit (PubMed:23146020). Hence, blocks of channels containing beta-1 and beta-3 subunits are more potent (compared to channels without beta subunits), whereas blocks of channels containing beta-2 and beta-4 subunits are less potent (compared to channels without beta subunits) (PubMed:23146020).