FEATURES

FAMILY

DESCRIPTION

Also known as O16E_CONCT, O16E. Omega-conotoxins act at presynaptic membranes, they bind and block voltage-gated calcium channels. This toxin blocks N-type calcium channels (Cav2.2/CACNA1B). It shows a higher potency when Cav2.2/CACNA1B is only expressed with the ancillary subunit CACNB3 (IC(50)=0.12 nM) than on Cav2.2/CACNA1B expressed with the ancillary subunits CACNA2D1 and CACNB3 (IC(50)=2.6 nM). The Cav2.2/CACNA1B block by this toxin is voltage-independent, whereas the recovery from toxin block is voltage-dependent (PubMed:19892914). There is a low recovery at physiological membrane potential and a high recovery with hyperpolarized potential (PubMed:19892914). This indicates that the toxin has a higher affinity for Cav2.2/CACNA1B in the inactivated state (PubMed:19892914). It is noteworthy that ancillary subunits beta modulate recovery from this toxin block (PubMed:19892914). Cav2.2/CACNA1B expressed with the ancillary subunit CACNB2a (isoform 2a) almost recover completely from this toxin block, whereas Cav2.2/CACNA1B expressed with CACNB3 exhibits relatively weak recovery (PubMed:19892914). Inhibition by this toxin of excitatory synaptic transmission is reversible (PubMed:19892914). In vivo, when tested on rat model of persistent pain, this toxin blocks chronic pain behavior (PubMed:19892914).

EXTERNAL LINKS

O16E

Omega conotoxin-CVIE

O16E

Molecular Synopsis