Ryanodine receptor acts as a sensor for redox stress.

Ryanoids have not attained importance as insecticides, but the increasing number of xenobiotic effectors known to influence Ca2+ signalling by interaction with ryanodine receptors (RyRs) may serve to identify new targets for insect control. A historical review of redox control of microsomal Ca2+ transport is given here, followed by recent evidence indicating that hyperactive Cys residues are an essential component of a transmembrane redox sensor. Focus is on the role of sulfhydryl chemistry in RyR regulation; metabolic quinonoid intermediates from pesticides and other environmental contaminants are of interest in this context.