The retinal phototransduction process: enzymatic cascade and regulation.

Among cellular systems performing the transduction of an external stimulus, phototransduction in vertebrate rod cells is a unique case which allows convergent approaches to electrophysiological, biophysical and biochemical analyses. The framework of the molecular processes involved in the corresponding enzymatic cascade is now elucidated and can be considered as a model for G protein mediated transductions. We present here the main features of this cascade, its amplification and regulation properties. The mode of stimulation by the aluminofluoride ion is particularly addressed.