A physiological role for the supramolecular organization of rhodopsin and transducin in rod photoreceptors

摘要: Vertebrate vision in rod photoreceptors begins when a photon hits the visual pigment rhodopsin (Rh) and triggers phototransduction cascade. Although fine biochemical biophysical details of this paradigmatic signalling pathway have been studied for decades, still presents unclear mechanistic aspects. Increasing lines evidence suggest that is natively organized dimers on surface disc membranes, may form higher order “paracrystalline” assemblies, which are not easy to reconcile with classical collision-coupling scenario evoked explain extremely fast molecular processes required phototransduction. The questioned criticized existence paracrystalline Rh rafts can be fully accepted only if it explained functional terms by solid picture. Here we discuss how recent data physiological role supramolecular assemblies its cognate G protein transducin (Gt), forming transient complexes dark ensure rapid activation cascade even crowded environment that, according picture, would otherwise stop