In retinal rods the receptor rhodopsin and visual arrestin are at the interlink between three modular functions, namely, G protein coupled signaling, receptor regeneration and translocation of proteins. We want to study how the channeling of the retinal ligand during rhodopsin regeneration works. Main goals are the characterization of the retinal entrance and exit routes and the role of protein flexibility in retinal channeling. We also want to explore the interplay between retinal release and arrestin binding, in order to understand how arrestin protects the rod cell from toxic levels of all-trans-retinal