A variant of arrestin-1 binds rod outer segment membranes in a light-independent manner

► A 50-kDa variant of arrestin-1 that is peripherally bound to ROS membranes is reported. ► The 50-kDa protein interacted with the ROS membranes in a light-independent manner, either in the presence or absence of ATP. ► Phosphorylated and illuminated rhodopsin is not the membrane anchor for this variant of arrestin-1. ► The 50-kDa protein was phosphorylated by both Ser/Thr and Tyr kinases.