The visual transduction system provides a model for GPCR signaling and inactivation, where rhodopsin activation is quenched through retinal release, photoproduct conversion, and arrestin binding. This study investigated how arrestin influences retinal release and rhodopsin photoproduct dynamics. Fluorescent assays demonstrated a direct link between arrestin binding and retinal release, while acidic phospholipids were found to restore arrestin interaction in purified systems. Arrestin stabilized the active Meta II state and converted Meta III to a Meta II–like form. Findings suggest arrestin plays a broader role in regulating rhodopsin photochemistry and protecting photoreceptor cells beyond simple signal termination.
