Regulator of G protein-coupled receptor (GPCR) signaling in phototransduction. Participates in the recovery phase of visual transduction via its interaction with RGS9-1 isoform. Acts as a membrane-anchor that mediates the targeting of RGS9-1 to the photoreceptor outer segment, where phototransduction takes place. Enhances the ability of RGS9-1 to stimulate G protein GTPase activity, allowing the visual signal to be terminated on the physiologically time scale. It also controls the proteolytic stability of RGS9-1, probably by protecting it from degradation (By similarity). . This is the function of ENSG00000186326 (RGS9BP, regulator of G protein signaling 9 binding protein).