Melanopsin: in vertebrate retina, mediates pupillary reflex, involved in regulation of circadian rhythms Photopsin: reception of various colors of light in the cone cells of vertebrate retina Rhodopsin: green-blue light reception in the rod cells of vertebrate retina Protein Kinase C: mediates photoreceptor deactivation, and retinal degeneration[1] OPN5: sensitive to UV-light[2]