Photon Melanospin:photon Melanospin is stimulated by light Authored: Jassal, B, 2009-05-07 08:25:16 Edited: Jassal, B, 2009-06-03 Melanopsin (Opsin-4) (Provencio I et al, 2000) is a member of the opsin family encoded by the OPN4 gene. It is found in specialized photosensitive ganglion cells of the retina that are involved in the regulation of circadian rhythms, pupillary light reflex, and other non-visual responses to light. Melanopsin is expressed only in the retina and there, only in 1-2% of the ganglion cells. The effects of melanopsin are mediated by coupling to Gq/11 proteins which results in increased intracellular calcium levels (Qiu X et al, 2005). Pubmed10632589 Pubmed15674243 Reactome Database ID Release 43419861 Reactome, http://www.reactome.org ReactomeREACT_18262 Reviewed: D'Eustachio, P, 2009-05-29 07:44:22