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. Author manuscript; available in PMC: 2018 Oct 6.
Published in final edited form as: Annu Rev Cell Dev Biol. 2017 Jun 9;33:241–264. doi: 10.1146/annurev-cellbio-100616-060432

Table 2. Classification and expression of selected vertebrate opsins.

The opsins belong to three main opsin classes (c-opsin, r-opsin, RGR/Go-opsins). The opsin names that are based on the human isoforms are indicated (*). An X denotes opsins expressed in humans, rodents, teleosts, and birds. The ocular and extra-ocular cell types or tissues expressing a given opsin are listed, along with the animal in parenthesis: B, bird; H, human; R, rodent; T, teleost. Additional abbreviations: HC, horizontal cells; ipRGC, intrinsically photosensitive retinal ganglion cells; LW, long-wave; MW, medium-wave; OS, outer segment; RGR, retinal G protein-coupled receptor opsin; RPE, retinal pigment epithelium; RRH, retinal pigment epithelium-derived rhodopsin homolog; SW, short-wave; TMT, teleost multiple tissue; VA, vertebrate ancient; VAL, vertebrate ancient long.

Group G protein Name Other name (s) Animal Expression
Human Rodent Teleost Bird Ocular Extra-ocular
c-opsin (ciliary) Gt rhodopsin* × × × × rods (H) skin (H,R), pineal (R), sperm (H,R)
Gt OPN1-SW* blue opsin × × × × cones (H) skin (H,R), pineal (R), sperm (H,R)
Gt
Gs 		OPN1-MW* green opsin × × × × cones (H) skin (H), sperm (H,R)
erythrophore (T)
Gt OPN1-LW* red opsin × × × cones (H) skin (H)
Gi/Go OPN3* encephalopsin
panopsin
TMT		 × × × × retina (H,R), HC (B), interneurons (T) brain (R,T), spinal cord, skin, testis (R), sperm (H,R), pineal, heart (T), placenta (H), kidney, liver (H,T)
Gt/Ggust OPNP pinopsin
pineal opsin		 × retina OS (gecko) pineal (B, gecko, lizard)
Gi parapinopsin × parapineal, pineal, testis (T)
Gi VA-opsin VAL-opsin × × HC (T), iris (T) brain (T,B), ovary (T)
Go parietopsin × parietal eye (lizard)
r-opsin (rhabdomeric) Gq OPN4* melanopsin × × × × ipRGCs (H,R), cones (H), HC (T,B), RPE (frog), iris (frog), cornea (frog) brain (H,T,B), trigeminal ganglia (H,R), skin (R, frog), blood vessels (R), pineal (B), sperm (H,R)
RGR/Go -opsins RGR opsin* × × × × RPE, Müller cells (bovine) brain (T,B), pineal (B), liver (T)
peropsin* RRH × × × × RPE (H), ganglion cells (B) brain (B), skin (H), pineal (B)
Gi OPN5* neuropsin Gpr136, PGR12, TMEM13 × × × × retina (H,R) brain (H,R,B), spinal cord (H,R), skin (R), sperm (H,R), testis (H,R), outer ears (R), adrenal gland (B)