Table 3. Classification and expression of selected invertebrate opsins.
nvertebrate c-opsin, r-opsin, RGR/Go-opsins, and cnidops. The opsin names based on Drosophila are indicated (*). Expression of opsins in flies, mosquitoes, and squid are indicated with an X. The ocular and extra-ocular expression of the opsins is indicated followed by the animal or animal group: F, fly; M, mosquito; Oc, Onychophora (velvet worm); S, squid. Additional abbreviations: IS, inner segment; OS, outer segment; PNS, peripheral nervous system.
| Group | G protein | Name | Other name (s) | Animal Expression | ||||
|---|---|---|---|---|---|---|---|---|
| Fly | Mosquito | Squid | Ocular | Extra-ocular | ||||
| c-opsin (ciliary) | c-opsin | GPROP12 (M) | × | eye (Oc) | brain (spider, Oc), pedicellariae (urchin) | |||
| Gi/Go | pteropsin | brain (honey bee) | ||||||
| Platynereis c-opsin |
brain (ragworm) | |||||||
| r-opsin (rhabdomeric) | Gq | Rh1* | × | × | R1–R6 (F) | PNS (F) | ||
| Gq | Rh2* | × | ocelli (F) | testis (F) | ||||
| Gq | Rh3* | × | × | R7 (F) | ||||
| Gq | Rh4* | × | R7 (F) | |||||
| Gq | Rh5* | × | × | R8 (F) | Johnston’s organ, brain, PNS (F) | |||
| Gq | Rh6* | × | × | R8 (F) | Johnston’s organ, brain, PNS (F) | |||
| Rh7* | × | × | brain (F) | |||||
| r-opsin | onychopsin (Oc) | retina OS (S), eye (Oc) | brain (butterfly, Oc), nerve cord, tail (crayfish), skin (S, octopus), tube feet, pedicellariae (urchin), light organ et al. (S), genitalia (butterfly) | |||||
| melanopsin | neural tube (amphioxus) | |||||||
| arthropsin | brain (spider, Oc), ventral nerve cord (Oc) | |||||||
| RGR/Go-opsins | retinochrome | × | retina IS, OS (S) | parolfactory vesicles et al. (S) | ||||
| RGR opsin | Ci-opsin3 (tunicate) | ocelli (tunicate) | ||||||
| peropsin | non-visual cells (spider) | brain (spider, horseshoe crab), abdomen (krill) | ||||||
| Go | Go-opsin | retina (scallop) | tube feet, pedicellariae (urchin) | |||||
| cnidops | Gq/Gs | lens eye (jellyfish) | neuropil (jellyfish), battery complex (hydra) | |||||