title: Jellyfish vision starts with cAMP signaling mediated by opsin-G(s) cascade.
abstract: Light sensing starts with phototransduction in photoreceptor cells. The phototransduction cascade has diverged in different species, such as those mediated by transducin in vertebrate rods and cones, by G(q)-type G protein in insect and molluscan rhabdomeric-type visual cells and vertebrate photosensitive retinal ganglion cells, and by G(o)-type G protein in scallop ciliary-type visual cells. Here, we investigated the phototransduction cascade of a prebilaterian box jellyfish, the most basal animal having eyes containing lens and ciliary-type visual cells similar to vertebrate eyes, to examine the similarity at the molecular level and to obtain an implication of the origin of the vertebrate phototransduction cascade. We showed that the opsin-based pigment functions as a green-sensitive visual pigment and triggers the G(s)-type G protein-mediated phototransduction cascade in the ciliary-type visual cells of the box jellyfish lens eyes. We also demonstrated the light-dependent cAMP increase in the jellyfish visual cells and HEK293S cells expressing the jellyfish opsin. The first identified prebilaterian cascade was distinct from known phototransduction cascades but exhibited significant partial similarity with those in vertebrate and molluscan ciliary-type visual cells, because all involved cyclic nucleotide signaling. These similarities imply a monophyletic origin of ciliary phototransduction cascades distributed from prebilaterian to vertebrate.
authors.affiliation: Department of Biology and Geosciences, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto-cho, Sumiyoshi-ku, Osaka 558-8585, Japan. koyanagi@sci.osaka-cu.ac.jp
authors.forename: Mitsumasa
authors.initials: M
authors.lastname: Koyanagi
authors.forename: Kosuke
authors.initials: K
authors.lastname: Takano
authors.forename: Hisao
authors.initials: H
authors.lastname: Tsukamoto
authors.forename: Kohzoh
authors.initials: K
authors.lastname: Ohtsu
authors.forename: Fumio
authors.initials: F
authors.lastname: Tokunaga
authors.forename: Akihisa
authors.initials: A
authors.lastname: Terakita
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D037462:Cubozoa / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism*; D019143:Evolution, Molecular; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000378:metabolism*; D006801:Humans; D055537:Light Signal Transduction; D008969:Molecular Sequence Data; D055355:Opsins / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D017949:Retinal Cone Photoreceptor Cells / Q000378:metabolism; D017948:Retinal Rod Photoreceptor Cells / Q000378:metabolism
chemical_list: D055355:Opsins; D000242:Cyclic AMP; D019205:GTP-Binding Protein alpha Subunits, Gs