{"doi":"10.1152/jn.01066.2007","title":"Melanopsin Ganglion Cells Use a Membrane-Associated Rhabdomeric Phototransduction Cascade","abstract":"<jats:p>Intrinsically photosensitive retinal ganglion cells (ipRGCs) are photoreceptors of the mammalian eye that drive pupillary responses, synchronization of circadian rhythms, and other reflexive responses to daylight. Melanopsin is the ipRGC photopigment, but the signaling cascade through which this invertebrate-like opsin triggers the photocurrent in these cells is unknown. Here, using patch-clamp recordings from dissociated ipRGCs in culture, we show that a membrane-associated phosphoinositide cascade lies at the heart of the ipRGC phototransduction mechanism, similar to the cascade in rhabdomeric photoreceptors of invertebrate eyes. When ipRGCs were illuminated, melanopsin activated a G protein of the G<jats:sub>q/11</jats:sub>class, stimulating the effector enzyme phospholipase C. The presence of these signaling components in ipRGCs was confirmed by single-cell RT-PCR and immunofluorescence. The photoresponse was fully functional in excised inside-out patches of ipRGC membrane, indicating that all core signaling components are within or tightly coupled to the plasma membrane. The striking similarity of phototransduction in ipRGCs and invertebrate rhabdomeric photoreceptors reinforces the emerging view that these cells have a common evolutionary origin.</jats:p>","journal":"Journal of Neurophysiology","year":2008,"id":678548,"datarank":0.7954957362088615,"base_score":5.303304908059076,"endowment":5.303304908059076,"self_citation_contribution":0.7954957362088615,"citation_network_contribution":0.0,"self_endowment_contribution":0.7954957362088615,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":200,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":772345,"name":"Kwoon Y. 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Melanopsin is the ipRGC photopigment, but the signaling cascade through which this invertebrate-like opsin triggers the photocurrent in these cells is unknown. Here, using patch-clamp recordings from dissociated ipRGCs in culture, we show that a membrane-associated phosphoinositide cascade lies at the heart of the ipRGC phototransduction mechanism, similar to the cascade in rhabdomeric photoreceptors of invertebrate eyes. When ipRGCs were illuminated, melanopsin activated a G protein of the G<jats:sub>q/11</jats:sub>class, stimulating the effector enzyme phospholipase C. The presence of these signaling components in ipRGCs was confirmed by single-cell RT-PCR and immunofluorescence. The photoresponse was fully functional in excised inside-out patches of ipRGC membrane, indicating that all core signaling components are within or tightly coupled to the plasma membrane. The striking similarity of phototransduction in ipRGCs and invertebrate rhabdomeric photoreceptors reinforces the emerging view that these cells have a common evolutionary origin.</jats:p>","is_dataset_classified":null,"base_score":0.0,"endowment":0.0,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"18305089","pmcid":null,"openalex_id":null,"authors":[],"funders":[{"funder_name":"NEI NIH HHS","grant_id":"R01 EY 12793","title":null},{"funder_name":"NEI NIH HHS","grant_id":"EY 17137","title":null},{"funder_name":"NEI NIH HHS","grant_id":"F32 EY016678","title":null},{"funder_name":"NEI NIH HHS","grant_id":"T32 EY018080","title":null}],"total_grants":4,"fwci":null,"citation_percentile":null,"influential_citations":0,"citation_trend":[],"oa_status":"closed","license":null,"oa_locations":[{"url":"https://www.physiology.org/doi/pdf/10.1152/jn.01066.2007","host_type":"publisher"}],"fields_of_study":[],"mesh_terms":["Retinal Ganglion Cells","Cell Line","PC12 Cells","Cell Membrane","Animals","Rats","Rats, Sprague-Dawley","Calcium","Egtazic Acid","Thapsigargin","GTP-Binding Proteins","Protein Kinase C","Heparin","Diglycerides","Enzyme Inhibitors","Fluorescent Antibody Technique","Patch-Clamp Techniques","Reverse Transcriptase Polymerase Chain Reaction","Biosensing Techniques","Photic Stimulation","Electrophysiology","Male","Inositol 1,4,5-Trisphosphate Receptors","Rod Opsins","Light Signal Transduction","In Vitro Techniques","Melanopsin"],"keywords":[],"sdg_mappings":[],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-08-17T05:34:51.518279Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}