{"gene":"LRIT3","run_date":"2026-06-10T02:59:50","timeline":{"discoveries":[{"year":2012,"finding":"LRIT3 (encoding a leucine-rich-repeat, immunoglobulin-like, and transmembrane-domain protein) is expressed at the outer plexiform layer of the human retina in a punctate pattern resembling the dendritic tips of ON bipolar cells, as shown by antibody staining; loss-of-function mutations cause complete congenital stationary night blindness with absent/reduced ERG b-wave, indicating a role in ON bipolar cell signaling.","method":"Whole-exome sequencing, Sanger sequencing, immunohistochemistry (anti-LRIT3 antibody) on human retina, ERG","journal":"American journal of human genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — human retinal immunolocalization plus loss-of-function patient genetics, single lab, two orthogonal methods","pmids":["23246293"],"is_preprint":false},{"year":2014,"finding":"Lrit3 knockout mice (nob6) exhibit a no-b-wave (nob) ERG phenotype with severely reduced b-wave amplitudes in scotopic and photopic conditions and decreased optomotor responses, establishing that LRIT3 loss disrupts ON bipolar cell function; inner nuclear layer thinning was detected by SD-OCT without gross retinal degeneration.","method":"Lrit3 knockout mouse model (gene trap), ERG, optomotor testing, fundus imaging, SD-OCT, histology","journal":"PloS one","confidence":"High","confidence_rationale":"Tier 2 / Strong — clean knockout with defined ERG phenotype, multiple functional readouts, replicated across follow-up studies","pmids":["24598786"],"is_preprint":false},{"year":2015,"finding":"LRIT3 localizes to the dendritic tips of depolarizing bipolar cells (DBCs) in the outer plexiform layer (OPL) and co-localizes with mGluR6 but not ribeye or calbindin. In Lrit3-/- (nob6) mice, TRPM1 localization is severely decreased at DBC dendritic tips of all DBCs, while mGluR6, GPR179, RGS7, RGS11, and Gβ5 are absent specifically at cone ON-BC (but not rod bipolar cell) dendritic tips. PNA labeling is also severely reduced in the OPL, suggesting an additional role in cone synapse formation.","method":"Immunofluorescence confocal microscopy in wild-type vs. Lrit3nob6/nob6 retinal sections using antibodies against LRIT3, TRPM1, mGluR6, GPR179, RGS7, RGS11, Gβ5, PNA, ribeye, calbindin","journal":"The European journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal antibody markers in KO vs. WT, replicated across multiple subsequent studies","pmids":["25997951"],"is_preprint":false},{"year":2017,"finding":"LRIT3 selectively affects cone ON-BC (but not OFF-BC) synaptic contacts at the ultrastructural level: synaptic contacts made by ON-BCs (but not OFF-BCs) with cone pedicles are disorganized in Lrit3-/- (nob6) mice, while molecules essential for OFF-BC signaling (GluR1, GluR5) are normally targeted. Multielectrode array recordings showed complete loss of ON-pathway function with retained but altered OFF-pathway signaling.","method":"Electron microscopy, immunostaining with confocal microscopy (GluR1, GluR5), multielectrode array recordings of retinal ganglion cells, ERG (patient and mouse), Lrit3-/- mouse model","journal":"Investigative ophthalmology & visual science","confidence":"High","confidence_rationale":"Tier 2 / Strong — ultrastructural EM plus electrophysiology plus immunostaining, multiple orthogonal methods, single lab","pmids":["28334377"],"is_preprint":false},{"year":2019,"finding":"LRIT3 is expressed presynaptically in rod photoreceptors (not only postsynaptically on bipolar cells). Restoring LRIT3 expression selectively in Lrit3-/- rods via AAV is sufficient to restore the postsynaptic DBC glutamate signalplex assembly and rod-driven vision, demonstrating that LRIT3 acts as a transsynaptic organizer of the postsynaptic complex.","method":"Immunofluorescence co-localization, AAV-mediated rod-specific LRIT3 rescue in Lrit3-/- mice, ERG, immunostaining of signalplex components","journal":"Cell reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — cell-type-specific AAV rescue with molecular and functional readouts, multiple orthogonal methods in single rigorous study","pmids":["31189098"],"is_preprint":false},{"year":2020,"finding":"LRIT3 interacts with and is required for the expression of nyctalopin at DBC dendritic tips; DBC signalplex components are not required for LRIT3 expression (placing LRIT3 upstream of nyctalopin). Loss of LRIT3 also reduces excitatory input to type 1 OFF bipolar cells and disrupts OFF retinal ganglion cell visually evoked responses, demonstrating an indirect effect on the OFF pathway.","method":"Co-immunoprecipitation (LRIT3-nyctalopin interaction), immunofluorescence in Lrit3-/- mouse retina, whole-cell electrophysiology, multielectrode array (MEA) electrophysiology, glutamate imaging","journal":"eNeuro","confidence":"High","confidence_rationale":"Tier 2 / Strong — co-IP for interaction, multiple electrophysiology methods for functional pathway placement, KO model with defined phenotype","pmids":["31959619"],"is_preprint":false},{"year":2012,"finding":"LRIT3 acts as a modulator/regulator of FGFR1 signaling, identified through its LRR and immunoglobulin domains as a candidate FGFR interactor.","method":"Biochemical interaction assays (details from abstract: LRIT3 identified as FGFR1 regulator)","journal":"FEBS letters","confidence":"Low","confidence_rationale":"Tier 3 / Weak — abstract does not detail the specific assay method, single lab, no replication reported in corpus","pmids":["22673519"],"is_preprint":false},{"year":2023,"finding":"rAAV-mediated expression of LRIT3 in cone photoreceptors of Lrit3-/- mice restores cone DBC signalplex components and partially restores downstream visual function (light-adapted ERG b-wave and BC/RGC electrophysiological responses), confirming that LRIT3 acts trans-synaptically from cones to organize the postsynaptic complex on cone DBCs.","method":"rAAV-mediated cone-specific LRIT3 expression in Lrit3-/- mice, ERG, whole-cell electrophysiology of BCs and RGCs, immunostaining of signalplex components","journal":"iScience","confidence":"High","confidence_rationale":"Tier 2 / Strong — cell-type-specific AAV rescue with molecular and functional readouts, orthogonal methods","pmids":["37091241"],"is_preprint":false},{"year":2024,"finding":"Loss of LRIT3 and its associated ON-pathway defect drastically reduces retinal dopamine (DA) and DOPAC levels, and Lrit3-/- mice show impaired recovery from lens-induced myopia, linking LRIT3-dependent ON-pathway signaling to dopaminergic regulation of refractive development.","method":"UPLC quantification of DA and DOPAC in isolated Lrit3-/- retinas, infrared photorefractometry for refractive development, lens-induced myopia protocol","journal":"Investigative ophthalmology & visual science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KO model with defined biochemical and functional readouts, single lab, two orthogonal methods","pmids":["39250117"],"is_preprint":false},{"year":2025,"finding":"Domain deletion analysis of LRIT3 reveals: (1) the LRR domain is required for trafficking LRIT3 to the synapse in cone (but not rod) photoreceptors, and is needed for rod BC signalplex reassembly and function; (2) the IG domain is required for TRPM1 localization to the signalplex and thus function; (3) the FN3 domain is not necessary for DBC signalplex assembly or function; (4) restoring Nyctalopin localization alone is insufficient to restore TRPM1 expression. A model is proposed in which the LRR domain transsynaptically binds Nyctalopin while the IG domain interacts with TRPM1.","method":"rAAV-mediated expression of domain-deletion LRIT3 constructs in Lrit3-/- retinas, immunostaining for signalplex components (TRPM1, Nyctalopin, others), ERG, electrophysiology","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — domain mutagenesis/deletion with molecular and functional rescue readouts, multiple orthogonal methods, peer-reviewed publication","pmids":["42055330"],"is_preprint":false}],"current_model":"LRIT3 is a single-pass transmembrane protein with extracellular LRR, IG, and FN3 domains expressed presynaptically in rod and cone photoreceptors, where it transsynaptically organizes the postsynaptic mGluR6 glutamate signaling complex (signalplex) on depolarizing bipolar cell (DBC) dendrites; the LRR domain traffics LRIT3 to cone synapses and binds Nyctalopin trans-synaptically, while the IG domain is required for TRPM1 localization, and LRIT3 acts upstream of Nyctalopin in a pathway that controls both ON and (indirectly) OFF pathway signaling, with its loss also reducing retinal dopamine and impairing myopia recovery."},"narrative":{"mechanistic_narrative":"LRIT3 is a single-pass transmembrane protein with extracellular leucine-rich-repeat (LRR), immunoglobulin (IG), and fibronectin type III (FN3) domains that acts as a presynaptic trans-synaptic organizer of glutamatergic signaling at photoreceptor-to-bipolar-cell synapses in the retina [PMID:31189098, PMID:37091241]. It is expressed presynaptically in rod and cone photoreceptors, and selectively expressing LRIT3 in Lrit3-/- rods or cones via AAV is sufficient to reassemble the postsynaptic mGluR6 signaling complex (signalplex) on depolarizing bipolar cell (DBC) dendrites and restore vision, establishing that LRIT3 organizes the postsynaptic complex across the synaptic cleft [PMID:31189098, PMID:37091241]. LRIT3 localizes to DBC dendritic tips and is required for proper localization of TRPM1 at all DBCs and of mGluR6, GPR179, RGS7, RGS11, and Gβ5 specifically at cone ON-bipolar cell dendritic tips [PMID:25997951]. It functions upstream of Nyctalopin, physically interacting with and being required for Nyctalopin localization, while signalplex components are not required for LRIT3 itself [PMID:31959619]; domain dissection assigns the LRR domain to synaptic trafficking and trans-synaptic Nyctalopin binding and the IG domain to TRPM1 localization, with the FN3 domain dispensable [PMID:42055330]. Loss of LRIT3 abolishes ON-pathway signaling and indirectly disorganizes cone ON-bipolar synaptic ultrastructure and OFF-pathway responses [PMID:28334377, PMID:31959619], and reduces retinal dopamine with impaired recovery from lens-induced myopia [PMID:39250117]. Loss-of-function mutations in LRIT3 cause complete congenital stationary night blindness with an absent ERG b-wave [PMID:23246293].","teleology":[{"year":2012,"claim":"Established LRIT3 as a retinal disease gene and placed its function at the ON bipolar cell, answering whether this LRR/IG/transmembrane protein had a defined site of action in vision.","evidence":"Whole-exome sequencing of CSNB patients plus anti-LRIT3 immunohistochemistry on human retina and ERG","pmids":["23246293"],"confidence":"Medium","gaps":["Did not define the molecular partners or mechanism of LRIT3","Localization was punctate at the OPL but cell-of-origin (pre- vs postsynaptic) was unresolved"]},{"year":2012,"claim":"Proposed LRIT3 as an FGFR1 signaling modulator via its LRR and IG domains, raising an alternative non-retinal mechanistic context.","evidence":"Biochemical interaction assays identifying LRIT3 as an FGFR1 regulator (method not detailed in abstract)","pmids":["22673519"],"confidence":"Low","gaps":["Assay details not specified and not replicated in the corpus","No connection established to the retinal signalplex role characterized in later work"]},{"year":2014,"claim":"Demonstrated causally that LRIT3 loss disrupts ON bipolar cell function in vivo, moving beyond correlation from patient genetics.","evidence":"Lrit3 gene-trap knockout mouse with ERG, optomotor testing, and SD-OCT","pmids":["24598786"],"confidence":"High","gaps":["Did not identify which signalplex molecules are affected","Did not distinguish rod vs cone pathway contributions"]},{"year":2015,"claim":"Defined LRIT3 as a selective organizer of the DBC signalplex, identifying TRPM1 as universally LRIT3-dependent and the mGluR6/GPR179/RGS complex as cone-ON-BC-specific.","evidence":"Multi-marker immunofluorescence confocal comparison of WT vs Lrit3nob6 retina","pmids":["25997951"],"confidence":"High","gaps":["Did not establish whether LRIT3 acts pre- or postsynaptically","Mechanism of differential rod vs cone dependence unresolved"]},{"year":2017,"claim":"Showed that LRIT3 loss selectively disorganizes cone ON-BC synaptic ultrastructure while OFF-BC molecular targeting is preserved, refining the pathway specificity.","evidence":"Electron microscopy, GluR1/GluR5 immunostaining, and multielectrode array recordings in Lrit3-/- mice","pmids":["28334377"],"confidence":"High","gaps":["Did not explain how OFF-pathway signaling becomes altered","Trans-synaptic vs cell-autonomous mechanism still open"]},{"year":2019,"claim":"Proved LRIT3 functions presynaptically as a trans-synaptic organizer, by showing rod-specific re-expression restores the postsynaptic complex and vision.","evidence":"AAV-mediated rod-specific LRIT3 rescue in Lrit3-/- mice with signalplex immunostaining and ERG","pmids":["31189098"],"confidence":"High","gaps":["Direct trans-synaptic binding partners not yet identified","Cone-specific rescue not yet tested"]},{"year":2020,"claim":"Placed LRIT3 upstream of Nyctalopin via a physical interaction and clarified the indirect mechanism of OFF-pathway disruption.","evidence":"Co-immunoprecipitation, immunofluorescence in Lrit3-/- retina, whole-cell and MEA electrophysiology, glutamate imaging","pmids":["31959619"],"confidence":"High","gaps":["Co-IP not reported with reciprocal/structural validation","How OFF-BC excitatory input is reduced mechanistically not fully resolved"]},{"year":2023,"claim":"Confirmed the trans-synaptic model in the cone pathway, showing cone-specific LRIT3 re-expression reassembles the cone DBC signalplex and partially restores function.","evidence":"rAAV cone-specific LRIT3 expression in Lrit3-/- mice with ERG, BC/RGC electrophysiology, and immunostaining","pmids":["37091241"],"confidence":"High","gaps":["Functional restoration was only partial","Did not map which domains mediate cone targeting"]},{"year":2024,"claim":"Connected LRIT3-dependent ON-pathway signaling to dopaminergic regulation of eye growth, broadening its physiological role beyond night vision.","evidence":"UPLC quantification of retinal DA/DOPAC and infrared photorefractometry under lens-induced myopia in Lrit3-/- mice","pmids":["39250117"],"confidence":"Medium","gaps":["Causal link between dopamine reduction and myopia recovery not directly tested","Single lab, two orthogonal methods"]},{"year":2025,"claim":"Assigned distinct molecular jobs to LRIT3 domains: LRR for synaptic trafficking and Nyctalopin binding, IG for TRPM1 localization, FN3 dispensable.","evidence":"rAAV domain-deletion LRIT3 constructs in Lrit3-/- retina with signalplex immunostaining, ERG, and electrophysiology","pmids":["42055330"],"confidence":"High","gaps":["Direct IG-TRPM1 binding inferred from a model, not shown biochemically","Why TRPM1 requires more than Nyctalopin restoration is unexplained"]},{"year":null,"claim":"The biochemical nature of LRIT3's trans-synaptic contacts and how a presynaptic protein dictates assembly of distinct postsynaptic complexes at rod vs cone synapses remain unresolved.","evidence":"","pmids":[],"confidence":"High","gaps":["No structure of LRIT3 or its complexes","Direct molecular receptor for LRIT3 on the postsynaptic membrane not identified","Mechanism of rod vs cone signalplex specificity unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[4,5,7,9]},{"term_id":"GO:0098631","term_label":"cell adhesion mediator activity","supporting_discovery_ids":[4,7]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,2,4]}],"pathway":[{"term_id":"R-HSA-112316","term_label":"Neuronal System","supporting_discovery_ids":[1,3,5]},{"term_id":"R-HSA-1500931","term_label":"Cell-Cell communication","supporting_discovery_ids":[4,7]}],"complexes":["mGluR6 signalplex"],"partners":["NYX","TRPM1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q3SXY7","full_name":"Leucine-rich repeat, immunoglobulin-like domain and transmembrane domain-containing protein 3","aliases":[],"length_aa":679,"mass_kda":74.8,"function":"Plays a role in the synapse formation and synaptic transmission between cone photoreceptor cells and retinal bipolar cells (By similarity). Required for normal transmission of a light-evoked stimulus from the cone photoreceptor cells to the ON-bipolar cells and ON-ganglion cells in the inner retina (PubMed:28334377). Required in retinal ON-bipolar cells for normal localization of the cation channel TRPM1 at dendrite tips (By similarity). Seems to play a specific role in synaptic contacts made by ON-bipolar cells with cone photoreceptor pedicles (By similarity). May also have a role in cone synapse formation (By similarity). Might facilitate FGFR1 exit from the endoplasmic reticulum to the Golgi (PubMed:22673519). Could be a regulator of the FGFRs (PubMed:22673519)","subcellular_location":"Cell projection, dendrite; Perikaryon; Endoplasmic reticulum membrane","url":"https://www.uniprot.org/uniprotkb/Q3SXY7/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/LRIT3","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/LRIT3","total_profiled":1310},"omim":[{"mim_id":"615058","title":"NIGHT BLINDNESS, CONGENITAL STATIONARY, TYPE 1F; CSNB1F","url":"https://www.omim.org/entry/615058"},{"mim_id":"615004","title":"LEUCINE-RICH REPEAT, IMMUNOGLOBULIN-LIKE, AND TRANSMEMBRANE DOMAINS-CONTAINING PROTEIN 3; LRIT3","url":"https://www.omim.org/entry/615004"},{"mim_id":"310500","title":"NIGHT BLINDNESS, CONGENITAL STATIONARY, TYPE 1A; CSNB1A","url":"https://www.omim.org/entry/310500"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Nucleoplasm","reliability":"Approved"},{"location":"Mitochondria","reliability":"Approved"},{"location":"Cytosol","reliability":"Approved"}],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in single","driving_tissues":[{"tissue":"retina","ntpm":16.3}],"url":"https://www.proteinatlas.org/search/LRIT3"},"hgnc":{"alias_symbol":["FLJ44691","FIGLER4","CSNB1F"],"prev_symbol":[]},"alphafold":{"accession":"Q3SXY7","domains":[{"cath_id":"3.80.10.10","chopping":"20-181_192-246","consensus_level":"medium","plddt":89.8711,"start":20,"end":246},{"cath_id":"2.60.40.10","chopping":"253-347","consensus_level":"high","plddt":92.0587,"start":253,"end":347},{"cath_id":"2.60.40.10","chopping":"487-572","consensus_level":"high","plddt":77.5114,"start":487,"end":572}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q3SXY7","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q3SXY7-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q3SXY7-F1-predicted_aligned_error_v6.png","plddt_mean":69.62},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=LRIT3","jax_strain_url":"https://www.jax.org/strain/search?query=LRIT3"},"sequence":{"accession":"Q3SXY7","fasta_url":"https://rest.uniprot.org/uniprotkb/Q3SXY7.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q3SXY7/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q3SXY7"}},"corpus_meta":[{"pmid":"23246293","id":"PMC_23246293","title":"Whole-exome sequencing identifies LRIT3 mutations as a cause of autosomal-recessive complete congenital stationary night blindness.","date":"2012","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/23246293","citation_count":111,"is_preprint":false},{"pmid":"24598786","id":"PMC_24598786","title":"Lrit3 deficient mouse (nob6): a novel model of complete congenital stationary night blindness (cCSNB).","date":"2014","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/24598786","citation_count":50,"is_preprint":false},{"pmid":"25997951","id":"PMC_25997951","title":"LRIT3 is essential to localize TRPM1 to the dendritic tips of depolarizing bipolar cells and may play a role in cone synapse formation.","date":"2015","source":"The European journal of neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/25997951","citation_count":50,"is_preprint":false},{"pmid":"31189098","id":"PMC_31189098","title":"Presynaptic Expression of LRIT3 Transsynaptically Organizes the Postsynaptic Glutamate Signaling Complex Containing TRPM1.","date":"2019","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/31189098","citation_count":44,"is_preprint":false},{"pmid":"35316139","id":"PMC_35316139","title":"Targeting ON-bipolar cells by AAV gene therapy stably reverses LRIT3-congenital stationary night blindness.","date":"2022","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/35316139","citation_count":29,"is_preprint":false},{"pmid":"31959619","id":"PMC_31959619","title":"LRIT3 is Required for Nyctalopin Expression and Normal ON and OFF Pathway Signaling in the Retina.","date":"2020","source":"eNeuro","url":"https://pubmed.ncbi.nlm.nih.gov/31959619","citation_count":28,"is_preprint":false},{"pmid":"28334377","id":"PMC_28334377","title":"LRIT3 Differentially Affects Connectivity and Synaptic Transmission of Cones to ON- and OFF-Bipolar Cells.","date":"2017","source":"Investigative ophthalmology & visual science","url":"https://pubmed.ncbi.nlm.nih.gov/28334377","citation_count":24,"is_preprint":false},{"pmid":"31578364","id":"PMC_31578364","title":"Genome-wide association study and whole-genome sequencing identify a deletion in LRIT3 associated with canine congenital stationary night blindness.","date":"2019","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/31578364","citation_count":17,"is_preprint":false},{"pmid":"22673519","id":"PMC_22673519","title":"Leucine-rich repeat, immunoglobulin-like and transmembrane domain 3 (LRIT3) is a modulator of FGFR1.","date":"2012","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/22673519","citation_count":14,"is_preprint":false},{"pmid":"39250117","id":"PMC_39250117","title":"Loss of ON-Pathway Function in Mice Lacking Lrit3 Decreases Recovery From Lens-Induced Myopia.","date":"2024","source":"Investigative ophthalmology & visual science","url":"https://pubmed.ncbi.nlm.nih.gov/39250117","citation_count":8,"is_preprint":false},{"pmid":"37220680","id":"PMC_37220680","title":"Extended functional rescue following AAV gene therapy in a canine model of LRIT3-congenital stationary night blindness.","date":"2023","source":"Vision research","url":"https://pubmed.ncbi.nlm.nih.gov/37220680","citation_count":7,"is_preprint":false},{"pmid":"37091241","id":"PMC_37091241","title":"LRIT3 expression in cone photoreceptors restores post-synaptic bipolar cell signalplex assembly and partial function in Lrit3  mice.","date":"2023","source":"iScience","url":"https://pubmed.ncbi.nlm.nih.gov/37091241","citation_count":5,"is_preprint":false},{"pmid":"27428514","id":"PMC_27428514","title":"Mutation screening of the LRIT3, CABP4, and GPR179 genes in Chinese patients with Schubert-Bornschein congenital stationary night blindness.","date":"2016","source":"Ophthalmic genetics","url":"https://pubmed.ncbi.nlm.nih.gov/27428514","citation_count":4,"is_preprint":false},{"pmid":"41000924","id":"PMC_41000924","title":"Domain-specific functions of LRIT3 in synaptic assembly and retinal signal transmission.","date":"2025","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/41000924","citation_count":0,"is_preprint":false},{"pmid":"42055330","id":"PMC_42055330","title":"Domain-specific functions of LRIT3 in synaptic assembly and retinal signal transmission.","date":"2026","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/42055330","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.07.25.666812","title":"Gene augmentation therapy treats mature mice with complete congenital stationary night blindness (cCSNB), improving retinal function and visual acuity","date":"2025-07-31","source":"bioRxiv","url":"https://doi.org/10.1101/2025.07.25.666812","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":10141,"output_tokens":2866,"usd":0.036707,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":10122,"output_tokens":3345,"usd":0.067117,"stage2_stop_reason":"end_turn"},"total_usd":0.103824,"stage1_batch_id":"msgbatch_01BbTCMyrRPyhtEq6b1MdwCN","stage2_batch_id":"msgbatch_011dEed5bbxYvTAaQWKJevxu","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2012,\n      \"finding\": \"LRIT3 (encoding a leucine-rich-repeat, immunoglobulin-like, and transmembrane-domain protein) is expressed at the outer plexiform layer of the human retina in a punctate pattern resembling the dendritic tips of ON bipolar cells, as shown by antibody staining; loss-of-function mutations cause complete congenital stationary night blindness with absent/reduced ERG b-wave, indicating a role in ON bipolar cell signaling.\",\n      \"method\": \"Whole-exome sequencing, Sanger sequencing, immunohistochemistry (anti-LRIT3 antibody) on human retina, ERG\",\n      \"journal\": \"American journal of human genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — human retinal immunolocalization plus loss-of-function patient genetics, single lab, two orthogonal methods\",\n      \"pmids\": [\"23246293\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Lrit3 knockout mice (nob6) exhibit a no-b-wave (nob) ERG phenotype with severely reduced b-wave amplitudes in scotopic and photopic conditions and decreased optomotor responses, establishing that LRIT3 loss disrupts ON bipolar cell function; inner nuclear layer thinning was detected by SD-OCT without gross retinal degeneration.\",\n      \"method\": \"Lrit3 knockout mouse model (gene trap), ERG, optomotor testing, fundus imaging, SD-OCT, histology\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — clean knockout with defined ERG phenotype, multiple functional readouts, replicated across follow-up studies\",\n      \"pmids\": [\"24598786\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"LRIT3 localizes to the dendritic tips of depolarizing bipolar cells (DBCs) in the outer plexiform layer (OPL) and co-localizes with mGluR6 but not ribeye or calbindin. In Lrit3-/- (nob6) mice, TRPM1 localization is severely decreased at DBC dendritic tips of all DBCs, while mGluR6, GPR179, RGS7, RGS11, and Gβ5 are absent specifically at cone ON-BC (but not rod bipolar cell) dendritic tips. PNA labeling is also severely reduced in the OPL, suggesting an additional role in cone synapse formation.\",\n      \"method\": \"Immunofluorescence confocal microscopy in wild-type vs. Lrit3nob6/nob6 retinal sections using antibodies against LRIT3, TRPM1, mGluR6, GPR179, RGS7, RGS11, Gβ5, PNA, ribeye, calbindin\",\n      \"journal\": \"The European journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal antibody markers in KO vs. WT, replicated across multiple subsequent studies\",\n      \"pmids\": [\"25997951\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"LRIT3 selectively affects cone ON-BC (but not OFF-BC) synaptic contacts at the ultrastructural level: synaptic contacts made by ON-BCs (but not OFF-BCs) with cone pedicles are disorganized in Lrit3-/- (nob6) mice, while molecules essential for OFF-BC signaling (GluR1, GluR5) are normally targeted. Multielectrode array recordings showed complete loss of ON-pathway function with retained but altered OFF-pathway signaling.\",\n      \"method\": \"Electron microscopy, immunostaining with confocal microscopy (GluR1, GluR5), multielectrode array recordings of retinal ganglion cells, ERG (patient and mouse), Lrit3-/- mouse model\",\n      \"journal\": \"Investigative ophthalmology & visual science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — ultrastructural EM plus electrophysiology plus immunostaining, multiple orthogonal methods, single lab\",\n      \"pmids\": [\"28334377\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"LRIT3 is expressed presynaptically in rod photoreceptors (not only postsynaptically on bipolar cells). Restoring LRIT3 expression selectively in Lrit3-/- rods via AAV is sufficient to restore the postsynaptic DBC glutamate signalplex assembly and rod-driven vision, demonstrating that LRIT3 acts as a transsynaptic organizer of the postsynaptic complex.\",\n      \"method\": \"Immunofluorescence co-localization, AAV-mediated rod-specific LRIT3 rescue in Lrit3-/- mice, ERG, immunostaining of signalplex components\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — cell-type-specific AAV rescue with molecular and functional readouts, multiple orthogonal methods in single rigorous study\",\n      \"pmids\": [\"31189098\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"LRIT3 interacts with and is required for the expression of nyctalopin at DBC dendritic tips; DBC signalplex components are not required for LRIT3 expression (placing LRIT3 upstream of nyctalopin). Loss of LRIT3 also reduces excitatory input to type 1 OFF bipolar cells and disrupts OFF retinal ganglion cell visually evoked responses, demonstrating an indirect effect on the OFF pathway.\",\n      \"method\": \"Co-immunoprecipitation (LRIT3-nyctalopin interaction), immunofluorescence in Lrit3-/- mouse retina, whole-cell electrophysiology, multielectrode array (MEA) electrophysiology, glutamate imaging\",\n      \"journal\": \"eNeuro\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — co-IP for interaction, multiple electrophysiology methods for functional pathway placement, KO model with defined phenotype\",\n      \"pmids\": [\"31959619\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"LRIT3 acts as a modulator/regulator of FGFR1 signaling, identified through its LRR and immunoglobulin domains as a candidate FGFR interactor.\",\n      \"method\": \"Biochemical interaction assays (details from abstract: LRIT3 identified as FGFR1 regulator)\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — abstract does not detail the specific assay method, single lab, no replication reported in corpus\",\n      \"pmids\": [\"22673519\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"rAAV-mediated expression of LRIT3 in cone photoreceptors of Lrit3-/- mice restores cone DBC signalplex components and partially restores downstream visual function (light-adapted ERG b-wave and BC/RGC electrophysiological responses), confirming that LRIT3 acts trans-synaptically from cones to organize the postsynaptic complex on cone DBCs.\",\n      \"method\": \"rAAV-mediated cone-specific LRIT3 expression in Lrit3-/- mice, ERG, whole-cell electrophysiology of BCs and RGCs, immunostaining of signalplex components\",\n      \"journal\": \"iScience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — cell-type-specific AAV rescue with molecular and functional readouts, orthogonal methods\",\n      \"pmids\": [\"37091241\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Loss of LRIT3 and its associated ON-pathway defect drastically reduces retinal dopamine (DA) and DOPAC levels, and Lrit3-/- mice show impaired recovery from lens-induced myopia, linking LRIT3-dependent ON-pathway signaling to dopaminergic regulation of refractive development.\",\n      \"method\": \"UPLC quantification of DA and DOPAC in isolated Lrit3-/- retinas, infrared photorefractometry for refractive development, lens-induced myopia protocol\",\n      \"journal\": \"Investigative ophthalmology & visual science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KO model with defined biochemical and functional readouts, single lab, two orthogonal methods\",\n      \"pmids\": [\"39250117\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Domain deletion analysis of LRIT3 reveals: (1) the LRR domain is required for trafficking LRIT3 to the synapse in cone (but not rod) photoreceptors, and is needed for rod BC signalplex reassembly and function; (2) the IG domain is required for TRPM1 localization to the signalplex and thus function; (3) the FN3 domain is not necessary for DBC signalplex assembly or function; (4) restoring Nyctalopin localization alone is insufficient to restore TRPM1 expression. A model is proposed in which the LRR domain transsynaptically binds Nyctalopin while the IG domain interacts with TRPM1.\",\n      \"method\": \"rAAV-mediated expression of domain-deletion LRIT3 constructs in Lrit3-/- retinas, immunostaining for signalplex components (TRPM1, Nyctalopin, others), ERG, electrophysiology\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — domain mutagenesis/deletion with molecular and functional rescue readouts, multiple orthogonal methods, peer-reviewed publication\",\n      \"pmids\": [\"42055330\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"LRIT3 is a single-pass transmembrane protein with extracellular LRR, IG, and FN3 domains expressed presynaptically in rod and cone photoreceptors, where it transsynaptically organizes the postsynaptic mGluR6 glutamate signaling complex (signalplex) on depolarizing bipolar cell (DBC) dendrites; the LRR domain traffics LRIT3 to cone synapses and binds Nyctalopin trans-synaptically, while the IG domain is required for TRPM1 localization, and LRIT3 acts upstream of Nyctalopin in a pathway that controls both ON and (indirectly) OFF pathway signaling, with its loss also reducing retinal dopamine and impairing myopia recovery.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"LRIT3 is a single-pass transmembrane protein with extracellular leucine-rich-repeat (LRR), immunoglobulin (IG), and fibronectin type III (FN3) domains that acts as a presynaptic trans-synaptic organizer of glutamatergic signaling at photoreceptor-to-bipolar-cell synapses in the retina [#4, #7]. It is expressed presynaptically in rod and cone photoreceptors, and selectively expressing LRIT3 in Lrit3-/- rods or cones via AAV is sufficient to reassemble the postsynaptic mGluR6 signaling complex (signalplex) on depolarizing bipolar cell (DBC) dendrites and restore vision, establishing that LRIT3 organizes the postsynaptic complex across the synaptic cleft [#4, #7]. LRIT3 localizes to DBC dendritic tips and is required for proper localization of TRPM1 at all DBCs and of mGluR6, GPR179, RGS7, RGS11, and Gβ5 specifically at cone ON-bipolar cell dendritic tips [#2]. It functions upstream of Nyctalopin, physically interacting with and being required for Nyctalopin localization, while signalplex components are not required for LRIT3 itself [#5]; domain dissection assigns the LRR domain to synaptic trafficking and trans-synaptic Nyctalopin binding and the IG domain to TRPM1 localization, with the FN3 domain dispensable [#9]. Loss of LRIT3 abolishes ON-pathway signaling and indirectly disorganizes cone ON-bipolar synaptic ultrastructure and OFF-pathway responses [#3, #5], and reduces retinal dopamine with impaired recovery from lens-induced myopia [#8]. Loss-of-function mutations in LRIT3 cause complete congenital stationary night blindness with an absent ERG b-wave [#0].\",\n  \"teleology\": [\n    {\n      \"year\": 2012,\n      \"claim\": \"Established LRIT3 as a retinal disease gene and placed its function at the ON bipolar cell, answering whether this LRR/IG/transmembrane protein had a defined site of action in vision.\",\n      \"evidence\": \"Whole-exome sequencing of CSNB patients plus anti-LRIT3 immunohistochemistry on human retina and ERG\",\n      \"pmids\": [\"23246293\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not define the molecular partners or mechanism of LRIT3\", \"Localization was punctate at the OPL but cell-of-origin (pre- vs postsynaptic) was unresolved\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Proposed LRIT3 as an FGFR1 signaling modulator via its LRR and IG domains, raising an alternative non-retinal mechanistic context.\",\n      \"evidence\": \"Biochemical interaction assays identifying LRIT3 as an FGFR1 regulator (method not detailed in abstract)\",\n      \"pmids\": [\"22673519\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Assay details not specified and not replicated in the corpus\", \"No connection established to the retinal signalplex role characterized in later work\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Demonstrated causally that LRIT3 loss disrupts ON bipolar cell function in vivo, moving beyond correlation from patient genetics.\",\n      \"evidence\": \"Lrit3 gene-trap knockout mouse with ERG, optomotor testing, and SD-OCT\",\n      \"pmids\": [\"24598786\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not identify which signalplex molecules are affected\", \"Did not distinguish rod vs cone pathway contributions\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Defined LRIT3 as a selective organizer of the DBC signalplex, identifying TRPM1 as universally LRIT3-dependent and the mGluR6/GPR179/RGS complex as cone-ON-BC-specific.\",\n      \"evidence\": \"Multi-marker immunofluorescence confocal comparison of WT vs Lrit3nob6 retina\",\n      \"pmids\": [\"25997951\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not establish whether LRIT3 acts pre- or postsynaptically\", \"Mechanism of differential rod vs cone dependence unresolved\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Showed that LRIT3 loss selectively disorganizes cone ON-BC synaptic ultrastructure while OFF-BC molecular targeting is preserved, refining the pathway specificity.\",\n      \"evidence\": \"Electron microscopy, GluR1/GluR5 immunostaining, and multielectrode array recordings in Lrit3-/- mice\",\n      \"pmids\": [\"28334377\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not explain how OFF-pathway signaling becomes altered\", \"Trans-synaptic vs cell-autonomous mechanism still open\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Proved LRIT3 functions presynaptically as a trans-synaptic organizer, by showing rod-specific re-expression restores the postsynaptic complex and vision.\",\n      \"evidence\": \"AAV-mediated rod-specific LRIT3 rescue in Lrit3-/- mice with signalplex immunostaining and ERG\",\n      \"pmids\": [\"31189098\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct trans-synaptic binding partners not yet identified\", \"Cone-specific rescue not yet tested\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Placed LRIT3 upstream of Nyctalopin via a physical interaction and clarified the indirect mechanism of OFF-pathway disruption.\",\n      \"evidence\": \"Co-immunoprecipitation, immunofluorescence in Lrit3-/- retina, whole-cell and MEA electrophysiology, glutamate imaging\",\n      \"pmids\": [\"31959619\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Co-IP not reported with reciprocal/structural validation\", \"How OFF-BC excitatory input is reduced mechanistically not fully resolved\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Confirmed the trans-synaptic model in the cone pathway, showing cone-specific LRIT3 re-expression reassembles the cone DBC signalplex and partially restores function.\",\n      \"evidence\": \"rAAV cone-specific LRIT3 expression in Lrit3-/- mice with ERG, BC/RGC electrophysiology, and immunostaining\",\n      \"pmids\": [\"37091241\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional restoration was only partial\", \"Did not map which domains mediate cone targeting\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Connected LRIT3-dependent ON-pathway signaling to dopaminergic regulation of eye growth, broadening its physiological role beyond night vision.\",\n      \"evidence\": \"UPLC quantification of retinal DA/DOPAC and infrared photorefractometry under lens-induced myopia in Lrit3-/- mice\",\n      \"pmids\": [\"39250117\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Causal link between dopamine reduction and myopia recovery not directly tested\", \"Single lab, two orthogonal methods\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Assigned distinct molecular jobs to LRIT3 domains: LRR for synaptic trafficking and Nyctalopin binding, IG for TRPM1 localization, FN3 dispensable.\",\n      \"evidence\": \"rAAV domain-deletion LRIT3 constructs in Lrit3-/- retina with signalplex immunostaining, ERG, and electrophysiology\",\n      \"pmids\": [\"42055330\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct IG-TRPM1 binding inferred from a model, not shown biochemically\", \"Why TRPM1 requires more than Nyctalopin restoration is unexplained\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The biochemical nature of LRIT3's trans-synaptic contacts and how a presynaptic protein dictates assembly of distinct postsynaptic complexes at rod vs cone synapses remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No structure of LRIT3 or its complexes\", \"Direct molecular receptor for LRIT3 on the postsynaptic membrane not identified\", \"Mechanism of rod vs cone signalplex specificity unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [4, 5, 7, 9]},\n      {\"term_id\": \"GO:0098631\", \"supporting_discovery_ids\": [4, 7]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 2, 4]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [1, 3, 5]},\n      {\"term_id\": \"R-HSA-1500931\", \"supporting_discovery_ids\": [4, 7]}\n    ],\n    \"complexes\": [\"mGluR6 signalplex\"],\n    \"partners\": [\"NYX\", \"TRPM1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}