Affinage

LCA5

Lebercilin · UniProt Q86VQ0

Length
697 aa
Mass
80.6 kDa
Annotated
2026-04-28
20 papers in source corpus 7 papers cited in narrative 7 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

LCA5 encodes lebercilin, a ciliary protein essential for intraflagellar transport (IFT)-dependent trafficking in photoreceptor outer segments. Lebercilin localizes to the connecting cilium/transition zone and the bulge region of photoreceptor outer segments, where it forms a complex with RP1, IFT81, IFT88, OFD1, and the dynein light chain LC8, and its loss causes mislocalization of opsins, rhodopsin, and IFT/transition zone components along the ciliary axoneme, leading to defective membrane disc formation and progressive photoreceptor degeneration (PMID:17546029, PMID:31348989, PMID:37071472, PMID:39934925). Lebercilin dimerizes via coiled-coil domains and undergoes LC8-dependent higher-order oligomerization, which is required for its scaffolding function (PMID:36114230). Loss-of-function mutations in LCA5 cause Leber congenital amaurosis, as demonstrated by homozygosity mapping, knockout models, and CRISPR-based gene correction in patient-derived retinal organoids that rescues opsin trafficking (PMID:17546029, PMID:37305852).

Mechanistic history

Synthesis pass · year-by-year structured walk · 7 steps
  1. 2007 High

    The identity of the LCA5 gene product and its ciliary localization were unknown; homozygosity mapping and proteomics established that LCA5 encodes lebercilin, a novel ciliary/centrosomal protein whose loss causes Leber congenital amaurosis.

    Evidence Homozygosity mapping in consanguineous families, immunolocalization in photoreceptors and cultured cells, tandem affinity purification–mass spectrometry

    PMID:17546029

    Open questions at the time
    • Specific molecular function of lebercilin at cilia was undefined
    • Which of the 24 identified interactors are functionally relevant was untested
    • Whether lebercilin is required for intraflagellar transport was unknown
  2. 2009 High

    It was unclear how lebercilin was anchored at the pericentriolar region; identification of the OFD1–lebercilin interaction and its abolition by dominant OFD1 mutations established that OFD1 is required for lebercilin's pericentriolar localization.

    Evidence Yeast two-hybrid screen of retinal cDNA library, co-immunoprecipitation, immunofluorescence in hTERT-RPE1 cells with disease-associated OFD1 mutants

    PMID:19800048

    Open questions at the time
    • Whether OFD1 loss phenocopies LCA5 loss in photoreceptors was not tested
    • Structural basis of the OFD1–lebercilin interaction was not resolved
    • Relevance of this interaction to IFT trafficking was unknown
  3. 2019 High

    Whether lebercilin is required for IFT-mediated protein trafficking in photoreceptors was untested; zebrafish lca5 knockout demonstrated selective mislocalization of red-cone opsin and cone transducin, and retention of IFT88 in outer segments, establishing lebercilin as essential for IFT-dependent outer segment protein trafficking.

    Evidence CRISPR/Cas9 knockout in zebrafish with ERG, immunofluorescence, and transmission electron microscopy

    PMID:31348989

    Open questions at the time
    • Mechanism by which lebercilin regulates IFT88 turnover was undefined
    • Whether mammalian photoreceptors show the same trafficking defects was unconfirmed
    • Whether lebercilin acts at a specific axonemal sub-compartment was unknown
  4. 2022 Medium

    The oligomeric state and structural organization of lebercilin were uncharacterized; biochemical analysis revealed that lebercilin dimerizes via coiled-coils and that LC8 dynein light chain binding through two short linear motifs drives higher-order oligomerization, suggesting a scaffolding mechanism.

    Evidence Biochemical interaction assays, biophysical characterization, mutagenesis of LC8-binding motifs and coiled-coil segments

    PMID:36114230

    Open questions at the time
    • Functional consequence of LC8-mediated oligomerization for IFT trafficking was not tested in vivo
    • No high-resolution structure of the lebercilin–LC8 complex was determined
    • Single-lab study without independent replication
  5. 2023 High

    The precise sub-ciliary localization and protein complex of lebercilin were undefined at nanoscale resolution; ultrastructure expansion microscopy and affinity proteomics placed lebercilin with RP1, IFT81, and IFT88 at the outer segment bulge region, and mouse knockout showed that lebercilin loss disrupts axonemal structure and membrane disc formation at this site, which was partially rescued by AAV gene augmentation.

    Evidence Retina-specific affinity proteomics, ultrastructure expansion microscopy, Lca5gt/gt mouse model, AAV-mediated gene augmentation

    PMID:37071472

    Open questions at the time
    • Mechanism by which lebercilin stabilizes RP1 and IFT proteins at the bulge was not resolved
    • Long-term efficacy and completeness of AAV rescue were not established
    • Whether lebercilin directly bridges RP1 to IFT complexes was not determined
  6. 2023 High

    Whether LCA5 mutations are the direct cause of opsin mislocalization in human photoreceptors was unconfirmed; CRISPR correction of the LCA5 nonsense mutation in patient iPSC-derived retinal organoids rescued lebercilin expression and corrected opsin/rhodopsin mislocalization, establishing causality in a human cellular model.

    Evidence CRISPR-Cas9 gene correction in patient iPSCs, retinal organoid differentiation, immunohistochemistry, whole-genome sequencing

    PMID:37305852

    Open questions at the time
    • Whether gene correction restores electrophysiological function was not assessed
    • Applicability of organoid findings to in vivo human retina was not demonstrated
  7. 2025 High

    The downstream molecular consequences of LCA5 loss on transition zone and IFT component distribution were incompletely understood; LCA5 KO retinal organoids showed aberrant axonemal accumulation of CEP290 and IFT88 alongside rhodopsin mislocalization, and pharmacological correction with eupatilin and fasudil reduced this accumulation, establishing that lebercilin regulates the distribution of transition zone/IFT proteins at photoreceptor cilia.

    Evidence CRISPR KO iPSC-derived retinal organoids, immunohistochemistry, western blotting, transcriptomics, proteomics, small molecule treatment

    PMID:39934925

    Open questions at the time
    • Molecular targets of eupatilin and fasudil that mediate rescue are unclear
    • Whether pharmacological rescue translates to in vivo photoreceptor preservation is unknown
    • Direct versus indirect role of lebercilin in CEP290 positioning is unresolved

Open questions

Synthesis pass · forward-looking unresolved questions
  • The precise molecular mechanism by which lebercilin coordinates IFT complex assembly, RP1 stabilization, and membrane disc formation at the bulge region remains unresolved, and no high-resolution structural model of lebercilin within its native ciliary complex exists.
  • No atomic-resolution structure of lebercilin or its complexes with IFT/RP1 partners
  • Whether lebercilin acts as a cargo adaptor, scaffold, or IFT regulator is not mechanistically distinguished
  • Therapeutic window and long-term outcomes for gene augmentation or pharmacological rescue in patients are unknown

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0008092 cytoskeletal protein binding 2 GO:0060090 molecular adaptor activity 2
Localization
GO:0005929 cilium 5 GO:0005815 microtubule organizing center 2 GO:0005856 cytoskeleton 1
Pathway
R-HSA-1852241 Organelle biogenesis and maintenance 4 R-HSA-9609507 Protein localization 4
Partners
CEP290DYNLL1IFT81IFT88OFD1RP1
Complex memberships
Lebercilin–IFT complex (IFT81, IFT88)Lebercilin–RP1 complex

Evidence

Reading pass · 7 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2007 LCA5 encodes lebercilin, a ciliary protein that localizes to the connecting cilia of photoreceptors and to microtubules, centrioles, and primary cilia of cultured mammalian cells. Tandem affinity purification identified 24 interacting proteins linking lebercilin to centrosomal and ciliary functions. Homozygosity mapping, immunolocalization, tandem affinity purification (TAP) proteomics Nature genetics High 17546029
2009 OFD1 interacts with LCA5-encoded lebercilin, identified by yeast two-hybrid screen of a retinal cDNA library. X-linked dominant OFD1 mutations completely abolish binding to lebercilin and disrupt its pericentriolar localization in hTERT-RPE1 cells, whereas recessive mutations only reduce (but do not eliminate) the interaction and do not affect pericentriolar localization. Yeast two-hybrid screen, Co-IP/interaction assays, immunofluorescence in hTERT-RPE1 cells with disease-associated mutants American journal of human genetics High 19800048
2019 Knockout of lca5 in zebrafish causes selective mislocalization of red-cone opsin and cone α-transducin to the inner segment and synaptic terminal, and retention of IFT88 (a key intraflagellar transport component) in the outer segment, indicating that LCA5 is required for IFT-mediated outer segment protein trafficking. CRISPR/Cas9 knockout in zebrafish, ERG, histology (HE staining), immunofluorescence, transmission electron microscopy Biochimica et biophysica acta. Molecular basis of disease High 31348989
2022 LCA5 (lebercilin) interacts with LC8 dynein light chain through two short linear motifs. LCA5 forms dimers independently via extensive coiled-coil formation, but LC8 enhances higher-order oligomerization of LCA5 through a mechanism requiring both LC8-binding motifs and coiled-coil segments. Biochemical interaction assays, structural/biophysical characterization, mutagenesis of linear motifs and coiled-coil segments Scientific reports Medium 36114230
2023 Using retina-specific affinity proteomics and ultrastructure expansion microscopy, lebercilin (LCA5) was shown to co-localize with RP1 and IFT proteins (IFT81, IFT88) at the bulge region of the photoreceptor outer segment. Lebercilin-deficient mice show early axonemal defects at the bulge region with reduced levels of RP1 and IFT proteins, disrupting membrane disc formation. AAV-based LCA5 gene augmentation partially restored bulge region structure and preserved outer segment axoneme and membrane disc formation. Retina-specific affinity proteomics, ultrastructure expansion microscopy (U-ExM), mouse knockout model (Lca5gt/gt), AAV gene augmentation, immunofluorescence JCI insight High 37071472
2023 CRISPR-Cas9 correction of the LCA5 nonsense mutation (c.835C>T; p.Q279*) in patient iPSC-derived retinal organoids rescued lebercilin expression and localization along the ciliary axoneme, and corrected mislocalization of opsin and rhodopsin to the outer nuclear layer, establishing that LCA5 loss directly causes opsin mislocalization in photoreceptors. CRISPR-Cas9 gene correction in patient iPSCs, retinal organoid differentiation, immunohistochemistry, whole-genome sequencing for off-target analysis Molecular therapy. Methods & clinical development High 37305852
2025 In LCA5 KO iPSC-derived retinal organoids, absence of LCA5 leads to altered localization of CEP290 and IFT88 along the photoreceptor cilia axoneme and mislocalization of rhodopsin to the outer nuclear layer. Small molecule treatments (eupatilin, fasudil) reduced CEP290 and IFT88 axonemal accumulation and improved rhodopsin trafficking, demonstrating that LCA5 normally regulates the distribution of transition zone/IFT components at photoreceptor cilia. CRISPR KO iPSC-derived retinal organoids, immunohistochemistry, western blotting, transcriptomics, proteomics, small molecule treatment Acta neuropathologica communications High 39934925

Source papers

Stage 0 corpus · 20 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2009 OFD1 is mutated in X-linked Joubert syndrome and interacts with LCA5-encoded lebercilin. American journal of human genetics 167 19800048
2007 Mutations in LCA5, encoding the ciliary protein lebercilin, cause Leber congenital amaurosis. Nature genetics 153 17546029
2009 Leber congenital amaurosis caused by Lebercilin (LCA5) mutation: retained photoreceptors adjacent to retinal disorganization. Molecular vision 32 19503738
2013 Screening of a large cohort of leber congenital amaurosis and retinitis pigmentosa patients identifies novel LCA5 mutations and new genotype-phenotype correlations. Human mutation 27 23946133
2003 Progression of phenotype in Leber's congenital amaurosis with a mutation at the LCA5 locus. The British journal of ophthalmology 27 12642313
2019 Knocking out lca5 in zebrafish causes cone-rod dystrophy due to impaired outer segment protein trafficking. Biochimica et biophysica acta. Molecular basis of disease 26 31348989
2023 CRISPR-Cas9 correction of a nonsense mutation in LCA5 rescues lebercilin expression and localization in human retinal organoids. Molecular therapy. Methods & clinical development 20 37305852
2008 Identification of a novel splice-site mutation in the Lebercilin (LCA5) gene causing Leber congenital amaurosis. Molecular vision 19 18334959
2007 Mutations in LCA5 are an uncommon cause of Leber congenital amaurosis (LCA) type II. Human mutation 19 18000884
2023 Gene augmentation of LCA5-associated Leber congenital amaurosis ameliorates bulge region defects of the photoreceptor ciliary axoneme. JCI insight 17 37071472
2013 Involvement of LCA5 in Leber congenital amaurosis and retinitis pigmentosa in the Spanish population. Ophthalmology 17 24144451
2020 Treatment Potential for LCA5-Associated Leber Congenital Amaurosis. Investigative ophthalmology & visual science 14 32428231
2011 Identification of a novel LCA5 mutation in a Pakistani family with Leber congenital amaurosis and cataracts. Molecular vision 11 21850168
2016 Next-generation Sequencing Extends the Phenotypic Spectrum for LCA5 Mutations: Novel LCA5 Mutations in Cone Dystrophy. Scientific reports 9 27067258
2009 LCA5, a rare genetic cause of leber congenital amaurosis in Koreans. Ophthalmic genetics 7 19172513
2025 Small molecule treatment alleviates photoreceptor cilia defects in LCA5-deficient human retinal organoids. Acta neuropathologica communications 6 39934925
2005 Exclusion of LCA5 locus in a consanguineous Turkish family with macular coloboma-type LCA. Eye (London, England) 6 16082399
2022 The interaction between LC8 and LCA5 reveals a novel oligomerization function of LC8 in the ciliary-centrosome system. Scientific reports 4 36114230
2022 Relative preservation of the extramacular retina in LCA5-associated Leber congenital amaurosis. American journal of ophthalmology case reports 3 35128149
2022 Prenatal detection of pure proximal 6q14.1 microduplication encompassing LCA5 gene: A variant of likely benign. Medicine 0 35713440