{"gene":"FYCO1","run_date":"2026-06-09T23:54:44","timeline":{"discoveries":[{"year":2010,"finding":"FYCO1 forms an adaptor complex with LC3, Rab7, and PI3P (phosphatidylinositol-3-phosphate) on autophagosomal membranes to mediate microtubule plus end-directed vesicle transport. FYCO1 depletion causes perinuclear clustering of autophagosomes, while overexpression redistributes Rab7-positive vesicles to the cell periphery.","method":"Co-IP/pulldown identification of binding partners, domain mapping of LC3/Rab7/PI3P-binding regions, knockdown and overexpression with live-cell imaging readout","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal binding assays with domain mapping, knockdown and overexpression with defined organelle-transport phenotypes, foundational paper widely replicated","pmids":["20100911"],"is_preprint":false},{"year":2010,"finding":"A proposed mechanism for selective autophagosomal membrane recruitment of FYCO1 involves a conformational change upon LC3-LIR interaction that exposes the FYVE domain for PI3P binding.","method":"Domain binding assays and functional analysis discussed in review/commentary context with reference to original experimental data","journal":"Autophagy","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — mechanistic model supported by domain mapping from primary paper (PMID:20100911); this commentary consolidates those findings without new experiments","pmids":["20364109"],"is_preprint":false},{"year":2015,"finding":"FYCO1 contains a C-terminally extended, F-type LIR motif (9 amino acids) that preferentially binds LC3A and LC3B. Crystal structure of FYCO1 LIR peptide–LC3B complex at 1.53 Å resolution revealed that residues at positions 8 (acidic, Asp1285) and 9 (hydrophobic) beyond the core LIR are required for efficient LC3B binding, with Asp1285 contacting His57 of LC3B conferring LC3A/B specificity. A functional LIR motif is required for efficient maturation of autophagosomes under basal (but not starvation-induced) autophagy conditions.","method":"Crystal structure determination (1.53 Å), peptide array-based 2D mutational scanning, mutational analysis, FYCO1 knockout cell reconstitution with WT and LIR-mutant constructs","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure plus mutagenesis plus functional rescue experiments in KO cells, multiple orthogonal methods in single study","pmids":["26468287"],"is_preprint":false},{"year":2017,"finding":"Crystal structure of mouse LC3B in complex with the FYCO1 LIR peptide confirmed that flanking sequences N-terminal and C-terminal to the core LIR tetrapeptide are specifically recognized by LC3B and contribute to binding, and that this recognition mechanism is conserved across LC3 isoforms and species.","method":"X-ray crystallography; structural comparison with related LC3-LIR complexes","journal":"Acta crystallographica. Section F, Structural biology communications","confidence":"High","confidence_rationale":"Tier 1 / Strong — independent crystal structure replicating and extending findings of PMID:26468287, confirming flanking-region contacts","pmids":["28291748"],"is_preprint":false},{"year":2020,"finding":"Crystal structure of the FYCO1 RUN domain was determined at 1.3 Å resolution; structural comparisons and docking studies identified possible interaction interfaces with small GTPases of the Ras superfamily, but no binding partner was experimentally confirmed.","method":"X-ray crystallography (1.3 Å), structural comparison, computational docking","journal":"Acta crystallographica. Section F, Structural biology communications","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — high-resolution structure, but interaction partner not experimentally validated; docking is computational only","pmids":["32744243"],"is_preprint":false},{"year":2011,"finding":"Loss-of-function mutations in FYCO1 cause autosomal-recessive congenital cataracts. Wild-type and the missense mutant p.L1376Pro FYCO1 expressed in human lens epithelial cells colocalize to autophagosomes and partially to microtubules, consistent with a role in autophagosomal transport in the lens.","method":"Human genetics (linkage + Sanger sequencing), immunoblot of truncated mutant proteins, subcellular localization by immunofluorescence in human lens epithelial cells","journal":"American journal of human genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct localization experiments in relevant cell type plus genetic evidence; mechanism inferred from co-localization without functional rescue","pmids":["21636066"],"is_preprint":false},{"year":2014,"finding":"During LC3-associated phagocytosis, FYCO1 is recruited directly by LC3 to Dectin-1 phagosomes and facilitates maturation of early p40phox+ phagosomes into late LAMP1+ phagosomes. Loss of FYCO1 prolongs p40phox+ phagosome stage and increases reactive oxygen production.","method":"FYCO1 knockdown/knockout in macrophages, live imaging and immunofluorescence of phagosome maturation markers, ROS measurement","journal":"Journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function with two defined functional readouts (maturation markers and ROS), single lab","pmids":["24442442"],"is_preprint":false},{"year":2021,"finding":"STK4/MST1-mediated phosphorylation of LC3B on threonine 50 (LC3B-T50) reduces FYCO1 binding to LC3B. Impairment of LC3B-T50 phosphorylation (T50A mutation) decreases starvation-induced perinuclear positioning of autophagosomes and their colocalization with lysosomes, and causes aberrant anterograde movement of autophagosomes in neurons and peripheral cells. This defines a nutrient-sensitive STK4–LC3B–FYCO1 axis regulating directional autophagosomal transport.","method":"In vitro binding assays with phospho-LC3B, LC3B phosphorylation mutants, autophagosome tracking by live imaging in neurons and cell lines, lysosome colocalization assays","journal":"Current biology","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — in vitro binding + phospho-mutant phenotyping + live-cell imaging in multiple cell types, multiple orthogonal methods in one study","pmids":["34146484"],"is_preprint":false},{"year":2021,"finding":"The centrosomal protein Nlp interacts physically with LC3, Rab7, and FYCO1, and enhances the Rab7–FYCO1 interaction, thereby accelerating autophagic flux and autophagolysosome formation.","method":"Co-IP, colocalization by immunofluorescence, autophagic flux assays, genetic knockout in mice","journal":"Signal transduction and targeted therapy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP and defined functional readout (autophagic flux), single lab","pmids":["33859171"],"is_preprint":false},{"year":2018,"finding":"FYCO1 mediates Rab7-dependent clearance of α-synuclein aggregates. FYCO1-decorated vesicles contained α-synuclein (unlike RILP-decorated vesicles). FYCO1 overexpression reduced α-synuclein aggregate number and protein levels; FYCO1 knockdown reduced Rab7-induced aggregate clearance. The effect of FYCO1 required active (GTP-bound) Rab7, as dominant-negative Rab7 blocked FYCO1-mediated clearance. FYCO1 coexpression in a Drosophila A53T-α-synuclein model reduced aggregates and rescued locomotor deficits.","method":"Live-cell imaging, western blot, siRNA knockdown, dominant-negative Rab7, Trypan blue viability, time-lapse microscopy, Drosophila model with filter trap assay and locomotor assay","journal":"Journal of neurochemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods across mammalian cells and Drosophila in vivo model, gain- and loss-of-function, epistasis with dominant-negative Rab7","pmids":["29747217"],"is_preprint":false},{"year":2016,"finding":"FYCO1 is a component of the chromatoid body (CB) in haploid round spermatids. Autophagy induction recruits lysosomal vesicles to the CB in a FYCO1-dependent manner; in germ cell-specific Fyco1 conditional knockout mice, this recruitment is lost and the CB becomes fragmented, indicating FYCO1-mediated autophagy regulates RNP granule integrity.","method":"Germ cell-specific conditional Fyco1 knockout mouse model, electron microscopy, immunofluorescence, autophagy induction assays","journal":"Autophagy","confidence":"High","confidence_rationale":"Tier 2 / Moderate — conditional KO mouse with defined organelle phenotype (CB fragmentation, loss of lysosome recruitment), multiple imaging methods","pmids":["27929729"],"is_preprint":false},{"year":2017,"finding":"FYCO1 is responsible for formation of LC3-containing membrane around post-mitotic midbodies and regulates midbody degradation by autophagy. FYCO1 knockdown increases midbody accumulation, which in turn promotes anchorage-independent growth and invadopodia formation in HeLa and squamous carcinoma cells.","method":"FYCO1 siRNA knockdown, immunofluorescence for LC3/midbody markers, midbody accumulation quantification, anchorage-independent growth assay, invadopodia assay","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — knockdown with defined mechanistic phenotype (LC3 membrane around midbody) and downstream cellular readouts, single lab","pmids":["29196475"],"is_preprint":false},{"year":2022,"finding":"Loss of FYCO1 in fyco1 knockout mice results in diminished autophagic flux, impaired organelle removal (organelles accumulate in the organelle-free zone of the lens), and cataractogenesis, confirming FYCO1's role in lens fiber cell differentiation via autophagy-dependent organelle clearance.","method":"Fyco1 knockout mice, flow cytometry of autophagic flux in FYCO1 knock-in human lens epithelial cells, transmission electron microscopy of lens organoids and mouse lenses, transcriptome/proteome/metabolome profiling","journal":"Autophagy","confidence":"High","confidence_rationale":"Tier 2 / Strong — knockout mouse + knock-in human cells + TEM + multiple omics, multiple orthogonal methods confirming autophagic flux impairment and organelle accumulation","pmids":["35343376"],"is_preprint":false},{"year":2021,"finding":"FYCO1 interacts with αA- and αB-crystallin (identified by yeast two-hybrid and confirmed by co-immunoprecipitation). In FYCO1 knockout mice, soluble αA- and αB-crystallin decrease, LC3-I to LC3-II conversion is reduced, and p62 accumulates, suggesting FYCO1 recruits damaged α-crystallin into autophagosomes.","method":"Yeast two-hybrid screening, co-immunoprecipitation, immunoblot of LC3-I/LC3-II conversion and p62 in KO mouse eyes","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — yeast two-hybrid plus co-IP for novel binding partners, KO mouse with defined biochemical readouts; single lab","pmids":["34215815"],"is_preprint":false},{"year":2023,"finding":"FYCO1 interacts with activated CASP8 (caspase 8) via its C-terminal GOLD domain and is a specific CASP8 substrate cleaved at aspartate 1306, releasing the GOLD domain and inactivating FYCO1. FYCO1 also interacts via its GOLD domain with the CCZ1–MON1A complex required for RAB7A activation and vesicle-lysosome fusion. Loss of FYCO1 impairs TNFRSF10B/TRAIL-R2 transport to lysosomes and stabilizes the DISC, sensitizing cells to TRAIL-induced apoptosis.","method":"Two-step Co-IP/affinity purification–mass spectrometry (AP-MS), CASP8 cleavage site mapping, FYCO1 KO and knockdown cell lines, DISC complex analysis, receptor trafficking assays, flow cytometry of apoptosis","journal":"Autophagy","confidence":"High","confidence_rationale":"Tier 1–2 / Moderate — AP-MS identification of interactions, caspase cleavage mapping with defined cleavage site, KO phenotype with mechanistic pathway placement, multiple orthogonal methods in single study","pmids":["37418591"],"is_preprint":false},{"year":2021,"finding":"FYCO1 is required for autophagy induction (but not basal autophagy) in cardiomyocytes in response to glucose deprivation. Fyco1-deficient mice subjected to starvation or pressure overload cannot induce autophagy and develop impaired cardiac function. FYCO1 overexpression induces autophagy in cardiomyocytes and rescues cardiac dysfunction under biomechanical stress.","method":"Fyco1 knockout mice with pressure-overload and starvation models, FYCO1 transgenic overexpression mice, autophagic flux measurement in isolated cardiomyocytes, cardiac function assessment","journal":"JACC. Basic to translational science","confidence":"High","confidence_rationale":"Tier 2 / Moderate — in vivo KO and transgenic overexpression with defined cardiac and autophagic phenotypes, multiple models","pmids":["33997522"],"is_preprint":false},{"year":2022,"finding":"FYCO1 promotes migration, invasion, invadopodia formation, and epithelial-mesenchymal transition in HeLa cells through the CDC42/N-WASP/Arp2/3 signaling pathway, as demonstrated by pharmacological inhibition of Arp2/3 with CK666 blocking FYCO1-dependent migration and invasion.","method":"FYCO1 overexpression/knockdown, wound healing assay, transwell invasion assay, immunofluorescence for invadopodia, western blot, Arp2/3 inhibitor (CK666) epistasis","journal":"Biochemistry and cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — pharmacological epistasis placing FYCO1 upstream of CDC42/N-WASP/Arp2/3, supported by gain- and loss-of-function assays; single lab","pmids":["36342046"],"is_preprint":false},{"year":2024,"finding":"FYCO1 knockout in human lens epithelial cells suppresses H2O2- and UVB-induced senescence and p21 levels by suppressing the expression of PAK1 (p21-activated kinase 1), identifying a FYCO1–PAK1–p21 axis in stress-induced autophagy and senescence in lens epithelial cells.","method":"FYCO1 knockout cell lines, CCK8 viability, SA-β-Gal senescence assay, qRT-PCR, western blot, immunofluorescence, UVB/H2O2 stress models","journal":"Archives of biochemistry and biophysics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function with defined pathway (PAK1/p21) by western blot and functional readouts, single lab, single publication","pmids":["39395618"],"is_preprint":false},{"year":2024,"finding":"Depletion of FYCO1 did NOT phenocopy protrudin or KIF5 depletion for endosomal tubule fission (ETF), establishing that FYCO1's role in late endosome motility is distinct from KIF5-mediated ETF at ER-endosome contacts.","method":"Knockdown epistasis; ETF phenotype (increased endosomal tubulation) was assessed by imaging","journal":"bioRxiv (preprint)","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single negative result in a preprint; single method, not directly focused on FYCO1 mechanism","pmids":["bio_10.1101_2024.07.15.602703"],"is_preprint":true}],"current_model":"FYCO1 is a multi-domain autophagy adaptor that simultaneously binds LC3A/B (via a C-terminally extended F-type LIR motif whose structural basis is resolved crystallographically), active Rab7, and PI3P (via its FYVE domain) on the cytoplasmic face of autophagosomes and late endosomes, coupling these vesicles to microtubule plus end-directed kinesin motors to drive their anterograde transport toward the cell periphery; directional bias is regulated by STK4/MST1-mediated phosphorylation of LC3B-T50, which reduces FYCO1 binding; FYCO1 is cleaved and inactivated by CASP8 at Asp1306, linking vesicle transport to apoptotic signaling; and FYCO1-dependent autophagic transport is required for organelle clearance in the lens, midbody degradation, RNP granule homeostasis in spermatids, cardiac stress responses, and Rab7-mediated α-synuclein aggregate clearance."},"narrative":{"mechanistic_narrative":"FYCO1 is a multivalent autophagy adaptor that links autophagosomes and late endosomes to plus end-directed microtubule transport, simultaneously engaging LC3, active Rab7, and PI3P to drive anterograde vesicle movement toward the cell periphery [PMID:20100911]. Membrane recruitment is governed by a C-terminally extended F-type LIR motif that selectively binds LC3A/B; crystal structures of the FYCO1 LIR–LC3B complex show that acidic and hydrophobic residues flanking the core tetrapeptide (notably Asp1285 contacting LC3B His57) confer isoform specificity and are required for efficient basal-autophagy autophagosome maturation [PMID:26468287, PMID:28291748]. The directionality of this transport is nutrient-tuned: STK4/MST1-mediated phosphorylation of LC3B on Thr50 reduces FYCO1 binding, biasing autophagosomes toward perinuclear lysosomes during starvation [PMID:34146484]. Through its C-terminal GOLD domain, FYCO1 binds the CCZ1–MON1A complex that activates RAB7A and is itself cleaved at Asp1306 by activated CASP8, coupling vesicle-to-lysosome transport and death-receptor trafficking to apoptotic signaling [PMID:37418591]. Functionally, FYCO1-dependent autophagic transport mediates organelle clearance during lens fiber differentiation—loss-of-function mutations cause autosomal-recessive congenital cataract [PMID:21636066, PMID:35343376]—as well as midbody degradation [PMID:29196475], chromatoid-body/RNP-granule integrity in spermatids [PMID:27929729], stress-induced cardiac autophagy [PMID:33997522], LC3-associated phagosome maturation [PMID:24442442], and Rab7-dependent clearance of α-synuclein aggregates [PMID:29747217].","teleology":[{"year":2010,"claim":"Established FYCO1 as the molecular bridge coupling autophagosomes to anterograde microtubule transport, answering how these vesicles are positioned within the cell.","evidence":"Co-IP/domain mapping of LC3/Rab7/PI3P-binding regions with knockdown and overexpression live-cell imaging","pmids":["20100911"],"confidence":"High","gaps":["Identity of the kinesin motor engaged was not biochemically resolved","Stoichiometry of the LC3/Rab7/PI3P co-recruitment not defined"]},{"year":2010,"claim":"Proposed that LC3-LIR binding triggers a conformational change exposing the FYVE domain, addressing how FYCO1 achieves selective membrane recruitment.","evidence":"Mechanistic model consolidating domain-mapping data in a commentary","pmids":["20364109"],"confidence":"Medium","gaps":["No structural or biophysical demonstration of the proposed conformational switch","No new experimental data beyond the primary paper"]},{"year":2011,"claim":"Linked FYCO1 to human disease by showing loss-of-function mutations cause autosomal-recessive congenital cataract, implicating autophagosomal transport in lens biology.","evidence":"Linkage and Sanger sequencing in families plus immunofluorescence localization of WT and p.L1376Pro mutant in lens epithelial cells","pmids":["21636066"],"confidence":"Medium","gaps":["Mechanism inferred from colocalization without functional rescue","How autophagic transport defects produce lens opacity not established"]},{"year":2014,"claim":"Extended FYCO1 function to LC3-associated phagocytosis, showing it is recruited by LC3 to drive phagosome maturation independent of canonical autophagy.","evidence":"Knockdown/knockout in macrophages with phagosome maturation marker imaging and ROS measurement","pmids":["24442442"],"confidence":"Medium","gaps":["Single lab","Whether Rab7/PI3P engagement is required for phagosomal recruitment not tested"]},{"year":2015,"claim":"Defined the structural basis for FYCO1's LC3 selectivity, resolving why it preferentially binds LC3A/B and how this supports basal autophagosome maturation.","evidence":"1.53 Å crystal structure of FYCO1 LIR–LC3B, peptide-array mutational scanning, and KO cell reconstitution with LIR mutants","pmids":["26468287"],"confidence":"High","gaps":["Why the LIR is dispensable under starvation but required basally not mechanistically explained"]},{"year":2016,"claim":"Showed FYCO1 maintains RNP granule integrity in spermatids by recruiting lysosomal vesicles to the chromatoid body via autophagy.","evidence":"Germ cell-specific conditional Fyco1 knockout mice with electron microscopy and autophagy induction assays","pmids":["27929729"],"confidence":"High","gaps":["Molecular tether linking FYCO1 to the chromatoid body not identified","Cargo selectivity at the CB unknown"]},{"year":2017,"claim":"Independently confirmed flanking-region recognition of the FYCO1 LIR by LC3B and established its conservation across LC3 isoforms and species.","evidence":"X-ray crystallography of mouse LC3B–FYCO1 LIR with structural comparison","pmids":["28291748"],"confidence":"High","gaps":["Does not address in-cell affinity differences among LC3 paralogs"]},{"year":2017,"claim":"Identified FYCO1 as the mediator of autophagic midbody degradation, connecting its loss to oncogenic phenotypes through midbody accumulation.","evidence":"siRNA knockdown with LC3/midbody imaging, anchorage-independent growth and invadopodia assays","pmids":["29196475"],"confidence":"Medium","gaps":["Single lab","How midbody accumulation mechanistically drives transformation not resolved"]},{"year":2018,"claim":"Demonstrated FYCO1 drives Rab7-dependent clearance of α-synuclein aggregates, with epistasis showing the effect requires GTP-bound Rab7.","evidence":"Gain/loss-of-function in mammalian cells, dominant-negative Rab7 epistasis, and a Drosophila A53T-α-synuclein rescue model","pmids":["29747217"],"confidence":"High","gaps":["Whether α-synuclein is captured by direct FYCO1 binding or as bulk cargo not determined"]},{"year":2021,"claim":"Revealed a nutrient-sensitive STK4–LC3B–FYCO1 axis in which LC3B-T50 phosphorylation tunes FYCO1 binding to control autophagosome directionality.","evidence":"In vitro binding with phospho-LC3B, T50A mutants, and autophagosome tracking in neurons and cell lines","pmids":["34146484"],"confidence":"High","gaps":["How STK4 activity is spatially coordinated with autophagosomes not defined","Quantitative effect on motor engagement unmeasured"]},{"year":2021,"claim":"Identified the centrosomal protein Nlp as an enhancer of the Rab7–FYCO1 interaction that accelerates autophagic flux.","evidence":"Co-IP, colocalization, autophagic flux assays, and mouse knockout","pmids":["33859171"],"confidence":"Medium","gaps":["Single lab","Direct vs scaffolded interaction with FYCO1 not distinguished"]},{"year":2021,"claim":"Showed FYCO1 binds α-crystallins and is required to maintain their solubility and autophagic turnover in the lens.","evidence":"Yeast two-hybrid, co-IP, and LC3/p62 immunoblotting in KO mouse eyes","pmids":["34215815"],"confidence":"Medium","gaps":["Single lab","Whether α-crystallin is a direct autophagic cargo of FYCO1 not formally shown"]},{"year":2021,"claim":"Established FYCO1 as selectively required for stress-induced (not basal) cardiac autophagy and protective against biomechanical stress.","evidence":"Fyco1 KO and transgenic overexpression mice in pressure-overload/starvation models with cardiomyocyte autophagic flux assays","pmids":["33997522"],"confidence":"High","gaps":["Molecular trigger distinguishing induced from basal autophagy dependence unknown"]},{"year":2020,"claim":"Determined the high-resolution structure of the FYCO1 RUN domain and modeled possible GTPase interfaces, addressing its potential small-GTPase recognition.","evidence":"1.3 Å X-ray crystallography with structural comparison and computational docking","pmids":["32744243"],"confidence":"Medium","gaps":["No binding partner experimentally validated","Docking is computational only"]},{"year":2022,"claim":"Confirmed in vivo that FYCO1 loss impairs autophagic flux and lens organelle clearance, causally linking the molecular defect to cataractogenesis.","evidence":"Fyco1 KO mice and human lens knock-in cells with TEM and multi-omics profiling","pmids":["35343376"],"confidence":"High","gaps":["Which organelle-clearance step is rate-limiting not pinpointed"]},{"year":2022,"claim":"Placed FYCO1 upstream of CDC42/N-WASP/Arp2/3 signaling in driving migration, invasion, and EMT, broadening its role beyond vesicle transport.","evidence":"Gain/loss-of-function migration/invasion assays with Arp2/3 inhibitor (CK666) epistasis in HeLa cells","pmids":["36342046"],"confidence":"Medium","gaps":["Single lab","How an autophagy adaptor connects to CDC42 signaling not mechanistically established"]},{"year":2023,"claim":"Defined the GOLD domain as a hub coupling FYCO1 to RAB7A-activating CCZ1–MON1A and to CASP8, with cleavage at Asp1306 linking vesicle transport to death-receptor trafficking and apoptosis.","evidence":"Two-step AP-MS, CASP8 cleavage-site mapping, KO/knockdown cells, DISC analysis, and TRAIL apoptosis assays","pmids":["37418591"],"confidence":"High","gaps":["Physiological contexts in which CASP8 cleavage of FYCO1 dominates not defined","Whether GOLD-mediated CCZ1–MON1A binding is required for all FYCO1 transport functions untested"]},{"year":2024,"claim":"Identified a FYCO1–PAK1–p21 axis governing stress-induced senescence in lens epithelial cells.","evidence":"FYCO1 KO cell lines with senescence assays, qRT-PCR, and immunoblot under UVB/H2O2 stress","pmids":["39395618"],"confidence":"Medium","gaps":["Single lab","How FYCO1 regulates PAK1 expression not mechanistically resolved"]},{"year":null,"claim":"It remains unknown which kinesin motor FYCO1 directly engages and how cargo selectivity (organelles, midbodies, protein aggregates, crystallins) is encoded across its diverse physiological roles.","evidence":"","pmids":[],"confidence":"Low","gaps":["Direct motor partner not biochemically identified","Cargo-recognition determinants beyond LC3/Rab7/PI3P not defined","Distinction between transport-dependent and signaling roles unresolved"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,2,14]},{"term_id":"GO:0008289","term_label":"lipid binding","supporting_discovery_ids":[0]},{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[0]}],"localization":[{"term_id":"GO:0031410","term_label":"cytoplasmic vesicle","supporting_discovery_ids":[0,5]},{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[0,14]},{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[0,5]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0]}],"pathway":[{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[0,2,12,15]},{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[0,14]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[14]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[6]}],"complexes":["chromatoid body"],"partners":["MAP1LC3B","MAP1LC3A","RAB7A","STK4","CASP8","CCZ1","MON1A","CRYAA"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9BQS8","full_name":"FYVE and coiled-coil domain-containing protein 1","aliases":["Zinc finger FYVE domain-containing protein 7"],"length_aa":1478,"mass_kda":167.0,"function":"May mediate microtubule plus end-directed vesicle transport","subcellular_location":"Cytoplasmic vesicle, autophagosome; Endosome; Lysosome","url":"https://www.uniprot.org/uniprotkb/Q9BQS8/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/FYCO1","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":[{"gene":"MAP1LC3B","stoichiometry":4.0}],"url":"https://opencell.sf.czbiohub.org/search/FYCO1","total_profiled":1310},"omim":[{"mim_id":"610243","title":"ZINC FINGER FYVE DOMAIN-CONTAINING PROTEIN 27; ZFYVE27","url":"https://www.omim.org/entry/610243"},{"mim_id":"610019","title":"CATARACT 18; CTRCT18","url":"https://www.omim.org/entry/610019"},{"mim_id":"607182","title":"FYVE AND COILED-COIL DOMAIN CONTAINING 1; FYCO1","url":"https://www.omim.org/entry/607182"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Vesicles","reliability":"Enhanced"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"skeletal muscle","ntpm":246.2}],"url":"https://www.proteinatlas.org/search/FYCO1"},"hgnc":{"alias_symbol":["FLJ13335","ZFYVE7"],"prev_symbol":[]},"alphafold":{"accession":"Q9BQS8","domains":[{"cath_id":"1.20.58.900","chopping":"5-179","consensus_level":"high","plddt":87.2161,"start":5,"end":179},{"cath_id":"3.30.40.10","chopping":"1170-1231","consensus_level":"medium","plddt":77.8097,"start":1170,"end":1231},{"cath_id":"2.60.120.680","chopping":"1337-1468","consensus_level":"high","plddt":92.4047,"start":1337,"end":1468}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9BQS8","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9BQS8-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9BQS8-F1-predicted_aligned_error_v6.png","plddt_mean":71.88},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=FYCO1","jax_strain_url":"https://www.jax.org/strain/search?query=FYCO1"},"sequence":{"accession":"Q9BQS8","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9BQS8.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9BQS8/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9BQS8"}},"corpus_meta":[{"pmid":"20100911","id":"PMC_20100911","title":"FYCO1 is a Rab7 effector that binds to LC3 and PI3P to mediate microtubule plus end-directed vesicle transport.","date":"2010","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/20100911","citation_count":514,"is_preprint":false},{"pmid":"21636066","id":"PMC_21636066","title":"Mutations in FYCO1 cause autosomal-recessive congenital cataracts.","date":"2011","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/21636066","citation_count":139,"is_preprint":false},{"pmid":"26468287","id":"PMC_26468287","title":"FYCO1 Contains a C-terminally Extended, LC3A/B-preferring LC3-interacting Region (LIR) Motif Required for Efficient Maturation of Autophagosomes during Basal Autophagy.","date":"2015","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/26468287","citation_count":107,"is_preprint":false},{"pmid":"20364109","id":"PMC_20364109","title":"FYCO1: linking autophagosomes to microtubule plus end-directing molecular motors.","date":"2010","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/20364109","citation_count":64,"is_preprint":false},{"pmid":"24442442","id":"PMC_24442442","title":"Cutting edge: FYCO1 recruitment to dectin-1 phagosomes is accelerated by light chain 3 protein and regulates phagosome maturation and reactive oxygen production.","date":"2014","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/24442442","citation_count":61,"is_preprint":false},{"pmid":"34146484","id":"PMC_34146484","title":"LC3B phosphorylation regulates FYCO1 binding and directional transport of autophagosomes.","date":"2021","source":"Current biology : CB","url":"https://pubmed.ncbi.nlm.nih.gov/34146484","citation_count":46,"is_preprint":false},{"pmid":"33859171","id":"PMC_33859171","title":"Nlp promotes autophagy through facilitating the interaction of Rab7 and FYCO1.","date":"2021","source":"Signal transduction and targeted 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Basic to translational science","url":"https://pubmed.ncbi.nlm.nih.gov/33997522","citation_count":17,"is_preprint":false},{"pmid":"32355443","id":"PMC_32355443","title":"Mutations in FYCO1 identified in families with congenital cataracts.","date":"2020","source":"Molecular vision","url":"https://pubmed.ncbi.nlm.nih.gov/32355443","citation_count":15,"is_preprint":false},{"pmid":"33767456","id":"PMC_33767456","title":"Autosomal recessive cataract (CTRCT18) in the Yakut population isolate of Eastern Siberia: a novel founder variant in the FYCO1 gene.","date":"2021","source":"European journal of human genetics : EJHG","url":"https://pubmed.ncbi.nlm.nih.gov/33767456","citation_count":11,"is_preprint":false},{"pmid":"36342046","id":"PMC_36342046","title":"FYCO1 regulates migration, invasion, and invadopodia formation in HeLa cells through CDC42/N-WASP/Arp2/3 signaling pathway.","date":"2022","source":"Biochemistry and cell biology = Biochimie et biologie cellulaire","url":"https://pubmed.ncbi.nlm.nih.gov/36342046","citation_count":8,"is_preprint":false},{"pmid":"39395618","id":"PMC_39395618","title":"FYCO1 regulates autophagy and senescence via PAK1/p21 in cataract.","date":"2024","source":"Archives of biochemistry and biophysics","url":"https://pubmed.ncbi.nlm.nih.gov/39395618","citation_count":7,"is_preprint":false},{"pmid":"37547597","id":"PMC_37547597","title":"GWAS reveals genetic basis of a predisposition to severe COVID-19 through in silico modeling of the FYCO1 protein.","date":"2023","source":"Frontiers in medicine","url":"https://pubmed.ncbi.nlm.nih.gov/37547597","citation_count":6,"is_preprint":false},{"pmid":"35205377","id":"PMC_35205377","title":"FYCO1 Frameshift Deletion in Wirehaired Pointing Griffon Dogs with Juvenile Cataract.","date":"2022","source":"Genes","url":"https://pubmed.ncbi.nlm.nih.gov/35205377","citation_count":5,"is_preprint":false},{"pmid":"32744243","id":"PMC_32744243","title":"Crystal structure of the FYCO1 RUN domain suggests possible interfaces with small GTPases.","date":"2020","source":"Acta crystallographica. 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FYCO1 depletion causes perinuclear clustering of autophagosomes, while overexpression redistributes Rab7-positive vesicles to the cell periphery.\",\n      \"method\": \"Co-IP/pulldown identification of binding partners, domain mapping of LC3/Rab7/PI3P-binding regions, knockdown and overexpression with live-cell imaging readout\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal binding assays with domain mapping, knockdown and overexpression with defined organelle-transport phenotypes, foundational paper widely replicated\",\n      \"pmids\": [\"20100911\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"A proposed mechanism for selective autophagosomal membrane recruitment of FYCO1 involves a conformational change upon LC3-LIR interaction that exposes the FYVE domain for PI3P binding.\",\n      \"method\": \"Domain binding assays and functional analysis discussed in review/commentary context with reference to original experimental data\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — mechanistic model supported by domain mapping from primary paper (PMID:20100911); this commentary consolidates those findings without new experiments\",\n      \"pmids\": [\"20364109\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"FYCO1 contains a C-terminally extended, F-type LIR motif (9 amino acids) that preferentially binds LC3A and LC3B. Crystal structure of FYCO1 LIR peptide–LC3B complex at 1.53 Å resolution revealed that residues at positions 8 (acidic, Asp1285) and 9 (hydrophobic) beyond the core LIR are required for efficient LC3B binding, with Asp1285 contacting His57 of LC3B conferring LC3A/B specificity. A functional LIR motif is required for efficient maturation of autophagosomes under basal (but not starvation-induced) autophagy conditions.\",\n      \"method\": \"Crystal structure determination (1.53 Å), peptide array-based 2D mutational scanning, mutational analysis, FYCO1 knockout cell reconstitution with WT and LIR-mutant constructs\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure plus mutagenesis plus functional rescue experiments in KO cells, multiple orthogonal methods in single study\",\n      \"pmids\": [\"26468287\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Crystal structure of mouse LC3B in complex with the FYCO1 LIR peptide confirmed that flanking sequences N-terminal and C-terminal to the core LIR tetrapeptide are specifically recognized by LC3B and contribute to binding, and that this recognition mechanism is conserved across LC3 isoforms and species.\",\n      \"method\": \"X-ray crystallography; structural comparison with related LC3-LIR complexes\",\n      \"journal\": \"Acta crystallographica. Section F, Structural biology communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — independent crystal structure replicating and extending findings of PMID:26468287, confirming flanking-region contacts\",\n      \"pmids\": [\"28291748\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Crystal structure of the FYCO1 RUN domain was determined at 1.3 Å resolution; structural comparisons and docking studies identified possible interaction interfaces with small GTPases of the Ras superfamily, but no binding partner was experimentally confirmed.\",\n      \"method\": \"X-ray crystallography (1.3 Å), structural comparison, computational docking\",\n      \"journal\": \"Acta crystallographica. Section F, Structural biology communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — high-resolution structure, but interaction partner not experimentally validated; docking is computational only\",\n      \"pmids\": [\"32744243\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Loss-of-function mutations in FYCO1 cause autosomal-recessive congenital cataracts. Wild-type and the missense mutant p.L1376Pro FYCO1 expressed in human lens epithelial cells colocalize to autophagosomes and partially to microtubules, consistent with a role in autophagosomal transport in the lens.\",\n      \"method\": \"Human genetics (linkage + Sanger sequencing), immunoblot of truncated mutant proteins, subcellular localization by immunofluorescence in human lens epithelial cells\",\n      \"journal\": \"American journal of human genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct localization experiments in relevant cell type plus genetic evidence; mechanism inferred from co-localization without functional rescue\",\n      \"pmids\": [\"21636066\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"During LC3-associated phagocytosis, FYCO1 is recruited directly by LC3 to Dectin-1 phagosomes and facilitates maturation of early p40phox+ phagosomes into late LAMP1+ phagosomes. Loss of FYCO1 prolongs p40phox+ phagosome stage and increases reactive oxygen production.\",\n      \"method\": \"FYCO1 knockdown/knockout in macrophages, live imaging and immunofluorescence of phagosome maturation markers, ROS measurement\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function with two defined functional readouts (maturation markers and ROS), single lab\",\n      \"pmids\": [\"24442442\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"STK4/MST1-mediated phosphorylation of LC3B on threonine 50 (LC3B-T50) reduces FYCO1 binding to LC3B. Impairment of LC3B-T50 phosphorylation (T50A mutation) decreases starvation-induced perinuclear positioning of autophagosomes and their colocalization with lysosomes, and causes aberrant anterograde movement of autophagosomes in neurons and peripheral cells. This defines a nutrient-sensitive STK4–LC3B–FYCO1 axis regulating directional autophagosomal transport.\",\n      \"method\": \"In vitro binding assays with phospho-LC3B, LC3B phosphorylation mutants, autophagosome tracking by live imaging in neurons and cell lines, lysosome colocalization assays\",\n      \"journal\": \"Current biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — in vitro binding + phospho-mutant phenotyping + live-cell imaging in multiple cell types, multiple orthogonal methods in one study\",\n      \"pmids\": [\"34146484\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"The centrosomal protein Nlp interacts physically with LC3, Rab7, and FYCO1, and enhances the Rab7–FYCO1 interaction, thereby accelerating autophagic flux and autophagolysosome formation.\",\n      \"method\": \"Co-IP, colocalization by immunofluorescence, autophagic flux assays, genetic knockout in mice\",\n      \"journal\": \"Signal transduction and targeted therapy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP and defined functional readout (autophagic flux), single lab\",\n      \"pmids\": [\"33859171\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"FYCO1 mediates Rab7-dependent clearance of α-synuclein aggregates. FYCO1-decorated vesicles contained α-synuclein (unlike RILP-decorated vesicles). FYCO1 overexpression reduced α-synuclein aggregate number and protein levels; FYCO1 knockdown reduced Rab7-induced aggregate clearance. The effect of FYCO1 required active (GTP-bound) Rab7, as dominant-negative Rab7 blocked FYCO1-mediated clearance. FYCO1 coexpression in a Drosophila A53T-α-synuclein model reduced aggregates and rescued locomotor deficits.\",\n      \"method\": \"Live-cell imaging, western blot, siRNA knockdown, dominant-negative Rab7, Trypan blue viability, time-lapse microscopy, Drosophila model with filter trap assay and locomotor assay\",\n      \"journal\": \"Journal of neurochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods across mammalian cells and Drosophila in vivo model, gain- and loss-of-function, epistasis with dominant-negative Rab7\",\n      \"pmids\": [\"29747217\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"FYCO1 is a component of the chromatoid body (CB) in haploid round spermatids. Autophagy induction recruits lysosomal vesicles to the CB in a FYCO1-dependent manner; in germ cell-specific Fyco1 conditional knockout mice, this recruitment is lost and the CB becomes fragmented, indicating FYCO1-mediated autophagy regulates RNP granule integrity.\",\n      \"method\": \"Germ cell-specific conditional Fyco1 knockout mouse model, electron microscopy, immunofluorescence, autophagy induction assays\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — conditional KO mouse with defined organelle phenotype (CB fragmentation, loss of lysosome recruitment), multiple imaging methods\",\n      \"pmids\": [\"27929729\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"FYCO1 is responsible for formation of LC3-containing membrane around post-mitotic midbodies and regulates midbody degradation by autophagy. FYCO1 knockdown increases midbody accumulation, which in turn promotes anchorage-independent growth and invadopodia formation in HeLa and squamous carcinoma cells.\",\n      \"method\": \"FYCO1 siRNA knockdown, immunofluorescence for LC3/midbody markers, midbody accumulation quantification, anchorage-independent growth assay, invadopodia assay\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — knockdown with defined mechanistic phenotype (LC3 membrane around midbody) and downstream cellular readouts, single lab\",\n      \"pmids\": [\"29196475\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Loss of FYCO1 in fyco1 knockout mice results in diminished autophagic flux, impaired organelle removal (organelles accumulate in the organelle-free zone of the lens), and cataractogenesis, confirming FYCO1's role in lens fiber cell differentiation via autophagy-dependent organelle clearance.\",\n      \"method\": \"Fyco1 knockout mice, flow cytometry of autophagic flux in FYCO1 knock-in human lens epithelial cells, transmission electron microscopy of lens organoids and mouse lenses, transcriptome/proteome/metabolome profiling\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — knockout mouse + knock-in human cells + TEM + multiple omics, multiple orthogonal methods confirming autophagic flux impairment and organelle accumulation\",\n      \"pmids\": [\"35343376\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"FYCO1 interacts with αA- and αB-crystallin (identified by yeast two-hybrid and confirmed by co-immunoprecipitation). In FYCO1 knockout mice, soluble αA- and αB-crystallin decrease, LC3-I to LC3-II conversion is reduced, and p62 accumulates, suggesting FYCO1 recruits damaged α-crystallin into autophagosomes.\",\n      \"method\": \"Yeast two-hybrid screening, co-immunoprecipitation, immunoblot of LC3-I/LC3-II conversion and p62 in KO mouse eyes\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — yeast two-hybrid plus co-IP for novel binding partners, KO mouse with defined biochemical readouts; single lab\",\n      \"pmids\": [\"34215815\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"FYCO1 interacts with activated CASP8 (caspase 8) via its C-terminal GOLD domain and is a specific CASP8 substrate cleaved at aspartate 1306, releasing the GOLD domain and inactivating FYCO1. FYCO1 also interacts via its GOLD domain with the CCZ1–MON1A complex required for RAB7A activation and vesicle-lysosome fusion. Loss of FYCO1 impairs TNFRSF10B/TRAIL-R2 transport to lysosomes and stabilizes the DISC, sensitizing cells to TRAIL-induced apoptosis.\",\n      \"method\": \"Two-step Co-IP/affinity purification–mass spectrometry (AP-MS), CASP8 cleavage site mapping, FYCO1 KO and knockdown cell lines, DISC complex analysis, receptor trafficking assays, flow cytometry of apoptosis\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Moderate — AP-MS identification of interactions, caspase cleavage mapping with defined cleavage site, KO phenotype with mechanistic pathway placement, multiple orthogonal methods in single study\",\n      \"pmids\": [\"37418591\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"FYCO1 is required for autophagy induction (but not basal autophagy) in cardiomyocytes in response to glucose deprivation. Fyco1-deficient mice subjected to starvation or pressure overload cannot induce autophagy and develop impaired cardiac function. FYCO1 overexpression induces autophagy in cardiomyocytes and rescues cardiac dysfunction under biomechanical stress.\",\n      \"method\": \"Fyco1 knockout mice with pressure-overload and starvation models, FYCO1 transgenic overexpression mice, autophagic flux measurement in isolated cardiomyocytes, cardiac function assessment\",\n      \"journal\": \"JACC. Basic to translational science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo KO and transgenic overexpression with defined cardiac and autophagic phenotypes, multiple models\",\n      \"pmids\": [\"33997522\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"FYCO1 promotes migration, invasion, invadopodia formation, and epithelial-mesenchymal transition in HeLa cells through the CDC42/N-WASP/Arp2/3 signaling pathway, as demonstrated by pharmacological inhibition of Arp2/3 with CK666 blocking FYCO1-dependent migration and invasion.\",\n      \"method\": \"FYCO1 overexpression/knockdown, wound healing assay, transwell invasion assay, immunofluorescence for invadopodia, western blot, Arp2/3 inhibitor (CK666) epistasis\",\n      \"journal\": \"Biochemistry and cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — pharmacological epistasis placing FYCO1 upstream of CDC42/N-WASP/Arp2/3, supported by gain- and loss-of-function assays; single lab\",\n      \"pmids\": [\"36342046\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"FYCO1 knockout in human lens epithelial cells suppresses H2O2- and UVB-induced senescence and p21 levels by suppressing the expression of PAK1 (p21-activated kinase 1), identifying a FYCO1–PAK1–p21 axis in stress-induced autophagy and senescence in lens epithelial cells.\",\n      \"method\": \"FYCO1 knockout cell lines, CCK8 viability, SA-β-Gal senescence assay, qRT-PCR, western blot, immunofluorescence, UVB/H2O2 stress models\",\n      \"journal\": \"Archives of biochemistry and biophysics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function with defined pathway (PAK1/p21) by western blot and functional readouts, single lab, single publication\",\n      \"pmids\": [\"39395618\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Depletion of FYCO1 did NOT phenocopy protrudin or KIF5 depletion for endosomal tubule fission (ETF), establishing that FYCO1's role in late endosome motility is distinct from KIF5-mediated ETF at ER-endosome contacts.\",\n      \"method\": \"Knockdown epistasis; ETF phenotype (increased endosomal tubulation) was assessed by imaging\",\n      \"journal\": \"bioRxiv (preprint)\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single negative result in a preprint; single method, not directly focused on FYCO1 mechanism\",\n      \"pmids\": [\"bio_10.1101_2024.07.15.602703\"],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"FYCO1 is a multi-domain autophagy adaptor that simultaneously binds LC3A/B (via a C-terminally extended F-type LIR motif whose structural basis is resolved crystallographically), active Rab7, and PI3P (via its FYVE domain) on the cytoplasmic face of autophagosomes and late endosomes, coupling these vesicles to microtubule plus end-directed kinesin motors to drive their anterograde transport toward the cell periphery; directional bias is regulated by STK4/MST1-mediated phosphorylation of LC3B-T50, which reduces FYCO1 binding; FYCO1 is cleaved and inactivated by CASP8 at Asp1306, linking vesicle transport to apoptotic signaling; and FYCO1-dependent autophagic transport is required for organelle clearance in the lens, midbody degradation, RNP granule homeostasis in spermatids, cardiac stress responses, and Rab7-mediated α-synuclein aggregate clearance.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"FYCO1 is a multivalent autophagy adaptor that links autophagosomes and late endosomes to plus end-directed microtubule transport, simultaneously engaging LC3, active Rab7, and PI3P to drive anterograde vesicle movement toward the cell periphery [#0]. Membrane recruitment is governed by a C-terminally extended F-type LIR motif that selectively binds LC3A/B; crystal structures of the FYCO1 LIR–LC3B complex show that acidic and hydrophobic residues flanking the core tetrapeptide (notably Asp1285 contacting LC3B His57) confer isoform specificity and are required for efficient basal-autophagy autophagosome maturation [#2, #3]. The directionality of this transport is nutrient-tuned: STK4/MST1-mediated phosphorylation of LC3B on Thr50 reduces FYCO1 binding, biasing autophagosomes toward perinuclear lysosomes during starvation [#7]. Through its C-terminal GOLD domain, FYCO1 binds the CCZ1–MON1A complex that activates RAB7A and is itself cleaved at Asp1306 by activated CASP8, coupling vesicle-to-lysosome transport and death-receptor trafficking to apoptotic signaling [#14]. Functionally, FYCO1-dependent autophagic transport mediates organelle clearance during lens fiber differentiation—loss-of-function mutations cause autosomal-recessive congenital cataract [#5, #12]—as well as midbody degradation [#11], chromatoid-body/RNP-granule integrity in spermatids [#10], stress-induced cardiac autophagy [#15], LC3-associated phagosome maturation [#6], and Rab7-dependent clearance of α-synuclein aggregates [#9].\",\n  \"teleology\": [\n    {\n      \"year\": 2010,\n      \"claim\": \"Established FYCO1 as the molecular bridge coupling autophagosomes to anterograde microtubule transport, answering how these vesicles are positioned within the cell.\",\n      \"evidence\": \"Co-IP/domain mapping of LC3/Rab7/PI3P-binding regions with knockdown and overexpression live-cell imaging\",\n      \"pmids\": [\"20100911\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of the kinesin motor engaged was not biochemically resolved\", \"Stoichiometry of the LC3/Rab7/PI3P co-recruitment not defined\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Proposed that LC3-LIR binding triggers a conformational change exposing the FYVE domain, addressing how FYCO1 achieves selective membrane recruitment.\",\n      \"evidence\": \"Mechanistic model consolidating domain-mapping data in a commentary\",\n      \"pmids\": [\"20364109\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No structural or biophysical demonstration of the proposed conformational switch\", \"No new experimental data beyond the primary paper\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Linked FYCO1 to human disease by showing loss-of-function mutations cause autosomal-recessive congenital cataract, implicating autophagosomal transport in lens biology.\",\n      \"evidence\": \"Linkage and Sanger sequencing in families plus immunofluorescence localization of WT and p.L1376Pro mutant in lens epithelial cells\",\n      \"pmids\": [\"21636066\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism inferred from colocalization without functional rescue\", \"How autophagic transport defects produce lens opacity not established\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Extended FYCO1 function to LC3-associated phagocytosis, showing it is recruited by LC3 to drive phagosome maturation independent of canonical autophagy.\",\n      \"evidence\": \"Knockdown/knockout in macrophages with phagosome maturation marker imaging and ROS measurement\",\n      \"pmids\": [\"24442442\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab\", \"Whether Rab7/PI3P engagement is required for phagosomal recruitment not tested\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Defined the structural basis for FYCO1's LC3 selectivity, resolving why it preferentially binds LC3A/B and how this supports basal autophagosome maturation.\",\n      \"evidence\": \"1.53 Å crystal structure of FYCO1 LIR–LC3B, peptide-array mutational scanning, and KO cell reconstitution with LIR mutants\",\n      \"pmids\": [\"26468287\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Why the LIR is dispensable under starvation but required basally not mechanistically explained\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Showed FYCO1 maintains RNP granule integrity in spermatids by recruiting lysosomal vesicles to the chromatoid body via autophagy.\",\n      \"evidence\": \"Germ cell-specific conditional Fyco1 knockout mice with electron microscopy and autophagy induction assays\",\n      \"pmids\": [\"27929729\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular tether linking FYCO1 to the chromatoid body not identified\", \"Cargo selectivity at the CB unknown\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Independently confirmed flanking-region recognition of the FYCO1 LIR by LC3B and established its conservation across LC3 isoforms and species.\",\n      \"evidence\": \"X-ray crystallography of mouse LC3B–FYCO1 LIR with structural comparison\",\n      \"pmids\": [\"28291748\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not address in-cell affinity differences among LC3 paralogs\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Identified FYCO1 as the mediator of autophagic midbody degradation, connecting its loss to oncogenic phenotypes through midbody accumulation.\",\n      \"evidence\": \"siRNA knockdown with LC3/midbody imaging, anchorage-independent growth and invadopodia assays\",\n      \"pmids\": [\"29196475\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab\", \"How midbody accumulation mechanistically drives transformation not resolved\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Demonstrated FYCO1 drives Rab7-dependent clearance of α-synuclein aggregates, with epistasis showing the effect requires GTP-bound Rab7.\",\n      \"evidence\": \"Gain/loss-of-function in mammalian cells, dominant-negative Rab7 epistasis, and a Drosophila A53T-α-synuclein rescue model\",\n      \"pmids\": [\"29747217\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether α-synuclein is captured by direct FYCO1 binding or as bulk cargo not determined\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Revealed a nutrient-sensitive STK4–LC3B–FYCO1 axis in which LC3B-T50 phosphorylation tunes FYCO1 binding to control autophagosome directionality.\",\n      \"evidence\": \"In vitro binding with phospho-LC3B, T50A mutants, and autophagosome tracking in neurons and cell lines\",\n      \"pmids\": [\"34146484\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How STK4 activity is spatially coordinated with autophagosomes not defined\", \"Quantitative effect on motor engagement unmeasured\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Identified the centrosomal protein Nlp as an enhancer of the Rab7–FYCO1 interaction that accelerates autophagic flux.\",\n      \"evidence\": \"Co-IP, colocalization, autophagic flux assays, and mouse knockout\",\n      \"pmids\": [\"33859171\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab\", \"Direct vs scaffolded interaction with FYCO1 not distinguished\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Showed FYCO1 binds α-crystallins and is required to maintain their solubility and autophagic turnover in the lens.\",\n      \"evidence\": \"Yeast two-hybrid, co-IP, and LC3/p62 immunoblotting in KO mouse eyes\",\n      \"pmids\": [\"34215815\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab\", \"Whether α-crystallin is a direct autophagic cargo of FYCO1 not formally shown\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Established FYCO1 as selectively required for stress-induced (not basal) cardiac autophagy and protective against biomechanical stress.\",\n      \"evidence\": \"Fyco1 KO and transgenic overexpression mice in pressure-overload/starvation models with cardiomyocyte autophagic flux assays\",\n      \"pmids\": [\"33997522\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular trigger distinguishing induced from basal autophagy dependence unknown\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Determined the high-resolution structure of the FYCO1 RUN domain and modeled possible GTPase interfaces, addressing its potential small-GTPase recognition.\",\n      \"evidence\": \"1.3 Å X-ray crystallography with structural comparison and computational docking\",\n      \"pmids\": [\"32744243\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No binding partner experimentally validated\", \"Docking is computational only\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Confirmed in vivo that FYCO1 loss impairs autophagic flux and lens organelle clearance, causally linking the molecular defect to cataractogenesis.\",\n      \"evidence\": \"Fyco1 KO mice and human lens knock-in cells with TEM and multi-omics profiling\",\n      \"pmids\": [\"35343376\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Which organelle-clearance step is rate-limiting not pinpointed\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Placed FYCO1 upstream of CDC42/N-WASP/Arp2/3 signaling in driving migration, invasion, and EMT, broadening its role beyond vesicle transport.\",\n      \"evidence\": \"Gain/loss-of-function migration/invasion assays with Arp2/3 inhibitor (CK666) epistasis in HeLa cells\",\n      \"pmids\": [\"36342046\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab\", \"How an autophagy adaptor connects to CDC42 signaling not mechanistically established\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Defined the GOLD domain as a hub coupling FYCO1 to RAB7A-activating CCZ1–MON1A and to CASP8, with cleavage at Asp1306 linking vesicle transport to death-receptor trafficking and apoptosis.\",\n      \"evidence\": \"Two-step AP-MS, CASP8 cleavage-site mapping, KO/knockdown cells, DISC analysis, and TRAIL apoptosis assays\",\n      \"pmids\": [\"37418591\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological contexts in which CASP8 cleavage of FYCO1 dominates not defined\", \"Whether GOLD-mediated CCZ1–MON1A binding is required for all FYCO1 transport functions untested\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identified a FYCO1–PAK1–p21 axis governing stress-induced senescence in lens epithelial cells.\",\n      \"evidence\": \"FYCO1 KO cell lines with senescence assays, qRT-PCR, and immunoblot under UVB/H2O2 stress\",\n      \"pmids\": [\"39395618\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab\", \"How FYCO1 regulates PAK1 expression not mechanistically resolved\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unknown which kinesin motor FYCO1 directly engages and how cargo selectivity (organelles, midbodies, protein aggregates, crystallins) is encoded across its diverse physiological roles.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Direct motor partner not biochemically identified\", \"Cargo-recognition determinants beyond LC3/Rab7/PI3P not defined\", \"Distinction between transport-dependent and signaling roles unresolved\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 2, 14]},\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [0, 5]},\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [0, 14]},\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [0, 5]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [0, 2, 12, 15]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [0, 14]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [14]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [6]}\n    ],\n    \"complexes\": [\"chromatoid body\"],\n    \"partners\": [\"MAP1LC3B\", \"MAP1LC3A\", \"RAB7A\", \"STK4\", \"CASP8\", \"CCZ1\", \"MON1A\", \"CRYAA\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"faith_supported":5,"faith_total":5,"faith_pct":100.0}}