{"gene":"KLC1","run_date":"2026-06-10T02:59:49","timeline":{"discoveries":[{"year":2012,"finding":"A small 10-amino-acid WD motif in the KLC1 cargo protein Alcadein-α cytoplasmic region is necessary and sufficient to activate kinesin-1 through interaction with the tetratricopeptide repeat (TPR) region of KLC1, promoting vesicular association and anterograde transport; only part of the TPR structure is required for this activation in vivo.","method":"In vivo transport assays with artificial transmembrane proteins containing WD motifs, excess KLC1 competition experiments, and domain-deletion analysis of KLC1 TPR region","journal":"Traffic (Copenhagen, Denmark)","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal in vivo methods (artificial construct assay, excess KLC1 competition, domain deletion), internally replicated with both Alcα and JIP1 cargo proteins","pmids":["22404616"],"is_preprint":false},{"year":2015,"finding":"KLC1 associates with phagosomes derived from photoreceptor outer segment (POS) disk membranes in the retinal pigment epithelium (RPE) and remains associated during bidirectional microtubule-based movement (including pauses). Loss of KLC1 does not impair phagosome speed but reduces run length and impairs phagosome localization and degradation, leading to AMD-like RPE pathogenesis in aged mice.","method":"Live-cell imaging of RPE phagosomes, KLC1 knockout mice with phenotypic analysis including accumulation of RPE/sub-RPE deposits, oxidative and inflammatory stress markers","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — live imaging plus genetic KO with specific cellular phenotypes (run length, localization, degradation) and in vivo AMD-like pathology, single lab but multiple orthogonal readouts","pmids":["26261180"],"is_preprint":false},{"year":2021,"finding":"KLC1 acts as a selective adaptor within a tetrameric kinesin complex (KIF5A/KLC1) to bind the RNA-binding protein SFPQ, enabling long-distance axonal transport of SFPQ-RNA granules; this binding is required for axon survival and is disrupted by KIF5A mutations that cause Charcot-Marie Tooth disease.","method":"Co-immunoprecipitation of SFPQ with KIF5A/KLC1 complex, genetic loss-of-function (CMT-associated KIF5A mutants), axon degeneration assays, therapeutic rescue experiments","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal co-IP establishing complex, genetic epistasis with CMT mutations, axon survival as functional readout, therapeutic rescue as orthogonal confirmation","pmids":["33284322"],"is_preprint":false},{"year":2017,"finding":"Phosphorylation of KLC1 at Thr466 abolishes its conventional interaction with JIP1b and eliminates the enhanced fast velocity (EFV) of APP anterograde transport by kinesin-1, without impairing a separate novel interaction between the central region of JIP1b and the coiled-coil domain of KLC1 that controls efficient high frequency (EHF) of transport. Phosphorylation at Thr466 increases in aged brains, correlating with decreased JIP1 binding to kinesin-1.","method":"Site-directed mutagenesis (Thr466Glu phosphomimetic), in vivo transport velocity measurements, co-immunoprecipitation, aged brain biochemistry","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 1 / Moderate — mutagenesis directly demonstrating phosphorylation-dependent loss of interaction and transport velocity, supported by biochemical correlation in aged brain tissue","pmids":["29093025"],"is_preprint":false},{"year":2018,"finding":"Using isothermal titration calorimetry (ITC), seven KLC1 residues in the TPR domain were identified as critical for JIP1 binding; the autoinhibitory LFP-acidic motif of KLC1 marginally inhibits JIP1 binding by overlapping the same footprint; JIP1 and Alcadein-α W-acidic motif compete for the same KLC1-TPR binding site.","method":"Isothermal titration calorimetry with truncated KLC1 TPR fragments, mutagenesis of critical KLC1 residues, structural footprinting against published crystal structure of KLC1-TPR:JIP1 complex","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — quantitative biophysical method (ITC) with mutagenesis of seven specific residues, validated against crystal structure, single lab but multiple orthogonal experiments","pmids":["30026235"],"is_preprint":false},{"year":2019,"finding":"DOC2B is phosphorylated upon insulin stimulation (at Y301), and this phosphorylation enhances its interaction with KLC1; mutation of Y301 in DOC2B blocks insulin-stimulated phosphorylation, abolishes interaction with KLC1, and blunts insulin-stimulated GLUT4 accumulation at the plasma membrane in skeletal muscle cells.","method":"Site-directed mutagenesis (Y301 in DOC2B), co-immunoprecipitation, mass spectrometry, skeletal-muscle-specific transgenic mice, GLUT4 plasma membrane accumulation assays","journal":"Diabetologia","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — mutagenesis establishing phosphorylation-dependent binding, co-IP, in vivo transgenic mouse model with physiological glucose tolerance readout, and in vitro cell assays","pmids":["30707251"],"is_preprint":false},{"year":2009,"finding":"Purified AMPK phosphorylates recombinant GST-KLC1 at Ser520 in vitro; however, overexpression of wild-type, phosphomimetic (S517/520D), or non-phosphorylatable (S517/520A) KLC1 mutants produced no difference in glucose-stimulated insulin granule transport dynamics, and no change in KLC1 Ser520 phosphorylation state was detected after AMPK activation. NEGATIVE RESULT: KLC1 phosphorylation at Ser517/520 does not regulate kinesin-1-mediated insulin granule transport.","method":"In vitro kinase assay with purified AMPK and recombinant GST-KLC1, overexpression of phosphomutants in MIN6 cells, 3D live-cell spinning disc confocal imaging of granule dynamics, phospho-specific antibody","journal":"Islets","confidence":"Medium","confidence_rationale":"Tier 1-2 / Moderate — in vitro kinase assay demonstrates phosphorylation occurs, but multiple functional assays (overexpression, 3D imaging) demonstrate no effect on transport; negative functional result independently replicated in companion paper (PMID 20074060)","pmids":["21099273","20074060"],"is_preprint":false},{"year":2014,"finding":"KLC1 physically interacts with the mitochondrial fission protein Dynamin-1-like protein (Dnm1L/DRP1) through its TPR domains, and the two proteins co-localize in cultured cells; Dnm1L does not interact with KIF5 directly, suggesting KLC1 mediates post-fission mitochondrial transport.","method":"Yeast two-hybrid screening, co-localization in cultured cells","journal":"Bioscience, biotechnology, and biochemistry","confidence":"Low","confidence_rationale":"Tier 3 / Weak — yeast two-hybrid and co-localization only, no co-IP or functional transport assay in mammalian cells, single lab","pmids":["25082190"],"is_preprint":false},{"year":1993,"finding":"The human KLC1 gene was cloned; the encoded 569-amino-acid protein contains heptad repeats in the N-terminal domain (typical of cytoskeletal rod domains) and 21-mer repeats in the central and C-terminal domains; the gene was expressed in bacteria and CHO cells and provisionally assigned to chromosome 14q.","method":"cDNA cloning and sequencing, bacterial and CHO cell expression, chromosomal mapping","journal":"DNA and cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct cloning and sequence determination with heterologous expression confirming functional product; foundational structural characterization","pmids":["8274221"],"is_preprint":false},{"year":2024,"finding":"CELF1 protein directly binds KLC1 RNA (demonstrated by CLIP-seq) and down-regulates the splice variant E of KLC1 (KLC1_vE); depletion of CELF1 in cultured cells increases KLC1_vE levels, while overexpression decreases them, establishing CELF1 as a writer controlling KLC1 alternative splicing.","method":"CELF1 depletion and overexpression in cultured cells, CLIP-seq database analysis, transcriptomic correlation in human brain samples","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — CLIP-seq demonstrates direct RNA binding, functional gain/loss-of-function experiments confirm splicing regulation, but functional consequence of the splice switch on KLC1 transport activity not directly tested","pmids":["38768546"],"is_preprint":false},{"year":2024,"finding":"KLC1 binds CRMP2 in a manner dependent on CRMP2 residue R565 (R566 in zebrafish); the CRMP2 R566C mutation abolishes binding to KLC1 in transfected cultured cells, and knockdown of klc1a in zebrafish produces defective anterior commissure and postoptic commissure formation, phenocopying crmp2 knockdown, establishing a genetic interaction between CRMP2 and KLC1 in forebrain commissure formation.","method":"Co-immunoprecipitation in transfected cells (CRMP2 WT vs R566C mutant), zebrafish klc1a morpholino knockdown with commissure formation readout, crmp2 knockdown rescue experiments","journal":"Developmental neurobiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP with mutagenesis identifying binding residue plus in vivo genetic interaction in zebrafish, but single lab and zebrafish model only","pmids":["38830696"],"is_preprint":false},{"year":2025,"finding":"Cryo-EM structure of the autoinhibited kinesin-1 heterotetramer reveals that KLC tetratricopeptide repeat (TPR) domains bind across folded KHC coiled-coils and wedge between KHC motor domains; additionally, KLC C-terminal helices occlude the TPR cargo-binding interfaces, providing a second layer of autoinhibition that directly blocks cargo engagement. Binding of regulatory factors (e.g., MAP7D3) competes with intramolecular KHC coiled-coil interactions to unfurl the autoinhibited structure.","method":"Cryo-EM structure determination, crosslinking mass spectrometry validation, functional motility studies, structural modeling","journal":"bioRxiv","confidence":"High","confidence_rationale":"Tier 1 / Moderate — cryo-EM structure validated by crosslinking MS and functional studies; multiple orthogonal methods in one study; preprint not yet peer-reviewed lowers confidence slightly","pmids":["bio_10.1101_2025.07.15.665000"],"is_preprint":true},{"year":2025,"finding":"Binding of cargo-adaptor SLiM peptides to the KLC1 TPR domain dislocates the TPR 'shoulder' formed by docking of KHC coiled-coil 1 (CC1) onto the KLC TPR in the autoinhibited complex, freeing motor domains and promoting transition to the open, active state; this opening facilitates binding of the kinesin-1 cofactor MAP7 to the microtubule.","method":"Protein design, computational modelling, biophysical analysis (EM), electron microscopy of complete heterotetrameric holoenzyme with and without SLiM peptides","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 1-2 / Moderate — EM plus biophysical and computational approaches in single preprint lab; mechanistically detailed but not yet peer-reviewed","pmids":["bio_10.1101_2025.04.08.647705"],"is_preprint":true},{"year":2025,"finding":"In vitro liposome transport assays show that kinesin-1 motors with KLC bound (KinΔC) exhibit autoinhibition on cargo: reduced MT run lengths, lower detachment forces, and ~3-fold lower MT landing rates compared to constitutively active motors; this autoinhibition is reversed by kinesore (a small molecule that overcomes KLC-mediated autoinhibition), demonstrating that cargo-bound KLC maintains partial autoinhibition that fine-tunes transport directionality at 3D microtubule intersections.","method":"In vitro liposome transport assay with near-full-length kinesin-1 + KLC, single-MT motility assays, kinesore pharmacological rescue, in silico mechanistic modeling","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — reconstituted in vitro system with pharmacological rescue and computational modeling; preprint, single lab","pmids":["bio_10.1101_2025.05.06.652443"],"is_preprint":true},{"year":2025,"finding":"KLC1 interacts with dengue virus NS1 protein (confirmed by proximity ligation and co-immunoprecipitation in Aedes albopictus C6/36 cells); KLC1 decorates NS1-associated vacuoles; silencing KLC1 reduces viral genome synthesis, NS1 secretion, and virus progeny by ~1 log, and disrupts lipid droplet organization, establishing KLC1 as a host susceptibility factor for DENV replication in mosquito cells.","method":"Proximity ligation assay, co-immunoprecipitation, transmission immunoelectron microscopy, siRNA silencing, competitive peptide interference, viral titer and genome quantification, lipid droplet imaging","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal co-IP plus proximity ligation confirming interaction, multiple functional readouts (viral replication, NS1 secretion, LD organization) with siRNA and peptide competition; mosquito cell (non-mammalian) context","pmids":["40166163"],"is_preprint":true}],"current_model":"KLC1 is the cargo-binding light chain subunit of kinesin-1 that uses its tetratricopeptide repeat (TPR) domain to recognize short linear motifs (SLiMs) on diverse cargo adaptors (including JIP1, Alcadein-α, SFPQ, DOC2B, and CRMP2), and whose C-terminal helices occlude the TPR interface in the autoinhibited heterotetramer; cargo-SLiM binding dislocates the TPR 'shoulder' formed by KHC coiled-coil 1, allosterically releasing motor-domain autoinhibition and enabling processive microtubule-based anterograde transport of vesicles, RNA granules, phagosomes, and other cargoes, with transport velocity and cargo selectivity further tuned by phosphorylation of KLC1 (e.g., at Thr466 by aging-associated kinases) and alternative splicing regulated by CELF1."},"narrative":{"mechanistic_narrative":"KLC1 is the cargo-binding light chain subunit of kinesin-1, coupling diverse cargoes to microtubule-based anterograde transport while regulating motor activation [PMID:22404616, PMID:30026235]. Its tetratricopeptide repeat (TPR) domain recognizes short linear motifs on cargo adaptors, including the WD motif of Alcadein-α and the W-acidic/JIP1 motif, which bind a shared TPR footprint defined by seven critical residues and partially overlap with the autoinhibitory LFP-acidic motif of KLC1 itself [PMID:22404616, PMID:30026235]. Cargo-SLiM engagement is the activating signal: it dislocates the TPR 'shoulder' formed by docking of KHC coiled-coil 1 onto the KLC TPR in the autoinhibited heterotetramer, in which the KLC TPR also wedges between motor domains and its C-terminal helices occlude the cargo-binding interface as a second autoinhibitory layer [PMID:bio_10.1101_2025.07.15.665000, PMID:bio_10.1101_2025.04.08.647705]. This breadth of adaptor recognition lets KLC1 select among physiologically distinct cargoes—SFPQ-RNA granules for long-distance axonal transport [PMID:33284322], APP/JIP1b vesicles [PMID:29093025], RPE phagosomes derived from photoreceptor outer segments [PMID:26261180], and insulin-stimulated GLUT4 vesicles via DOC2B [PMID:30707251]—with several of these interactions gated by phosphorylation: Thr466 phosphorylation, which rises in aged brain, abolishes JIP1b binding and the enhanced fast velocity of APP transport [PMID:29093025], while DOC2B Tyr301 phosphorylation upon insulin stimulation promotes KLC1 binding and GLUT4 surface accumulation [PMID:30707251]. Transport output is further tuned at the cargo level, since KLC-bound motors retain partial autoinhibition that shapes directionality at microtubule intersections [PMID:bio_10.1101_2025.05.06.652443], and at the transcript level, where CELF1 binds KLC1 mRNA and represses its splice variant E [PMID:38768546]. Loss of KLC1 reduces phagosome run length and impairs degradation, producing age-related macular degeneration-like RPE pathology in mice [PMID:26261180], and disruption of the KLC1-SFPQ interaction by Charcot-Marie-Tooth-associated KIF5A mutations compromises axon survival [PMID:33284322].","teleology":[{"year":1993,"claim":"Establishing the primary structure of human KLC1 was the prerequisite for assigning its modular architecture, revealing N-terminal heptad (rod) repeats and central/C-terminal repeat units that would later be recognized as the cargo-binding and regulatory domains.","evidence":"cDNA cloning, sequencing, heterologous expression in bacteria and CHO cells, chromosomal mapping","pmids":["8274221"],"confidence":"Medium","gaps":["Did not assign function to any domain","No interaction partners or cargo identified","Repeat regions not yet linked to TPR cargo recognition"]},{"year":2012,"claim":"Defining a minimal 10-residue WD motif in Alcadein-α that activates kinesin-1 through the KLC1 TPR established that short cargo motifs, not just stable docking, drive motor activation and anterograde transport.","evidence":"In vivo transport assays with artificial WD-motif transmembrane proteins, excess-KLC1 competition, TPR domain-deletion analysis","pmids":["22404616"],"confidence":"High","gaps":["Structural basis of how WD binding releases motor autoinhibition not resolved","Only part of TPR required, but the activating allosteric step undefined"]},{"year":2014,"claim":"A yeast two-hybrid link between KLC1 and the fission protein Dnm1L/DRP1 raised the possibility that KLC1 mediates post-fission mitochondrial transport independently of direct KIF5 binding.","evidence":"Yeast two-hybrid screen and co-localization in cultured cells","pmids":["25082190"],"confidence":"Low","gaps":["Yeast two-hybrid and co-localization only; no co-IP or reciprocal validation","No functional mitochondrial transport assay in mammalian cells","Single lab, unconfirmed"]},{"year":2015,"claim":"Genetic loss of KLC1 separated cargo speed from processivity in vivo, showing KLC1 controls phagosome run length, localization, and degradation rather than velocity, and links this to age-related RPE pathology.","evidence":"Live-cell imaging of RPE phagosomes plus KLC1 knockout mice with AMD-like phenotypic analysis","pmids":["26261180"],"confidence":"High","gaps":["Cargo adaptor coupling phagosomes to KLC1 not identified","Molecular basis of run-length dependence on KLC1 unresolved"]},{"year":2017,"claim":"Demonstrating that Thr466 phosphorylation selectively abolishes the JIP1b interaction and the fast-velocity mode of APP transport, while sparing a separate coiled-coil-mediated interaction, established phosphorylation as a cargo- and mode-specific regulatory switch relevant to brain aging.","evidence":"Phosphomimetic mutagenesis (T466E), in vivo transport velocity measurement, co-IP, aged brain biochemistry","pmids":["29093025"],"confidence":"High","gaps":["Kinase responsible for Thr466 phosphorylation not identified","Direct causal link between Thr466 phosphorylation and aging phenotype not established"]},{"year":2018,"claim":"Quantitative mapping of seven TPR residues critical for JIP1 binding, and the demonstration that JIP1 and Alcadein-α compete for the same site overlapping the autoinhibitory LFP-acidic motif, defined the molecular footprint of cargo recognition and intramolecular autoinhibition.","evidence":"Isothermal titration calorimetry with truncated TPR fragments, residue mutagenesis, footprinting against the KLC1-TPR:JIP1 crystal structure","pmids":["30026235"],"confidence":"High","gaps":["Does not show how cargo binding relieves whole-motor autoinhibition","Affinity hierarchy among competing cargoes in cells not resolved"]},{"year":2019,"claim":"Showing that insulin-stimulated DOC2B Tyr301 phosphorylation drives KLC1 binding and GLUT4 plasma-membrane accumulation extended KLC1's role to signal-dependent metabolic cargo delivery in skeletal muscle.","evidence":"Y301 mutagenesis, co-IP, mass spectrometry, skeletal-muscle transgenic mice, GLUT4 surface assays","pmids":["30707251"],"confidence":"High","gaps":["Whether DOC2B engages the canonical TPR SLiM site not defined","Identity of the DOC2B Y301 kinase not established"]},{"year":2009,"claim":"Testing whether AMPK-mediated KLC1 phosphorylation regulates insulin-granule transport yielded a negative result, constraining the set of functionally relevant phosphosites by showing Ser517/520 modification does not alter granule dynamics.","evidence":"In vitro AMPK kinase assay on GST-KLC1, phosphomutant overexpression in MIN6 cells, 3D live-cell imaging, phospho-specific antibody; replicated in companion paper","pmids":["21099273","20074060"],"confidence":"Medium","gaps":["In vitro phosphorylation occurs but no cellular function identified","Does not exclude regulation under conditions not tested"]},{"year":2021,"claim":"Identifying SFPQ as a KLC1-selected cargo within a KIF5A/KLC1 complex required for long-distance axonal RNA-granule transport, and showing CMT-causing KIF5A mutations disrupt this, established KLC1 as an adaptor for RNA-granule transport with disease relevance.","evidence":"Reciprocal co-IP, CMT-mutant loss-of-function, axon degeneration assays, therapeutic rescue","pmids":["33284322"],"confidence":"High","gaps":["KLC1 SLiM/motif on SFPQ not mapped","Whether KLC1 directly contacts SFPQ or via another adaptor not resolved"]},{"year":2024,"claim":"Defining CELF1 as a direct binder of KLC1 mRNA that represses splice variant E added a transcript-level layer of regulation governing which KLC1 isoform is produced.","evidence":"CELF1 depletion/overexpression, CLIP-seq analysis, human brain transcriptomic correlation","pmids":["38768546"],"confidence":"Medium","gaps":["Functional consequence of the splice switch on KLC1 transport activity not tested","Physiological contexts driving CELF1 control of KLC1 unclear"]},{"year":2024,"claim":"Mapping a CRMP2 residue (R565/R566) required for KLC1 binding and showing klc1a phenocopies crmp2 knockdown in zebrafish commissure formation extended KLC1 cargo recognition to a neurodevelopmental adaptor.","evidence":"Co-IP of CRMP2 WT vs R566C mutant, zebrafish klc1a morpholino knockdown, crmp2 knockdown comparison","pmids":["38830696"],"confidence":"Medium","gaps":["Single lab, zebrafish model only","Mammalian validation of the CRMP2-KLC1 interaction lacking"]},{"year":2025,"claim":"Cryo-EM of the autoinhibited heterotetramer resolved the structural logic of KLC autoinhibition—TPR domains wedge between motor domains and KLC C-terminal helices occlude the cargo-binding interface—providing the framework for how cargo and regulators release the motor.","evidence":"Cryo-EM structure, crosslinking mass spectrometry, functional motility studies (preprint)","pmids":["bio_10.1101_2025.07.15.665000"],"confidence":"High","gaps":["Preprint, not yet peer-reviewed","Dynamics of the autoinhibition-to-active transition inferred, not directly captured"]},{"year":2025,"claim":"Showing that cargo-adaptor SLiM binding dislocates the TPR shoulder formed by KHC coiled-coil 1 and facilitates MAP7 recruitment provided a direct allosteric mechanism linking cargo recognition to motor activation.","evidence":"Protein design, computational modelling, EM of the holoenzyme with and without SLiM peptides (preprint)","pmids":["bio_10.1101_2025.04.08.647705"],"confidence":"Medium","gaps":["Preprint, single lab","Kinetics of the shoulder dislocation step not quantified"]},{"year":2025,"claim":"Reconstituted liposome transport showed KLC retains partial autoinhibition even when cargo-bound, reducing run length and landing rate and tuning directionality, reframing KLC as a continuous regulator rather than a simple on/off switch.","evidence":"In vitro liposome and single-MT motility assays, kinesore pharmacological rescue, in silico modeling (preprint)","pmids":["bio_10.1101_2025.05.06.652443"],"confidence":"Medium","gaps":["Preprint, single lab","Generality of residual autoinhibition across different cargoes not established"]},{"year":2025,"claim":"Identifying KLC1 as a host factor co-opted by dengue virus NS1 for replication and lipid droplet organization in mosquito cells extended KLC1's transport function to viral pathogenesis.","evidence":"Proximity ligation, reciprocal co-IP, immunoelectron microscopy, siRNA silencing, peptide competition, viral titer/genome quantification (preprint)","pmids":["40166163"],"confidence":"Medium","gaps":["Preprint, mosquito (non-mammalian) cell context","Whether NS1 engages the canonical TPR cargo site unknown"]},{"year":null,"claim":"How the affinity hierarchy and phosphorylation status of competing TPR-binding adaptors are integrated to determine cargo selection and transport mode in a given cell remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No quantitative competition model across the full adaptor set in vivo","Kinases for several functionally relevant phosphosites unidentified","Functional consequences of KLC1 splice isoforms on cargo selectivity untested"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,2,4,5,10]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[11,12,13]}],"localization":[{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[1,13]},{"term_id":"GO:0031410","term_label":"cytoplasmic vesicle","supporting_discovery_ids":[1,5]}],"pathway":[{"term_id":"R-HSA-9609507","term_label":"Protein localization","supporting_discovery_ids":[0,1,2,5]},{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[0,1,5]}],"complexes":["kinesin-1 heterotetramer"],"partners":["JIP1","SFPQ","DOC2B","CRMP2","KIF5A","CELF1","DNM1L","MAP7"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q07866","full_name":"Kinesin light chain 1","aliases":[],"length_aa":573,"mass_kda":65.3,"function":"Kinesin is a microtubule-associated force-producing protein that may play a role in organelle transport (PubMed:21385839). The light chain may function in coupling of cargo to the heavy chain or in the modulation of its ATPase activity (By similarity)","subcellular_location":"Cell projection, growth cone; Cytoplasmic vesicle; Cytoplasm, cytoskeleton","url":"https://www.uniprot.org/uniprotkb/Q07866/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/KLC1","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000126214","cell_line_id":"CID001431","localizations":[{"compartment":"centrosome","grade":3},{"compartment":"cytoplasmic","grade":3}],"interactors":[{"gene":"KIF5B","stoichiometry":10.0},{"gene":"KLC4","stoichiometry":10.0},{"gene":"KLC2","stoichiometry":10.0},{"gene":"KIF5A","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID001431","total_profiled":1310},"omim":[{"mim_id":"618277","title":"NHL REPEAT-CONTAINING PROTEIN 2; NHLRC2","url":"https://www.omim.org/entry/618277"},{"mim_id":"615759","title":"KINASE D-INTERACTING SUBSTRATE, 220-KD; KIDINS220","url":"https://www.omim.org/entry/615759"},{"mim_id":"615535","title":"SPECTRIN REPEAT-CONTAINING NUCLEAR ENVELOPE PROTEIN 4; SYNE4","url":"https://www.omim.org/entry/615535"},{"mim_id":"611729","title":"KINESIN LIGHT CHAIN 2; KLC2","url":"https://www.omim.org/entry/611729"},{"mim_id":"611321","title":"CALSYNTENIN 1; CLSTN1","url":"https://www.omim.org/entry/611321"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Plasma membrane","reliability":"Approved"},{"location":"Acrosome","reliability":"Approved"},{"location":"Equatorial segment","reliability":"Approved"},{"location":"Nucleoplasm","reliability":"Additional"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"brain","ntpm":513.1}],"url":"https://www.proteinatlas.org/search/KLC1"},"hgnc":{"alias_symbol":["KNS2A","KLC","hKLC1S","hKLC1N","hKLC1P","hKLC1G","hKLC1R","hKLC1J","hKLC1B"],"prev_symbol":["KNS2"]},"alphafold":{"accession":"Q07866","domains":[{"cath_id":"-","chopping":"21-151","consensus_level":"high","plddt":92.9097,"start":21,"end":151},{"cath_id":"1.25.40.10","chopping":"396-434_459-513","consensus_level":"medium","plddt":78.0189,"start":396,"end":513}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q07866","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q07866-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q07866-F1-predicted_aligned_error_v6.png","plddt_mean":75.0},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=KLC1","jax_strain_url":"https://www.jax.org/strain/search?query=KLC1"},"sequence":{"accession":"Q07866","fasta_url":"https://rest.uniprot.org/uniprotkb/Q07866.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q07866/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q07866"}},"corpus_meta":[{"pmid":"22347464","id":"PMC_22347464","title":"KLC1-ALK: a novel fusion in lung cancer identified using a formalin-fixed paraffin-embedded tissue only.","date":"2012","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/22347464","citation_count":196,"is_preprint":false},{"pmid":"26261180","id":"PMC_26261180","title":"Microtubule motors transport phagosomes in the RPE, and lack of KLC1 leads to AMD-like pathogenesis.","date":"2015","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/26261180","citation_count":68,"is_preprint":false},{"pmid":"33284322","id":"PMC_33284322","title":"Binding and transport of SFPQ-RNA granules by KIF5A/KLC1 motors promotes axon survival.","date":"2021","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/33284322","citation_count":56,"is_preprint":false},{"pmid":"22404616","id":"PMC_22404616","title":"A small peptide sequence is sufficient for initiating kinesin-1 activation through part of TPR region of KLC1.","date":"2012","source":"Traffic (Copenhagen, 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activation in vivo.\",\n      \"method\": \"In vivo transport assays with artificial transmembrane proteins containing WD motifs, excess KLC1 competition experiments, and domain-deletion analysis of KLC1 TPR region\",\n      \"journal\": \"Traffic (Copenhagen, Denmark)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal in vivo methods (artificial construct assay, excess KLC1 competition, domain deletion), internally replicated with both Alcα and JIP1 cargo proteins\",\n      \"pmids\": [\"22404616\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"KLC1 associates with phagosomes derived from photoreceptor outer segment (POS) disk membranes in the retinal pigment epithelium (RPE) and remains associated during bidirectional microtubule-based movement (including pauses). Loss of KLC1 does not impair phagosome speed but reduces run length and impairs phagosome localization and degradation, leading to AMD-like RPE pathogenesis in aged mice.\",\n      \"method\": \"Live-cell imaging of RPE phagosomes, KLC1 knockout mice with phenotypic analysis including accumulation of RPE/sub-RPE deposits, oxidative and inflammatory stress markers\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — live imaging plus genetic KO with specific cellular phenotypes (run length, localization, degradation) and in vivo AMD-like pathology, single lab but multiple orthogonal readouts\",\n      \"pmids\": [\"26261180\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"KLC1 acts as a selective adaptor within a tetrameric kinesin complex (KIF5A/KLC1) to bind the RNA-binding protein SFPQ, enabling long-distance axonal transport of SFPQ-RNA granules; this binding is required for axon survival and is disrupted by KIF5A mutations that cause Charcot-Marie Tooth disease.\",\n      \"method\": \"Co-immunoprecipitation of SFPQ with KIF5A/KLC1 complex, genetic loss-of-function (CMT-associated KIF5A mutants), axon degeneration assays, therapeutic rescue experiments\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal co-IP establishing complex, genetic epistasis with CMT mutations, axon survival as functional readout, therapeutic rescue as orthogonal confirmation\",\n      \"pmids\": [\"33284322\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Phosphorylation of KLC1 at Thr466 abolishes its conventional interaction with JIP1b and eliminates the enhanced fast velocity (EFV) of APP anterograde transport by kinesin-1, without impairing a separate novel interaction between the central region of JIP1b and the coiled-coil domain of KLC1 that controls efficient high frequency (EHF) of transport. Phosphorylation at Thr466 increases in aged brains, correlating with decreased JIP1 binding to kinesin-1.\",\n      \"method\": \"Site-directed mutagenesis (Thr466Glu phosphomimetic), in vivo transport velocity measurements, co-immunoprecipitation, aged brain biochemistry\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — mutagenesis directly demonstrating phosphorylation-dependent loss of interaction and transport velocity, supported by biochemical correlation in aged brain tissue\",\n      \"pmids\": [\"29093025\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Using isothermal titration calorimetry (ITC), seven KLC1 residues in the TPR domain were identified as critical for JIP1 binding; the autoinhibitory LFP-acidic motif of KLC1 marginally inhibits JIP1 binding by overlapping the same footprint; JIP1 and Alcadein-α W-acidic motif compete for the same KLC1-TPR binding site.\",\n      \"method\": \"Isothermal titration calorimetry with truncated KLC1 TPR fragments, mutagenesis of critical KLC1 residues, structural footprinting against published crystal structure of KLC1-TPR:JIP1 complex\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — quantitative biophysical method (ITC) with mutagenesis of seven specific residues, validated against crystal structure, single lab but multiple orthogonal experiments\",\n      \"pmids\": [\"30026235\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"DOC2B is phosphorylated upon insulin stimulation (at Y301), and this phosphorylation enhances its interaction with KLC1; mutation of Y301 in DOC2B blocks insulin-stimulated phosphorylation, abolishes interaction with KLC1, and blunts insulin-stimulated GLUT4 accumulation at the plasma membrane in skeletal muscle cells.\",\n      \"method\": \"Site-directed mutagenesis (Y301 in DOC2B), co-immunoprecipitation, mass spectrometry, skeletal-muscle-specific transgenic mice, GLUT4 plasma membrane accumulation assays\",\n      \"journal\": \"Diabetologia\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — mutagenesis establishing phosphorylation-dependent binding, co-IP, in vivo transgenic mouse model with physiological glucose tolerance readout, and in vitro cell assays\",\n      \"pmids\": [\"30707251\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Purified AMPK phosphorylates recombinant GST-KLC1 at Ser520 in vitro; however, overexpression of wild-type, phosphomimetic (S517/520D), or non-phosphorylatable (S517/520A) KLC1 mutants produced no difference in glucose-stimulated insulin granule transport dynamics, and no change in KLC1 Ser520 phosphorylation state was detected after AMPK activation. NEGATIVE RESULT: KLC1 phosphorylation at Ser517/520 does not regulate kinesin-1-mediated insulin granule transport.\",\n      \"method\": \"In vitro kinase assay with purified AMPK and recombinant GST-KLC1, overexpression of phosphomutants in MIN6 cells, 3D live-cell spinning disc confocal imaging of granule dynamics, phospho-specific antibody\",\n      \"journal\": \"Islets\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — in vitro kinase assay demonstrates phosphorylation occurs, but multiple functional assays (overexpression, 3D imaging) demonstrate no effect on transport; negative functional result independently replicated in companion paper (PMID 20074060)\",\n      \"pmids\": [\"21099273\", \"20074060\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"KLC1 physically interacts with the mitochondrial fission protein Dynamin-1-like protein (Dnm1L/DRP1) through its TPR domains, and the two proteins co-localize in cultured cells; Dnm1L does not interact with KIF5 directly, suggesting KLC1 mediates post-fission mitochondrial transport.\",\n      \"method\": \"Yeast two-hybrid screening, co-localization in cultured cells\",\n      \"journal\": \"Bioscience, biotechnology, and biochemistry\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — yeast two-hybrid and co-localization only, no co-IP or functional transport assay in mammalian cells, single lab\",\n      \"pmids\": [\"25082190\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1993,\n      \"finding\": \"The human KLC1 gene was cloned; the encoded 569-amino-acid protein contains heptad repeats in the N-terminal domain (typical of cytoskeletal rod domains) and 21-mer repeats in the central and C-terminal domains; the gene was expressed in bacteria and CHO cells and provisionally assigned to chromosome 14q.\",\n      \"method\": \"cDNA cloning and sequencing, bacterial and CHO cell expression, chromosomal mapping\",\n      \"journal\": \"DNA and cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct cloning and sequence determination with heterologous expression confirming functional product; foundational structural characterization\",\n      \"pmids\": [\"8274221\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"CELF1 protein directly binds KLC1 RNA (demonstrated by CLIP-seq) and down-regulates the splice variant E of KLC1 (KLC1_vE); depletion of CELF1 in cultured cells increases KLC1_vE levels, while overexpression decreases them, establishing CELF1 as a writer controlling KLC1 alternative splicing.\",\n      \"method\": \"CELF1 depletion and overexpression in cultured cells, CLIP-seq database analysis, transcriptomic correlation in human brain samples\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — CLIP-seq demonstrates direct RNA binding, functional gain/loss-of-function experiments confirm splicing regulation, but functional consequence of the splice switch on KLC1 transport activity not directly tested\",\n      \"pmids\": [\"38768546\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"KLC1 binds CRMP2 in a manner dependent on CRMP2 residue R565 (R566 in zebrafish); the CRMP2 R566C mutation abolishes binding to KLC1 in transfected cultured cells, and knockdown of klc1a in zebrafish produces defective anterior commissure and postoptic commissure formation, phenocopying crmp2 knockdown, establishing a genetic interaction between CRMP2 and KLC1 in forebrain commissure formation.\",\n      \"method\": \"Co-immunoprecipitation in transfected cells (CRMP2 WT vs R566C mutant), zebrafish klc1a morpholino knockdown with commissure formation readout, crmp2 knockdown rescue experiments\",\n      \"journal\": \"Developmental neurobiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP with mutagenesis identifying binding residue plus in vivo genetic interaction in zebrafish, but single lab and zebrafish model only\",\n      \"pmids\": [\"38830696\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Cryo-EM structure of the autoinhibited kinesin-1 heterotetramer reveals that KLC tetratricopeptide repeat (TPR) domains bind across folded KHC coiled-coils and wedge between KHC motor domains; additionally, KLC C-terminal helices occlude the TPR cargo-binding interfaces, providing a second layer of autoinhibition that directly blocks cargo engagement. Binding of regulatory factors (e.g., MAP7D3) competes with intramolecular KHC coiled-coil interactions to unfurl the autoinhibited structure.\",\n      \"method\": \"Cryo-EM structure determination, crosslinking mass spectrometry validation, functional motility studies, structural modeling\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — cryo-EM structure validated by crosslinking MS and functional studies; multiple orthogonal methods in one study; preprint not yet peer-reviewed lowers confidence slightly\",\n      \"pmids\": [\"bio_10.1101_2025.07.15.665000\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Binding of cargo-adaptor SLiM peptides to the KLC1 TPR domain dislocates the TPR 'shoulder' formed by docking of KHC coiled-coil 1 (CC1) onto the KLC TPR in the autoinhibited complex, freeing motor domains and promoting transition to the open, active state; this opening facilitates binding of the kinesin-1 cofactor MAP7 to the microtubule.\",\n      \"method\": \"Protein design, computational modelling, biophysical analysis (EM), electron microscopy of complete heterotetrameric holoenzyme with and without SLiM peptides\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — EM plus biophysical and computational approaches in single preprint lab; mechanistically detailed but not yet peer-reviewed\",\n      \"pmids\": [\"bio_10.1101_2025.04.08.647705\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"In vitro liposome transport assays show that kinesin-1 motors with KLC bound (KinΔC) exhibit autoinhibition on cargo: reduced MT run lengths, lower detachment forces, and ~3-fold lower MT landing rates compared to constitutively active motors; this autoinhibition is reversed by kinesore (a small molecule that overcomes KLC-mediated autoinhibition), demonstrating that cargo-bound KLC maintains partial autoinhibition that fine-tunes transport directionality at 3D microtubule intersections.\",\n      \"method\": \"In vitro liposome transport assay with near-full-length kinesin-1 + KLC, single-MT motility assays, kinesore pharmacological rescue, in silico mechanistic modeling\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — reconstituted in vitro system with pharmacological rescue and computational modeling; preprint, single lab\",\n      \"pmids\": [\"bio_10.1101_2025.05.06.652443\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"KLC1 interacts with dengue virus NS1 protein (confirmed by proximity ligation and co-immunoprecipitation in Aedes albopictus C6/36 cells); KLC1 decorates NS1-associated vacuoles; silencing KLC1 reduces viral genome synthesis, NS1 secretion, and virus progeny by ~1 log, and disrupts lipid droplet organization, establishing KLC1 as a host susceptibility factor for DENV replication in mosquito cells.\",\n      \"method\": \"Proximity ligation assay, co-immunoprecipitation, transmission immunoelectron microscopy, siRNA silencing, competitive peptide interference, viral titer and genome quantification, lipid droplet imaging\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal co-IP plus proximity ligation confirming interaction, multiple functional readouts (viral replication, NS1 secretion, LD organization) with siRNA and peptide competition; mosquito cell (non-mammalian) context\",\n      \"pmids\": [\"40166163\"],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"KLC1 is the cargo-binding light chain subunit of kinesin-1 that uses its tetratricopeptide repeat (TPR) domain to recognize short linear motifs (SLiMs) on diverse cargo adaptors (including JIP1, Alcadein-α, SFPQ, DOC2B, and CRMP2), and whose C-terminal helices occlude the TPR interface in the autoinhibited heterotetramer; cargo-SLiM binding dislocates the TPR 'shoulder' formed by KHC coiled-coil 1, allosterically releasing motor-domain autoinhibition and enabling processive microtubule-based anterograde transport of vesicles, RNA granules, phagosomes, and other cargoes, with transport velocity and cargo selectivity further tuned by phosphorylation of KLC1 (e.g., at Thr466 by aging-associated kinases) and alternative splicing regulated by CELF1.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"KLC1 is the cargo-binding light chain subunit of kinesin-1, coupling diverse cargoes to microtubule-based anterograde transport while regulating motor activation [#0, #4]. Its tetratricopeptide repeat (TPR) domain recognizes short linear motifs on cargo adaptors, including the WD motif of Alcadein-\\u03b1 and the W-acidic/JIP1 motif, which bind a shared TPR footprint defined by seven critical residues and partially overlap with the autoinhibitory LFP-acidic motif of KLC1 itself [#0, #4]. Cargo-SLiM engagement is the activating signal: it dislocates the TPR 'shoulder' formed by docking of KHC coiled-coil 1 onto the KLC TPR in the autoinhibited heterotetramer, in which the KLC TPR also wedges between motor domains and its C-terminal helices occlude the cargo-binding interface as a second autoinhibitory layer [#11, #12]. This breadth of adaptor recognition lets KLC1 select among physiologically distinct cargoes\\u2014SFPQ-RNA granules for long-distance axonal transport [#2], APP/JIP1b vesicles [#3], RPE phagosomes derived from photoreceptor outer segments [#1], and insulin-stimulated GLUT4 vesicles via DOC2B [#5]\\u2014with several of these interactions gated by phosphorylation: Thr466 phosphorylation, which rises in aged brain, abolishes JIP1b binding and the enhanced fast velocity of APP transport [#3], while DOC2B Tyr301 phosphorylation upon insulin stimulation promotes KLC1 binding and GLUT4 surface accumulation [#5]. Transport output is further tuned at the cargo level, since KLC-bound motors retain partial autoinhibition that shapes directionality at microtubule intersections [#13], and at the transcript level, where CELF1 binds KLC1 mRNA and represses its splice variant E [#9]. Loss of KLC1 reduces phagosome run length and impairs degradation, producing age-related macular degeneration-like RPE pathology in mice [#1], and disruption of the KLC1-SFPQ interaction by Charcot-Marie-Tooth-associated KIF5A mutations compromises axon survival [#2].\",\n  \"teleology\": [\n    {\n      \"year\": 1993,\n      \"claim\": \"Establishing the primary structure of human KLC1 was the prerequisite for assigning its modular architecture, revealing N-terminal heptad (rod) repeats and central/C-terminal repeat units that would later be recognized as the cargo-binding and regulatory domains.\",\n      \"evidence\": \"cDNA cloning, sequencing, heterologous expression in bacteria and CHO cells, chromosomal mapping\",\n      \"pmids\": [\"8274221\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not assign function to any domain\", \"No interaction partners or cargo identified\", \"Repeat regions not yet linked to TPR cargo recognition\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Defining a minimal 10-residue WD motif in Alcadein-\\u03b1 that activates kinesin-1 through the KLC1 TPR established that short cargo motifs, not just stable docking, drive motor activation and anterograde transport.\",\n      \"evidence\": \"In vivo transport assays with artificial WD-motif transmembrane proteins, excess-KLC1 competition, TPR domain-deletion analysis\",\n      \"pmids\": [\"22404616\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of how WD binding releases motor autoinhibition not resolved\", \"Only part of TPR required, but the activating allosteric step undefined\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"A yeast two-hybrid link between KLC1 and the fission protein Dnm1L/DRP1 raised the possibility that KLC1 mediates post-fission mitochondrial transport independently of direct KIF5 binding.\",\n      \"evidence\": \"Yeast two-hybrid screen and co-localization in cultured cells\",\n      \"pmids\": [\"25082190\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Yeast two-hybrid and co-localization only; no co-IP or reciprocal validation\", \"No functional mitochondrial transport assay in mammalian cells\", \"Single lab, unconfirmed\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Genetic loss of KLC1 separated cargo speed from processivity in vivo, showing KLC1 controls phagosome run length, localization, and degradation rather than velocity, and links this to age-related RPE pathology.\",\n      \"evidence\": \"Live-cell imaging of RPE phagosomes plus KLC1 knockout mice with AMD-like phenotypic analysis\",\n      \"pmids\": [\"26261180\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Cargo adaptor coupling phagosomes to KLC1 not identified\", \"Molecular basis of run-length dependence on KLC1 unresolved\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Demonstrating that Thr466 phosphorylation selectively abolishes the JIP1b interaction and the fast-velocity mode of APP transport, while sparing a separate coiled-coil-mediated interaction, established phosphorylation as a cargo- and mode-specific regulatory switch relevant to brain aging.\",\n      \"evidence\": \"Phosphomimetic mutagenesis (T466E), in vivo transport velocity measurement, co-IP, aged brain biochemistry\",\n      \"pmids\": [\"29093025\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Kinase responsible for Thr466 phosphorylation not identified\", \"Direct causal link between Thr466 phosphorylation and aging phenotype not established\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Quantitative mapping of seven TPR residues critical for JIP1 binding, and the demonstration that JIP1 and Alcadein-\\u03b1 compete for the same site overlapping the autoinhibitory LFP-acidic motif, defined the molecular footprint of cargo recognition and intramolecular autoinhibition.\",\n      \"evidence\": \"Isothermal titration calorimetry with truncated TPR fragments, residue mutagenesis, footprinting against the KLC1-TPR:JIP1 crystal structure\",\n      \"pmids\": [\"30026235\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not show how cargo binding relieves whole-motor autoinhibition\", \"Affinity hierarchy among competing cargoes in cells not resolved\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Showing that insulin-stimulated DOC2B Tyr301 phosphorylation drives KLC1 binding and GLUT4 plasma-membrane accumulation extended KLC1's role to signal-dependent metabolic cargo delivery in skeletal muscle.\",\n      \"evidence\": \"Y301 mutagenesis, co-IP, mass spectrometry, skeletal-muscle transgenic mice, GLUT4 surface assays\",\n      \"pmids\": [\"30707251\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether DOC2B engages the canonical TPR SLiM site not defined\", \"Identity of the DOC2B Y301 kinase not established\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Testing whether AMPK-mediated KLC1 phosphorylation regulates insulin-granule transport yielded a negative result, constraining the set of functionally relevant phosphosites by showing Ser517/520 modification does not alter granule dynamics.\",\n      \"evidence\": \"In vitro AMPK kinase assay on GST-KLC1, phosphomutant overexpression in MIN6 cells, 3D live-cell imaging, phospho-specific antibody; replicated in companion paper\",\n      \"pmids\": [\"21099273\", \"20074060\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"In vitro phosphorylation occurs but no cellular function identified\", \"Does not exclude regulation under conditions not tested\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Identifying SFPQ as a KLC1-selected cargo within a KIF5A/KLC1 complex required for long-distance axonal RNA-granule transport, and showing CMT-causing KIF5A mutations disrupt this, established KLC1 as an adaptor for RNA-granule transport with disease relevance.\",\n      \"evidence\": \"Reciprocal co-IP, CMT-mutant loss-of-function, axon degeneration assays, therapeutic rescue\",\n      \"pmids\": [\"33284322\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"KLC1 SLiM/motif on SFPQ not mapped\", \"Whether KLC1 directly contacts SFPQ or via another adaptor not resolved\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Defining CELF1 as a direct binder of KLC1 mRNA that represses splice variant E added a transcript-level layer of regulation governing which KLC1 isoform is produced.\",\n      \"evidence\": \"CELF1 depletion/overexpression, CLIP-seq analysis, human brain transcriptomic correlation\",\n      \"pmids\": [\"38768546\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of the splice switch on KLC1 transport activity not tested\", \"Physiological contexts driving CELF1 control of KLC1 unclear\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Mapping a CRMP2 residue (R565/R566) required for KLC1 binding and showing klc1a phenocopies crmp2 knockdown in zebrafish commissure formation extended KLC1 cargo recognition to a neurodevelopmental adaptor.\",\n      \"evidence\": \"Co-IP of CRMP2 WT vs R566C mutant, zebrafish klc1a morpholino knockdown, crmp2 knockdown comparison\",\n      \"pmids\": [\"38830696\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab, zebrafish model only\", \"Mammalian validation of the CRMP2-KLC1 interaction lacking\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Cryo-EM of the autoinhibited heterotetramer resolved the structural logic of KLC autoinhibition\\u2014TPR domains wedge between motor domains and KLC C-terminal helices occlude the cargo-binding interface\\u2014providing the framework for how cargo and regulators release the motor.\",\n      \"evidence\": \"Cryo-EM structure, crosslinking mass spectrometry, functional motility studies (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.07.15.665000\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Preprint, not yet peer-reviewed\", \"Dynamics of the autoinhibition-to-active transition inferred, not directly captured\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Showing that cargo-adaptor SLiM binding dislocates the TPR shoulder formed by KHC coiled-coil 1 and facilitates MAP7 recruitment provided a direct allosteric mechanism linking cargo recognition to motor activation.\",\n      \"evidence\": \"Protein design, computational modelling, EM of the holoenzyme with and without SLiM peptides (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.04.08.647705\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint, single lab\", \"Kinetics of the shoulder dislocation step not quantified\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Reconstituted liposome transport showed KLC retains partial autoinhibition even when cargo-bound, reducing run length and landing rate and tuning directionality, reframing KLC as a continuous regulator rather than a simple on/off switch.\",\n      \"evidence\": \"In vitro liposome and single-MT motility assays, kinesore pharmacological rescue, in silico modeling (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.05.06.652443\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint, single lab\", \"Generality of residual autoinhibition across different cargoes not established\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identifying KLC1 as a host factor co-opted by dengue virus NS1 for replication and lipid droplet organization in mosquito cells extended KLC1's transport function to viral pathogenesis.\",\n      \"evidence\": \"Proximity ligation, reciprocal co-IP, immunoelectron microscopy, siRNA silencing, peptide competition, viral titer/genome quantification (preprint)\",\n      \"pmids\": [\"40166163\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint, mosquito (non-mammalian) cell context\", \"Whether NS1 engages the canonical TPR cargo site unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How the affinity hierarchy and phosphorylation status of competing TPR-binding adaptors are integrated to determine cargo selection and transport mode in a given cell remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No quantitative competition model across the full adaptor set in vivo\", \"Kinases for several functionally relevant phosphosites unidentified\", \"Functional consequences of KLC1 splice isoforms on cargo selectivity untested\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 2, 4, 5, 10]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [11, 12, 13]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [1, 13]},\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [1, 5]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [0, 1, 2, 5]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [0, 1, 5]}\n    ],\n    \"complexes\": [\"kinesin-1 heterotetramer\"],\n    \"partners\": [\"JIP1\", \"SFPQ\", \"DOC2B\", \"CRMP2\", \"KIF5A\", \"CELF1\", \"DNM1L\", \"MAP7\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}