{"gene":"DNAJC5","run_date":"2026-06-09T23:54:42","timeline":{"discoveries":[{"year":2011,"finding":"Disease-causing mutations p.Leu116del and p.Leu115Arg in the cysteine-string domain of DNAJC5/CSPα affect palmitoylation-dependent sorting and reduce the amount of CSPα in neuronal cells, implying the cysteine-string domain is required for proper membrane targeting.","method":"Exome sequencing, candidate-gene sequencing, and cell-based assays of palmitoylation-dependent sorting in neuronal cells","journal":"American journal of human genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional sorting assays in neuronal cells with two independent mutations, single lab but orthogonal genetic and cellular methods","pmids":["21820099"],"is_preprint":false},{"year":2015,"finding":"DNAJC5/CSPα is a substrate of the depalmitoylating enzyme PPT1/CLN1; in DNAJC5/CLN4 patient brains PPT1 is massively increased, mis-localized, and has dramatically reduced specific enzymatic activity, establishing a biochemical link between two NCL disease proteins and revealing global changes in protein palmitoylation at synaptic and lysosomal proteins.","method":"Biochemical fractionation, enzymatic activity assays, quantitative palmitoyl-proteomics (palmitome mass spectrometry) of patient versus control brain tissue","journal":"Acta neuropathologica","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — direct in vitro depalmitoylation assay establishing CSPα as PPT1 substrate, plus quantitative proteomics of patient brains; multiple orthogonal methods in one study","pmids":["26659577"],"is_preprint":false},{"year":2018,"finding":"DNAJC5 acts as an essential mediator of misfolding-associated protein secretion (MAPS), a pathway for unconventional secretion of misfolded cytosolic proteins. USP19 deubiquitinase binds HSC70 and acts upstream of HSC70 and DNAJC5. As a membrane-associated protein preferentially localized to late endosomes/lysosomes, DNAJC5 chaperones MAPS client proteins to the cell exterior; secreted misfolded proteins can be endocytosed and degraded in recipient-cell lysosomes.","method":"Co-immunoprecipitation, knockdown/knockout cellular assays, subcellular fractionation, secretion assays with defined client proteins","journal":"Cell discovery","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal Co-IP, multiple KO/KD experiments with defined secretion phenotype, subcellular fractionation; replicated pathway epistasis by placing USP19 upstream","pmids":["29531792"],"is_preprint":false},{"year":2019,"finding":"CLN4 mutations in DNAJC5/CSPα drive excessive oligomerization and mislocalization of CSPα from synaptic vesicles to prelysosomal (HRS/LAMP1-positive) compartments in Drosophila neurons. Reducing endogenous wild-type dCSP or Hsc70 gene dosage attenuates CLN4 phenotypes (lethality, oligomerization, prelysosomal accumulation), establishing a dominant hypermorphic gain-of-function mechanism requiring wild-type CSPα and Hsc70.","method":"Drosophila transgenic models, immunofluorescence co-localization, genetic epistasis (dosage reduction of dCSP and Hsc70), ultrastructural analysis","journal":"eLife","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis across multiple alleles in vivo, ultrastructural validation, dose-response with wild-type partner; multiple orthogonal methods in one study","pmids":["31663851"],"is_preprint":false},{"year":2022,"finding":"DNAJC5 has two functionally distinct but coupled chaperoning activities: endolysosome-associated DNAJC5 promotes ESCRT-dependent microautophagy, while a perinuclear non-lysosomal pool mediates MAPS. The interactor SLC3A2/CD98hc is essential for perinuclear DNAJC5 localization and MAPS but dispensable for microautophagy. Uncoupling these two processes (by loss of SLC3A2 or expression of ANCL mutants) generates DNAJC5-containing autofluorescent storage materials resembling NCL lipofuscin and induces neurodegeneration in a Drosophila model.","method":"Functional proteomics (proximity labeling/BioID), Co-IP, shRNA knockdown/KO, fluorescence microscopy, Drosophila neurodegeneration model, ESCRT perturbation assays","journal":"Autophagy","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (proteomics, Co-IP, KO, in vivo Drosophila epistasis), identification of novel interactor SLC3A2 with functional validation","pmids":["35506243"],"is_preprint":false},{"year":2023,"finding":"DNAJC5 undergoes palmitoylation and anchors on endosomal membranes; palmitoylation is essential for DNAJC5-induced α-synuclein secretion. Cytosolic α-syn is actively translocated into an endosomal membrane compartment in a DNAJC5-dependent manner. A palmitoylation-deficient mutation reduces α-syn secretion, which can be rescued by a membrane-targeting peptide that forces DNAJC5 oligomerization, indicating that palmitoylated DNAJC5 oligomers drive α-syn unconventional secretion.","method":"Reconstitution in HEK293T cells, palmitoylation-deficient mutants, membrane fractionation, endosomal translocation assays, rescue with membrane-targeting peptide, validation in SH-SY5Y neurons and iPSC-derived midbrain dopamine neurons","journal":"eLife","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — reconstitution of secretion pathway, mutagenesis of palmitoylation sites, mechanistic rescue experiment, validated in multiple neuronal cell types","pmids":["36626307"],"is_preprint":false},{"year":2021,"finding":"DNAJC5 interacts with SKP2 and enhances SKP2-mediated degradation of the cyclin-dependent kinase inhibitor p27, promoting G1-to-S cell-cycle progression in hepatocellular carcinoma cells; DNAJC5 knockdown rescues p27 protein levels.","method":"Co-immunoprecipitation, overexpression/knockdown, cell-cycle flow cytometry, western blotting","journal":"Biochimica et biophysica acta. Molecular cell research","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — Co-IP plus knockdown rescue, single lab, two orthogonal methods; context is cancer rather than canonical neuronal function","pmids":["33662413"],"is_preprint":false},{"year":2024,"finding":"Proximity labeling in PC12 neuroendocrine cells confirmed DNAJC5 interacts with Hsc70 and SNAP-25, and identified STXBP1/Munc18-1 as a novel DNAJC5-binding protein. The ANCL mutation L115R inhibits interactions with SNAP-25 and STXBP1/Munc18-1 but does not affect Hsc70 binding, mapping which interactions are disrupted by disease mutation.","method":"Proximity labeling (miniTurbo) in stable PC12 cell lines, LC-MS proteomics, western blot validation","journal":"The Biochemical journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — proximity labeling plus western blot validation, single lab; identifies novel interactor with mutation-dependent loss of interaction","pmids":["38193346"],"is_preprint":false},{"year":2025,"finding":"CLN4-linked DNAJC5 mutant aggregates on lysosomal membranes cause direct lysosomal membrane damage in iPSC-derived neurons (established by in vitro membrane-damaging assay). The ubiquitin ligase CHIP acts as a central microautophagy regulator that ubiquitinates CLN4 aggregates to protect lysosomes; ectopic CHIP improves lysosomal function in CLN4 neurons and alleviates lipofuscin accumulation and neurodegeneration in a Drosophila CLN4 model.","method":"iPSC-derived neurons (i3Neuron) with DNAJC5 CLN4 mutations, in vitro lysosome membrane damage assay, genome-wide CRISPR screen, organelle-specific proteomics, Drosophila in vivo model","journal":"Nature cell biology","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — genome-wide CRISPR screen, in vitro reconstitution of membrane damage, iPSC neuron disease model, and Drosophila epistasis; multiple orthogonal methods replicated across cell and animal models","pmids":["40855364"],"is_preprint":false},{"year":2025,"finding":"Mice overexpressing CLN4 mutant (Leu115Arg or Leu116Δ) CSPα develop motor deficits and neuronal lipofuscinosis with GROD-like structures, whereas conventional or conditional DNAJC5 knockout mice show no lipofuscinosis or GRODs, establishing that DNAJC5 mutations cause neuronal lipofuscinosis through a cell-autonomous gain of pathological function, not loss of function.","method":"Transgenic mouse lines (Thy1-promoter WT, Leu115Arg, Leu116Δ CSPα), conventional and conditional knockout mice, neuropathological analysis, behavioral testing","journal":"Science advances","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple independent transgenic and knockout mouse lines with neuropathological validation; definitive gain-of-function vs. loss-of-function comparison in vivo","pmids":["40397740"],"is_preprint":false},{"year":2026,"finding":"DNAJC5 is palmitoylated by multiple DHHC palmitoyl acyltransferases in human cells; DHHC11 overexpression enriches DNAJC5 in a Golgi-associated compartment and increases unconventional protein secretion. Mutagenesis defined a minimal module (DC95: CS domain plus C-terminal 62 residues and short upstream segment) sufficient for palmitoylation, Golgi translocation, and secretion; deletion of 5 residues from DC95 abolishes all three activities.","method":"Palmitoylation assays with DHHC enzyme panel, subcellular fractionation/immunofluorescence, deletion mutagenesis, secretion assays in human cells","journal":"Traffic (Copenhagen, Denmark)","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct in vitro palmitoylation assays with mutagenesis mapping minimal functional module, single lab but multiple orthogonal biochemical methods","pmids":["41657026"],"is_preprint":false},{"year":2025,"finding":"Misfolded protein secretion in senescent human cells requires DNAJC5; the vesicle-associated HSP70 co-chaperone DNAJC5 mediates expulsion of misfolded proteins (including TDP-43) through the endo-lysosomal system during proteotoxic stress in senescent cells.","method":"Multi-dimensional transcriptomics and proteomics, knockdown of DNAJC5 in senescent human cells, secretion assays under proteotoxic stress","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — proteomics plus KD secretion assay; preprint, single lab, not yet peer-reviewed","pmids":["bio_10.1101_2025.09.07.674107"],"is_preprint":true},{"year":2025,"finding":"DNAJC5 interacts with the intracellular domain of EGFR and with the endocytosis adaptor AP2A1; DNAJC5 overexpression enhances EGFR endocytosis and recycling, augmenting downstream EGFR signaling. AP2A1 knockdown attenuates DNAJC5-driven EGFR trafficking and lung adenocarcinoma cell proliferation/migration.","method":"Co-immunoprecipitation, overexpression/knockdown in LUAD cell lines, in vitro and in vivo proliferation/migration assays, EGFR trafficking assays","journal":"Communications biology","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — Co-IP plus functional knockdown rescue, single lab; novel context (EGFR trafficking) with two orthogonal functional methods","pmids":["40374748"],"is_preprint":false},{"year":2026,"finding":"TDP43 and hnRNP K regulate canonical splicing of DNAJC5 pre-mRNA; their interaction is RNA-dependent, and DNAJC5 canonical splicing depends on internal TDP43 and hnRNP K binding sites. Loss of either factor introduces aberrant splicing of DNAJC5, affecting its role in endosomal trafficking.","method":"siRNA knockdown of TDP43 and hnRNP K, RNA immunoprecipitation, RT-PCR splicing assays, RNA-dependency of protein interaction assays","journal":"Cell biology international","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RNA-IP plus splicing assays with internal binding site mutagenesis; single lab, direct mechanistic validation of splicing regulation","pmids":["41983529"],"is_preprint":false}],"current_model":"DNAJC5/CSPα is a palmitoylated, membrane-associated HSC70 co-chaperone that localizes to synaptic vesicles and endolysosomes, where it performs two coupled protein quality-control functions: promoting ESCRT-dependent endosomal microautophagy and mediating misfolding-associated protein secretion (MAPS) of cytosolic misfolded proteins (including α-synuclein) via palmitoylation-dependent oligomerization on late endosomal/lysosomal membranes; disease-causing CLN4 mutations (Leu115Arg, Leu116del) drive dominant gain-of-function excessive oligomerization that deposits CLN4 aggregates on lysosomal membranes causing direct membrane damage, lysosomal dysfunction, and lipofuscin accumulation, with the ubiquitin ligase CHIP acting as a protective microautophagy regulator that clears these aggregates, while PPT1/CLN1 depalmitoylates CSPα and DHHC palmitoyl acyltransferases control its membrane targeting and secretory function."},"narrative":{"mechanistic_narrative":"DNAJC5/CSPα is a palmitoylated, membrane-associated HSC70 co-chaperone that operates in protein quality control by directing misfolded cytosolic proteins through the endo-lysosomal system [PMID:29531792, PMID:36626307]. It serves as an essential mediator of misfolding-associated protein secretion (MAPS), chaperoning client proteins to the cell exterior downstream of the USP19 deubiquitinase and HSC70 [PMID:29531792]. Palmitoylation, installed by multiple DHHC palmitoyl acyltransferases, anchors DNAJC5 on endosomal and Golgi-associated membranes and is required for its oligomerization and for secretion of clients including α-synuclein, with cytosolic α-synuclein being actively translocated into an endosomal compartment in a DNAJC5-dependent manner [PMID:36626307, PMID:41657026]. DNAJC5 carries two coupled chaperoning activities: an endolysosomal pool drives ESCRT-dependent microautophagy, while a perinuclear pool dependent on the interactor SLC3A2/CD98hc mediates MAPS; uncoupling these processes generates autofluorescent storage material resembling NCL lipofuscin [PMID:35506243]. The protein engages the synaptic machinery, interacting with HSC70, SNAP-25, and STXBP1/Munc18-1 [PMID:38193346], and is depalmitoylated by PPT1/CLN1, linking it biochemically to a second neuronal ceroid lipofuscinosis protein [PMID:26659577]. DNAJC5 mutations (Leu115Arg, Leu116del) in the cysteine-string domain cause autosomal dominant neuronal ceroid lipofuscinosis (CLN4) through a gain of pathological function: the mutants oligomerize excessively, mislocalize from synaptic vesicles to prelysosomal compartments, deposit aggregates that directly damage lysosomal membranes, and drive lipofuscinosis and neurodegeneration, whereas knockout animals show no such pathology [PMID:31663851, PMID:40855364, PMID:40397740]. The ubiquitin ligase CHIP acts as a protective microautophagy regulator that ubiquitinates and clears these aggregates [PMID:40855364]. Beyond its neuronal role, DNAJC5 has been implicated in cancer-cell contexts via SKP2/p27 and EGFR/AP2A1 trafficking [PMID:33662413, PMID:40374748].","teleology":[{"year":2011,"claim":"Establishing the disease relevance of the cysteine-string domain showed that CLN4 mutations act by perturbing palmitoylation-dependent membrane targeting rather than by simple loss of expression.","evidence":"Exome/candidate-gene sequencing plus palmitoylation-dependent sorting assays in neuronal cells with two independent mutations","pmids":["21820099"],"confidence":"Medium","gaps":["Did not establish whether reduced CSPα was cause or consequence","No in vivo demonstration of pathogenic mechanism","Did not resolve gain- vs loss-of-function"]},{"year":2015,"claim":"Identifying CSPα as a PPT1/CLN1 depalmitoylation substrate connected two NCL disease proteins biochemically and placed DNAJC5 within a palmitoylation cycle at synaptic and lysosomal membranes.","evidence":"In vitro depalmitoylation assays and quantitative palmitoyl-proteomics of patient versus control brain","pmids":["26659577"],"confidence":"High","gaps":["Did not define the DHHC enzymes installing the modification","Functional consequence of the palmitoylation cycle for chaperone activity not resolved"]},{"year":2018,"claim":"Defining DNAJC5 as an essential mediator of MAPS revealed a function for the protein in unconventional secretion of misfolded cytosolic clients and placed USP19 and HSC70 upstream in the pathway.","evidence":"Reciprocal Co-IP, knockdown/knockout secretion assays with defined clients, subcellular fractionation","pmids":["29531792"],"confidence":"High","gaps":["Mechanism of client translocation across membranes not defined","Did not establish palmitoylation requirement","Physiological clients in neurons not enumerated"]},{"year":2019,"claim":"Demonstrating that CLN4 mutants oligomerize excessively and mislocalize to prelysosomal compartments, with phenotypes attenuated by reducing wild-type CSPα or Hsc70 dosage, established a dominant hypermorphic gain-of-function mechanism.","evidence":"Drosophila transgenic models, immunofluorescence co-localization, genetic dosage epistasis, ultrastructural analysis","pmids":["31663851"],"confidence":"High","gaps":["Did not identify the lysosomal damage mechanism","Mammalian validation absent","Clearance pathways for aggregates unknown"]},{"year":2021,"claim":"Linking DNAJC5 to SKP2-mediated p27 degradation extended its functional repertoire to cell-cycle control in hepatocellular carcinoma, beyond the canonical neuronal context.","evidence":"Co-IP, overexpression/knockdown, cell-cycle flow cytometry in HCC cells","pmids":["33662413"],"confidence":"Medium","gaps":["Single lab, cancer-specific context","Mechanism connecting chaperone activity to SKP2 not resolved","No in vivo tumor confirmation"]},{"year":2022,"claim":"Resolving DNAJC5 into two coupled activities — endolysosomal microautophagy and SLC3A2-dependent perinuclear MAPS — showed how uncoupling the pathways produces NCL-like autofluorescent storage material and neurodegeneration.","evidence":"Proximity labeling/BioID, Co-IP, shRNA/KO, microscopy, ESCRT perturbation, Drosophila neurodegeneration model","pmids":["35506243"],"confidence":"High","gaps":["Molecular basis of SLC3A2-dependent perinuclear targeting not defined","How the two pools interconvert unknown"]},{"year":2023,"claim":"Showing that palmitoylation-driven DNAJC5 oligomerization on endosomal membranes drives α-synuclein translocation and secretion provided a mechanistic basis for the secretory function and its disease relevance.","evidence":"HEK293T reconstitution, palmitoylation-deficient mutants, endosomal translocation and rescue assays, validation in SH-SY5Y and iPSC dopamine neurons","pmids":["36626307"],"confidence":"High","gaps":["Structure of the active oligomer not determined","Physiological vs pathological balance of α-syn secretion unresolved"]},{"year":2024,"claim":"Mapping the DNAJC5 interactome in neuroendocrine cells confirmed Hsc70 and SNAP-25 binding, identified STXBP1/Munc18-1 as a partner, and showed the L115R mutation selectively disrupts SNAP-25 and STXBP1 interactions while sparing Hsc70.","evidence":"miniTurbo proximity labeling in PC12 cells, LC-MS proteomics, western blot validation","pmids":["38193346"],"confidence":"Medium","gaps":["Functional consequence of lost SNAP-25/STXBP1 interactions not tested","Single cell type"]},{"year":2025,"claim":"Identifying direct lysosomal membrane damage by CLN4 aggregates and CHIP as a protective microautophagy regulator defined both the proximate cytotoxic event and a clearance mechanism that rescues lysosomal function in vivo.","evidence":"iPSC i3Neurons with CLN4 mutations, in vitro membrane damage assay, genome-wide CRISPR screen, organelle proteomics, Drosophila model","pmids":["40855364"],"confidence":"High","gaps":["Mechanism of physical membrane permeabilization not fully resolved","Whether CHIP modulation is therapeutically tractable unknown"]},{"year":2025,"claim":"Transgenic mouse modeling settled the gain- versus loss-of-function question, showing CLN4 mutant overexpression causes lipofuscinosis and GRODs while knockouts do not.","evidence":"Thy1-promoter WT and mutant CSPα transgenic lines, conventional and conditional knockouts, neuropathology and behavior","pmids":["40397740"],"confidence":"High","gaps":["Does not address normal physiological role lost in knockouts","Cell-type specificity of vulnerability incompletely mapped"]},{"year":2025,"claim":"Implicating DNAJC5 in misfolded protein secretion during cellular senescence extended the MAPS function to proteotoxic stress and additional clients such as TDP-43.","evidence":"Transcriptomics/proteomics and DNAJC5 knockdown secretion assays in senescent cells (preprint)","pmids":["bio_10.1101_2025.09.07.674107"],"confidence":"Medium","gaps":["Preprint, not peer-reviewed","Single lab","Mechanistic detail of TDP-43 secretion not resolved"]},{"year":2026,"claim":"Defining DHHC enzymes as the palmitoylating machinery and mapping a minimal DC95 module sufficient for palmitoylation, Golgi translocation, and secretion completed the upstream control logic of DNAJC5 membrane targeting.","evidence":"Palmitoylation assays with DHHC panel, subcellular fractionation/IF, deletion mutagenesis, secretion assays in human cells","pmids":["41657026"],"confidence":"High","gaps":["Which DHHC enzyme acts physiologically in neurons unresolved","Relationship between Golgi and endosomal pools not defined"]},{"year":2026,"claim":"Identifying TDP43 and hnRNP K as regulators of DNAJC5 pre-mRNA splicing introduced an upstream RNA-level control layer that links DNAJC5 abundance to RNA-binding proteins implicated in neurodegeneration.","evidence":"siRNA knockdown, RNA immunoprecipitation, RT-PCR splicing assays with internal binding-site mutagenesis","pmids":["41983529"],"confidence":"Medium","gaps":["Functional impact of aberrant isoforms on trafficking not quantified","Single lab"]},{"year":null,"claim":"The structural basis of the palmitoylated DNAJC5 oligomer and how it physically translocates clients across or permeabilizes lysosomal membranes remains undefined.","evidence":"","pmids":[],"confidence":"High","gaps":["No high-resolution structure of the functional oligomer","Mechanism of membrane translocation/permeabilization unresolved","Native physiological MAPS clients in healthy neurons not enumerated"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0044183","term_label":"protein folding chaperone","supporting_discovery_ids":[2,4,11]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[2,5]},{"term_id":"GO:0008289","term_label":"lipid binding","supporting_discovery_ids":[5,10]}],"localization":[{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[2,3,5]},{"term_id":"GO:0005764","term_label":"lysosome","supporting_discovery_ids":[3,4,8]},{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[10]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[5]}],"pathway":[{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[4,8]},{"term_id":"R-HSA-9609507","term_label":"Protein localization","supporting_discovery_ids":[2,5]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[2,4]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[8,9]}],"complexes":[],"partners":["HSPA8","USP19","SLC3A2","SNAP25","STXBP1","CHIP","SKP2","EGFR"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9H3Z4","full_name":"DnaJ homolog subfamily C member 5","aliases":["Ceroid-lipofuscinosis neuronal protein 4","Cysteine string protein","CSP"],"length_aa":198,"mass_kda":22.1,"function":"Acts as a general chaperone in regulated exocytosis (By similarity). Acts as a co-chaperone for the SNARE protein SNAP-25 (By similarity). Involved in the calcium-mediated control of a late stage of exocytosis (By similarity). May have an important role in presynaptic function. May be involved in calcium-dependent neurotransmitter release at nerve endings (By similarity)","subcellular_location":"Cytoplasm, cytosol; Membrane; Cytoplasmic vesicle, secretory vesicle, chromaffin granule membrane; Melanosome; Cell membrane","url":"https://www.uniprot.org/uniprotkb/Q9H3Z4/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/DNAJC5","classification":"Not Classified","n_dependent_lines":2,"n_total_lines":1208,"dependency_fraction":0.0016556291390728477},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000101152","cell_line_id":"CID000034","localizations":[{"compartment":"cytoplasmic","grade":3},{"compartment":"vesicles","grade":3},{"compartment":"membrane","grade":2},{"compartment":"nucleoplasm","grade":1}],"interactors":[{"gene":"DNAJA2","stoichiometry":10.0},{"gene":"GDI1","stoichiometry":10.0},{"gene":"HSPA14","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID000034","total_profiled":1310},"omim":[{"mim_id":"620526","title":"SMALL GLUTAMINE-RICH TETRATRICOPEPTIDE REPEAT COCHAPERONE, BETA; SGTB","url":"https://www.omim.org/entry/620526"},{"mim_id":"613945","title":"DNAJ/HSP40 HOMOLOG, SUBFAMILY C, MEMBER 5, BETA; DNAJC5B","url":"https://www.omim.org/entry/613945"},{"mim_id":"611203","title":"DNAJ/HSP40 HOMOLOG, SUBFAMILY C, MEMBER 5; DNAJC5","url":"https://www.omim.org/entry/611203"},{"mim_id":"607822","title":"ALZHEIMER DISEASE 3; AD3","url":"https://www.omim.org/entry/607822"},{"mim_id":"603419","title":"SMALL GLUTAMINE-RICH TETRATRICOPEPTIDE REPEAT-CONTAINING COCHAPERONE, ALPHA; SGTA","url":"https://www.omim.org/entry/603419"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Vesicles","reliability":"Supported"},{"location":"Golgi apparatus","reliability":"Additional"},{"location":"Perinuclear theca","reliability":"Additional"},{"location":"Principal piece","reliability":"Additional"},{"location":"End piece","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/DNAJC5"},"hgnc":{"alias_symbol":["FLJ00118","FLJ13070","DNAJC5A"],"prev_symbol":["CLN4"]},"alphafold":{"accession":"Q9H3Z4","domains":[{"cath_id":"1.20.5","chopping":"103-133","consensus_level":"medium","plddt":74.5448,"start":103,"end":133}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9H3Z4","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9H3Z4-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9H3Z4-F1-predicted_aligned_error_v6.png","plddt_mean":73.56},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=DNAJC5","jax_strain_url":"https://www.jax.org/strain/search?query=DNAJC5"},"sequence":{"accession":"Q9H3Z4","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9H3Z4.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9H3Z4/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9H3Z4"}},"corpus_meta":[{"pmid":"21820099","id":"PMC_21820099","title":"Mutations in DNAJC5, encoding cysteine-string protein alpha, cause autosomal-dominant adult-onset neuronal ceroid lipofuscinosis.","date":"2011","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/21820099","citation_count":214,"is_preprint":false},{"pmid":"22073189","id":"PMC_22073189","title":"Exome-sequencing confirms DNAJC5 mutations as cause of adult neuronal ceroid-lipofuscinosis.","date":"2011","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/22073189","citation_count":98,"is_preprint":false},{"pmid":"29531792","id":"PMC_29531792","title":"DNAJC5 facilitates USP19-dependent unconventional secretion of misfolded cytosolic proteins.","date":"2018","source":"Cell discovery","url":"https://pubmed.ncbi.nlm.nih.gov/29531792","citation_count":88,"is_preprint":false},{"pmid":"26659577","id":"PMC_26659577","title":"Neuronal ceroid lipofuscinosis with DNAJC5/CSPα mutation has PPT1 pathology and exhibit aberrant protein palmitoylation.","date":"2015","source":"Acta neuropathologica","url":"https://pubmed.ncbi.nlm.nih.gov/26659577","citation_count":69,"is_preprint":false},{"pmid":"22235333","id":"PMC_22235333","title":"Mutations in the gene DNAJC5 cause autosomal dominant Kufs disease in a proportion of cases: study of the Parry family and 8 other families.","date":"2012","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/22235333","citation_count":67,"is_preprint":false},{"pmid":"22978711","id":"PMC_22978711","title":"Recurrent mutations in DNAJC5 cause autosomal dominant Kufs disease.","date":"2012","source":"Clinical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/22978711","citation_count":51,"is_preprint":false},{"pmid":"36626307","id":"PMC_36626307","title":"Unconventional secretion of α-synuclein mediated by palmitoylated DNAJC5 oligomers.","date":"2023","source":"eLife","url":"https://pubmed.ncbi.nlm.nih.gov/36626307","citation_count":44,"is_preprint":false},{"pmid":"24947438","id":"PMC_24947438","title":"Caenorhabditis elegans dnj-14, the orthologue of the DNAJC5 gene mutated in adult onset neuronal ceroid lipofuscinosis, provides a new platform for neuroprotective drug screening and identifies a SIR-2.1-independent action of resveratrol.","date":"2014","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/24947438","citation_count":42,"is_preprint":false},{"pmid":"35506243","id":"PMC_35506243","title":"Abnormal triaging of misfolded proteins by adult neuronal ceroid lipofuscinosis-associated DNAJC5/CSPα mutants causes lipofuscin accumulation.","date":"2022","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/35506243","citation_count":38,"is_preprint":false},{"pmid":"33662413","id":"PMC_33662413","title":"DNAJC5 promotes hepatocellular carcinoma cells proliferation though regulating SKP2 mediated p27 degradation.","date":"2021","source":"Biochimica et biophysica acta. 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domain of DNAJC5/CSPα affect palmitoylation-dependent sorting and reduce the amount of CSPα in neuronal cells, implying the cysteine-string domain is required for proper membrane targeting.\",\n      \"method\": \"Exome sequencing, candidate-gene sequencing, and cell-based assays of palmitoylation-dependent sorting in neuronal cells\",\n      \"journal\": \"American journal of human genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional sorting assays in neuronal cells with two independent mutations, single lab but orthogonal genetic and cellular methods\",\n      \"pmids\": [\"21820099\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"DNAJC5/CSPα is a substrate of the depalmitoylating enzyme PPT1/CLN1; in DNAJC5/CLN4 patient brains PPT1 is massively increased, mis-localized, and has dramatically reduced specific enzymatic activity, establishing a biochemical link between two NCL disease proteins and revealing global changes in protein palmitoylation at synaptic and lysosomal proteins.\",\n      \"method\": \"Biochemical fractionation, enzymatic activity assays, quantitative palmitoyl-proteomics (palmitome mass spectrometry) of patient versus control brain tissue\",\n      \"journal\": \"Acta neuropathologica\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — direct in vitro depalmitoylation assay establishing CSPα as PPT1 substrate, plus quantitative proteomics of patient brains; multiple orthogonal methods in one study\",\n      \"pmids\": [\"26659577\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"DNAJC5 acts as an essential mediator of misfolding-associated protein secretion (MAPS), a pathway for unconventional secretion of misfolded cytosolic proteins. USP19 deubiquitinase binds HSC70 and acts upstream of HSC70 and DNAJC5. As a membrane-associated protein preferentially localized to late endosomes/lysosomes, DNAJC5 chaperones MAPS client proteins to the cell exterior; secreted misfolded proteins can be endocytosed and degraded in recipient-cell lysosomes.\",\n      \"method\": \"Co-immunoprecipitation, knockdown/knockout cellular assays, subcellular fractionation, secretion assays with defined client proteins\",\n      \"journal\": \"Cell discovery\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal Co-IP, multiple KO/KD experiments with defined secretion phenotype, subcellular fractionation; replicated pathway epistasis by placing USP19 upstream\",\n      \"pmids\": [\"29531792\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"CLN4 mutations in DNAJC5/CSPα drive excessive oligomerization and mislocalization of CSPα from synaptic vesicles to prelysosomal (HRS/LAMP1-positive) compartments in Drosophila neurons. Reducing endogenous wild-type dCSP or Hsc70 gene dosage attenuates CLN4 phenotypes (lethality, oligomerization, prelysosomal accumulation), establishing a dominant hypermorphic gain-of-function mechanism requiring wild-type CSPα and Hsc70.\",\n      \"method\": \"Drosophila transgenic models, immunofluorescence co-localization, genetic epistasis (dosage reduction of dCSP and Hsc70), ultrastructural analysis\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis across multiple alleles in vivo, ultrastructural validation, dose-response with wild-type partner; multiple orthogonal methods in one study\",\n      \"pmids\": [\"31663851\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"DNAJC5 has two functionally distinct but coupled chaperoning activities: endolysosome-associated DNAJC5 promotes ESCRT-dependent microautophagy, while a perinuclear non-lysosomal pool mediates MAPS. The interactor SLC3A2/CD98hc is essential for perinuclear DNAJC5 localization and MAPS but dispensable for microautophagy. Uncoupling these two processes (by loss of SLC3A2 or expression of ANCL mutants) generates DNAJC5-containing autofluorescent storage materials resembling NCL lipofuscin and induces neurodegeneration in a Drosophila model.\",\n      \"method\": \"Functional proteomics (proximity labeling/BioID), Co-IP, shRNA knockdown/KO, fluorescence microscopy, Drosophila neurodegeneration model, ESCRT perturbation assays\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (proteomics, Co-IP, KO, in vivo Drosophila epistasis), identification of novel interactor SLC3A2 with functional validation\",\n      \"pmids\": [\"35506243\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"DNAJC5 undergoes palmitoylation and anchors on endosomal membranes; palmitoylation is essential for DNAJC5-induced α-synuclein secretion. Cytosolic α-syn is actively translocated into an endosomal membrane compartment in a DNAJC5-dependent manner. A palmitoylation-deficient mutation reduces α-syn secretion, which can be rescued by a membrane-targeting peptide that forces DNAJC5 oligomerization, indicating that palmitoylated DNAJC5 oligomers drive α-syn unconventional secretion.\",\n      \"method\": \"Reconstitution in HEK293T cells, palmitoylation-deficient mutants, membrane fractionation, endosomal translocation assays, rescue with membrane-targeting peptide, validation in SH-SY5Y neurons and iPSC-derived midbrain dopamine neurons\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — reconstitution of secretion pathway, mutagenesis of palmitoylation sites, mechanistic rescue experiment, validated in multiple neuronal cell types\",\n      \"pmids\": [\"36626307\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"DNAJC5 interacts with SKP2 and enhances SKP2-mediated degradation of the cyclin-dependent kinase inhibitor p27, promoting G1-to-S cell-cycle progression in hepatocellular carcinoma cells; DNAJC5 knockdown rescues p27 protein levels.\",\n      \"method\": \"Co-immunoprecipitation, overexpression/knockdown, cell-cycle flow cytometry, western blotting\",\n      \"journal\": \"Biochimica et biophysica acta. Molecular cell research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — Co-IP plus knockdown rescue, single lab, two orthogonal methods; context is cancer rather than canonical neuronal function\",\n      \"pmids\": [\"33662413\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Proximity labeling in PC12 neuroendocrine cells confirmed DNAJC5 interacts with Hsc70 and SNAP-25, and identified STXBP1/Munc18-1 as a novel DNAJC5-binding protein. The ANCL mutation L115R inhibits interactions with SNAP-25 and STXBP1/Munc18-1 but does not affect Hsc70 binding, mapping which interactions are disrupted by disease mutation.\",\n      \"method\": \"Proximity labeling (miniTurbo) in stable PC12 cell lines, LC-MS proteomics, western blot validation\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — proximity labeling plus western blot validation, single lab; identifies novel interactor with mutation-dependent loss of interaction\",\n      \"pmids\": [\"38193346\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"CLN4-linked DNAJC5 mutant aggregates on lysosomal membranes cause direct lysosomal membrane damage in iPSC-derived neurons (established by in vitro membrane-damaging assay). The ubiquitin ligase CHIP acts as a central microautophagy regulator that ubiquitinates CLN4 aggregates to protect lysosomes; ectopic CHIP improves lysosomal function in CLN4 neurons and alleviates lipofuscin accumulation and neurodegeneration in a Drosophila CLN4 model.\",\n      \"method\": \"iPSC-derived neurons (i3Neuron) with DNAJC5 CLN4 mutations, in vitro lysosome membrane damage assay, genome-wide CRISPR screen, organelle-specific proteomics, Drosophila in vivo model\",\n      \"journal\": \"Nature cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — genome-wide CRISPR screen, in vitro reconstitution of membrane damage, iPSC neuron disease model, and Drosophila epistasis; multiple orthogonal methods replicated across cell and animal models\",\n      \"pmids\": [\"40855364\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Mice overexpressing CLN4 mutant (Leu115Arg or Leu116Δ) CSPα develop motor deficits and neuronal lipofuscinosis with GROD-like structures, whereas conventional or conditional DNAJC5 knockout mice show no lipofuscinosis or GRODs, establishing that DNAJC5 mutations cause neuronal lipofuscinosis through a cell-autonomous gain of pathological function, not loss of function.\",\n      \"method\": \"Transgenic mouse lines (Thy1-promoter WT, Leu115Arg, Leu116Δ CSPα), conventional and conditional knockout mice, neuropathological analysis, behavioral testing\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple independent transgenic and knockout mouse lines with neuropathological validation; definitive gain-of-function vs. loss-of-function comparison in vivo\",\n      \"pmids\": [\"40397740\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"DNAJC5 is palmitoylated by multiple DHHC palmitoyl acyltransferases in human cells; DHHC11 overexpression enriches DNAJC5 in a Golgi-associated compartment and increases unconventional protein secretion. Mutagenesis defined a minimal module (DC95: CS domain plus C-terminal 62 residues and short upstream segment) sufficient for palmitoylation, Golgi translocation, and secretion; deletion of 5 residues from DC95 abolishes all three activities.\",\n      \"method\": \"Palmitoylation assays with DHHC enzyme panel, subcellular fractionation/immunofluorescence, deletion mutagenesis, secretion assays in human cells\",\n      \"journal\": \"Traffic (Copenhagen, Denmark)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct in vitro palmitoylation assays with mutagenesis mapping minimal functional module, single lab but multiple orthogonal biochemical methods\",\n      \"pmids\": [\"41657026\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Misfolded protein secretion in senescent human cells requires DNAJC5; the vesicle-associated HSP70 co-chaperone DNAJC5 mediates expulsion of misfolded proteins (including TDP-43) through the endo-lysosomal system during proteotoxic stress in senescent cells.\",\n      \"method\": \"Multi-dimensional transcriptomics and proteomics, knockdown of DNAJC5 in senescent human cells, secretion assays under proteotoxic stress\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — proteomics plus KD secretion assay; preprint, single lab, not yet peer-reviewed\",\n      \"pmids\": [\"bio_10.1101_2025.09.07.674107\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"DNAJC5 interacts with the intracellular domain of EGFR and with the endocytosis adaptor AP2A1; DNAJC5 overexpression enhances EGFR endocytosis and recycling, augmenting downstream EGFR signaling. AP2A1 knockdown attenuates DNAJC5-driven EGFR trafficking and lung adenocarcinoma cell proliferation/migration.\",\n      \"method\": \"Co-immunoprecipitation, overexpression/knockdown in LUAD cell lines, in vitro and in vivo proliferation/migration assays, EGFR trafficking assays\",\n      \"journal\": \"Communications biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — Co-IP plus functional knockdown rescue, single lab; novel context (EGFR trafficking) with two orthogonal functional methods\",\n      \"pmids\": [\"40374748\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"TDP43 and hnRNP K regulate canonical splicing of DNAJC5 pre-mRNA; their interaction is RNA-dependent, and DNAJC5 canonical splicing depends on internal TDP43 and hnRNP K binding sites. Loss of either factor introduces aberrant splicing of DNAJC5, affecting its role in endosomal trafficking.\",\n      \"method\": \"siRNA knockdown of TDP43 and hnRNP K, RNA immunoprecipitation, RT-PCR splicing assays, RNA-dependency of protein interaction assays\",\n      \"journal\": \"Cell biology international\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RNA-IP plus splicing assays with internal binding site mutagenesis; single lab, direct mechanistic validation of splicing regulation\",\n      \"pmids\": [\"41983529\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"DNAJC5/CSPα is a palmitoylated, membrane-associated HSC70 co-chaperone that localizes to synaptic vesicles and endolysosomes, where it performs two coupled protein quality-control functions: promoting ESCRT-dependent endosomal microautophagy and mediating misfolding-associated protein secretion (MAPS) of cytosolic misfolded proteins (including α-synuclein) via palmitoylation-dependent oligomerization on late endosomal/lysosomal membranes; disease-causing CLN4 mutations (Leu115Arg, Leu116del) drive dominant gain-of-function excessive oligomerization that deposits CLN4 aggregates on lysosomal membranes causing direct membrane damage, lysosomal dysfunction, and lipofuscin accumulation, with the ubiquitin ligase CHIP acting as a protective microautophagy regulator that clears these aggregates, while PPT1/CLN1 depalmitoylates CSPα and DHHC palmitoyl acyltransferases control its membrane targeting and secretory function.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"DNAJC5/CSPα is a palmitoylated, membrane-associated HSC70 co-chaperone that operates in protein quality control by directing misfolded cytosolic proteins through the endo-lysosomal system [#2, #5]. It serves as an essential mediator of misfolding-associated protein secretion (MAPS), chaperoning client proteins to the cell exterior downstream of the USP19 deubiquitinase and HSC70 [#2]. Palmitoylation, installed by multiple DHHC palmitoyl acyltransferases, anchors DNAJC5 on endosomal and Golgi-associated membranes and is required for its oligomerization and for secretion of clients including α-synuclein, with cytosolic α-synuclein being actively translocated into an endosomal compartment in a DNAJC5-dependent manner [#5, #10]. DNAJC5 carries two coupled chaperoning activities: an endolysosomal pool drives ESCRT-dependent microautophagy, while a perinuclear pool dependent on the interactor SLC3A2/CD98hc mediates MAPS; uncoupling these processes generates autofluorescent storage material resembling NCL lipofuscin [#4]. The protein engages the synaptic machinery, interacting with HSC70, SNAP-25, and STXBP1/Munc18-1 [#7], and is depalmitoylated by PPT1/CLN1, linking it biochemically to a second neuronal ceroid lipofuscinosis protein [#1]. DNAJC5 mutations (Leu115Arg, Leu116del) in the cysteine-string domain cause autosomal dominant neuronal ceroid lipofuscinosis (CLN4) through a gain of pathological function: the mutants oligomerize excessively, mislocalize from synaptic vesicles to prelysosomal compartments, deposit aggregates that directly damage lysosomal membranes, and drive lipofuscinosis and neurodegeneration, whereas knockout animals show no such pathology [#3, #8, #9]. The ubiquitin ligase CHIP acts as a protective microautophagy regulator that ubiquitinates and clears these aggregates [#8]. Beyond its neuronal role, DNAJC5 has been implicated in cancer-cell contexts via SKP2/p27 and EGFR/AP2A1 trafficking [#6, #12].\",\n  \"teleology\": [\n    {\n      \"year\": 2011,\n      \"claim\": \"Establishing the disease relevance of the cysteine-string domain showed that CLN4 mutations act by perturbing palmitoylation-dependent membrane targeting rather than by simple loss of expression.\",\n      \"evidence\": \"Exome/candidate-gene sequencing plus palmitoylation-dependent sorting assays in neuronal cells with two independent mutations\",\n      \"pmids\": [\"21820099\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not establish whether reduced CSPα was cause or consequence\", \"No in vivo demonstration of pathogenic mechanism\", \"Did not resolve gain- vs loss-of-function\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Identifying CSPα as a PPT1/CLN1 depalmitoylation substrate connected two NCL disease proteins biochemically and placed DNAJC5 within a palmitoylation cycle at synaptic and lysosomal membranes.\",\n      \"evidence\": \"In vitro depalmitoylation assays and quantitative palmitoyl-proteomics of patient versus control brain\",\n      \"pmids\": [\"26659577\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not define the DHHC enzymes installing the modification\", \"Functional consequence of the palmitoylation cycle for chaperone activity not resolved\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Defining DNAJC5 as an essential mediator of MAPS revealed a function for the protein in unconventional secretion of misfolded cytosolic clients and placed USP19 and HSC70 upstream in the pathway.\",\n      \"evidence\": \"Reciprocal Co-IP, knockdown/knockout secretion assays with defined clients, subcellular fractionation\",\n      \"pmids\": [\"29531792\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of client translocation across membranes not defined\", \"Did not establish palmitoylation requirement\", \"Physiological clients in neurons not enumerated\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Demonstrating that CLN4 mutants oligomerize excessively and mislocalize to prelysosomal compartments, with phenotypes attenuated by reducing wild-type CSPα or Hsc70 dosage, established a dominant hypermorphic gain-of-function mechanism.\",\n      \"evidence\": \"Drosophila transgenic models, immunofluorescence co-localization, genetic dosage epistasis, ultrastructural analysis\",\n      \"pmids\": [\"31663851\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not identify the lysosomal damage mechanism\", \"Mammalian validation absent\", \"Clearance pathways for aggregates unknown\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Linking DNAJC5 to SKP2-mediated p27 degradation extended its functional repertoire to cell-cycle control in hepatocellular carcinoma, beyond the canonical neuronal context.\",\n      \"evidence\": \"Co-IP, overexpression/knockdown, cell-cycle flow cytometry in HCC cells\",\n      \"pmids\": [\"33662413\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab, cancer-specific context\", \"Mechanism connecting chaperone activity to SKP2 not resolved\", \"No in vivo tumor confirmation\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Resolving DNAJC5 into two coupled activities — endolysosomal microautophagy and SLC3A2-dependent perinuclear MAPS — showed how uncoupling the pathways produces NCL-like autofluorescent storage material and neurodegeneration.\",\n      \"evidence\": \"Proximity labeling/BioID, Co-IP, shRNA/KO, microscopy, ESCRT perturbation, Drosophila neurodegeneration model\",\n      \"pmids\": [\"35506243\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis of SLC3A2-dependent perinuclear targeting not defined\", \"How the two pools interconvert unknown\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Showing that palmitoylation-driven DNAJC5 oligomerization on endosomal membranes drives α-synuclein translocation and secretion provided a mechanistic basis for the secretory function and its disease relevance.\",\n      \"evidence\": \"HEK293T reconstitution, palmitoylation-deficient mutants, endosomal translocation and rescue assays, validation in SH-SY5Y and iPSC dopamine neurons\",\n      \"pmids\": [\"36626307\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structure of the active oligomer not determined\", \"Physiological vs pathological balance of α-syn secretion unresolved\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Mapping the DNAJC5 interactome in neuroendocrine cells confirmed Hsc70 and SNAP-25 binding, identified STXBP1/Munc18-1 as a partner, and showed the L115R mutation selectively disrupts SNAP-25 and STXBP1 interactions while sparing Hsc70.\",\n      \"evidence\": \"miniTurbo proximity labeling in PC12 cells, LC-MS proteomics, western blot validation\",\n      \"pmids\": [\"38193346\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of lost SNAP-25/STXBP1 interactions not tested\", \"Single cell type\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identifying direct lysosomal membrane damage by CLN4 aggregates and CHIP as a protective microautophagy regulator defined both the proximate cytotoxic event and a clearance mechanism that rescues lysosomal function in vivo.\",\n      \"evidence\": \"iPSC i3Neurons with CLN4 mutations, in vitro membrane damage assay, genome-wide CRISPR screen, organelle proteomics, Drosophila model\",\n      \"pmids\": [\"40855364\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of physical membrane permeabilization not fully resolved\", \"Whether CHIP modulation is therapeutically tractable unknown\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Transgenic mouse modeling settled the gain- versus loss-of-function question, showing CLN4 mutant overexpression causes lipofuscinosis and GRODs while knockouts do not.\",\n      \"evidence\": \"Thy1-promoter WT and mutant CSPα transgenic lines, conventional and conditional knockouts, neuropathology and behavior\",\n      \"pmids\": [\"40397740\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not address normal physiological role lost in knockouts\", \"Cell-type specificity of vulnerability incompletely mapped\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Implicating DNAJC5 in misfolded protein secretion during cellular senescence extended the MAPS function to proteotoxic stress and additional clients such as TDP-43.\",\n      \"evidence\": \"Transcriptomics/proteomics and DNAJC5 knockdown secretion assays in senescent cells (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.09.07.674107\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint, not peer-reviewed\", \"Single lab\", \"Mechanistic detail of TDP-43 secretion not resolved\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Defining DHHC enzymes as the palmitoylating machinery and mapping a minimal DC95 module sufficient for palmitoylation, Golgi translocation, and secretion completed the upstream control logic of DNAJC5 membrane targeting.\",\n      \"evidence\": \"Palmitoylation assays with DHHC panel, subcellular fractionation/IF, deletion mutagenesis, secretion assays in human cells\",\n      \"pmids\": [\"41657026\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Which DHHC enzyme acts physiologically in neurons unresolved\", \"Relationship between Golgi and endosomal pools not defined\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Identifying TDP43 and hnRNP K as regulators of DNAJC5 pre-mRNA splicing introduced an upstream RNA-level control layer that links DNAJC5 abundance to RNA-binding proteins implicated in neurodegeneration.\",\n      \"evidence\": \"siRNA knockdown, RNA immunoprecipitation, RT-PCR splicing assays with internal binding-site mutagenesis\",\n      \"pmids\": [\"41983529\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional impact of aberrant isoforms on trafficking not quantified\", \"Single lab\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The structural basis of the palmitoylated DNAJC5 oligomer and how it physically translocates clients across or permeabilizes lysosomal membranes remains undefined.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No high-resolution structure of the functional oligomer\", \"Mechanism of membrane translocation/permeabilization unresolved\", \"Native physiological MAPS clients in healthy neurons not enumerated\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0044183\", \"supporting_discovery_ids\": [2, 4, 11]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [2, 5]},\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [5, 10]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [2, 3, 5]},\n      {\"term_id\": \"GO:0005764\", \"supporting_discovery_ids\": [3, 4, 8]},\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [10]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [5]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [4, 8]},\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [2, 5]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [2, 4]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [8, 9]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"HSPA8\", \"USP19\", \"SLC3A2\", \"SNAP25\", \"STXBP1\", \"CHIP\", \"SKP2\", \"EGFR\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":8,"faith_total":8,"faith_pct":100.0}}