{"gene":"HSPA14","run_date":"2026-04-28T18:06:53","timeline":{"discoveries":[{"year":2005,"finding":"HSPA14 (Hsp70L1) forms a stable heterodimeric complex with MPP11 on ribosomes, constituting the mammalian ribosome-associated complex (RAC) that cotranslationally interacts with nascent polypeptides; complementation experiments showed this complex is functional in yeast, demonstrating conservation of ribosome-associated chaperone function.","method":"Purification/co-purification of endogenous complex, ribosome association assay, yeast complementation experiments","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 — reciprocal purification, functional complementation across species, multiple orthogonal methods in a highly-cited foundational paper","pmids":["16002468"],"is_preprint":false},{"year":2011,"finding":"Extracellular HSPA14 (Hsp70L1) binds directly to TLR4 on the surface of dendritic cells, activating MAPK and NF-κB signaling pathways, upregulating MHC II (I-a^b), CD40, CD80, and CD86 co-stimulatory molecules, and promoting production of TNF-α, IL-1β, and IL-12p70; TLR4-deficient DCs fail to respond, establishing TLR4 as the essential receptor for HSPA14-induced DC activation.","method":"Direct binding assay, TLR4-deficient DC experiments, signaling pathway analysis (MAPK/NF-κB), in vivo immunization with TLR4 antagonist","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — loss-of-function TLR4 KO DCs with defined signaling readouts, replicated in vitro and in vivo, highly cited","pmids":["21730052"],"is_preprint":false},{"year":2003,"finding":"HSPA14 (Hsp70L1) activates dendritic cells by interacting with shared Hsp70 surface receptors, promoting DC maturation and stimulating secretion of IL-12p70, IL-1β, TNF-α, IP-10, MIP-1α, MIP-1β, and RANTES, and polarizing T helper responses toward Th1; it also uniquely induces IP-10 secretion not shared by Hsp70.","method":"Recombinant protein stimulation of DCs, cytokine/chemokine ELISA, receptor competition assay, in vivo tumor challenge","journal":"Blood","confidence":"Medium","confidence_rationale":"Tier 2 — multiple cytokine readouts and in vivo validation, single lab but multiple methods","pmids":["14592822"],"is_preprint":false},{"year":2019,"finding":"Intracellular HSPA14 (HSP70L1) inhibits human dendritic cell maturation by suppressing MHC and co-stimulatory molecule expression; mechanistically, it inhibits the recruitment of the histone methyltransferase Ash1l to promoters of costimulatory, MHC, and STAT3 genes, maintaining repressive H3K27me3 and H2AK119Ub1 histone modifications. HSPA14 stability depends on its interaction with DNAJC2 (a known epigenetic regulator).","method":"Intracellular HSPA14 overexpression/knockdown, chromatin immunoprecipitation (ChIP) for histone marks, Co-IP with DNAJC2, flow cytometry for DC maturation markers","journal":"Cellular & molecular immunology","confidence":"Medium","confidence_rationale":"Tier 2 — ChIP and Co-IP with defined mechanistic readouts, single lab","pmids":["30635648"],"is_preprint":false},{"year":2011,"finding":"NBS1 overexpression induces HSPA14 expression through upregulation of heat shock transcription factor 4b (HSF4b); siRNA-mediated knockdown of HSPA14 decreases in vitro migration, invasion, and transformation activity, identifying HSPA14 as a downstream effector in the NBS1-HSF4b-HSPA14 signaling axis.","method":"siRNA knockdown, RT-PCR, Western blot, in vitro migration/invasion assay, soft agar colony formation","journal":"Journal of biomedical science","confidence":"Medium","confidence_rationale":"Tier 2 — loss-of-function with defined functional phenotypes and pathway placement, single lab","pmids":["21208456"],"is_preprint":false},{"year":2023,"finding":"HSPA14 interacts with HspBP1 (an HIV transcriptional inhibitor); overexpression of HSPA14 inhibits HIV-1 replication while knockdown promotes it, suggesting HSPA14 restricts HIV replication by regulating HspBP1.","method":"Co-immunoprecipitation (Co-IP), HSPA14 overexpression and knockdown in Jurkat and primary CD4+ T cells, intracellular HIV replication assay","journal":"Frontiers in immunology","confidence":"Medium","confidence_rationale":"Tier 3 — Co-IP plus gain/loss-of-function with defined viral replication readout, single lab, single study","pmids":["36845091"],"is_preprint":false}],"current_model":"HSPA14 (Hsp70L1) is an atypical Hsp70-family chaperone that, in the cytosol, forms the mammalian ribosome-associated complex (RAC) with MPP11 to cotranslationally assist nascent polypeptides; when released extracellularly it acts as a TLR4 agonist on dendritic cells activating MAPK/NF-κB signaling to drive Th1 immune polarization, whereas intracellularly it suppresses DC maturation by maintaining repressive H3K27me3/H2AK119Ub1 histone marks at costimulatory and MHC gene promoters through inhibition of Ash1l recruitment, and it also participates in NBS1-HSF4b-driven cell migration/transformation and restriction of HIV-1 replication via interaction with HspBP1."},"narrative":{"teleology":[{"year":2003,"claim":"The first functional characterization revealed that extracellular HSPA14 activates dendritic cells and drives Th1 polarization, establishing it as an immunostimulatory Hsp70-family member with unique chemokine-inducing properties (e.g., IP-10).","evidence":"Recombinant HSPA14 stimulation of DCs with cytokine/chemokine ELISA, receptor competition, and in vivo tumor challenge","pmids":["14592822"],"confidence":"Medium","gaps":["The specific receptor mediating DC activation was not identified","No mechanism distinguishing HSPA14 from canonical Hsp70 in receptor engagement","Endotoxin contamination of recombinant protein not fully excluded in this study"]},{"year":2005,"claim":"Identification of HSPA14 as a core subunit of the mammalian ribosome-associated complex (mRAC) with MPP11 resolved its primary cytosolic function: cotranslational chaperoning of nascent polypeptides, a role conserved from yeast.","evidence":"Endogenous complex purification, ribosome association assay, and yeast complementation","pmids":["16002468"],"confidence":"High","gaps":["Substrate specificity of mRAC on mammalian ribosomes was not determined","Whether HSPA14 ATPase activity is required for mRAC function was untested","The relationship between ribosomal and extracellular/immune functions was unexplored"]},{"year":2011,"claim":"Two independent studies clarified HSPA14's signaling context: extracellular HSPA14 was shown to signal through TLR4 on DCs via MAPK/NF-κB, while intracellularly HSPA14 was placed downstream of the NBS1–HSF4b axis as an effector of cell migration and transformation.","evidence":"TLR4-deficient DC experiments with signaling pathway analysis (MAPK/NF-κB) for immune function; siRNA knockdown with migration/invasion/soft-agar assays for oncogenic function","pmids":["21730052","21208456"],"confidence":"High","gaps":["The structural basis of HSPA14–TLR4 interaction was not defined","Whether HSPA14-driven migration requires its chaperone activity or a distinct domain was unknown","The physiological route by which HSPA14 reaches the extracellular space was not addressed"]},{"year":2019,"claim":"Intracellular HSPA14 was discovered to exert an opposing, immunosuppressive effect by maintaining repressive histone marks (H3K27me3, H2AK119Ub1) at costimulatory and MHC gene promoters through inhibition of Ash1l recruitment, with DNAJC2 stabilizing HSPA14 protein levels — revealing an unexpected epigenetic regulatory axis.","evidence":"ChIP for histone marks, Co-IP with DNAJC2, overexpression/knockdown in human DCs with flow cytometry for maturation markers","pmids":["30635648"],"confidence":"Medium","gaps":["Whether HSPA14 directly binds Ash1l or acts indirectly was not resolved","Single-lab finding without independent replication","How HSPA14's epigenetic role relates to its ribosome-associated chaperone function is unclear"]},{"year":2023,"claim":"HSPA14 was identified as a host restriction factor for HIV-1 replication, acting through physical interaction with HspBP1, extending its functional repertoire to antiviral defense.","evidence":"Co-IP of HSPA14–HspBP1, overexpression and knockdown in Jurkat and primary CD4+ T cells with HIV replication assay","pmids":["36845091"],"confidence":"Medium","gaps":["Single study from one laboratory; awaits independent confirmation","The mechanism by which HSPA14–HspBP1 interaction suppresses HIV transcription/replication was not delineated","Whether the antiviral function depends on HSPA14 chaperone or epigenetic activity is unknown"]},{"year":null,"claim":"How HSPA14's ribosome-associated chaperone function, extracellular TLR4 agonism, intracellular epigenetic suppression, and antiviral activity are coordinated or partitioned across cellular compartments and physiological states remains unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural data exist for HSPA14 in the mRAC complex or bound to TLR4","The secretion or release mechanism for extracellular HSPA14 has not been defined","Whether HSPA14 ATPase activity is required for any of its non-chaperone functions is untested"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0044183","term_label":"protein folding chaperone","supporting_discovery_ids":[0]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[3,5]},{"term_id":"GO:0048018","term_label":"receptor ligand activity","supporting_discovery_ids":[1,2]}],"localization":[{"term_id":"GO:0005840","term_label":"ribosome","supporting_discovery_ids":[0]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0,3]},{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[1,2]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[3]}],"pathway":[{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[0]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[1,2,3]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[1,4]},{"term_id":"R-HSA-4839726","term_label":"Chromatin organization","supporting_discovery_ids":[3]}],"complexes":["mammalian ribosome-associated complex (mRAC)"],"partners":["MPP11","TLR4","DNAJC2","HSPBP1","HSF4B","ASH1L"],"other_free_text":[]},"mechanistic_narrative":"HSPA14 (Hsp70L1) is an atypical Hsp70-family chaperone that functions both as a ribosome-associated cotranslational chaperone and as an immunomodulatory molecule with context-dependent effects on dendritic cell activation. Together with MPP11, HSPA14 forms the mammalian ribosome-associated complex (mRAC), which directly contacts nascent polypeptides on ribosomes and is functionally conserved with yeast RAC [PMID:16002468]. Extracellular HSPA14 binds TLR4 on dendritic cells, activating MAPK/NF-κB signaling to upregulate MHC II and costimulatory molecules and drive Th1-polarizing cytokine secretion [PMID:21730052, PMID:14592822], whereas intracellular HSPA14 suppresses DC maturation by blocking Ash1l recruitment to costimulatory and MHC gene promoters, thereby maintaining repressive H3K27me3 and H2AK119Ub1 histone marks in a DNAJC2-dependent manner [PMID:30635648]. HSPA14 also serves as a downstream effector of NBS1–HSF4b signaling that promotes cell migration and transformation [PMID:21208456] and restricts HIV-1 replication through interaction with HspBP1 [PMID:36845091]."},"prefetch_data":{"uniprot":{"accession":"Q0VDF9","full_name":"Heat shock 70 kDa protein 14","aliases":["HSP70-like protein 1","Heat shock protein HSP60","Heat shock protein family A member 14"],"length_aa":509,"mass_kda":54.8,"function":"Component of the ribosome-associated complex (RAC), a complex involved in folding or maintaining nascent polypeptides in a folding-competent state. In the RAC complex, binds to the nascent polypeptide chain, while DNAJC2 stimulates its ATPase activity","subcellular_location":"Cytoplasm, cytosol","url":"https://www.uniprot.org/uniprotkb/Q0VDF9/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/HSPA14","classification":"Not Classified","n_dependent_lines":472,"n_total_lines":1208,"dependency_fraction":0.39072847682119205},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000187522","cell_line_id":"CID000045","localizations":[{"compartment":"cytoplasmic","grade":3},{"compartment":"nucleoplasm","grade":1}],"interactors":[{"gene":"DNAJC2","stoichiometry":10.0},{"gene":"DNAJC5","stoichiometry":0.2},{"gene":"DRG1","stoichiometry":0.2},{"gene":"GDI1","stoichiometry":0.2},{"gene":"HSP90B1","stoichiometry":0.2},{"gene":"SURF6","stoichiometry":0.2},{"gene":"MZT2B;MZT2A","stoichiometry":0.2},{"gene":"ATF6B","stoichiometry":0.2},{"gene":"S100A13","stoichiometry":0.2},{"gene":"STIM1","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID000045","total_profiled":1310},"omim":[{"mim_id":"610369","title":"HEAT-SHOCK 70-KD PROTEIN 14; HSPA14","url":"https://www.omim.org/entry/610369"},{"mim_id":"605502","title":"DNAJ/HSP40 HOMOLOG, SUBFAMILY C, MEMBER 2; DNAJC2","url":"https://www.omim.org/entry/605502"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/HSPA14"},"hgnc":{"alias_symbol":["HSP70-4","HSP70L1"],"prev_symbol":[]},"alphafold":{"accession":"Q0VDF9","domains":[{"cath_id":"3.30.420.40","chopping":"3-164","consensus_level":"high","plddt":94.4653,"start":3,"end":164},{"cath_id":"3.30.420.40","chopping":"186-225_304-364","consensus_level":"medium","plddt":92.825,"start":186,"end":364},{"cath_id":"3.90.640.10","chopping":"229-300","consensus_level":"medium","plddt":96.7737,"start":229,"end":300},{"cath_id":"2.60.34.10","chopping":"395-507","consensus_level":"high","plddt":86.3174,"start":395,"end":507}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q0VDF9","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q0VDF9-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q0VDF9-F1-predicted_aligned_error_v6.png","plddt_mean":91.38},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=HSPA14","jax_strain_url":"https://www.jax.org/strain/search?query=HSPA14"},"sequence":{"accession":"Q0VDF9","fasta_url":"https://rest.uniprot.org/uniprotkb/Q0VDF9.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q0VDF9/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q0VDF9"}},"corpus_meta":[{"pmid":"16002468","id":"PMC_16002468","title":"The chaperones MPP11 and Hsp70L1 form the mammalian ribosome-associated complex.","date":"2005","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/16002468","citation_count":115,"is_preprint":false},{"pmid":"21730052","id":"PMC_21730052","title":"Toll-like receptor 4 (TLR4) is essential for Hsp70-like protein 1 (HSP70L1) to activate dendritic cells and induce Th1 response.","date":"2011","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/21730052","citation_count":94,"is_preprint":false},{"pmid":"14592822","id":"PMC_14592822","title":"Novel heat shock protein Hsp70L1 activates dendritic cells and acts as a Th1 polarizing adjuvant.","date":"2003","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/14592822","citation_count":85,"is_preprint":false},{"pmid":"21208456","id":"PMC_21208456","title":"Induction of HSPA4 and HSPA14 by NBS1 overexpression contributes to NBS1-induced in vitro metastatic and transformation activity.","date":"2011","source":"Journal of biomedical science","url":"https://pubmed.ncbi.nlm.nih.gov/21208456","citation_count":67,"is_preprint":false},{"pmid":"33991823","id":"PMC_33991823","title":"HSP70-4 and farnesylated AtJ3 constitute a specific HSP70/HSP40-based chaperone machinery essential for prolonged heat stress tolerance in Arabidopsis.","date":"2021","source":"Journal of plant physiology","url":"https://pubmed.ncbi.nlm.nih.gov/33991823","citation_count":24,"is_preprint":false},{"pmid":"21785448","id":"PMC_21785448","title":"Efficient induction of a Her2-specific anti-tumor response by dendritic cells pulsed with a Hsp70L1-Her2(341-456) fusion protein.","date":"2011","source":"Cellular & molecular immunology","url":"https://pubmed.ncbi.nlm.nih.gov/21785448","citation_count":13,"is_preprint":false},{"pmid":"27345726","id":"PMC_27345726","title":"HSP70L1-mediated intracellular priming of dendritic cell vaccination induces more potent CTL response against cancer.","date":"2016","source":"Cellular & molecular immunology","url":"https://pubmed.ncbi.nlm.nih.gov/27345726","citation_count":11,"is_preprint":false},{"pmid":"30635648","id":"PMC_30635648","title":"Intracellular HSP70L1 inhibits human dendritic cell maturation by promoting suppressive H3K27me3 and H2AK119Ub1 histone modifications.","date":"2019","source":"Cellular & molecular immunology","url":"https://pubmed.ncbi.nlm.nih.gov/30635648","citation_count":10,"is_preprint":false},{"pmid":"31766407","id":"PMC_31766407","title":"Trypanosoma brucei J-Protein 2 Functionally Co-Operates with the Cytosolic Hsp70 and Hsp70.4 Proteins.","date":"2019","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/31766407","citation_count":5,"is_preprint":false},{"pmid":"28706332","id":"PMC_28706332","title":"Role of Elsholtzia communis in counteracting stress by modulating expression of hspa14, C/EBP homologous protein, nuclear factor (erythroid-derived 2)-like-2 factor, Caspase-3, and brain-derived neurotrophic factor in rat hippocampus.","date":"2017","source":"Indian journal of pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/28706332","citation_count":4,"is_preprint":false},{"pmid":"36845091","id":"PMC_36845091","title":"Expression of HSPA14 in patients with acute HIV-1 infection and its effect on HIV-1 replication.","date":"2023","source":"Frontiers in immunology","url":"https://pubmed.ncbi.nlm.nih.gov/36845091","citation_count":3,"is_preprint":false},{"pmid":"39828281","id":"PMC_39828281","title":"The role of HSPA14 in breast cancer: implications for tumorigenesis, immune response modulation, and personalized therapies.","date":"2025","source":"International journal of hyperthermia : the official journal of European Society for Hyperthermic Oncology, North American Hyperthermia Group","url":"https://pubmed.ncbi.nlm.nih.gov/39828281","citation_count":3,"is_preprint":false},{"pmid":"31772283","id":"PMC_31772283","title":"Correction: HSP70L1-mediated intracellular priming of dendritic cell vaccination induces more potent CTL response against cancer.","date":"2020","source":"Cellular & molecular immunology","url":"https://pubmed.ncbi.nlm.nih.gov/31772283","citation_count":1,"is_preprint":false},{"pmid":"20368111","id":"PMC_20368111","title":"[Immunoadjuvant effect of Hsp70L1 in tumor vaccine].","date":"2010","source":"Xi bao yu fen zi mian yi xue za zhi = Chinese journal of cellular and molecular immunology","url":"https://pubmed.ncbi.nlm.nih.gov/20368111","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":8643,"output_tokens":1731,"usd":0.025947},"stage2":{"model":"claude-opus-4-6","input_tokens":4999,"output_tokens":2160,"usd":0.118493},"total_usd":0.14444,"stage1_batch_id":"msgbatch_01DzrsgVgYngY1hvM3DU1yF2","stage2_batch_id":"msgbatch_01KA9b7iRzKFdhoBUT7vCvSe","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2005,\n      \"finding\": \"HSPA14 (Hsp70L1) forms a stable heterodimeric complex with MPP11 on ribosomes, constituting the mammalian ribosome-associated complex (RAC) that cotranslationally interacts with nascent polypeptides; complementation experiments showed this complex is functional in yeast, demonstrating conservation of ribosome-associated chaperone function.\",\n      \"method\": \"Purification/co-purification of endogenous complex, ribosome association assay, yeast complementation experiments\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal purification, functional complementation across species, multiple orthogonal methods in a highly-cited foundational paper\",\n      \"pmids\": [\"16002468\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Extracellular HSPA14 (Hsp70L1) binds directly to TLR4 on the surface of dendritic cells, activating MAPK and NF-κB signaling pathways, upregulating MHC II (I-a^b), CD40, CD80, and CD86 co-stimulatory molecules, and promoting production of TNF-α, IL-1β, and IL-12p70; TLR4-deficient DCs fail to respond, establishing TLR4 as the essential receptor for HSPA14-induced DC activation.\",\n      \"method\": \"Direct binding assay, TLR4-deficient DC experiments, signaling pathway analysis (MAPK/NF-κB), in vivo immunization with TLR4 antagonist\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function TLR4 KO DCs with defined signaling readouts, replicated in vitro and in vivo, highly cited\",\n      \"pmids\": [\"21730052\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"HSPA14 (Hsp70L1) activates dendritic cells by interacting with shared Hsp70 surface receptors, promoting DC maturation and stimulating secretion of IL-12p70, IL-1β, TNF-α, IP-10, MIP-1α, MIP-1β, and RANTES, and polarizing T helper responses toward Th1; it also uniquely induces IP-10 secretion not shared by Hsp70.\",\n      \"method\": \"Recombinant protein stimulation of DCs, cytokine/chemokine ELISA, receptor competition assay, in vivo tumor challenge\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple cytokine readouts and in vivo validation, single lab but multiple methods\",\n      \"pmids\": [\"14592822\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Intracellular HSPA14 (HSP70L1) inhibits human dendritic cell maturation by suppressing MHC and co-stimulatory molecule expression; mechanistically, it inhibits the recruitment of the histone methyltransferase Ash1l to promoters of costimulatory, MHC, and STAT3 genes, maintaining repressive H3K27me3 and H2AK119Ub1 histone modifications. HSPA14 stability depends on its interaction with DNAJC2 (a known epigenetic regulator).\",\n      \"method\": \"Intracellular HSPA14 overexpression/knockdown, chromatin immunoprecipitation (ChIP) for histone marks, Co-IP with DNAJC2, flow cytometry for DC maturation markers\",\n      \"journal\": \"Cellular & molecular immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ChIP and Co-IP with defined mechanistic readouts, single lab\",\n      \"pmids\": [\"30635648\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"NBS1 overexpression induces HSPA14 expression through upregulation of heat shock transcription factor 4b (HSF4b); siRNA-mediated knockdown of HSPA14 decreases in vitro migration, invasion, and transformation activity, identifying HSPA14 as a downstream effector in the NBS1-HSF4b-HSPA14 signaling axis.\",\n      \"method\": \"siRNA knockdown, RT-PCR, Western blot, in vitro migration/invasion assay, soft agar colony formation\",\n      \"journal\": \"Journal of biomedical science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function with defined functional phenotypes and pathway placement, single lab\",\n      \"pmids\": [\"21208456\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"HSPA14 interacts with HspBP1 (an HIV transcriptional inhibitor); overexpression of HSPA14 inhibits HIV-1 replication while knockdown promotes it, suggesting HSPA14 restricts HIV replication by regulating HspBP1.\",\n      \"method\": \"Co-immunoprecipitation (Co-IP), HSPA14 overexpression and knockdown in Jurkat and primary CD4+ T cells, intracellular HIV replication assay\",\n      \"journal\": \"Frontiers in immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — Co-IP plus gain/loss-of-function with defined viral replication readout, single lab, single study\",\n      \"pmids\": [\"36845091\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"HSPA14 (Hsp70L1) is an atypical Hsp70-family chaperone that, in the cytosol, forms the mammalian ribosome-associated complex (RAC) with MPP11 to cotranslationally assist nascent polypeptides; when released extracellularly it acts as a TLR4 agonist on dendritic cells activating MAPK/NF-κB signaling to drive Th1 immune polarization, whereas intracellularly it suppresses DC maturation by maintaining repressive H3K27me3/H2AK119Ub1 histone marks at costimulatory and MHC gene promoters through inhibition of Ash1l recruitment, and it also participates in NBS1-HSF4b-driven cell migration/transformation and restriction of HIV-1 replication via interaction with HspBP1.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"HSPA14 (Hsp70L1) is an atypical Hsp70-family chaperone that functions both as a ribosome-associated cotranslational chaperone and as an immunomodulatory molecule with context-dependent effects on dendritic cell activation. Together with MPP11, HSPA14 forms the mammalian ribosome-associated complex (mRAC), which directly contacts nascent polypeptides on ribosomes and is functionally conserved with yeast RAC [PMID:16002468]. Extracellular HSPA14 binds TLR4 on dendritic cells, activating MAPK/NF-κB signaling to upregulate MHC II and costimulatory molecules and drive Th1-polarizing cytokine secretion [PMID:21730052, PMID:14592822], whereas intracellular HSPA14 suppresses DC maturation by blocking Ash1l recruitment to costimulatory and MHC gene promoters, thereby maintaining repressive H3K27me3 and H2AK119Ub1 histone marks in a DNAJC2-dependent manner [PMID:30635648]. HSPA14 also serves as a downstream effector of NBS1–HSF4b signaling that promotes cell migration and transformation [PMID:21208456] and restricts HIV-1 replication through interaction with HspBP1 [PMID:36845091].\",\n  \"teleology\": [\n    {\n      \"year\": 2003,\n      \"claim\": \"The first functional characterization revealed that extracellular HSPA14 activates dendritic cells and drives Th1 polarization, establishing it as an immunostimulatory Hsp70-family member with unique chemokine-inducing properties (e.g., IP-10).\",\n      \"evidence\": \"Recombinant HSPA14 stimulation of DCs with cytokine/chemokine ELISA, receptor competition, and in vivo tumor challenge\",\n      \"pmids\": [\"14592822\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"The specific receptor mediating DC activation was not identified\",\n        \"No mechanism distinguishing HSPA14 from canonical Hsp70 in receptor engagement\",\n        \"Endotoxin contamination of recombinant protein not fully excluded in this study\"\n      ]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Identification of HSPA14 as a core subunit of the mammalian ribosome-associated complex (mRAC) with MPP11 resolved its primary cytosolic function: cotranslational chaperoning of nascent polypeptides, a role conserved from yeast.\",\n      \"evidence\": \"Endogenous complex purification, ribosome association assay, and yeast complementation\",\n      \"pmids\": [\"16002468\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Substrate specificity of mRAC on mammalian ribosomes was not determined\",\n        \"Whether HSPA14 ATPase activity is required for mRAC function was untested\",\n        \"The relationship between ribosomal and extracellular/immune functions was unexplored\"\n      ]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Two independent studies clarified HSPA14's signaling context: extracellular HSPA14 was shown to signal through TLR4 on DCs via MAPK/NF-κB, while intracellularly HSPA14 was placed downstream of the NBS1–HSF4b axis as an effector of cell migration and transformation.\",\n      \"evidence\": \"TLR4-deficient DC experiments with signaling pathway analysis (MAPK/NF-κB) for immune function; siRNA knockdown with migration/invasion/soft-agar assays for oncogenic function\",\n      \"pmids\": [\"21730052\", \"21208456\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"The structural basis of HSPA14–TLR4 interaction was not defined\",\n        \"Whether HSPA14-driven migration requires its chaperone activity or a distinct domain was unknown\",\n        \"The physiological route by which HSPA14 reaches the extracellular space was not addressed\"\n      ]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Intracellular HSPA14 was discovered to exert an opposing, immunosuppressive effect by maintaining repressive histone marks (H3K27me3, H2AK119Ub1) at costimulatory and MHC gene promoters through inhibition of Ash1l recruitment, with DNAJC2 stabilizing HSPA14 protein levels — revealing an unexpected epigenetic regulatory axis.\",\n      \"evidence\": \"ChIP for histone marks, Co-IP with DNAJC2, overexpression/knockdown in human DCs with flow cytometry for maturation markers\",\n      \"pmids\": [\"30635648\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether HSPA14 directly binds Ash1l or acts indirectly was not resolved\",\n        \"Single-lab finding without independent replication\",\n        \"How HSPA14's epigenetic role relates to its ribosome-associated chaperone function is unclear\"\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"HSPA14 was identified as a host restriction factor for HIV-1 replication, acting through physical interaction with HspBP1, extending its functional repertoire to antiviral defense.\",\n      \"evidence\": \"Co-IP of HSPA14–HspBP1, overexpression and knockdown in Jurkat and primary CD4+ T cells with HIV replication assay\",\n      \"pmids\": [\"36845091\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Single study from one laboratory; awaits independent confirmation\",\n        \"The mechanism by which HSPA14–HspBP1 interaction suppresses HIV transcription/replication was not delineated\",\n        \"Whether the antiviral function depends on HSPA14 chaperone or epigenetic activity is unknown\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How HSPA14's ribosome-associated chaperone function, extracellular TLR4 agonism, intracellular epigenetic suppression, and antiviral activity are coordinated or partitioned across cellular compartments and physiological states remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No structural data exist for HSPA14 in the mRAC complex or bound to TLR4\",\n        \"The secretion or release mechanism for extracellular HSPA14 has not been defined\",\n        \"Whether HSPA14 ATPase activity is required for any of its non-chaperone functions is untested\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0044183\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [3, 5]},\n      {\"term_id\": \"GO:0048018\", \"supporting_discovery_ids\": [1, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005840\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0, 3]},\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [1, 2]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [3]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [1, 2, 3]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [1, 4]},\n      {\"term_id\": \"R-HSA-4839726\", \"supporting_discovery_ids\": [3]}\n    ],\n    \"complexes\": [\n      \"mammalian ribosome-associated complex (mRAC)\"\n    ],\n    \"partners\": [\n      \"MPP11\",\n      \"TLR4\",\n      \"DNAJC2\",\n      \"HspBP1\",\n      \"HSF4B\",\n      \"Ash1l\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}