{"gene":"HSPA14","run_date":"2026-06-10T01:55:22","timeline":{"discoveries":[{"year":2005,"finding":"HSPA14 (Hsp70L1) forms a stable heterodimeric complex with MPP11 (a zuotin-homology domain protein) on ribosomes, constituting the mammalian ribosome-associated complex (mRAC). MPP11 was purified from cytosolic fractions and shown to co-purify with Hsp70L1; the complex is functional in yeast complementation experiments, demonstrating conserved cooperation with the translational apparatus.","method":"Protein purification, co-purification/complex isolation, yeast complementation experiments, ribosome association assay","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — direct biochemical purification of the complex combined with functional complementation in yeast, two orthogonal methods establishing both physical interaction and biological activity","pmids":["16002468"],"is_preprint":false},{"year":2003,"finding":"HSPA14 (Hsp70L1) activates dendritic cells by binding to shared receptors on DC surfaces (shared with Hsp70), promoting DC maturation and stimulating secretion of IL-12p70, IL-1β, TNF-α, IP-10, MIP-1α, MIP-1β, and RANTES, thereby polarizing immune responses toward Th1. Immunization with an Hsp70L1-OVA hybrid peptide induced OVA-specific Th1 responses and CTL activity that inhibited tumor growth.","method":"Recombinant protein stimulation of DCs, cytokine ELISA, flow cytometry for DC maturation markers, in vivo mouse immunization and tumor challenge","journal":"Blood","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple functional readouts (cytokine production, DC maturation, CTL induction, tumor inhibition) in a single study; receptor identity not yet precisely defined","pmids":["14592822"],"is_preprint":false},{"year":2011,"finding":"HSPA14 (Hsp70L1) binds directly to TLR4 on the surface of dendritic cells. This interaction activates MAPK and NF-κB signaling pathways, upregulates MHC-II (I-a^b), CD40, CD80, and CD86 expression, and promotes production of TNF-α, IL-1β, and IL-12p70. TLR4-deficient DCs failed to undergo these phenotypic changes, establishing TLR4 as the key receptor mediating Hsp70L1's adjuvant activity.","method":"Direct binding assay (Hsp70L1 to TLR4), stimulation of wild-type vs. TLR4-deficient DCs, MAPK/NF-κB pathway activation assays, cytokine ELISA, TLR4 antagonist experiments in human co-culture system","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — direct binding demonstrated, genetic loss-of-function (TLR4-KO DCs) combined with pharmacological antagonism and multiple downstream pathway readouts in two species","pmids":["21730052"],"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 decreased in vitro migration, invasion, and transformation activity in NBS1-overexpressing H1299 cells, placing HSPA14 downstream of NBS1 in a NBS1–HSF4b–HSPA14 axis. This activity was not mediated through MMP2.","method":"RT-PCR, Western blot, siRNA knockdown, in vitro migration/invasion assays, soft agar colony formation assay, gelatin zymography","journal":"Journal of biomedical science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA loss-of-function with multiple cellular phenotype readouts in a single lab study; pathway placement by co-knockdown and epistasis","pmids":["21208456"],"is_preprint":false},{"year":2019,"finding":"Intracellular HSPA14 inhibits human DC maturation by suppressing MHC and costimulatory molecule expression. Mechanistically, intracellular HSPA14 inhibits recruitment of the histone methyltransferase Ash1l to promoter regions of costimulatory, MHC, and STAT3 genes, thereby maintaining repressive H3K27me3 and H2AK119Ub1 histone modifications. The stability of intracellular HSPA14 is dependent on DNAJC2 (a known epigenetic regulator).","method":"Overexpression and knockdown of HSPA14 in DCs, flow cytometry for maturation markers, chromatin immunoprecipitation (ChIP) for H3K27me3 and H2AK119Ub1, Ash1l recruitment assay, co-immunoprecipitation with DNAJC2","journal":"Cellular & molecular immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — ChIP-based epigenetic mechanism combined with loss/gain-of-function and interaction data; single lab, multiple orthogonal methods","pmids":["30635648"],"is_preprint":false},{"year":2023,"finding":"HSPA14 interacts with HspBP1 (an Hsp70 inhibitor/HIV transcriptional inhibitor) as detected by co-immunoprecipitation. HIV infection suppresses HSPA14 expression in Jurkat and primary CD4+ T cells; overexpression of HSPA14 inhibits HIV replication while knockdown promotes it, indicating HSPA14 restricts HIV replication, potentially by modulating HspBP1.","method":"Co-immunoprecipitation (HSPA14 with HspBP1), HSPA14 overexpression/knockdown cells, in vitro HIV infection, HIV replication quantification","journal":"Frontiers in immunology","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — co-IP for binding partner plus gain- and loss-of-function with functional readout; specific mechanism downstream of HspBP1 not fully resolved","pmids":["36845091"],"is_preprint":false}],"current_model":"HSPA14 (Hsp70L1) is a ribosome-associated chaperone that forms the mammalian ribosome-associated complex (mRAC) with MPP11 to assist cotranslational protein folding; extracellularly, it activates dendritic cells by directly binding TLR4 and triggering MAPK/NF-κB pathways to drive Th1 polarization, while intracellularly it suppresses DC maturation by stabilizing repressive H3K27me3/H2AK119Ub1 chromatin marks at immune gene promoters via DNAJC2 and inhibition of Ash1l recruitment; additionally, HSPA14 is induced downstream of a NBS1–HSF4b axis to promote cell migration and transformation, and it inhibits HIV replication at least in part through interaction with the viral transcriptional inhibitor HspBP1."},"narrative":{"mechanistic_narrative":"HSPA14 (Hsp70L1) is a ribosome-associated Hsp70-family chaperone that operates both intracellularly in cotranslational protein folding and immune-gene regulation and extracellularly as an immune adjuvant [PMID:16002468, PMID:21730052, PMID:30635648]. On ribosomes it forms a stable heterodimeric mammalian ribosome-associated complex (mRAC) with the zuotin-homology protein MPP11, a partnership that functionally complements the analogous yeast machinery and links HSPA14 to the translational apparatus [PMID:16002468]. As an extracellular signal, HSPA14 binds directly to TLR4 on dendritic cells and activates MAPK and NF-κB signaling, driving DC maturation, upregulation of MHC-II and the costimulatory molecules CD40/CD80/CD86, and secretion of proinflammatory cytokines including TNF-α, IL-1β and IL-12p70 to polarize Th1 responses [PMID:14592822, PMID:21730052]. In striking contrast, intracellular HSPA14 restrains DC maturation by blocking recruitment of the histone methyltransferase Ash1l to promoters of MHC, costimulatory and STAT3 genes, thereby preserving repressive H3K27me3 and H2AK119Ub1 marks; its intracellular stability depends on the epigenetic regulator DNAJC2 [PMID:30635648]. HSPA14 also functions downstream of an NBS1–HSF4b axis to promote cell migration, invasion and transformation [PMID:21208456], and it restricts HIV replication in CD4+ T cells in association with the Hsp70 inhibitor HspBP1 [PMID:36845091].","teleology":[{"year":2003,"claim":"Established that extracellular HSPA14 is not merely a folding chaperone but an immune effector capable of activating dendritic cells and shaping adaptive immunity toward a Th1 program.","evidence":"Recombinant Hsp70L1 stimulation of DCs with cytokine ELISA, maturation-marker flow cytometry, and in vivo Hsp70L1-OVA immunization with tumor challenge in mice","pmids":["14592822"],"confidence":"Medium","gaps":["Receptor identity on the DC surface was not defined in this study","Mechanism linking receptor engagement to cytokine output not resolved","Distinction between extracellular and intracellular roles not yet appreciated"]},{"year":2005,"claim":"Defined the core intracellular molecular partnership of HSPA14 by showing it forms the mammalian ribosome-associated complex with MPP11, placing it at the ribosome to assist cotranslational folding.","evidence":"Protein purification, co-purification of Hsp70L1 with MPP11, ribosome-association assay, and yeast complementation","pmids":["16002468"],"confidence":"High","gaps":["Specific nascent-chain substrates of the mRAC not identified","Structural basis of the Hsp70L1–MPP11 interaction not determined","Functional consequence of mRAC loss in mammalian cells not measured"]},{"year":2011,"claim":"Identified TLR4 as the receptor mediating HSPA14's adjuvant activity, converting the earlier 'shared receptor' observation into a defined signaling axis.","evidence":"Direct Hsp70L1–TLR4 binding assay, WT vs TLR4-deficient DC comparison, MAPK/NF-κB readouts, cytokine ELISA, and TLR4 antagonism in human co-culture","pmids":["21730052"],"confidence":"High","gaps":["Whether endogenous HSPA14 reaches the extracellular space physiologically not established","Binding interface between HSPA14 and TLR4 not mapped","Role of co-receptors (e.g. MD-2/CD14) not addressed"]},{"year":2011,"claim":"Placed HSPA14 in an oncogenic signaling cascade downstream of NBS1 and HSF4b that promotes migratory and transforming behavior.","evidence":"RT-PCR/Western for NBS1-induced HSPA14, siRNA knockdown with migration/invasion and soft-agar assays, gelatin zymography in H1299 cells","pmids":["21208456"],"confidence":"Medium","gaps":["Effector mechanism downstream of HSPA14 driving transformation unknown (excluded MMP2)","Single cell-line context; in vivo tumor relevance not tested","Whether this depends on chaperone activity not addressed"]},{"year":2019,"claim":"Resolved a paradoxical intracellular role opposite to the extracellular one: intracellular HSPA14 suppresses DC maturation through an epigenetic mechanism, revealing functional duality based on localization.","evidence":"HSPA14 gain/loss-of-function in DCs, maturation flow cytometry, ChIP for H3K27me3 and H2AK119Ub1, Ash1l recruitment assay, and co-IP with DNAJC2","pmids":["30635648"],"confidence":"Medium","gaps":["How a cytosolic/ribosomal chaperone reaches gene promoters mechanistically unclear","Whether HSPA14 directly contacts chromatin or acts via partners not determined","Reconciliation with its extracellular pro-maturation activity not established"]},{"year":2023,"claim":"Extended HSPA14 function to antiviral restriction, linking it physically to HspBP1 and to suppression of HIV replication.","evidence":"Co-IP of HSPA14 with HspBP1, HSPA14 overexpression/knockdown in Jurkat and CD4+ T cells, in vitro HIV infection and replication quantification","pmids":["36845091"],"confidence":"Medium","gaps":["Mechanism downstream of HspBP1 mediating restriction not resolved","Co-IP not reciprocally validated or reconstituted","Step of HIV life cycle affected not defined"]},{"year":null,"claim":"It remains unknown how HSPA14's chaperone function on the ribosome mechanistically connects to its diverse signaling, epigenetic, oncogenic, and antiviral roles, and how its subcellular distribution is controlled to switch between them.","evidence":"No single study integrates the cotranslational, extracellular-adjuvant, and intracellular-repressive activities","pmids":[],"confidence":"Low","gaps":["No structural model of HSPA14 in any of its complexes","Trafficking that determines extracellular vs intracellular vs chromatin localization unknown","No defined endogenous folding substrates"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0]},{"term_id":"GO:0044183","term_label":"protein folding chaperone","supporting_discovery_ids":[0]},{"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]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[4]},{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[1,2]}],"pathway":[{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[1,2,4]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[0]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[2]},{"term_id":"R-HSA-4839726","term_label":"Chromatin organization","supporting_discovery_ids":[4]}],"complexes":["mammalian ribosome-associated complex (mRAC)"],"partners":["MPP11","TLR4","DNAJC2","HSPBP1"],"other_free_text":[]}},"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":96,"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":68,"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":8805,"output_tokens":1989,"usd":0.028125,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8910,"output_tokens":3007,"usd":0.059862,"stage2_stop_reason":"end_turn"},"total_usd":0.087987,"stage1_batch_id":"msgbatch_01DUPACZi7AAWwuZiUjseQF4","stage2_batch_id":"msgbatch_018yt7chE3f48PEFtDwtj6AE","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 (a zuotin-homology domain protein) on ribosomes, constituting the mammalian ribosome-associated complex (mRAC). MPP11 was purified from cytosolic fractions and shown to co-purify with Hsp70L1; the complex is functional in yeast complementation experiments, demonstrating conserved cooperation with the translational apparatus.\",\n      \"method\": \"Protein purification, co-purification/complex isolation, yeast complementation experiments, ribosome association assay\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — direct biochemical purification of the complex combined with functional complementation in yeast, two orthogonal methods establishing both physical interaction and biological activity\",\n      \"pmids\": [\"16002468\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"HSPA14 (Hsp70L1) activates dendritic cells by binding to shared receptors on DC surfaces (shared with Hsp70), promoting DC maturation and stimulating secretion of IL-12p70, IL-1β, TNF-α, IP-10, MIP-1α, MIP-1β, and RANTES, thereby polarizing immune responses toward Th1. Immunization with an Hsp70L1-OVA hybrid peptide induced OVA-specific Th1 responses and CTL activity that inhibited tumor growth.\",\n      \"method\": \"Recombinant protein stimulation of DCs, cytokine ELISA, flow cytometry for DC maturation markers, in vivo mouse immunization and tumor challenge\",\n      \"journal\": \"Blood\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple functional readouts (cytokine production, DC maturation, CTL induction, tumor inhibition) in a single study; receptor identity not yet precisely defined\",\n      \"pmids\": [\"14592822\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"HSPA14 (Hsp70L1) binds directly to TLR4 on the surface of dendritic cells. This interaction activates MAPK and NF-κB signaling pathways, upregulates MHC-II (I-a^b), CD40, CD80, and CD86 expression, and promotes production of TNF-α, IL-1β, and IL-12p70. TLR4-deficient DCs failed to undergo these phenotypic changes, establishing TLR4 as the key receptor mediating Hsp70L1's adjuvant activity.\",\n      \"method\": \"Direct binding assay (Hsp70L1 to TLR4), stimulation of wild-type vs. TLR4-deficient DCs, MAPK/NF-κB pathway activation assays, cytokine ELISA, TLR4 antagonist experiments in human co-culture system\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — direct binding demonstrated, genetic loss-of-function (TLR4-KO DCs) combined with pharmacological antagonism and multiple downstream pathway readouts in two species\",\n      \"pmids\": [\"21730052\"],\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 decreased in vitro migration, invasion, and transformation activity in NBS1-overexpressing H1299 cells, placing HSPA14 downstream of NBS1 in a NBS1–HSF4b–HSPA14 axis. This activity was not mediated through MMP2.\",\n      \"method\": \"RT-PCR, Western blot, siRNA knockdown, in vitro migration/invasion assays, soft agar colony formation assay, gelatin zymography\",\n      \"journal\": \"Journal of biomedical science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA loss-of-function with multiple cellular phenotype readouts in a single lab study; pathway placement by co-knockdown and epistasis\",\n      \"pmids\": [\"21208456\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Intracellular HSPA14 inhibits human DC maturation by suppressing MHC and costimulatory molecule expression. Mechanistically, intracellular HSPA14 inhibits recruitment of the histone methyltransferase Ash1l to promoter regions of costimulatory, MHC, and STAT3 genes, thereby maintaining repressive H3K27me3 and H2AK119Ub1 histone modifications. The stability of intracellular HSPA14 is dependent on DNAJC2 (a known epigenetic regulator).\",\n      \"method\": \"Overexpression and knockdown of HSPA14 in DCs, flow cytometry for maturation markers, chromatin immunoprecipitation (ChIP) for H3K27me3 and H2AK119Ub1, Ash1l recruitment assay, co-immunoprecipitation with DNAJC2\",\n      \"journal\": \"Cellular & molecular immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — ChIP-based epigenetic mechanism combined with loss/gain-of-function and interaction data; single lab, multiple orthogonal methods\",\n      \"pmids\": [\"30635648\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"HSPA14 interacts with HspBP1 (an Hsp70 inhibitor/HIV transcriptional inhibitor) as detected by co-immunoprecipitation. HIV infection suppresses HSPA14 expression in Jurkat and primary CD4+ T cells; overexpression of HSPA14 inhibits HIV replication while knockdown promotes it, indicating HSPA14 restricts HIV replication, potentially by modulating HspBP1.\",\n      \"method\": \"Co-immunoprecipitation (HSPA14 with HspBP1), HSPA14 overexpression/knockdown cells, in vitro HIV infection, HIV replication quantification\",\n      \"journal\": \"Frontiers in immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — co-IP for binding partner plus gain- and loss-of-function with functional readout; specific mechanism downstream of HspBP1 not fully resolved\",\n      \"pmids\": [\"36845091\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"HSPA14 (Hsp70L1) is a ribosome-associated chaperone that forms the mammalian ribosome-associated complex (mRAC) with MPP11 to assist cotranslational protein folding; extracellularly, it activates dendritic cells by directly binding TLR4 and triggering MAPK/NF-κB pathways to drive Th1 polarization, while intracellularly it suppresses DC maturation by stabilizing repressive H3K27me3/H2AK119Ub1 chromatin marks at immune gene promoters via DNAJC2 and inhibition of Ash1l recruitment; additionally, HSPA14 is induced downstream of a NBS1–HSF4b axis to promote cell migration and transformation, and it inhibits HIV replication at least in part through interaction with the viral transcriptional inhibitor HspBP1.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"HSPA14 (Hsp70L1) is a ribosome-associated Hsp70-family chaperone that operates both intracellularly in cotranslational protein folding and immune-gene regulation and extracellularly as an immune adjuvant [#0, #2, #4]. On ribosomes it forms a stable heterodimeric mammalian ribosome-associated complex (mRAC) with the zuotin-homology protein MPP11, a partnership that functionally complements the analogous yeast machinery and links HSPA14 to the translational apparatus [#0]. As an extracellular signal, HSPA14 binds directly to TLR4 on dendritic cells and activates MAPK and NF-\\u03baB signaling, driving DC maturation, upregulation of MHC-II and the costimulatory molecules CD40/CD80/CD86, and secretion of proinflammatory cytokines including TNF-\\u03b1, IL-1\\u03b2 and IL-12p70 to polarize Th1 responses [#1, #2]. In striking contrast, intracellular HSPA14 restrains DC maturation by blocking recruitment of the histone methyltransferase Ash1l to promoters of MHC, costimulatory and STAT3 genes, thereby preserving repressive H3K27me3 and H2AK119Ub1 marks; its intracellular stability depends on the epigenetic regulator DNAJC2 [#4]. HSPA14 also functions downstream of an NBS1\\u2013HSF4b axis to promote cell migration, invasion and transformation [#3], and it restricts HIV replication in CD4+ T cells in association with the Hsp70 inhibitor HspBP1 [#5].\",\n  \"teleology\": [\n    {\n      \"year\": 2003,\n      \"claim\": \"Established that extracellular HSPA14 is not merely a folding chaperone but an immune effector capable of activating dendritic cells and shaping adaptive immunity toward a Th1 program.\",\n      \"evidence\": \"Recombinant Hsp70L1 stimulation of DCs with cytokine ELISA, maturation-marker flow cytometry, and in vivo Hsp70L1-OVA immunization with tumor challenge in mice\",\n      \"pmids\": [\"14592822\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Receptor identity on the DC surface was not defined in this study\",\n        \"Mechanism linking receptor engagement to cytokine output not resolved\",\n        \"Distinction between extracellular and intracellular roles not yet appreciated\"\n      ]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Defined the core intracellular molecular partnership of HSPA14 by showing it forms the mammalian ribosome-associated complex with MPP11, placing it at the ribosome to assist cotranslational folding.\",\n      \"evidence\": \"Protein purification, co-purification of Hsp70L1 with MPP11, ribosome-association assay, and yeast complementation\",\n      \"pmids\": [\"16002468\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Specific nascent-chain substrates of the mRAC not identified\",\n        \"Structural basis of the Hsp70L1\\u2013MPP11 interaction not determined\",\n        \"Functional consequence of mRAC loss in mammalian cells not measured\"\n      ]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Identified TLR4 as the receptor mediating HSPA14's adjuvant activity, converting the earlier 'shared receptor' observation into a defined signaling axis.\",\n      \"evidence\": \"Direct Hsp70L1\\u2013TLR4 binding assay, WT vs TLR4-deficient DC comparison, MAPK/NF-\\u03baB readouts, cytokine ELISA, and TLR4 antagonism in human co-culture\",\n      \"pmids\": [\"21730052\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Whether endogenous HSPA14 reaches the extracellular space physiologically not established\",\n        \"Binding interface between HSPA14 and TLR4 not mapped\",\n        \"Role of co-receptors (e.g. MD-2/CD14) not addressed\"\n      ]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Placed HSPA14 in an oncogenic signaling cascade downstream of NBS1 and HSF4b that promotes migratory and transforming behavior.\",\n      \"evidence\": \"RT-PCR/Western for NBS1-induced HSPA14, siRNA knockdown with migration/invasion and soft-agar assays, gelatin zymography in H1299 cells\",\n      \"pmids\": [\"21208456\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Effector mechanism downstream of HSPA14 driving transformation unknown (excluded MMP2)\",\n        \"Single cell-line context; in vivo tumor relevance not tested\",\n        \"Whether this depends on chaperone activity not addressed\"\n      ]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Resolved a paradoxical intracellular role opposite to the extracellular one: intracellular HSPA14 suppresses DC maturation through an epigenetic mechanism, revealing functional duality based on localization.\",\n      \"evidence\": \"HSPA14 gain/loss-of-function in DCs, maturation flow cytometry, ChIP for H3K27me3 and H2AK119Ub1, Ash1l recruitment assay, and co-IP with DNAJC2\",\n      \"pmids\": [\"30635648\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"How a cytosolic/ribosomal chaperone reaches gene promoters mechanistically unclear\",\n        \"Whether HSPA14 directly contacts chromatin or acts via partners not determined\",\n        \"Reconciliation with its extracellular pro-maturation activity not established\"\n      ]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Extended HSPA14 function to antiviral restriction, linking it physically to HspBP1 and to suppression of HIV replication.\",\n      \"evidence\": \"Co-IP of HSPA14 with HspBP1, HSPA14 overexpression/knockdown in Jurkat and CD4+ T cells, in vitro HIV infection and replication quantification\",\n      \"pmids\": [\"36845091\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Mechanism downstream of HspBP1 mediating restriction not resolved\",\n        \"Co-IP not reciprocally validated or reconstituted\",\n        \"Step of HIV life cycle affected not defined\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unknown how HSPA14's chaperone function on the ribosome mechanistically connects to its diverse signaling, epigenetic, oncogenic, and antiviral roles, and how its subcellular distribution is controlled to switch between them.\",\n      \"evidence\": \"No single study integrates the cotranslational, extracellular-adjuvant, and intracellular-repressive activities\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No structural model of HSPA14 in any of its complexes\",\n        \"Trafficking that determines extracellular vs intracellular vs chromatin localization unknown\",\n        \"No defined endogenous folding substrates\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0044183\", \"supporting_discovery_ids\": [0]},\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]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [4]},\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [1, 2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [1, 2, 4]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"R-HSA-4839726\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"complexes\": [\"mammalian ribosome-associated complex (mRAC)\"],\n    \"partners\": [\"MPP11\", \"TLR4\", \"DNAJC2\", \"HspBP1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":4,"faith_total":5,"faith_pct":80.0}}