{"gene":"PARD6A","run_date":"2026-06-10T05:19:53","timeline":{"discoveries":[{"year":2004,"finding":"Overexpression of mPar6alpha disrupts the perinuclear tubulin cage, retargets PKCzeta and gamma-tubulin away from the centrosome, and inhibits centrosomal motion and neuronal migration along glial fibers, indicating Par6alpha mediates signaling that coordinates cytoskeletal dynamics at the centrosome during glial-guided neuronal migration.","method":"Live imaging of cytoskeletal dynamics in migrating neurons; overexpression of mPar6alpha with readout of centrosome positioning, tubulin cage integrity, and neuronal migration","journal":"Nature neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — live imaging with functional overexpression readout, single lab, multiple cellular phenotypes observed","pmids":["15475953"],"is_preprint":false},{"year":2009,"finding":"In NSCLC cells, Ect2 (a Rho GEF) is mislocalized to the cytoplasm where it physically binds the PKCiota-Par6alpha complex; knockdown of either PKCiota or Par6alpha causes Ect2 to redistribute to the nucleus. This PKCiota-Par6alpha-Ect2 complex activates Rac1, driving transformed growth and invasion.","method":"RNA interference knockdown of PKCiota, Par6alpha, and Ect2; co-immunoprecipitation of complex; Rac1 activity assays; subcellular localization by immunofluorescence","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP and RNAi with functional readouts, single lab, multiple orthogonal methods","pmids":["19617897"],"is_preprint":false},{"year":2008,"finding":"PKCiota activates Rac1 in NSCLC cells through a PKCiota-Par6alpha complex that drives anchorage-independent growth and invasion via induction of MMP-10 expression. Par6alpha mutants unable to bind PKCiota (K19A) or couple to Rac1 (DeltaCRIB) fail to restore transformation and MMP-10 expression in Par6alpha-deficient cells.","method":"RNAi knockdown of PKCiota, Par6alpha, Rac1, and MMP-10; rescue with wild-type and domain mutants of Par6alpha; in vitro and in vivo (subcutaneous tumor) assays","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 2 / Strong — RNAi knockdown combined with structure-function mutagenesis rescue experiments and in vivo tumor models, defining a PKCiota-Par6alpha-Rac1-MMP-10 axis","pmids":["18427549"],"is_preprint":false},{"year":2013,"finding":"Lgl1 forms two distinct complexes in vivo: Lgl1-NMII-A and Lgl1-Par6alpha-aPKCzeta. Phosphorylation of Lgl1 by aPKCzeta prevents its interaction with NMII-A and affects its cellular localization. The Lgl1-Par6alpha-aPKCzeta complex localizes to the leading edge of migrating cells, and aPKCzeta and NMII-A compete to bind the same domain of Lgl1.","method":"Co-immunoprecipitation; in vitro binding and filament assembly assays; phosphorylation assays; immunofluorescence localization in migrating cells","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vitro and in vivo Co-IP with phosphorylation assays, single lab, multiple orthogonal methods","pmids":["24213535"],"is_preprint":false},{"year":2012,"finding":"Par6gamma depletion causes loss of Par6alpha from the centrosome; Par6alpha in turn controls centrosomal protein recruitment through p150(Glued), affecting ciliogenesis, microtubule organization, and centrosome reorientation during migration. Par6gamma was shown to associate with Par6alpha.","method":"Par6gamma depletion (siRNA); immunofluorescence for centrosomal protein composition; co-immunoprecipitation of Par6gamma with Par6alpha","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP and knockdown with functional centrosomal localization readout, single lab","pmids":["23264737"],"is_preprint":false},{"year":2016,"finding":"Hook2 (a microtubule-binding protein) interacts with PAR6alpha via its C-terminal domain binding the aPKC-binding domain of PAR6alpha, and this interaction localizes PAR6alpha to the centrosome during polarized cell migration. Depletion of Hook2 reduces PAR6alpha at the centrosome; overexpression of Hook2 recruits PAR6alpha, aPKC, and PAR3 to aggresomes.","method":"Co-immunoprecipitation; siRNA depletion of Hook2; immunofluorescence of centrosomal PAR6alpha; domain mapping","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP with domain mapping and siRNA knockdown with localization readout, single lab","pmids":["27624926"],"is_preprint":false},{"year":2007,"finding":"Par6alpha interacts directly with aPKC (via its PB1 domain), and the Par6alpha/aPKC complex inhibits insulin-induced Akt1 activation by aPKC-mediated phosphorylation of Akt1 at Thr34. A DeltaPB1-Par6alpha mutant that cannot bind aPKC does not inhibit Akt1 activation; T34A-Akt1 is resistant to Par6alpha/aPKC-mediated inhibition and restores insulin-induced glycogen synthesis.","method":"Deletion mutagenesis; overexpression in C2C12 myoblasts; phosphorylation assay on Akt1 T34; glycogen synthesis reconstitution","journal":"Molecular and cellular endocrinology","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — phosphorylation assay with mutagenesis (T34A and DeltaPB1) and functional reconstitution, single lab","pmids":["17335965"],"is_preprint":false},{"year":2022,"finding":"PARD6A promotes EMT in ovarian cancer cells via integrin beta1-ILK-SNAIL1 signaling, modulating E-cadherin and vimentin expression. PARD6A knockdown suppressed and overexpression promoted EMT and metastasis in vitro and in vivo.","method":"siRNA knockdown and overexpression of PARD6A; knockdown/overexpression of SNAIL1 and ILK; in vitro migration/invasion assays; in vivo metastasis model","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss- and gain-of-function experiments with pathway epistasis (SNAIL1/ILK), single lab, multiple orthogonal assays","pmids":["35379775"],"is_preprint":false},{"year":2024,"finding":"PARD6A promotes lung adenocarcinoma cell proliferation, migration, and invasion through induction of Serpina3; ectopic Serpina3 expression rescues defects caused by PARD6A knockdown, and Serpina3 silencing impedes the enhanced phenotype caused by PARD6A overexpression.","method":"PARD6A knockdown and overexpression; RNA-seq to identify downstream targets; Serpina3 rescue and knockdown experiments; in vitro proliferation/migration/invasion assays; subcutaneous tumor mouse model","journal":"Cancer gene therapy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — epistasis rescue experiments with transcriptomic identification of downstream effector, single lab","pmids":["39300216"],"is_preprint":false},{"year":2017,"finding":"Par6alpha is necessary for neuronal differentiation of bone marrow mesenchymal stem cells; siRNA silencing of Par6alpha impairs MSC-to-neuron-like cell differentiation. Let-7f-5p directly targets Par6alpha mRNA (validated by luciferase reporter assay), and downregulation of let-7f-5p during differentiation increases Par6alpha expression.","method":"siRNA knockdown of Par6alpha; luciferase reporter assay for let-7f-5p targeting; gain- and loss-of-function of let-7f-5p","journal":"Biochemical and biophysical research communications","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, single-method siRNA knockdown with neuronal differentiation readout; miRNA targeting validated by reporter assay","pmids":["29155179"],"is_preprint":false}],"current_model":"PARD6A (Par6alpha) is a scaffold polarity protein that forms complexes with aPKC and Par3 to coordinate centrosome positioning and cytoskeletal organization during neuronal migration and polarized cell migration; it directly binds PKCiota to activate Rac1 (via Ect2) and MMP-10 in oncogenic signaling, binds aPKC to inhibit Akt1 via Thr34 phosphorylation, associates with Lgl1 at the leading edge, is recruited to the centrosome by Hook2, and drives EMT in cancer through integrin beta1-ILK-SNAIL1 and Serpina3-dependent pathways."},"narrative":{"mechanistic_narrative":"PARD6A (Par6alpha) is a scaffold polarity protein that organizes aPKC-containing complexes to coordinate centrosome positioning, cytoskeletal dynamics, and polarized cell migration [PMID:15475953, PMID:23264737]. It binds atypical PKC directly through its PB1 domain, and this Par6alpha/aPKC module phosphorylates Akt1 at Thr34 to restrain insulin-induced Akt1 activation and glycogen synthesis [PMID:17335965], and partitions Lgl1 into a Par6alpha-aPKCzeta complex at the leading edge of migrating cells, where aPKCzeta phosphorylation of Lgl1 blocks its association with non-muscle myosin IIA [PMID:24213535]. Par6alpha is recruited to the centrosome through interactions with Par6gamma and with the microtubule-binding protein Hook2, which binds the aPKC-binding domain of Par6alpha; from the centrosome it controls recruitment of components such as p150(Glued) to govern ciliogenesis, microtubule organization, and centrosome reorientation during migration [PMID:23264737, PMID:27624926]. In cancer, Par6alpha couples PKCiota to Rac1 activation: the PKCiota-Par6alpha complex retains the Rho GEF Ect2 in the cytoplasm and induces MMP-10 to drive transformed, anchorage-independent growth and invasion, with Par6alpha mutants unable to bind PKCiota or couple to Rac1 failing to support transformation [PMID:19617897, PMID:18427549]. PARD6A further promotes epithelial-mesenchymal transition and metastasis through integrin beta1-ILK-SNAIL1 signaling and through induction of the downstream effector Serpina3 [PMID:35379775, PMID:39300216].","teleology":[{"year":2004,"claim":"Established that Par6alpha acts upstream of centrosomal cytoskeletal organization, linking a polarity protein to centrosome positioning during directed cell migration.","evidence":"Live imaging of cytoskeletal dynamics and centrosome positioning following mPar6alpha overexpression in glial-guided migrating neurons","pmids":["15475953"],"confidence":"Medium","gaps":["Based on overexpression, leaving endogenous requirement undefined","Molecular partners mediating the centrosomal effect not identified here"]},{"year":2007,"claim":"Defined a direct PB1-domain interaction between Par6alpha and aPKC and showed the complex acts as a kinase scaffold that negatively regulates Akt1 signaling.","evidence":"Deletion mutagenesis (DeltaPB1, T34A-Akt1), phosphorylation assay, and glycogen synthesis reconstitution in C2C12 myoblasts","pmids":["17335965"],"confidence":"Medium","gaps":["Performed in overexpression context","Physiological setting of Akt1 inhibition by Par6alpha/aPKC not established beyond myoblasts"]},{"year":2008,"claim":"Showed Par6alpha is a required adaptor coupling PKCiota to Rac1 activation and MMP-10 induction, establishing it as an effector node in oncogenic transformation.","evidence":"RNAi knockdown with domain-mutant rescue (K19A, DeltaCRIB) and in vivo subcutaneous tumor assays in NSCLC cells","pmids":["18427549"],"confidence":"High","gaps":["Mechanism by which the complex activates Rac1 not fully resolved at this stage","Generality beyond NSCLC unknown"]},{"year":2009,"claim":"Identified Ect2 as the GEF physically bound by the PKCiota-Par6alpha complex, explaining how the complex activates Rac1 by retaining Ect2 in the cytoplasm.","evidence":"Reciprocal Co-IP, RNAi of PKCiota/Par6alpha/Ect2, Rac1 activity assays, and subcellular localization in NSCLC cells","pmids":["19617897"],"confidence":"Medium","gaps":["Structural basis of the Ect2 interaction not defined","How cytoplasmic retention triggers Rac1 GEF activity not detailed"]},{"year":2012,"claim":"Placed Par6alpha downstream of Par6gamma for centrosomal targeting and showed Par6alpha controls centrosomal protein recruitment affecting ciliogenesis and centrosome reorientation.","evidence":"siRNA depletion of Par6gamma, Co-IP with Par6alpha, and immunofluorescence of centrosomal composition","pmids":["23264737"],"confidence":"Medium","gaps":["Direct vs indirect Par6gamma-Par6alpha association not distinguished","Mechanism of p150(Glued) recruitment unresolved"]},{"year":2013,"claim":"Resolved how Par6alpha-aPKCzeta and Lgl1 act at the leading edge, showing aPKCzeta phosphorylation of Lgl1 switches it away from NMII-A binding.","evidence":"Co-IP, in vitro binding and filament assembly assays, phosphorylation assays, and localization in migrating cells","pmids":["24213535"],"confidence":"Medium","gaps":["Functional consequence of the Lgl1 switch for migration not quantified","Competition dynamics in vivo not measured"]},{"year":2016,"claim":"Identified Hook2 as a centrosomal recruitment factor that binds the aPKC-binding domain of Par6alpha, providing a physical mechanism for Par6alpha centrosomal localization during migration.","evidence":"Co-IP, domain mapping, and siRNA depletion of Hook2 with immunofluorescence of centrosomal PAR6alpha","pmids":["27624926"],"confidence":"Medium","gaps":["Competition between Hook2 and aPKC for the same Par6alpha domain not resolved","Relationship to the Par6gamma recruitment pathway unclear"]},{"year":2022,"claim":"Extended Par6alpha's oncogenic role to EMT, defining an integrin beta1-ILK-SNAIL1 axis driving metastasis in ovarian cancer.","evidence":"siRNA/overexpression of PARD6A with epistasis to SNAIL1/ILK and in vitro and in vivo metastasis assays","pmids":["35379775"],"confidence":"Medium","gaps":["Direct molecular link between Par6alpha and integrin beta1-ILK not defined","Whether this acts through aPKC scaffolding unknown"]},{"year":2024,"claim":"Identified Serpina3 as a transcriptional/downstream effector through which PARD6A drives lung adenocarcinoma proliferation and invasion.","evidence":"PARD6A knockdown/overexpression with RNA-seq, Serpina3 rescue/silencing epistasis, and subcutaneous tumor model","pmids":["39300216"],"confidence":"Medium","gaps":["Mechanism connecting PARD6A to Serpina3 induction not defined","Whether Serpina3 axis intersects the PKCiota-Rac1 pathway unknown"]},{"year":null,"claim":"How Par6alpha's polarity-scaffolding activity (aPKC/Lgl1/centrosome) is mechanistically reconciled with its distinct oncogenic outputs (Rac1-MMP-10, EMT-SNAIL1, Serpina3) within a single regulatory framework remains unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No unifying structural or regulatory model linking polarity and oncogenic functions","Endogenous physiological role in normal tissue largely uncharacterized","Upstream signals controlling complex assembly not defined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[2,5,6]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[1,3,6]}],"localization":[{"term_id":"GO:0005815","term_label":"microtubule organizing center","supporting_discovery_ids":[0,4,5]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[1]},{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[0,4]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[2,6]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[2,7,8]}],"complexes":["PKCiota-Par6alpha-Ect2 complex","Par6alpha-aPKC complex","Lgl1-Par6alpha-aPKCzeta complex"],"partners":["PRKCI","PRKCZ","ECT2","LLGL1","PARD6G","HOOK2","AKT1","PARD3"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q9NPB6","full_name":"Partitioning defective 6 homolog alpha","aliases":["PAR6C","Tax interaction protein 40","TIP-40"],"length_aa":346,"mass_kda":37.4,"function":"Adapter protein involved in asymmetrical cell division and cell polarization processes. Probably involved in the formation of epithelial tight junctions. Association with PARD3 may prevent the interaction of PARD3 with F11R/JAM1, thereby preventing tight junction assembly. The PARD6-PARD3 complex links GTP-bound Rho small GTPases to atypical protein kinase C proteins (PubMed:10873802). Regulates centrosome organization and function. Essential for the centrosomal recruitment of key proteins that control centrosomal microtubule organization (PubMed:20719959)","subcellular_location":"Cytoplasm; Cell membrane; Cell projection, ruffle; Cell junction, tight junction; Cytoplasm, cytoskeleton, microtubule organizing center, centrosome, centriolar satellite; Cytoplasm, cytoskeleton, microtubule organizing center, centrosome","url":"https://www.uniprot.org/uniprotkb/Q9NPB6/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/PARD6A","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/PARD6A","total_profiled":1310},"omim":[{"mim_id":"619353","title":"PAR3 FAMILY CELL POLARITY REGULATOR, BETA; PARD3B","url":"https://www.omim.org/entry/619353"},{"mim_id":"609737","title":"CRUMBS CELL POLARITY COMPLEX COMPONENT 3; CRB3","url":"https://www.omim.org/entry/609737"},{"mim_id":"607484","title":"PAR6 FAMILY CELL POLARITY REGULATOR ALPHA; PARD6A","url":"https://www.omim.org/entry/607484"},{"mim_id":"607215","title":"NEPHROCYSTIN 4; NPHP4","url":"https://www.omim.org/entry/607215"},{"mim_id":"607100","title":"NEPHROCYSTIN 1; NPHP1","url":"https://www.omim.org/entry/607100"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Actin filaments","reliability":"Approved"},{"location":"Plasma membrane","reliability":"Additional"},{"location":"Cell Junctions","reliability":"Additional"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"brain","ntpm":45.1},{"tissue":"testis","ntpm":41.3}],"url":"https://www.proteinatlas.org/search/PARD6A"},"hgnc":{"alias_symbol":["PAR-6","PAR-6A","TAX40","PAR6alpha","TIP-40"],"prev_symbol":[]},"alphafold":{"accession":"Q9NPB6","domains":[{"cath_id":"3.10.20.90","chopping":"15-98","consensus_level":"high","plddt":90.2907,"start":15,"end":98},{"cath_id":"2.30.42.10","chopping":"142-252","consensus_level":"high","plddt":93.3318,"start":142,"end":252}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9NPB6","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9NPB6-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9NPB6-F1-predicted_aligned_error_v6.png","plddt_mean":73.5},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=PARD6A","jax_strain_url":"https://www.jax.org/strain/search?query=PARD6A"},"sequence":{"accession":"Q9NPB6","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9NPB6.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9NPB6/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9NPB6"}},"corpus_meta":[{"pmid":"15475953","id":"PMC_15475953","title":"Par6alpha signaling controls glial-guided neuronal migration.","date":"2004","source":"Nature neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/15475953","citation_count":240,"is_preprint":false},{"pmid":"19617897","id":"PMC_19617897","title":"Ect2 links the PKCiota-Par6alpha complex to Rac1 activation and cellular transformation.","date":"2009","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/19617897","citation_count":119,"is_preprint":false},{"pmid":"18427549","id":"PMC_18427549","title":"Matrix metalloproteinase-10 is a critical effector of protein kinase Ciota-Par6alpha-mediated lung cancer.","date":"2008","source":"Oncogene","url":"https://pubmed.ncbi.nlm.nih.gov/18427549","citation_count":80,"is_preprint":false},{"pmid":"24213535","id":"PMC_24213535","title":"The tumor suppressor Lgl1 forms discrete complexes with NMII-A and Par6α-aPKCζ that are affected by Lgl1 phosphorylation.","date":"2013","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/24213535","citation_count":29,"is_preprint":false},{"pmid":"35379775","id":"PMC_35379775","title":"Partitioning defective 6 homolog alpha (PARD6A) promotes epithelial-mesenchymal transition via integrin β1-ILK-SNAIL1 pathway in ovarian cancer.","date":"2022","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/35379775","citation_count":21,"is_preprint":false},{"pmid":"23264737","id":"PMC_23264737","title":"Par6γ is at the mother centriole and controls centrosomal protein composition through a Par6α-dependent pathway.","date":"2012","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/23264737","citation_count":19,"is_preprint":false},{"pmid":"27624926","id":"PMC_27624926","title":"Hook2, a microtubule-binding protein, interacts with Par6α and controls centrosome orientation during polarized cell migration.","date":"2016","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/27624926","citation_count":15,"is_preprint":false},{"pmid":"17335965","id":"PMC_17335965","title":"The Par6alpha/aPKC complex regulates Akt1 activity by phosphorylating Thr34 in the PH-domain.","date":"2007","source":"Molecular and cellular endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/17335965","citation_count":11,"is_preprint":false},{"pmid":"29155179","id":"PMC_29155179","title":"MicroRNA let-7f-5p regulates neuronal differentiation of rat bone marrow mesenchymal stem cells by targeting Par6α.","date":"2017","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/29155179","citation_count":10,"is_preprint":false},{"pmid":"39300216","id":"PMC_39300216","title":"PARD6A promotes lung adenocarcinoma cell proliferation and invasion through Serpina3.","date":"2024","source":"Cancer gene therapy","url":"https://pubmed.ncbi.nlm.nih.gov/39300216","citation_count":1,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":6768,"output_tokens":2719,"usd":0.030544,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":9955,"output_tokens":3367,"usd":0.066975,"stage2_stop_reason":"end_turn"},"total_usd":0.097519,"stage1_batch_id":"msgbatch_013a8chtv3AWyTqv4z4sEF4C","stage2_batch_id":"msgbatch_01AHsuW63vinsvuTgzmQ3n62","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2004,\n      \"finding\": \"Overexpression of mPar6alpha disrupts the perinuclear tubulin cage, retargets PKCzeta and gamma-tubulin away from the centrosome, and inhibits centrosomal motion and neuronal migration along glial fibers, indicating Par6alpha mediates signaling that coordinates cytoskeletal dynamics at the centrosome during glial-guided neuronal migration.\",\n      \"method\": \"Live imaging of cytoskeletal dynamics in migrating neurons; overexpression of mPar6alpha with readout of centrosome positioning, tubulin cage integrity, and neuronal migration\",\n      \"journal\": \"Nature neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — live imaging with functional overexpression readout, single lab, multiple cellular phenotypes observed\",\n      \"pmids\": [\"15475953\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"In NSCLC cells, Ect2 (a Rho GEF) is mislocalized to the cytoplasm where it physically binds the PKCiota-Par6alpha complex; knockdown of either PKCiota or Par6alpha causes Ect2 to redistribute to the nucleus. This PKCiota-Par6alpha-Ect2 complex activates Rac1, driving transformed growth and invasion.\",\n      \"method\": \"RNA interference knockdown of PKCiota, Par6alpha, and Ect2; co-immunoprecipitation of complex; Rac1 activity assays; subcellular localization by immunofluorescence\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP and RNAi with functional readouts, single lab, multiple orthogonal methods\",\n      \"pmids\": [\"19617897\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"PKCiota activates Rac1 in NSCLC cells through a PKCiota-Par6alpha complex that drives anchorage-independent growth and invasion via induction of MMP-10 expression. Par6alpha mutants unable to bind PKCiota (K19A) or couple to Rac1 (DeltaCRIB) fail to restore transformation and MMP-10 expression in Par6alpha-deficient cells.\",\n      \"method\": \"RNAi knockdown of PKCiota, Par6alpha, Rac1, and MMP-10; rescue with wild-type and domain mutants of Par6alpha; in vitro and in vivo (subcutaneous tumor) assays\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — RNAi knockdown combined with structure-function mutagenesis rescue experiments and in vivo tumor models, defining a PKCiota-Par6alpha-Rac1-MMP-10 axis\",\n      \"pmids\": [\"18427549\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Lgl1 forms two distinct complexes in vivo: Lgl1-NMII-A and Lgl1-Par6alpha-aPKCzeta. Phosphorylation of Lgl1 by aPKCzeta prevents its interaction with NMII-A and affects its cellular localization. The Lgl1-Par6alpha-aPKCzeta complex localizes to the leading edge of migrating cells, and aPKCzeta and NMII-A compete to bind the same domain of Lgl1.\",\n      \"method\": \"Co-immunoprecipitation; in vitro binding and filament assembly assays; phosphorylation assays; immunofluorescence localization in migrating cells\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vitro and in vivo Co-IP with phosphorylation assays, single lab, multiple orthogonal methods\",\n      \"pmids\": [\"24213535\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Par6gamma depletion causes loss of Par6alpha from the centrosome; Par6alpha in turn controls centrosomal protein recruitment through p150(Glued), affecting ciliogenesis, microtubule organization, and centrosome reorientation during migration. Par6gamma was shown to associate with Par6alpha.\",\n      \"method\": \"Par6gamma depletion (siRNA); immunofluorescence for centrosomal protein composition; co-immunoprecipitation of Par6gamma with Par6alpha\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP and knockdown with functional centrosomal localization readout, single lab\",\n      \"pmids\": [\"23264737\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Hook2 (a microtubule-binding protein) interacts with PAR6alpha via its C-terminal domain binding the aPKC-binding domain of PAR6alpha, and this interaction localizes PAR6alpha to the centrosome during polarized cell migration. Depletion of Hook2 reduces PAR6alpha at the centrosome; overexpression of Hook2 recruits PAR6alpha, aPKC, and PAR3 to aggresomes.\",\n      \"method\": \"Co-immunoprecipitation; siRNA depletion of Hook2; immunofluorescence of centrosomal PAR6alpha; domain mapping\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP with domain mapping and siRNA knockdown with localization readout, single lab\",\n      \"pmids\": [\"27624926\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Par6alpha interacts directly with aPKC (via its PB1 domain), and the Par6alpha/aPKC complex inhibits insulin-induced Akt1 activation by aPKC-mediated phosphorylation of Akt1 at Thr34. A DeltaPB1-Par6alpha mutant that cannot bind aPKC does not inhibit Akt1 activation; T34A-Akt1 is resistant to Par6alpha/aPKC-mediated inhibition and restores insulin-induced glycogen synthesis.\",\n      \"method\": \"Deletion mutagenesis; overexpression in C2C12 myoblasts; phosphorylation assay on Akt1 T34; glycogen synthesis reconstitution\",\n      \"journal\": \"Molecular and cellular endocrinology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — phosphorylation assay with mutagenesis (T34A and DeltaPB1) and functional reconstitution, single lab\",\n      \"pmids\": [\"17335965\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"PARD6A promotes EMT in ovarian cancer cells via integrin beta1-ILK-SNAIL1 signaling, modulating E-cadherin and vimentin expression. PARD6A knockdown suppressed and overexpression promoted EMT and metastasis in vitro and in vivo.\",\n      \"method\": \"siRNA knockdown and overexpression of PARD6A; knockdown/overexpression of SNAIL1 and ILK; in vitro migration/invasion assays; in vivo metastasis model\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss- and gain-of-function experiments with pathway epistasis (SNAIL1/ILK), single lab, multiple orthogonal assays\",\n      \"pmids\": [\"35379775\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"PARD6A promotes lung adenocarcinoma cell proliferation, migration, and invasion through induction of Serpina3; ectopic Serpina3 expression rescues defects caused by PARD6A knockdown, and Serpina3 silencing impedes the enhanced phenotype caused by PARD6A overexpression.\",\n      \"method\": \"PARD6A knockdown and overexpression; RNA-seq to identify downstream targets; Serpina3 rescue and knockdown experiments; in vitro proliferation/migration/invasion assays; subcutaneous tumor mouse model\",\n      \"journal\": \"Cancer gene therapy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — epistasis rescue experiments with transcriptomic identification of downstream effector, single lab\",\n      \"pmids\": [\"39300216\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Par6alpha is necessary for neuronal differentiation of bone marrow mesenchymal stem cells; siRNA silencing of Par6alpha impairs MSC-to-neuron-like cell differentiation. Let-7f-5p directly targets Par6alpha mRNA (validated by luciferase reporter assay), and downregulation of let-7f-5p during differentiation increases Par6alpha expression.\",\n      \"method\": \"siRNA knockdown of Par6alpha; luciferase reporter assay for let-7f-5p targeting; gain- and loss-of-function of let-7f-5p\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, single-method siRNA knockdown with neuronal differentiation readout; miRNA targeting validated by reporter assay\",\n      \"pmids\": [\"29155179\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"PARD6A (Par6alpha) is a scaffold polarity protein that forms complexes with aPKC and Par3 to coordinate centrosome positioning and cytoskeletal organization during neuronal migration and polarized cell migration; it directly binds PKCiota to activate Rac1 (via Ect2) and MMP-10 in oncogenic signaling, binds aPKC to inhibit Akt1 via Thr34 phosphorylation, associates with Lgl1 at the leading edge, is recruited to the centrosome by Hook2, and drives EMT in cancer through integrin beta1-ILK-SNAIL1 and Serpina3-dependent pathways.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PARD6A (Par6alpha) is a scaffold polarity protein that organizes aPKC-containing complexes to coordinate centrosome positioning, cytoskeletal dynamics, and polarized cell migration [#0, #4]. It binds atypical PKC directly through its PB1 domain, and this Par6alpha/aPKC module phosphorylates Akt1 at Thr34 to restrain insulin-induced Akt1 activation and glycogen synthesis [#6], and partitions Lgl1 into a Par6alpha-aPKCzeta complex at the leading edge of migrating cells, where aPKCzeta phosphorylation of Lgl1 blocks its association with non-muscle myosin IIA [#3]. Par6alpha is recruited to the centrosome through interactions with Par6gamma and with the microtubule-binding protein Hook2, which binds the aPKC-binding domain of Par6alpha; from the centrosome it controls recruitment of components such as p150(Glued) to govern ciliogenesis, microtubule organization, and centrosome reorientation during migration [#4, #5]. In cancer, Par6alpha couples PKCiota to Rac1 activation: the PKCiota-Par6alpha complex retains the Rho GEF Ect2 in the cytoplasm and induces MMP-10 to drive transformed, anchorage-independent growth and invasion, with Par6alpha mutants unable to bind PKCiota or couple to Rac1 failing to support transformation [#1, #2]. PARD6A further promotes epithelial-mesenchymal transition and metastasis through integrin beta1-ILK-SNAIL1 signaling and through induction of the downstream effector Serpina3 [#7, #8].\",\n  \"teleology\": [\n    {\n      \"year\": 2004,\n      \"claim\": \"Established that Par6alpha acts upstream of centrosomal cytoskeletal organization, linking a polarity protein to centrosome positioning during directed cell migration.\",\n      \"evidence\": \"Live imaging of cytoskeletal dynamics and centrosome positioning following mPar6alpha overexpression in glial-guided migrating neurons\",\n      \"pmids\": [\"15475953\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Based on overexpression, leaving endogenous requirement undefined\", \"Molecular partners mediating the centrosomal effect not identified here\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Defined a direct PB1-domain interaction between Par6alpha and aPKC and showed the complex acts as a kinase scaffold that negatively regulates Akt1 signaling.\",\n      \"evidence\": \"Deletion mutagenesis (DeltaPB1, T34A-Akt1), phosphorylation assay, and glycogen synthesis reconstitution in C2C12 myoblasts\",\n      \"pmids\": [\"17335965\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Performed in overexpression context\", \"Physiological setting of Akt1 inhibition by Par6alpha/aPKC not established beyond myoblasts\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Showed Par6alpha is a required adaptor coupling PKCiota to Rac1 activation and MMP-10 induction, establishing it as an effector node in oncogenic transformation.\",\n      \"evidence\": \"RNAi knockdown with domain-mutant rescue (K19A, DeltaCRIB) and in vivo subcutaneous tumor assays in NSCLC cells\",\n      \"pmids\": [\"18427549\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which the complex activates Rac1 not fully resolved at this stage\", \"Generality beyond NSCLC unknown\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Identified Ect2 as the GEF physically bound by the PKCiota-Par6alpha complex, explaining how the complex activates Rac1 by retaining Ect2 in the cytoplasm.\",\n      \"evidence\": \"Reciprocal Co-IP, RNAi of PKCiota/Par6alpha/Ect2, Rac1 activity assays, and subcellular localization in NSCLC cells\",\n      \"pmids\": [\"19617897\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structural basis of the Ect2 interaction not defined\", \"How cytoplasmic retention triggers Rac1 GEF activity not detailed\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Placed Par6alpha downstream of Par6gamma for centrosomal targeting and showed Par6alpha controls centrosomal protein recruitment affecting ciliogenesis and centrosome reorientation.\",\n      \"evidence\": \"siRNA depletion of Par6gamma, Co-IP with Par6alpha, and immunofluorescence of centrosomal composition\",\n      \"pmids\": [\"23264737\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct vs indirect Par6gamma-Par6alpha association not distinguished\", \"Mechanism of p150(Glued) recruitment unresolved\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Resolved how Par6alpha-aPKCzeta and Lgl1 act at the leading edge, showing aPKCzeta phosphorylation of Lgl1 switches it away from NMII-A binding.\",\n      \"evidence\": \"Co-IP, in vitro binding and filament assembly assays, phosphorylation assays, and localization in migrating cells\",\n      \"pmids\": [\"24213535\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of the Lgl1 switch for migration not quantified\", \"Competition dynamics in vivo not measured\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Identified Hook2 as a centrosomal recruitment factor that binds the aPKC-binding domain of Par6alpha, providing a physical mechanism for Par6alpha centrosomal localization during migration.\",\n      \"evidence\": \"Co-IP, domain mapping, and siRNA depletion of Hook2 with immunofluorescence of centrosomal PAR6alpha\",\n      \"pmids\": [\"27624926\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Competition between Hook2 and aPKC for the same Par6alpha domain not resolved\", \"Relationship to the Par6gamma recruitment pathway unclear\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Extended Par6alpha's oncogenic role to EMT, defining an integrin beta1-ILK-SNAIL1 axis driving metastasis in ovarian cancer.\",\n      \"evidence\": \"siRNA/overexpression of PARD6A with epistasis to SNAIL1/ILK and in vitro and in vivo metastasis assays\",\n      \"pmids\": [\"35379775\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct molecular link between Par6alpha and integrin beta1-ILK not defined\", \"Whether this acts through aPKC scaffolding unknown\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Identified Serpina3 as a transcriptional/downstream effector through which PARD6A drives lung adenocarcinoma proliferation and invasion.\",\n      \"evidence\": \"PARD6A knockdown/overexpression with RNA-seq, Serpina3 rescue/silencing epistasis, and subcutaneous tumor model\",\n      \"pmids\": [\"39300216\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism connecting PARD6A to Serpina3 induction not defined\", \"Whether Serpina3 axis intersects the PKCiota-Rac1 pathway unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How Par6alpha's polarity-scaffolding activity (aPKC/Lgl1/centrosome) is mechanistically reconciled with its distinct oncogenic outputs (Rac1-MMP-10, EMT-SNAIL1, Serpina3) within a single regulatory framework remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No unifying structural or regulatory model linking polarity and oncogenic functions\", \"Endogenous physiological role in normal tissue largely uncharacterized\", \"Upstream signals controlling complex assembly not defined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [2, 5, 6]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [1, 3, 6]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005815\", \"supporting_discovery_ids\": [0, 4, 5]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [0, 4]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [2, 6]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [2, 7, 8]}\n    ],\n    \"complexes\": [\"PKCiota-Par6alpha-Ect2 complex\", \"Par6alpha-aPKC complex\", \"Lgl1-Par6alpha-aPKCzeta complex\"],\n    \"partners\": [\"PRKCI\", \"PRKCZ\", \"ECT2\", \"LLGL1\", \"PARD6G\", \"HOOK2\", \"AKT1\", \"PARD3\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}