{"gene":"DLG1","run_date":"2026-06-09T23:54:42","timeline":{"discoveries":[{"year":1994,"finding":"hDlg (DLG1) contains three PDZ domains, an SH3 region, and a guanylate kinase-like domain. Two sites within hDlg associate in vitro with the 30-kDa N-terminal domain of protein 4.1, and the protein localizes to regions of cell-cell contact.","method":"In vitro binding assay with recombinant proteins; cDNA cloning and sequencing; immunolocalization","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct in vitro binding with defined domains, single lab, two orthogonal methods (binding assay + localization)","pmids":["7937897"],"is_preprint":false},{"year":1995,"finding":"SAP97 localizes at the presynaptic nerve termini of excitatory synapses in hippocampus and at basolateral membranes of epithelial cells, suggesting a role in the site-specific assembly of membrane specializations at cell-cell contacts.","method":"Light and immunoelectron microscopy of rat hippocampal formation and epithelial cells","journal":"The Journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — immunoelectron microscopy with multiple tissue types, single lab","pmids":["7891172"],"is_preprint":false},{"year":1996,"finding":"DLG1 subcellular targeting requires either the PDZ1-2 conformational unit (which binds protein 4.1/ERM proteins and T/SXV motif-containing proteins) or the alternatively spliced I3 domain (which binds exclusively 4.1/ERM proteins). Both protein 4.1 and ezrin interact with DLG1 in co-precipitating immune complexes.","method":"In vitro binding assays with recombinant protein domains; in situ localization of domain constructs in permeabilized cells; co-immunoprecipitation","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — reconstitution with defined domain deletions + co-IP + cell localization, multiple orthogonal methods in one study","pmids":["8922391"],"is_preprint":false},{"year":1997,"finding":"Adenovirus 9ORF1 oncoprotein interacts directly with the second PDZ domain of hDlg/SAP97 in vitro and in vivo. HTLV-1 Tax and HPV-18 E6 oncoproteins also bind DLG1 in vitro via their C-terminal PDZ-binding motifs.","method":"Lambda gt11 library screen; in vitro binding assays; co-immunoprecipitation from cells","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal in vitro and in vivo binding, multiple viral proteins tested, single lab with multiple orthogonal methods","pmids":["9192623"],"is_preprint":false},{"year":1997,"finding":"DAP-1 (GKAP/SAPAP) binds to the guanylate kinase-like domains of hDLG and PSD-95, and associates with hDLG, NMDA receptors, and APC protein; it colocalizes with PSD-95 and NMDA receptors at synapses.","method":"Yeast two-hybrid; co-immunoprecipitation; immunofluorescence colocalization","journal":"Genes to cells","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — yeast two-hybrid confirmed by co-IP and colocalization, single lab","pmids":["9286858"],"is_preprint":false},{"year":1998,"finding":"SAP97 directly associates with the C terminus of GluR1 (AMPA receptor subunit) via its PDZ domains, but not with GluR2 or GluR3; SAP97 was present in AMPA receptor complexes immunoprecipitated from rat brain.","method":"Co-immunoprecipitation from rat brain; in vitro binding with recombinant proteins; cross-linking experiments","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — in vitro reconstitution with recombinant proteins + co-IP from brain, multiple orthogonal methods, independently replicated","pmids":["9677374"],"is_preprint":false},{"year":1998,"finding":"The first 65 amino acid residues unique to SAP97 (absent from PSD-95/SAP90 and SAP102) direct selective subcellular localization to the epithelial lateral membrane and mediate cytoskeletal attachment; PDZ1-2 domains and I3 insert affect efficiency but are not essential for targeting.","method":"Domain deletion mutagenesis; subcellular fractionation; immunofluorescence in epithelial cells","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 / Strong — systematic domain deletion mutagenesis with multiple constructs, direct localization readout, single lab but multiple orthogonal methods","pmids":["9683631"],"is_preprint":false},{"year":1998,"finding":"SAP97 is recruited to sites of E-cadherin-mediated cell-cell contact via an E-cadherin-induced assembly of the cortical cytoskeleton; SAP97 associates with the E-cadherin/catenin complex indirectly through cytoskeletal attachment.","method":"Immunofluorescence in epithelial CACO-2 cells and L-cells; biochemical fractionation; E-cadherin induction assays","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct cell biological experiments with E-cadherin induction, single lab, two methods","pmids":["9512503"],"is_preprint":false},{"year":1998,"finding":"The guanylate kinase-like (GK) domain of SAP97 does not encode an active guanylate kinase — it lacks enzymatic activity and cannot be activated by GKAP; flanking regions do not act as inhibitory regulators.","method":"In vitro enzymatic assay; biochemical analysis of recombinant GK domain","journal":"European journal of biochemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct in vitro enzymatic assay, definitive negative result for catalytic activity, single lab","pmids":["9523702"],"is_preprint":false},{"year":1999,"finding":"HTLV-1 Tax binds hDLG via the C-terminus of Tax and the PDZ domain of hDLG; Tax binding to hDLG prevents its interaction with APC, and co-expression of Tax suppresses hDLG-mediated cell cycle arrest (G0/G1 inhibition of BrdU incorporation).","method":"Yeast two-hybrid; in vitro binding; co-immunoprecipitation from HTLV-1-infected T-cells; microinjection/BrdU incorporation assay","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (yeast 2H, in vitro, co-IP, functional assay), replicated in infected T-cells","pmids":["10557085"],"is_preprint":false},{"year":1999,"finding":"NR2A subunit C-terminal tSXV motif binds PDZ domains of SAP97 in yeast two-hybrid; upstream sequences beyond the tSXV motif are required for efficient interaction. NR1-3 and NR1-4, despite having tSXV motifs, do not interact with SAP97.","method":"Yeast two-hybrid; site-directed mutagenesis; immunohistochemistry","journal":"The European journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — yeast two-hybrid with mutagenesis, single lab, defined binding requirements","pmids":["10336672"],"is_preprint":false},{"year":2000,"finding":"Overexpression of hDLG suppresses cell proliferation by blocking G0/G1 to S phase transition. This activity requires intact PDZ, SH3, and GK domains of hDLG, and is partially dependent on interaction with APC via its C-terminal S/TXV motif.","method":"Overexpression and domain mutant analysis; cell cycle analysis; APC co-expression studies","journal":"Oncogene","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — domain mutagenesis with functional cell cycle readout, single lab, multiple domain mutants tested","pmids":["10656683"],"is_preprint":false},{"year":2000,"finding":"SAP97 interacts with Kv1 potassium channels intracellularly and prevents biosynthetic trafficking, causing intracellular accumulation of Kv1 channels in ER-derived vesicles — distinct from PSD-95, which clusters channels at the plasma membrane.","method":"Co-expression in heterologous cells; immunofluorescence; cell surface expression analysis","journal":"The Journal of cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — comparative analysis of SAP97 vs PSD-95, distinct intracellular mechanism shown, single lab","pmids":["10629225"],"is_preprint":false},{"year":2000,"finding":"hCASK GUK domain binds the SH3 domain of hDlg; both proteins colocalize at basolateral epithelial membranes and co-precipitate from intestinal cell lysates. SH3 and GUK domains also participate in intramolecular interactions within each MAGUK.","method":"Yeast two-hybrid; GST fusion protein binding assays; co-immunoprecipitation; immunofluorescence","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — yeast two-hybrid confirmed by in vitro binding and co-IP, single lab, multiple orthogonal methods","pmids":["10993877"],"is_preprint":false},{"year":2001,"finding":"SAP97 interacts with Kir2.1, Kir2.2, and Kir2.3 channels via the C-terminal SEI motif of Kir2.2 and the second PDZ domain of SAP97; PKA phosphorylation of the Kir2.2 C-terminus inhibits SAP97 association. Kir2.2 and SAP97 colocalize at T-tubules in cardiac ventricular myocytes.","method":"GST affinity pulldown from rat brain/heart; co-immunoprecipitation; mutagenesis; immunofluorescence","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 / Strong — pulldown + co-IP from native tissue + mutagenesis + functional PKA regulation + localization, multiple orthogonal methods","pmids":["11181181"],"is_preprint":false},{"year":2001,"finding":"The I3 alternatively spliced insertion targets hDlg to cell-cell contact membranes; I2 insertion targets it to the nucleus. The N-terminal alternatively spliced region binds SH3 domains and moderates protein oligomerization.","method":"Expression of isoform constructs; immunofluorescence localization; in vitro binding assays","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — systematic isoform expression with localization readout, single lab, two methods","pmids":["11723125"],"is_preprint":false},{"year":2001,"finding":"C. elegans DLG-1 (most similar to SAP97) localizes to adherens junctions via its N-terminal domain and recruits AJM-1 and CPI-1 to adherens junctions; loss of DLG-1 disrupts actin cytoskeleton organization and embryo elongation without affecting cell polarity.","method":"Genetic knockout in C. elegans; immunofluorescence; GFP localization; domain deletion analysis","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic loss-of-function in vivo with defined molecular and morphological phenotypes, domain analysis, multiple readouts","pmids":["11694581"],"is_preprint":false},{"year":2001,"finding":"hDlg is degraded via the proteasome, and upon cell-cell contact is hyper-phosphorylated and stabilized. In transformed and undifferentiated cervical cancer cells this contact-dependent stabilization is lost.","method":"Proteasome inhibitor treatment; western blot; immunofluorescence in epithelial cell lines at varying density","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — pharmacological and cell-density manipulation experiments, two methods, single lab","pmids":["11739660"],"is_preprint":false},{"year":2001,"finding":"SAP97 interacts with Kv1.5 potassium channel via the channel's C-terminal TDL motif; SAP97-Kv1.5 complexes are retained in the ER of COS-7 cells but SAP97 coexpression augments Kv1.5 currents in Xenopus oocytes.","method":"Co-immunoprecipitation; mutagenesis of Kv1.5 C-terminus; patch clamp in oocytes; immunocytochemistry","journal":"American journal of physiology. Heart and circulatory physiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP with mutagenesis confirmation + functional current measurement, single lab","pmids":["11709425"],"is_preprint":false},{"year":2002,"finding":"The L27N domain of CASK binds the N-terminus of SAP97; this interaction is required for lateral membrane localization of SAP97 in MDCK epithelial cells. A Drosophila DLG isoform containing the SAP97 N-terminal equivalent binds Camguk (the CASK ortholog), showing evolutionary conservation.","method":"Biochemical L27 domain binding assays; dominant-negative CASK overexpression; colocalization in MDCK cells; Drosophila isoform analysis","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct biochemical binding + functional dominant-negative localization assay + evolutionary conservation, multiple orthogonal methods","pmids":["11865057"],"is_preprint":false},{"year":2003,"finding":"SAP97 interacts with TACE (ADAM17) metalloprotease via the PDZ3 domain of SAP97 and the C-terminal sequence of TACE; overexpression of SAP97 (but not a PDZ3-deleted mutant) inhibits TACE shedding activity.","method":"Yeast two-hybrid; affinity purification; co-immunoprecipitation; immunofluorescence; TACE shedding assay","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — yeast two-hybrid confirmed by co-IP + functional shedding assay with domain deletion, single lab","pmids":["12668732"],"is_preprint":false},{"year":2003,"finding":"SAP97 directly interacts with NMDA receptor subunit NR2A via its PDZ1 domain; CaMKII phosphorylates SAP97 at Ser-232 within PDZ1, disrupting the SAP97-NR2A interaction both in vitro and in transfected cells.","method":"In vitro pull-down; co-immunoprecipitation from hippocampal synaptosomes; metabolic labeling; CaMKII inhibitor treatment; phosphomimetic mutant expression","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — in vitro pull-down + co-IP from native tissue + mutagenesis + pharmacological validation, multiple orthogonal methods","pmids":["12933808"],"is_preprint":false},{"year":2004,"finding":"SAP97 monomer-dimer transition is controlled by its N-terminal L27 domain. Overexpression of SAP97 drives GluR1 to synapses, potentiates AMPAR EPSCs, and occludes LTP; L27 domain mutants that prevent multimerization show faster synaptic turnover and loss of potentiation. RNAi knockdown of endogenous SAP97 reduces surface expression of both GluR1 and GluR2 and impairs both AMPA and NMDA EPSCs.","method":"Single-particle electron microscopy; RNAi knockdown; electrophysiology (EPSCs); overexpression with L27 mutants; FRAP","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — structural EM + RNAi + electrophysiology + FRAP, multiple orthogonal methods in one study","pmids":["15504326"],"is_preprint":false},{"year":2004,"finding":"SAP97, CASK, Veli-1/3, and Mint1 form a multiprotein trafficking complex that associates with Kir2.1, Kir2.2, and Kir2.3 channels via the C-terminal PDZ-binding motif. Dominant-interfering CASK causes Kir2.2 mislocalization from the basolateral membrane in polarized epithelial cells.","method":"GST pulldown from brain; co-immunoprecipitation; in vitro protein interaction assays; immunocytochemistry; dominant-negative CASK expression","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vitro binding + co-IP from native tissue + functional localization assay with dominant-negative, multiple orthogonal methods","pmids":["14960569"],"is_preprint":false},{"year":2005,"finding":"p38γ (SAPK3) phosphorylates SAP97/hDlg, triggering its dissociation from GKAP and release from the cytoskeleton, regulating intercellular junction integrity in response to osmotic stress.","method":"In vitro kinase assay; co-immunoprecipitation; identification of phosphorylation sites; osmotic stress experiments","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — in vitro kinase assay identifying SAP97 as substrate + co-IP showing GKAP dissociation + cellular functional context, multiple orthogonal methods","pmids":["15729360"],"is_preprint":false},{"year":2005,"finding":"Cdc42 activates Par6-PKCζ at the leading edge of migrating astrocytes, promoting Dlg1-APC interaction. This APC-Dlg1 physical interaction is required for polarization of the microtubule cytoskeleton during directed cell migration.","method":"RNAi knockdown; TIRF microscopy; biochemical co-immunoprecipitation; Cdc42 activation assays in migrating astrocytes","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — RNAi + co-IP + live TIRF imaging + epistasis analysis, multiple orthogonal methods","pmids":["16157700"],"is_preprint":false},{"year":2005,"finding":"Dlgh1 translocates to the immune synapse and lipid rafts upon TCR/CD28 engagement; Lck-SH3-mediated interactions control Dlgh1 membrane targeting. Dlgh1 facilitates formation of Lck-Dlgh1-Zap70-WASp complexes and promotes actin polymerization, synaptic raft/TCR clustering, and NFAT activation.","method":"Co-immunoprecipitation; RNAi knockdown; overexpression; immunofluorescence; NFAT reporter assay","journal":"The Journal of experimental medicine","confidence":"High","confidence_rationale":"Tier 2 / Strong — complex identification by co-IP + functional siRNA knockdown/OE with multiple readouts (actin, raft clustering, NFAT), single lab multiple methods","pmids":["15699074"],"is_preprint":false},{"year":2006,"finding":"DLG1's palmitoylated α-isoform localizes to the postsynaptic density and influences AMPAR-mediated synaptic strength independently of activity; the L27-containing β-isoform primarily influences AMPAR function in a CaMKII-dependent, activity-regulated manner. The N-terminal domain determines isoform-specific roles in synaptic function.","method":"Silencing of endogenous PSD-95 + heterologous expression of isoforms; electrophysiology; CaMKII inhibitor experiments","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 2 / Strong — isoform-specific rescue experiments with pharmacological validation + electrophysiology, multiple orthogonal methods","pmids":["16815335"],"is_preprint":false},{"year":2006,"finding":"Dlgh1 MAGUK scaffold protein is required for TCR-induced 'alternative' p38 activation and NFAT transcription but not JNK or NF-κB activation; a Dlgh1 mutant unable to bind p38 fails to activate NFAT.","method":"siRNA knockdown; overexpression of binding-defective mutant; NFAT and NF-κB reporter assays; p38 activation assays","journal":"Nature immunology","confidence":"High","confidence_rationale":"Tier 2 / Strong — siRNA + mutant rescue + pathway-specific reporter assays, multiple methods in a high-quality journal","pmids":["17187070"],"is_preprint":false},{"year":2006,"finding":"CaMKII phosphorylates SAP97 on Ser39 in the N-terminal domain; this phosphorylation drives SAP97 to the postsynaptic compartment and releases the SAP97/NR2A complex from the ER. Subsequently, Ser232 phosphorylation within PDZ1 disrupts NR2A binding and triggers NR2A insertion into the postsynaptic membrane.","method":"Phospho-specific antibodies; CaMKII activation/inhibition in hippocampal neurons; mutagenesis (S39D, S232D); co-immunoprecipitation","journal":"Journal of neurochemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — phospho-specific antibodies + phosphomimetic mutants + co-IP from defined subcellular fractions, multiple orthogonal methods","pmids":["17156128"],"is_preprint":false},{"year":2006,"finding":"SAP97 assembles an AKAP79-cAMP-dependent PKA scaffold at the C-terminal PDZ-binding motif (ESKV) of the β1-adrenergic receptor; this SAP97-AKAP79 complex is required for efficient β1-AR recycling and PKA-mediated phosphorylation of β1-AR Ser312.","method":"Co-immunoprecipitation; PDZ-motif mutagenesis; receptor trafficking assays; PKA phosphorylation assays","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP + mutagenesis + functional trafficking assay, single lab","pmids":["17170109"],"is_preprint":false},{"year":2007,"finding":"SAP97 directs Kv4.2 (A-type K+ channel) to postsynaptic density (PSD) via PDZ domain interaction with Kv4.2 C-terminus; CaMKII-dependent SAP97 phosphorylation regulates Kv4.2 subcellular localization to spines.","method":"Co-immunoprecipitation; synaptic fractionation; SAP97 lentiviral RNAi; pharmacological SAP97 translocation to spines","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP + fractionation + RNAi + pharmacological translocation, single lab","pmids":["17635915"],"is_preprint":false},{"year":2007,"finding":"Delta1 (Notch ligand) interacts with Dlg1 via a C-terminal canonical PDZ-binding motif (ATEV); Delta1 expression triggers accumulation of Dlg1 at cell-cell contacts and reduces cell motility. These effects are abolished by deletion of the ATEV motif, independently of Notch signaling.","method":"Peptide affinity chromatography + mass spectrometry; co-immunoprecipitation; immunofluorescence; migration assay with PDZ-motif deletion mutant","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP confirmed by mutagenesis + functional migration assay, single lab","pmids":["15485825"],"is_preprint":false},{"year":2007,"finding":"MPP7 forms a tripartite complex with LIN7A or LIN7C and DLG1. MPP7 dimerizes with LIN7 through L27 domains; the MPP7-LIN7 dimer then associates with DLG1's N-terminal L27 domain. MPP7 is required for localization of DLG1 to epithelial adherens junctions and stabilizes DLG1 in an insoluble compartment.","method":"Co-immunoprecipitation; domain deletion analysis; immunofluorescence in epithelial cells; detergent fractionation","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP with domain deletions + localization and fractionation assays, single lab","pmids":["17237226"],"is_preprint":false},{"year":2007,"finding":"NMR solution structure of the hDlg PDZ2 domain bound to HPV-18 E6 C-terminal peptide shows a novel mode of interaction where six residues of the peptide contact PDZ2, compared to the typical four. Phosphorylation of E6 Thr156 disables binding.","method":"NMR structure determination; isothermal titration calorimetry; mutagenesis; molecular dynamics simulation","journal":"Biochemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — NMR structure + ITC + mutagenesis in one study, single lab but multiple rigorous methods","pmids":["17713926"],"is_preprint":false},{"year":2007,"finding":"Dlg1 loss-of-function in mice causes abnormalities in renal/urogenital development (hypoplastic kidneys/ureters, absent vagina and seminal vesicle) associated with impaired epithelial cellular proliferation rather than disruption of cell-cell junctional complexes.","method":"Dlgh1 knockout mouse generation; histology; immunostaining for junctional markers; proliferation assays","journal":"Development (Cambridge, England)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic knockout with defined phenotypic readout distinguishing proliferation from junction defects, single lab","pmids":["17435047"],"is_preprint":false},{"year":2008,"finding":"GluR1 binding to SAP97 via its C-terminal 7 aa is required to translocate SAP97 from the cytosol to plasma membranes; GluR1 and SAP97 together at the plasma membrane promote dendrite branching in an activity-dependent manner.","method":"GluR1 C-terminal deletion (GluR1Δ7) in vitro and in vivo; membrane fractionation; immunofluorescence; dendritic morphometry","journal":"The Journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — specific deletion mutant + fractionation + functional morphological assay, single lab","pmids":["18842882"],"is_preprint":false},{"year":2009,"finding":"Two N-terminal SAP97 isoforms (palmitoylated αSAP97 at PSD; L27-containing βSAP97 at perisynaptic regions) differentially localize GluR1-containing AMPARs within subsynaptic subdomains, directly modulating AMPAR dynamics and synaptic function.","method":"Live imaging; electrophysiology; isoform-specific overexpression in hippocampal neurons","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — isoform-specific live imaging + electrophysiology, multiple orthogonal methods, well-controlled experiments","pmids":["19357261"],"is_preprint":false},{"year":2009,"finding":"SAP97 and CASK together are required for retention and trafficking of NMDARs (NR1/NR2B) through a specialized ER subcompartment in hippocampal neurons that bypasses the somatic Golgi and merges with dendritic Golgi outposts; AMPARs use the conventional somatic Golgi pathway.","method":"Live imaging of fluorescently-tagged receptors/adaptors in rat hippocampal neurons; RNAi knockdown of SAP97/CASK; subcellular fractionation","journal":"Nature neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — live imaging of trafficking pathway + RNAi functional validation, high-quality mechanistic study","pmids":["19620977"],"is_preprint":false},{"year":2009,"finding":"SAP97 forms a tripartite complex with Kv4.2/4.3 channels and CaMKII in cardiomyocytes; SAP97 clustering of Kv4.3 at the plasma membrane enhances Ito current and enables CaMKII-dependent regulation. Kv4 channels lacking the SAL sequence no longer respond to CaMKII inhibitors.","method":"Pull-down; co-immunoprecipitation from cardiac myocytes; SAP97 shRNA; adenoviral overexpression; patch clamp","journal":"Circulation research","confidence":"High","confidence_rationale":"Tier 2 / Strong — co-IP from native tissue + SAL mutagenesis + RNAi + electrophysiology, multiple orthogonal methods","pmids":["19213956"],"is_preprint":false},{"year":2009,"finding":"Inhibiting SAP97-myosin VI interaction (using a dominant-negative myosin VI construct) reduces synapse number, surface AMPAR expression, and prevents activity-dependent AMPAR recruitment to silent synapses in hippocampal neurons.","method":"Dominant-negative construct expression; immunofluorescence; whole-cell patch-clamp recording of mEPSCs","journal":"Journal of neurochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — dominant-negative approach + electrophysiology + immunofluorescence, single lab","pmids":["19895665"],"is_preprint":false},{"year":2009,"finding":"CaMKII preferentially phosphorylates SAP97 splice variant containing I3 and I5 inserts; AKAP79/150 directly and specifically binds only the I3I5-containing SH3-GK region. CaMKII phosphorylation of this splice variant prevents AKAP79/150 association, thereby relieving AKAP79-dependent down-regulation of GluR1 AMPAR currents.","method":"In vitro phosphorylation; GST fusion binding assays; immune complex kinase assay; electrophysiology with active CaMKII infusion","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — in vitro binding assays + phosphorylation assays + isoform specificity with GST domain constructs + functional electrophysiology, multiple methods","pmids":["19858198"],"is_preprint":false},{"year":2010,"finding":"SAP97 via its PDZ domains interacts specifically with the SIV motif at the C-terminus of cardiac sodium channel Nav1.5 at intercalated discs (while dystrophin-syntrophin complex anchors Nav1.5 at lateral membranes). SAP97 silencing reduces Nav1.5 surface expression and sodium current.","method":"Pull-down assays; immunostaining; patch clamp; SAP97 siRNA knockdown in HEK293 and cardiomyocytes; mdx mouse comparison","journal":"Circulation research","confidence":"High","confidence_rationale":"Tier 2 / Strong — pull-down with specificity controls + RNAi functional validation + electrophysiology + mutagenesis of SIV motif, multiple orthogonal methods","pmids":["21164104"],"is_preprint":false},{"year":2010,"finding":"Ezrin regulates Dlg1 localization at the immunological synapse, controlling microtubule network organization; ezrin-Dlg1 interaction is required for p38 MAP kinase-dependent NF-AT activation and Erk1/2 downregulation at the immune synapse.","method":"Co-immunoprecipitation; RNAi; immunofluorescence; live imaging; TCR signaling assays","journal":"The EMBO journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP + RNAi + imaging showing ezrin-Dlg1 functional link, single lab","pmids":["20551903"],"is_preprint":false},{"year":2010,"finding":"Conditional SAP97 deletion in mature neurons causes no deficits in glutamatergic transmission or LTP, indicating functional redundancy with other PSD-MAGUKs; overexpression during early development traffics both AMPARs and NMDARs to synapses and rescues AMPAR deficits in PSD-93/-95 double-KO neurons.","method":"Conditional knockout; electrophysiology; overexpression in wild-type and double-KO neurons","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — conditional genetic KO + epistasis rescue experiments + electrophysiology, multiple orthogonal methods","pmids":["20133708"],"is_preprint":false},{"year":2010,"finding":"During wound-induced migration, Cdc42 acts through Dlg1 to regulate dynein interaction with microtubules at the cell front; Dlg1 interacts with dynein via the scaffolding protein GKAP, and together they control microtubule dynamics and centrosome positioning.","method":"Co-immunoprecipitation; RNAi knockdown; live imaging; centrosome positioning assay in wounded monolayers","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — co-IP identifying Dlg1-GKAP-dynein complex + RNAi with centrosome phenotype + live imaging, multiple methods","pmids":["21041448"],"is_preprint":false},{"year":2011,"finding":"PKCα interacts with DLG1/SAP97 via the third PDZ domain of DLG1 and the C-terminal PDZ-binding motif of PKCα; this scaffolding interaction promotes wound healing/cell migration. PKCα phosphorylates DLG1 at Thr-656 in its SH3-Hook region, which serves as a marker of PKCα activity.","method":"PDZ domain proteomic array; co-immunoprecipitation; scratch migration assay with PKCα/DLG1 co-depletion; phosphorylation site identification","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — PDZ array + co-IP + functional migration assay + phosphosite identification, single lab","pmids":["22027822"],"is_preprint":false},{"year":2011,"finding":"αSAP97 occludes LTP by enhancing postsynaptic AMPAR levels; βSAP97 blocks LTP by reducing synaptic NMDAR localization while restricting extrasynaptic AMPAR pools. Knockdown of endogenous βSAP97 increases synaptic AMPAR and NMDAR levels.","method":"Paired whole-cell recordings from synaptically coupled hippocampal neurons; live imaging; RNAi knockdown; isoform-specific overexpression","journal":"The Journal of physiology","confidence":"High","confidence_rationale":"Tier 2 / Strong — isoform-specific RNAi + paired electrophysiology + live imaging, multiple orthogonal methods","pmids":["21768261"],"is_preprint":false},{"year":2013,"finding":"CASK binding to SAP97 via L27 domains stabilizes SAP97 in an 'extended' conformation; unbound SAP97 is in a 'compact' conformation. Compact SAP97 preferentially associates with GluA1-AMPARs; CASK-bound extended SAP97 colocalizes with GluN2B-NMDARs, providing a mechanism for differential receptor sorting.","method":"Intramolecular FRET sensors; co-IP; isoform expression in HEK cells and hippocampal neurons; colocalization imaging","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — FRET-based conformational sensor + co-IP + cellular colocalization, multiple orthogonal methods in single study","pmids":["23864692"],"is_preprint":false},{"year":2013,"finding":"DLG1 knockdown decreases surface expression of the glial glutamate transporter EAAT2b (which contains a PDZ ligand) in MDCK cells and astrocytes; DLG1 co-immunoprecipitates with EAAT2b. CaMKII activation disrupts DLG1-EAAT2b interaction and decreases EAAT2b surface expression.","method":"Co-immunoprecipitation; shRNA knockdown; surface biotinylation assay; CaMKII pharmacological activation","journal":"The Journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP + RNAi + surface expression assay + pharmacological validation, single lab","pmids":["25834051"],"is_preprint":false},{"year":2013,"finding":"DLG1 is an anchor for the MARCH2 E3 ubiquitin ligase at cell-cell contact sites via PDZ domain interaction; MARCH2 promotes ubiquitination of DLG1 in vivo.","method":"Tandem affinity purification + mass spectrometry; co-immunoprecipitation; in vivo ubiquitination assay; immunofluorescence with PDZ-motif deletion","journal":"Cellular signalling","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — TAP-MS + co-IP + ubiquitination assay, single lab, multiple methods","pmids":["17980554"],"is_preprint":false},{"year":2013,"finding":"SAP97 governs ADAM10 trafficking from dendritic Golgi outposts to synaptic membranes in hippocampal neurons; this process requires PKC phosphorylation of SAP97's SH3 domain, which modulates SAP97-ADAM10 association. This mechanism is altered in Alzheimer's disease brains.","method":"Co-immunoprecipitation; phosphosite mapping; PKC inhibitor/activator treatment; siRNA knockdown; confocal imaging","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP + phosphosite identification + functional trafficking assay, single lab","pmids":["25429624"],"is_preprint":false},{"year":2014,"finding":"Dlg1 is localized at the basolateral cell cortex during mitosis and directly interacts with LGN, promoting cortical localization of the LGN complex to control planar spindle orientation in the chick neuroepithelium and human cells.","method":"Live imaging of spindle movements; RNAi knockdown; co-immunoprecipitation; overexpression on adhesive micropatterns","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct binding assay (co-IP) + live imaging of spindle dynamics + RNAi in multiple systems (chick and human), multiple methods","pmids":["25202028"],"is_preprint":false},{"year":2014,"finding":"Cardiac-specific SAP97 ablation in mice decreases IK1, Ito, and IKur potassium currents and prolongs action potential duration without affecting INa, confirming SAP97's role in regulating potassium channel function in vivo.","method":"Cardiac-specific Cre-lox knockout; patch clamp; ECG; immunostaining","journal":"Heart rhythm","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic cardiac-specific KO + patch clamp + ECG, multiple orthogonal methods, in vivo model","pmids":["25447080"],"is_preprint":false},{"year":2016,"finding":"Pten recruits Dlg1-Eg5 complexes to pre-mitotic centrosomes via its PDZ-binding domain; Eg5 phosphorylation by Nek9-Nek6 and Cdk1 kinases is required for docking onto Pten-Dlg1. Dlg1 ablation impairs Eg5 loading onto centrosomes and spindle pole motility, causing asymmetric spindles and chromosome missegregation.","method":"Co-immunoprecipitation; mouse genetic models (PDZ-BD deletion, Dlg1 ablation); centrosome fractionation; live imaging of spindle poles; aneuploidy assays","journal":"Nature cell biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple genetic models + co-IP + centrosome fractionation + live imaging + functional segregation readout, high-quality multi-method study","pmids":["27240320"],"is_preprint":false},{"year":2016,"finding":"In Schwann cells, Kif13b kinesin promotes p38γ MAPK-mediated phosphorylation and ubiquitination of Dlg1, downregulating Dlg1 and the PI3K/AKT pathway. In oligodendrocytes, Kif13b negatively regulates Dlg1 stability; Dlg1 in that context enhances AKT activation and myelination.","method":"Kif13b conditional knockout mice; immunoprecipitation; phosphorylation and ubiquitination assays; AKT pathway analysis","journal":"PLoS biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — conditional KO + biochemical phosphorylation/ubiquitination assays, single lab, cell-type-specific effects","pmids":["27070899"],"is_preprint":false},{"year":2019,"finding":"Vascular endothelial cell-specific loss of Dlg1 impairs β-catenin (canonical Wnt) signaling in the retina. Dlg1 transfection in reporter cells with Dlg1 inactivation enhances β-catenin signaling ~4-fold; the retinal vascular phenotype is rescued by stabilizing β-catenin in ECs.","method":"EC-specific Cre-lox knockout; genetic epistasis with β-catenin signaling components; CRISPR/Cas9 inactivation in reporter cells; β-catenin stabilization rescue","journal":"eLife","confidence":"High","confidence_rationale":"Tier 2 / Strong — conditional KO + genetic epistasis + CRISPR reporter cells + rescue experiments, multiple orthogonal methods","pmids":["31066677"],"is_preprint":false},{"year":2019,"finding":"SGEF forms a ternary complex with Scribble and Dlg1; SGEF targets to apical junctions in a Scribble-dependent manner and regulates actomyosin contractility and barrier function through RhoG activation coordinated by the Scribble-Dlg1 scaffold.","method":"Co-immunoprecipitation; RNAi knockdown; 3D cyst assay; immunofluorescence; Scribble-dependent targeting assay","journal":"The Journal of cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP confirming ternary complex + RNAi with functional readouts, single lab","pmids":["31248911"],"is_preprint":false},{"year":2020,"finding":"SAP97 maintains cardiac β1AR signaling integrity by scaffolding β1AR; GRK5 promotes agonist-induced dissociation of SAP97 from β1AR. Loss of SAP97 shifts β1AR toward arrestin2-CaMKII association and activates Epac-dependent CaMKII, causing cardiac remodeling.","method":"Cardiac-specific SAP97 deletion; co-immunoprecipitation; CaMKII activity assays; cardiac function measurements; GRK5 deletion epistasis","journal":"Circulation research","confidence":"High","confidence_rationale":"Tier 2 / Strong — cardiac-specific KO + GRK5 epistasis + co-IP + CaMKII activity + functional cardiac phenotype, multiple methods","pmids":["32507058"],"is_preprint":false}],"current_model":"DLG1/SAP97 is a multi-domain MAGUK scaffolding protein that uses its PDZ1, PDZ2, and PDZ3 domains to cluster and traffic ion channels (AMPA/NMDA glutamate receptors, Kv1.5, Kv4.2/4.3, Kir2.x, Nav1.5) and signaling proteins (APC, CASK, GKAP, AKAP79, ADAM10, CRFR1, β1AR) at synapses, epithelial junctions, and cardiomyocyte membrane domains; its N-terminal L27 domain controls CASK-dependent conformational switching between compact (AMPAR-preferring) and extended (NMDAR-preferring) states and mediates multimerization; CaMKII phosphorylation of Ser39 drives SAP97 to the postsynaptic compartment while Ser232 phosphorylation disrupts NR2A binding to trigger receptor insertion; p38γ phosphorylation releases SAP97 from cytoskeletal GKAP tethering; PKCα and PKC phosphorylation at SH3-domain sites regulate cell migration and ADAM10 trafficking, respectively; in dividing cells Dlg1 recruits LGN to the basolateral cortex for planar spindle orientation and recruits Eg5 to centrosomes via Pten-PDZ-BD to establish bipolar spindles; in T cells Dlg1 scaffolds alternative p38-NFAT signaling and coordinates immune synapse actin/TCR organization; and in the heart, cardiac-specific Dlg1 ablation selectively reduces potassium currents and prolongs action potential duration."},"narrative":{"mechanistic_narrative":"DLG1 (hDlg/SAP97) is a multidomain MAGUK scaffolding protein that organizes membrane signaling microdomains at epithelial junctions, neuronal synapses, the immune synapse, the mitotic cortex, and the cardiomyocyte membrane by clustering and trafficking transmembrane receptors and channels through its three PDZ domains, SH3 region, and a catalytically inactive guanylate kinase-like (GK) domain [PMID:7937897, PMID:9523702]. Subcellular targeting and cytoskeletal attachment are governed by an N-terminal region and alternatively spliced inserts: the unique SAP97 N-terminus and the I3 insert direct it to the epithelial lateral membrane and cell-cell contacts via protein 4.1/ERM and the CASK/MPP7-LIN7 L27-domain complexes, while the I2 insert directs nuclear localization [PMID:8922391, PMID:9683631, PMID:11723125, PMID:11865057, PMID:17237226]. In neurons, SAP97 binds the AMPA receptor subunit GluA1 (PDZ-dependent) and the NMDA receptor subunit NR2A (PDZ1), and its CASK-controlled monomer-dimer/compact-extended conformational switch sorts these receptors: compact SAP97 favors GluA1-AMPARs while CASK-bound extended SAP97 favors GluN2B-NMDARs [PMID:9677374, PMID:12933808, PMID:15504326, PMID:23864692]. CaMKII phosphorylation orchestrates this trafficking, driving SAP97 to the postsynaptic compartment via Ser39 and disrupting NR2A binding via Ser232 to trigger receptor insertion [PMID:12933808, PMID:17156128]; SAP97 and CASK route NMDARs through a specialized dendritic ER/Golgi-outpost pathway [PMID:19620977]. Distinct palmitoylated alpha and L27-containing beta isoforms partition AMPARs into subsynaptic domains and exert opposite effects on synaptic potentiation [PMID:19357261, PMID:21768261]. In epithelia DLG1 couples to E-cadherin-based junctions, is stabilized by cell contact and degraded by the proteasome, and its release from cytoskeletal GKAP tethering is triggered by p38gamma phosphorylation during osmotic stress [PMID:9512503, PMID:11739660, PMID:15729360]; it further scaffolds Scribble-SGEF-RhoG to control actomyosin contractility and barrier function [PMID:31248911] and is required for canonical Wnt/beta-catenin signaling in retinal endothelium [PMID:31066677]. In dividing cells DLG1 localizes to the basolateral cortex and binds LGN to orient the mitotic spindle, and is recruited by PTEN with Eg5 to centrosomes to build bipolar spindles and ensure faithful chromosome segregation [PMID:25202028, PMID:27240320]. In T cells DLG1 scaffolds an Lck-Zap70-WASp complex and an alternative p38-NFAT signaling pathway at the immune synapse, dependent on ezrin-controlled localization [PMID:15699074, PMID:17187070, PMID:20551903]. In the heart DLG1 anchors potassium channels (Kv4.x, Kir2.x, Kv1.5) and the sodium channel Nav1.5, and cardiac-specific ablation selectively reduces potassium currents and prolongs action potential duration while leaving INa intact [PMID:19213956, PMID:21164104, PMID:25447080]; it also maintains beta1-adrenergic receptor signaling integrity, with loss shifting beta1AR toward arrestin-CaMKII signaling and cardiac remodeling [PMID:32507058]. DLG1 is additionally targeted by viral oncoproteins (Ad9 ORF1, HTLV-1 Tax, HPV-18 E6) through PDZ-binding motifs, and Tax binding disrupts the DLG1-APC interaction that underlies DLG1-mediated G0/G1 cell-cycle arrest [PMID:9192623, PMID:10557085, PMID:10656683, PMID:17713926].","teleology":[{"year":1994,"claim":"Establishing DLG1's domain architecture and its association with the membrane-cytoskeleton adaptor protein 4.1 defined it as a junction-localized scaffold rather than an enzyme.","evidence":"cDNA cloning, in vitro binding with recombinant protein 4.1, and immunolocalization","pmids":["7937897"],"confidence":"Medium","gaps":["Did not define which PDZ domains engage transmembrane partners","No functional consequence of 4.1 binding established"]},{"year":1996,"claim":"Domain dissection showed that the PDZ1-2 unit and the alternatively spliced I3 insert provide redundant targeting routes binding 4.1/ERM and T/SXV-motif partners, explaining how DLG1 reaches cell-cell contacts.","evidence":"In vitro domain binding, domain-deletion localization in permeabilized cells, and co-IP of 4.1 and ezrin","pmids":["8922391"],"confidence":"High","gaps":["Did not identify the physiological transmembrane ligands at junctions","Conformational regulation of targeting unaddressed"]},{"year":1998,"claim":"Resolving the unique SAP97 N-terminal 65 residues as the primary lateral-membrane targeting determinant, and demonstrating the GK domain lacks guanylate kinase activity, recast DLG1 as a localization-driven, enzymatically inert scaffold; concurrent identification of GluA1 binding linked it to glutamate receptors.","evidence":"Domain-deletion mutagenesis with fractionation/IF; in vitro GK enzymatic assay; co-IP of GluR1 from rat brain with recombinant binding","pmids":["9683631","9523702","9677374"],"confidence":"High","gaps":["Mechanism coupling the N-terminus to the cytoskeleton not resolved","GluA1 binding specificity vs other AMPAR subunits explained but trafficking role not yet shown"]},{"year":1997,"claim":"Discovery that viral oncoproteins (Ad9 ORF1, HTLV-1 Tax, HPV-18 E6) bind DLG1 PDZ domains, and that DLG1 binds APC and arrests the cell cycle, established a tumor-suppressor axis disrupted by viral hijacking.","evidence":"Library screen, in vitro/in vivo binding, co-IP from infected T cells, and BrdU/cell-cycle assays with domain mutants","pmids":["9192623","9286858","10557085","10656683"],"confidence":"High","gaps":["How APC binding mechanistically blocks G1/S transition not defined","Endogenous (non-viral) regulators of the DLG1-APC axis unknown"]},{"year":2000,"claim":"Identifying CASK GUK-SH3 binding and demonstrating that SAP97 retains Kv1 channels in the ER while distinct from PSD-95 revealed DLG1 as a biosynthetic-trafficking scaffold, not merely a surface-clustering one.","evidence":"Yeast two-hybrid, GST binding, co-IP, and heterologous channel surface/IF analysis","pmids":["10993877","10629225"],"confidence":"Medium","gaps":["Whether ER retention reflects a regulated trafficking checkpoint not established","CASK's role in DLG1 conformation not yet probed"]},{"year":2001,"claim":"Mapping channel partners (Kir2.x via PDZ2, Kv1.5 via TDL motif) and the conserved CASK L27N-SAP97 N-terminal interaction tied DLG1 to cardiac/epithelial channel localization and defined the L27 module controlling targeting and oligomerization.","evidence":"GST pulldown from native tissue, co-IP, mutagenesis, oocyte patch clamp, dominant-negative CASK in MDCK, and Drosophila conservation","pmids":["11181181","11709425","11865057","11723125","11694581"],"confidence":"High","gaps":["Whether PKA regulation of channel binding occurs in vivo not shown","Stoichiometry of the SAP97-CASK-channel complex undefined"]},{"year":2003,"claim":"Demonstrating CaMKII phosphorylation of SAP97 Ser232 within PDZ1 disrupts NR2A binding provided the first phosphoregulatory switch coupling kinase activity to receptor release.","evidence":"In vitro pulldown, co-IP from synaptosomes, metabolic labeling, CaMKII inhibition, and phosphomimetic mutants","pmids":["12933808"],"confidence":"High","gaps":["Did not connect the switch to receptor surface insertion","Other CaMKII sites and their order unresolved"]},{"year":2004,"claim":"Linking the L27-controlled monomer-dimer transition to AMPAR synaptic delivery and LTP, while RNAi knockdown impaired AMPA and NMDA transmission, established SAP97 multimerization as functionally required for synaptic strength.","evidence":"Single-particle EM, RNAi, EPSC electrophysiology, L27 mutants, and FRAP","pmids":["15504326"],"confidence":"High","gaps":["Direct structural basis of the compact-extended switch not yet visualized","Redundancy with other PSD-MAGUKs not assessed"]},{"year":2005,"claim":"Identifying p38gamma phosphorylation as the trigger releasing SAP97 from GKAP/cytoskeleton, and the Cdc42-Par6-PKCzeta pathway promoting DLG1-APC for migratory microtubule polarization, extended DLG1 regulation to stress responses and directed cell migration.","evidence":"In vitro kinase assays, co-IP, phosphosite mapping, osmotic stress, RNAi, and TIRF imaging in astrocytes","pmids":["15729360","16157700"],"confidence":"High","gaps":["How GKAP release alters junctional integrity mechanistically not fully defined","Direct kinase-substrate stoichiometry in migration unresolved"]},{"year":2006,"claim":"Defining isoform-specific synaptic roles (palmitoylated alpha vs L27 beta) and the requirement of DLG1 for TCR-induced alternative p38-NFAT signaling and immune-synapse organization broadened DLG1 into activity-dependent and immune scaffolding.","evidence":"Isoform rescue electrophysiology with CaMKII inhibition; siRNA/mutant rescue with NFAT reporters; Lck/Zap70/WASp co-IP and imaging; AKAP79-beta1AR PKA scaffold co-IP","pmids":["16815335","17187070","15699074","17170109","17156128"],"confidence":"High","gaps":["How a single scaffold selectively activates p38-NFAT but not JNK/NF-kB not mechanistically resolved","Isoform expression regulation in vivo unaddressed"]},{"year":2007,"claim":"Structural and partner-mapping work (PDZ2-E6 NMR with non-canonical six-residue binding, TACE/ADAM17 via PDZ3, Delta1, MPP7-LIN7 L27 complex) detailed the diverse PDZ/L27 engagement modes underlying DLG1 specificity.","evidence":"NMR/ITC, yeast two-hybrid, co-IP, domain deletions, and shedding/migration assays","pmids":["17713926","12668732","15485825","17237226","17435047"],"confidence":"High","gaps":["Whether the non-canonical PDZ2 mode generalizes to endogenous ligands unclear","Knockout urogenital phenotype mechanism (proliferation vs junctions) not molecularly explained"]},{"year":2009,"claim":"Defining a specialized SAP97-CASK NMDAR ER/Golgi-outpost trafficking route, the cardiac SAP97-Kv4-CaMKII complex, the AKAP79 splice-variant phosphoswitch, and GluA1-driven membrane translocation integrated DLG1 into compartment-specific receptor and channel delivery.","evidence":"Live imaging, RNAi, fractionation, co-IP from cardiomyocytes, patch clamp, GST binding, and dendritic morphometry","pmids":["19620977","19213956","19858198","18842882","19357261","19895665"],"confidence":"High","gaps":["Molecular machinery routing cargo to dendritic Golgi outposts not fully defined","Relative contributions of multiple CaMKII sites in vivo unresolved"]},{"year":2010,"claim":"Cardiac Nav1.5 anchoring at intercalated discs, the Cdc42-Dlg1-GKAP-dynein control of centrosome positioning, ezrin-dependent immune-synapse localization, and conditional-KO redundancy with PSD-MAGUKs delineated context-specific essential and dispensable roles.","evidence":"Pulldown, RNAi, patch clamp, mdx comparison, live imaging, co-IP, and conditional KO with rescue electrophysiology","pmids":["21164104","21041448","20551903","20133708"],"confidence":"High","gaps":["Compensating MAGUKs in mature neurons not identified at the molecular level","How DLG1 partitions Nav1.5 between intercalated discs and lateral membrane not resolved"]},{"year":2013,"claim":"Direct demonstration that CASK binding stabilizes an extended SAP97 conformation preferring GluN2B-NMDARs while compact SAP97 prefers GluA1-AMPARs provided the conformational logic for differential receptor sorting; parallel work added EAAT2b, MARCH2-mediated ubiquitination, and PKC-dependent ADAM10 trafficking.","evidence":"Intramolecular FRET sensors, co-IP, colocalization, surface biotinylation, TAP-MS, and ubiquitination assays","pmids":["23864692","25834051","17980554","25429624"],"confidence":"High","gaps":["What sets the equilibrium between compact and extended states in vivo unclear","Physiological MARCH2-DLG1 turnover regulation not established"]},{"year":2014,"claim":"Identifying direct Dlg1-LGN binding for planar spindle orientation established DLG1 as a cortical determinant linking the cell-cortex scaffold to mitotic machinery.","evidence":"Live spindle imaging, RNAi in chick and human cells, co-IP, and micropattern overexpression","pmids":["25202028"],"confidence":"High","gaps":["Upstream cues localizing Dlg1 to the basolateral cortex during mitosis not defined","Relationship to the PTEN-Eg5 centrosomal role not yet integrated"]},{"year":2016,"claim":"Demonstrating PTEN-dependent recruitment of Dlg1-Eg5 to centrosomes for bipolar spindle assembly, and Kif13b/p38gamma-controlled Dlg1 stability regulating PI3K/AKT in glia, expanded DLG1 into centrosomal spindle control and myelination-linked AKT signaling.","evidence":"Genetic mouse models, co-IP, centrosome fractionation, live imaging, aneuploidy assays, and conditional Kif13b KO with phospho/ubiquitination analysis","pmids":["27240320","27070899"],"confidence":"High","gaps":["How DLG1 mechanically supports spindle-pole motility not fully resolved","Cell-type-specific opposite outcomes of Dlg1 turnover not mechanistically reconciled"]},{"year":2019,"claim":"Showing endothelial Dlg1 is required for canonical Wnt/beta-catenin signaling and that Dlg1 scaffolds Scribble-SGEF-RhoG for actomyosin/barrier control connected DLG1 to developmental signaling and junctional contractility.","evidence":"EC-specific KO, genetic epistasis, CRISPR reporter cells, beta-catenin rescue, co-IP, and 3D cyst assays","pmids":["31066677","31248911"],"confidence":"High","gaps":["Direct molecular link between Dlg1 and the beta-catenin destruction complex not defined","Whether Scribble-Dlg1-SGEF acts in vivo at endothelial junctions untested"]},{"year":2020,"claim":"Cardiac-specific KO work showed SAP97 maintains beta1AR signaling fidelity, with GRK5-driven dissociation shifting beta1AR toward arrestin-CaMKII and Epac-CaMKII activation and pathological remodeling, defining a protective cardiac signaling role.","evidence":"Cardiac-specific deletion, GRK5 epistasis, co-IP, CaMKII activity assays, and cardiac function measurements","pmids":["32507058"],"confidence":"High","gaps":["How SAP97 biases beta1AR away from arrestin coupling structurally unresolved","Therapeutic exploitability of the SAP97-beta1AR axis untested"]},{"year":null,"claim":"How DLG1's conformational state, isoform/splice composition, and phosphorylation code are integrated to select among its many partners within a single cell remains the central open question.","evidence":"","pmids":[],"confidence":"High","gaps":["No unified structural model of how PDZ/L27/SH3-GK states combinatorially set partner choice","Quantitative rules governing tissue-specific partner selection not established"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[2,19,22,33,48]},{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[0,2,6,7,45]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[12,18,20,30,58]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[1,7,14,36,42]},{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[12,18,29,38]},{"term_id":"GO:0005815","term_label":"microtubule organizing center","supporting_discovery_ids":[45,54]},{"term_id":"GO:0005856","term_label":"cytoskeleton","supporting_discovery_ids":[6,7,24,25]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[15]}],"pathway":[{"term_id":"R-HSA-112316","term_label":"Neuronal System","supporting_discovery_ids":[5,22,27,38,48]},{"term_id":"R-HSA-1640170","term_label":"Cell Cycle","supporting_discovery_ids":[11,52,54]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[26,28,43]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[25,30,56,58]},{"term_id":"R-HSA-397014","term_label":"Muscle contraction","supporting_discovery_ids":[39,42,53]},{"term_id":"R-HSA-9609507","term_label":"Protein localization","supporting_discovery_ids":[12,23,38,42,51]}],"complexes":["SAP97-CASK-Veli-Mint1 channel trafficking complex","MPP7-LIN7-DLG1 L27 complex","Scribble-Dlg1-SGEF complex","Lck-Dlg1-Zap70-WASp immune synapse complex"],"partners":["CASK","GKAP","GRIA1","GRIN2A","LGN","APC","AKAP79","EZR"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q12959","full_name":"Disks large homolog 1","aliases":["Synapse-associated protein 97","SAP-97","SAP97","hDlg"],"length_aa":904,"mass_kda":100.5,"function":"Essential multidomain scaffolding protein required for normal development (By similarity). Recruits channels, receptors and signaling molecules to discrete plasma membrane domains in polarized cells. Promotes epithelial cell layer barrier function via maintaining cell-cell adhesion (By similarity). May also play a role in adherens junction assembly, signal transduction, cell proliferation, synaptogenesis and lymphocyte activation. Regulates the excitability of cardiac myocytes by modulating the functional expression of Kv4 channels. Functional regulator of Kv1.5 channel. During long-term depression in hippocampal neurons, it recruits ADAM10 to the plasma membrane (PubMed:23676497)","subcellular_location":"Cell membrane; Basolateral cell membrane; Endoplasmic reticulum membrane; Postsynaptic density; Synapse; Cell membrane, sarcolemma; Apical cell membrane; Cell junction; Cytoplasm","url":"https://www.uniprot.org/uniprotkb/Q12959/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/DLG1","classification":"Not Classified","n_dependent_lines":3,"n_total_lines":1208,"dependency_fraction":0.0024834437086092716},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"SRP9","stoichiometry":10.0},{"gene":"PSPC1","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/DLG1","total_profiled":1310},"omim":[{"mim_id":"621476","title":"APICAL JUNCTION COMPONENT 1 HOMOLOG; AJM1","url":"https://www.omim.org/entry/621476"},{"mim_id":"618597","title":"BRAIN-ENRICHED GUANYLATE KINASE-ASSOCIATED PROTEIN; BEGAIN","url":"https://www.omim.org/entry/618597"},{"mim_id":"617859","title":"DISCS LARGE-ASSOCIATED PROTEIN 5; DLGAP5","url":"https://www.omim.org/entry/617859"},{"mim_id":"616191","title":"DISCS LARGE-ASSOCIATED PROTEIN 4; DLGAP4","url":"https://www.omim.org/entry/616191"},{"mim_id":"612808","title":"LEUCINE-RICH REPEAT AND FIBRONECTIN TYPE III DOMAIN-CONTAINING PROTEIN 2; LRFN2","url":"https://www.omim.org/entry/612808"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Vesicles","reliability":"Approved"},{"location":"Plasma membrane","reliability":"Additional"},{"location":"Basal body","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in 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signalling","url":"https://pubmed.ncbi.nlm.nih.gov/17980554","citation_count":30,"is_preprint":false},{"pmid":"30349305","id":"PMC_30349305","title":"Circ-DLG1 promotes the proliferation of esophageal squamous cell carcinoma.","date":"2018","source":"OncoTargets and therapy","url":"https://pubmed.ncbi.nlm.nih.gov/30349305","citation_count":29,"is_preprint":false},{"pmid":"11122378","id":"PMC_11122378","title":"The hDLG-associated protein DAP interacts with dynein light chain and neuronal nitric oxide synthase.","date":"2000","source":"Genes to cells : devoted to molecular & cellular mechanisms","url":"https://pubmed.ncbi.nlm.nih.gov/11122378","citation_count":28,"is_preprint":false},{"pmid":"21850710","id":"PMC_21850710","title":"Mutation screening of the 3q29 microdeletion syndrome candidate genes DLG1 and PAK2 in schizophrenia.","date":"2011","source":"American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/21850710","citation_count":28,"is_preprint":false},{"pmid":"30517074","id":"PMC_30517074","title":"Differential expression of DLG1 as a common trait in different human diseases: an encouraging issue in molecular pathology.","date":"2019","source":"Biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/30517074","citation_count":27,"is_preprint":false},{"pmid":"22657348","id":"PMC_22657348","title":"A functional interaction between the MAGUK protein hDlg and the gap junction protein connexin 43 in cervical tumour cells.","date":"2012","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/22657348","citation_count":27,"is_preprint":false},{"pmid":"12405965","id":"PMC_12405965","title":"Synaptic glutamate receptor clustering in mice lacking the SH3 and GK domains of SAP97.","date":"2002","source":"The European journal of neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/12405965","citation_count":27,"is_preprint":false},{"pmid":"23661808","id":"PMC_23661808","title":"Scaffolding proteins DLG1 and CASK cooperate to maintain the nephron progenitor population during kidney development.","date":"2013","source":"Journal of the American Society of Nephrology : JASN","url":"https://pubmed.ncbi.nlm.nih.gov/23661808","citation_count":26,"is_preprint":false},{"pmid":"34490521","id":"PMC_34490521","title":"Dlg1 Knockout Inhibits Microglial Activation and Alleviates Lipopolysaccharide-Induced Depression-Like Behavior in Mice.","date":"2021","source":"Neuroscience bulletin","url":"https://pubmed.ncbi.nlm.nih.gov/34490521","citation_count":25,"is_preprint":false},{"pmid":"23576434","id":"PMC_23576434","title":"Role of SAP97 protein in the regulation of corticotropin-releasing factor receptor 1 endocytosis and extracellular signal-regulated kinase 1/2 signaling.","date":"2013","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/23576434","citation_count":25,"is_preprint":false},{"pmid":"17042961","id":"PMC_17042961","title":"Inactivation of tumor suppressor Dlg1 augments transformation of a T-cell line induced by human T-cell leukemia virus type 1 Tax protein.","date":"2006","source":"Retrovirology","url":"https://pubmed.ncbi.nlm.nih.gov/17042961","citation_count":25,"is_preprint":false},{"pmid":"35039052","id":"PMC_35039052","title":"The SF3B1R625H mutation promotes prolactinoma tumor progression through aberrant splicing of DLG1.","date":"2022","source":"Journal of experimental & clinical cancer research : CR","url":"https://pubmed.ncbi.nlm.nih.gov/35039052","citation_count":24,"is_preprint":false},{"pmid":"33945310","id":"PMC_33945310","title":"Whole-Exome Sequencing Identified DLG1 as a Candidate Gene for Familial Exudative Vitreoretinopathy.","date":"2021","source":"Genetic testing and molecular biomarkers","url":"https://pubmed.ncbi.nlm.nih.gov/33945310","citation_count":24,"is_preprint":false},{"pmid":"32507058","id":"PMC_32507058","title":"GRK5 Controls SAP97-Dependent Cardiotoxic β1 Adrenergic Receptor-CaMKII Signaling in Heart Failure.","date":"2020","source":"Circulation research","url":"https://pubmed.ncbi.nlm.nih.gov/32507058","citation_count":23,"is_preprint":false},{"pmid":"18793635","id":"PMC_18793635","title":"Regulation of the hDlg/hScrib/Hugl-1 tumour suppressor complex.","date":"2008","source":"Experimental cell research","url":"https://pubmed.ncbi.nlm.nih.gov/18793635","citation_count":23,"is_preprint":false},{"pmid":"17574238","id":"PMC_17574238","title":"Changes in localization of human discs large (hDlg) during keratinocyte differentiation are [corrected] associated with expression of alternatively spliced hDlg variants.","date":"2007","source":"Experimental cell 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Neuropsychopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/26149358","citation_count":23,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":49656,"output_tokens":13540,"usd":0.176034,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":25297,"output_tokens":7309,"usd":0.154605,"stage2_stop_reason":"end_turn"},"total_usd":0.330639,"stage1_batch_id":"msgbatch_01AsR7g8dGTEiEw9U83bJeWn","stage2_batch_id":"msgbatch_01YV5ZyxtFNUZEjxRcpd9jzb","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1994,\n      \"finding\": \"hDlg (DLG1) contains three PDZ domains, an SH3 region, and a guanylate kinase-like domain. Two sites within hDlg associate in vitro with the 30-kDa N-terminal domain of protein 4.1, and the protein localizes to regions of cell-cell contact.\",\n      \"method\": \"In vitro binding assay with recombinant proteins; cDNA cloning and sequencing; immunolocalization\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct in vitro binding with defined domains, single lab, two orthogonal methods (binding assay + localization)\",\n      \"pmids\": [\"7937897\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"SAP97 localizes at the presynaptic nerve termini of excitatory synapses in hippocampus and at basolateral membranes of epithelial cells, suggesting a role in the site-specific assembly of membrane specializations at cell-cell contacts.\",\n      \"method\": \"Light and immunoelectron microscopy of rat hippocampal formation and epithelial cells\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — immunoelectron microscopy with multiple tissue types, single lab\",\n      \"pmids\": [\"7891172\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"DLG1 subcellular targeting requires either the PDZ1-2 conformational unit (which binds protein 4.1/ERM proteins and T/SXV motif-containing proteins) or the alternatively spliced I3 domain (which binds exclusively 4.1/ERM proteins). Both protein 4.1 and ezrin interact with DLG1 in co-precipitating immune complexes.\",\n      \"method\": \"In vitro binding assays with recombinant protein domains; in situ localization of domain constructs in permeabilized cells; co-immunoprecipitation\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — reconstitution with defined domain deletions + co-IP + cell localization, multiple orthogonal methods in one study\",\n      \"pmids\": [\"8922391\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"Adenovirus 9ORF1 oncoprotein interacts directly with the second PDZ domain of hDlg/SAP97 in vitro and in vivo. HTLV-1 Tax and HPV-18 E6 oncoproteins also bind DLG1 in vitro via their C-terminal PDZ-binding motifs.\",\n      \"method\": \"Lambda gt11 library screen; in vitro binding assays; co-immunoprecipitation from cells\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal in vitro and in vivo binding, multiple viral proteins tested, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"9192623\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"DAP-1 (GKAP/SAPAP) binds to the guanylate kinase-like domains of hDLG and PSD-95, and associates with hDLG, NMDA receptors, and APC protein; it colocalizes with PSD-95 and NMDA receptors at synapses.\",\n      \"method\": \"Yeast two-hybrid; co-immunoprecipitation; immunofluorescence colocalization\",\n      \"journal\": \"Genes to cells\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — yeast two-hybrid confirmed by co-IP and colocalization, single lab\",\n      \"pmids\": [\"9286858\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"SAP97 directly associates with the C terminus of GluR1 (AMPA receptor subunit) via its PDZ domains, but not with GluR2 or GluR3; SAP97 was present in AMPA receptor complexes immunoprecipitated from rat brain.\",\n      \"method\": \"Co-immunoprecipitation from rat brain; in vitro binding with recombinant proteins; cross-linking experiments\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — in vitro reconstitution with recombinant proteins + co-IP from brain, multiple orthogonal methods, independently replicated\",\n      \"pmids\": [\"9677374\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"The first 65 amino acid residues unique to SAP97 (absent from PSD-95/SAP90 and SAP102) direct selective subcellular localization to the epithelial lateral membrane and mediate cytoskeletal attachment; PDZ1-2 domains and I3 insert affect efficiency but are not essential for targeting.\",\n      \"method\": \"Domain deletion mutagenesis; subcellular fractionation; immunofluorescence in epithelial cells\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — systematic domain deletion mutagenesis with multiple constructs, direct localization readout, single lab but multiple orthogonal methods\",\n      \"pmids\": [\"9683631\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"SAP97 is recruited to sites of E-cadherin-mediated cell-cell contact via an E-cadherin-induced assembly of the cortical cytoskeleton; SAP97 associates with the E-cadherin/catenin complex indirectly through cytoskeletal attachment.\",\n      \"method\": \"Immunofluorescence in epithelial CACO-2 cells and L-cells; biochemical fractionation; E-cadherin induction assays\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct cell biological experiments with E-cadherin induction, single lab, two methods\",\n      \"pmids\": [\"9512503\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"The guanylate kinase-like (GK) domain of SAP97 does not encode an active guanylate kinase — it lacks enzymatic activity and cannot be activated by GKAP; flanking regions do not act as inhibitory regulators.\",\n      \"method\": \"In vitro enzymatic assay; biochemical analysis of recombinant GK domain\",\n      \"journal\": \"European journal of biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct in vitro enzymatic assay, definitive negative result for catalytic activity, single lab\",\n      \"pmids\": [\"9523702\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"HTLV-1 Tax binds hDLG via the C-terminus of Tax and the PDZ domain of hDLG; Tax binding to hDLG prevents its interaction with APC, and co-expression of Tax suppresses hDLG-mediated cell cycle arrest (G0/G1 inhibition of BrdU incorporation).\",\n      \"method\": \"Yeast two-hybrid; in vitro binding; co-immunoprecipitation from HTLV-1-infected T-cells; microinjection/BrdU incorporation assay\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (yeast 2H, in vitro, co-IP, functional assay), replicated in infected T-cells\",\n      \"pmids\": [\"10557085\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"NR2A subunit C-terminal tSXV motif binds PDZ domains of SAP97 in yeast two-hybrid; upstream sequences beyond the tSXV motif are required for efficient interaction. NR1-3 and NR1-4, despite having tSXV motifs, do not interact with SAP97.\",\n      \"method\": \"Yeast two-hybrid; site-directed mutagenesis; immunohistochemistry\",\n      \"journal\": \"The European journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — yeast two-hybrid with mutagenesis, single lab, defined binding requirements\",\n      \"pmids\": [\"10336672\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Overexpression of hDLG suppresses cell proliferation by blocking G0/G1 to S phase transition. This activity requires intact PDZ, SH3, and GK domains of hDLG, and is partially dependent on interaction with APC via its C-terminal S/TXV motif.\",\n      \"method\": \"Overexpression and domain mutant analysis; cell cycle analysis; APC co-expression studies\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — domain mutagenesis with functional cell cycle readout, single lab, multiple domain mutants tested\",\n      \"pmids\": [\"10656683\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"SAP97 interacts with Kv1 potassium channels intracellularly and prevents biosynthetic trafficking, causing intracellular accumulation of Kv1 channels in ER-derived vesicles — distinct from PSD-95, which clusters channels at the plasma membrane.\",\n      \"method\": \"Co-expression in heterologous cells; immunofluorescence; cell surface expression analysis\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — comparative analysis of SAP97 vs PSD-95, distinct intracellular mechanism shown, single lab\",\n      \"pmids\": [\"10629225\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"hCASK GUK domain binds the SH3 domain of hDlg; both proteins colocalize at basolateral epithelial membranes and co-precipitate from intestinal cell lysates. SH3 and GUK domains also participate in intramolecular interactions within each MAGUK.\",\n      \"method\": \"Yeast two-hybrid; GST fusion protein binding assays; co-immunoprecipitation; immunofluorescence\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — yeast two-hybrid confirmed by in vitro binding and co-IP, single lab, multiple orthogonal methods\",\n      \"pmids\": [\"10993877\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"SAP97 interacts with Kir2.1, Kir2.2, and Kir2.3 channels via the C-terminal SEI motif of Kir2.2 and the second PDZ domain of SAP97; PKA phosphorylation of the Kir2.2 C-terminus inhibits SAP97 association. Kir2.2 and SAP97 colocalize at T-tubules in cardiac ventricular myocytes.\",\n      \"method\": \"GST affinity pulldown from rat brain/heart; co-immunoprecipitation; mutagenesis; immunofluorescence\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — pulldown + co-IP from native tissue + mutagenesis + functional PKA regulation + localization, multiple orthogonal methods\",\n      \"pmids\": [\"11181181\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"The I3 alternatively spliced insertion targets hDlg to cell-cell contact membranes; I2 insertion targets it to the nucleus. The N-terminal alternatively spliced region binds SH3 domains and moderates protein oligomerization.\",\n      \"method\": \"Expression of isoform constructs; immunofluorescence localization; in vitro binding assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — systematic isoform expression with localization readout, single lab, two methods\",\n      \"pmids\": [\"11723125\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"C. elegans DLG-1 (most similar to SAP97) localizes to adherens junctions via its N-terminal domain and recruits AJM-1 and CPI-1 to adherens junctions; loss of DLG-1 disrupts actin cytoskeleton organization and embryo elongation without affecting cell polarity.\",\n      \"method\": \"Genetic knockout in C. elegans; immunofluorescence; GFP localization; domain deletion analysis\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic loss-of-function in vivo with defined molecular and morphological phenotypes, domain analysis, multiple readouts\",\n      \"pmids\": [\"11694581\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"hDlg is degraded via the proteasome, and upon cell-cell contact is hyper-phosphorylated and stabilized. In transformed and undifferentiated cervical cancer cells this contact-dependent stabilization is lost.\",\n      \"method\": \"Proteasome inhibitor treatment; western blot; immunofluorescence in epithelial cell lines at varying density\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — pharmacological and cell-density manipulation experiments, two methods, single lab\",\n      \"pmids\": [\"11739660\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"SAP97 interacts with Kv1.5 potassium channel via the channel's C-terminal TDL motif; SAP97-Kv1.5 complexes are retained in the ER of COS-7 cells but SAP97 coexpression augments Kv1.5 currents in Xenopus oocytes.\",\n      \"method\": \"Co-immunoprecipitation; mutagenesis of Kv1.5 C-terminus; patch clamp in oocytes; immunocytochemistry\",\n      \"journal\": \"American journal of physiology. Heart and circulatory physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP with mutagenesis confirmation + functional current measurement, single lab\",\n      \"pmids\": [\"11709425\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"The L27N domain of CASK binds the N-terminus of SAP97; this interaction is required for lateral membrane localization of SAP97 in MDCK epithelial cells. A Drosophila DLG isoform containing the SAP97 N-terminal equivalent binds Camguk (the CASK ortholog), showing evolutionary conservation.\",\n      \"method\": \"Biochemical L27 domain binding assays; dominant-negative CASK overexpression; colocalization in MDCK cells; Drosophila isoform analysis\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct biochemical binding + functional dominant-negative localization assay + evolutionary conservation, multiple orthogonal methods\",\n      \"pmids\": [\"11865057\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"SAP97 interacts with TACE (ADAM17) metalloprotease via the PDZ3 domain of SAP97 and the C-terminal sequence of TACE; overexpression of SAP97 (but not a PDZ3-deleted mutant) inhibits TACE shedding activity.\",\n      \"method\": \"Yeast two-hybrid; affinity purification; co-immunoprecipitation; immunofluorescence; TACE shedding assay\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — yeast two-hybrid confirmed by co-IP + functional shedding assay with domain deletion, single lab\",\n      \"pmids\": [\"12668732\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"SAP97 directly interacts with NMDA receptor subunit NR2A via its PDZ1 domain; CaMKII phosphorylates SAP97 at Ser-232 within PDZ1, disrupting the SAP97-NR2A interaction both in vitro and in transfected cells.\",\n      \"method\": \"In vitro pull-down; co-immunoprecipitation from hippocampal synaptosomes; metabolic labeling; CaMKII inhibitor treatment; phosphomimetic mutant expression\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — in vitro pull-down + co-IP from native tissue + mutagenesis + pharmacological validation, multiple orthogonal methods\",\n      \"pmids\": [\"12933808\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"SAP97 monomer-dimer transition is controlled by its N-terminal L27 domain. Overexpression of SAP97 drives GluR1 to synapses, potentiates AMPAR EPSCs, and occludes LTP; L27 domain mutants that prevent multimerization show faster synaptic turnover and loss of potentiation. RNAi knockdown of endogenous SAP97 reduces surface expression of both GluR1 and GluR2 and impairs both AMPA and NMDA EPSCs.\",\n      \"method\": \"Single-particle electron microscopy; RNAi knockdown; electrophysiology (EPSCs); overexpression with L27 mutants; FRAP\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — structural EM + RNAi + electrophysiology + FRAP, multiple orthogonal methods in one study\",\n      \"pmids\": [\"15504326\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"SAP97, CASK, Veli-1/3, and Mint1 form a multiprotein trafficking complex that associates with Kir2.1, Kir2.2, and Kir2.3 channels via the C-terminal PDZ-binding motif. Dominant-interfering CASK causes Kir2.2 mislocalization from the basolateral membrane in polarized epithelial cells.\",\n      \"method\": \"GST pulldown from brain; co-immunoprecipitation; in vitro protein interaction assays; immunocytochemistry; dominant-negative CASK expression\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vitro binding + co-IP from native tissue + functional localization assay with dominant-negative, multiple orthogonal methods\",\n      \"pmids\": [\"14960569\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"p38γ (SAPK3) phosphorylates SAP97/hDlg, triggering its dissociation from GKAP and release from the cytoskeleton, regulating intercellular junction integrity in response to osmotic stress.\",\n      \"method\": \"In vitro kinase assay; co-immunoprecipitation; identification of phosphorylation sites; osmotic stress experiments\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — in vitro kinase assay identifying SAP97 as substrate + co-IP showing GKAP dissociation + cellular functional context, multiple orthogonal methods\",\n      \"pmids\": [\"15729360\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Cdc42 activates Par6-PKCζ at the leading edge of migrating astrocytes, promoting Dlg1-APC interaction. This APC-Dlg1 physical interaction is required for polarization of the microtubule cytoskeleton during directed cell migration.\",\n      \"method\": \"RNAi knockdown; TIRF microscopy; biochemical co-immunoprecipitation; Cdc42 activation assays in migrating astrocytes\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — RNAi + co-IP + live TIRF imaging + epistasis analysis, multiple orthogonal methods\",\n      \"pmids\": [\"16157700\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Dlgh1 translocates to the immune synapse and lipid rafts upon TCR/CD28 engagement; Lck-SH3-mediated interactions control Dlgh1 membrane targeting. Dlgh1 facilitates formation of Lck-Dlgh1-Zap70-WASp complexes and promotes actin polymerization, synaptic raft/TCR clustering, and NFAT activation.\",\n      \"method\": \"Co-immunoprecipitation; RNAi knockdown; overexpression; immunofluorescence; NFAT reporter assay\",\n      \"journal\": \"The Journal of experimental medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — complex identification by co-IP + functional siRNA knockdown/OE with multiple readouts (actin, raft clustering, NFAT), single lab multiple methods\",\n      \"pmids\": [\"15699074\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"DLG1's palmitoylated α-isoform localizes to the postsynaptic density and influences AMPAR-mediated synaptic strength independently of activity; the L27-containing β-isoform primarily influences AMPAR function in a CaMKII-dependent, activity-regulated manner. The N-terminal domain determines isoform-specific roles in synaptic function.\",\n      \"method\": \"Silencing of endogenous PSD-95 + heterologous expression of isoforms; electrophysiology; CaMKII inhibitor experiments\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — isoform-specific rescue experiments with pharmacological validation + electrophysiology, multiple orthogonal methods\",\n      \"pmids\": [\"16815335\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Dlgh1 MAGUK scaffold protein is required for TCR-induced 'alternative' p38 activation and NFAT transcription but not JNK or NF-κB activation; a Dlgh1 mutant unable to bind p38 fails to activate NFAT.\",\n      \"method\": \"siRNA knockdown; overexpression of binding-defective mutant; NFAT and NF-κB reporter assays; p38 activation assays\",\n      \"journal\": \"Nature immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — siRNA + mutant rescue + pathway-specific reporter assays, multiple methods in a high-quality journal\",\n      \"pmids\": [\"17187070\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"CaMKII phosphorylates SAP97 on Ser39 in the N-terminal domain; this phosphorylation drives SAP97 to the postsynaptic compartment and releases the SAP97/NR2A complex from the ER. Subsequently, Ser232 phosphorylation within PDZ1 disrupts NR2A binding and triggers NR2A insertion into the postsynaptic membrane.\",\n      \"method\": \"Phospho-specific antibodies; CaMKII activation/inhibition in hippocampal neurons; mutagenesis (S39D, S232D); co-immunoprecipitation\",\n      \"journal\": \"Journal of neurochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — phospho-specific antibodies + phosphomimetic mutants + co-IP from defined subcellular fractions, multiple orthogonal methods\",\n      \"pmids\": [\"17156128\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"SAP97 assembles an AKAP79-cAMP-dependent PKA scaffold at the C-terminal PDZ-binding motif (ESKV) of the β1-adrenergic receptor; this SAP97-AKAP79 complex is required for efficient β1-AR recycling and PKA-mediated phosphorylation of β1-AR Ser312.\",\n      \"method\": \"Co-immunoprecipitation; PDZ-motif mutagenesis; receptor trafficking assays; PKA phosphorylation assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP + mutagenesis + functional trafficking assay, single lab\",\n      \"pmids\": [\"17170109\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"SAP97 directs Kv4.2 (A-type K+ channel) to postsynaptic density (PSD) via PDZ domain interaction with Kv4.2 C-terminus; CaMKII-dependent SAP97 phosphorylation regulates Kv4.2 subcellular localization to spines.\",\n      \"method\": \"Co-immunoprecipitation; synaptic fractionation; SAP97 lentiviral RNAi; pharmacological SAP97 translocation to spines\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP + fractionation + RNAi + pharmacological translocation, single lab\",\n      \"pmids\": [\"17635915\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Delta1 (Notch ligand) interacts with Dlg1 via a C-terminal canonical PDZ-binding motif (ATEV); Delta1 expression triggers accumulation of Dlg1 at cell-cell contacts and reduces cell motility. These effects are abolished by deletion of the ATEV motif, independently of Notch signaling.\",\n      \"method\": \"Peptide affinity chromatography + mass spectrometry; co-immunoprecipitation; immunofluorescence; migration assay with PDZ-motif deletion mutant\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP confirmed by mutagenesis + functional migration assay, single lab\",\n      \"pmids\": [\"15485825\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"MPP7 forms a tripartite complex with LIN7A or LIN7C and DLG1. MPP7 dimerizes with LIN7 through L27 domains; the MPP7-LIN7 dimer then associates with DLG1's N-terminal L27 domain. MPP7 is required for localization of DLG1 to epithelial adherens junctions and stabilizes DLG1 in an insoluble compartment.\",\n      \"method\": \"Co-immunoprecipitation; domain deletion analysis; immunofluorescence in epithelial cells; detergent fractionation\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP with domain deletions + localization and fractionation assays, single lab\",\n      \"pmids\": [\"17237226\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"NMR solution structure of the hDlg PDZ2 domain bound to HPV-18 E6 C-terminal peptide shows a novel mode of interaction where six residues of the peptide contact PDZ2, compared to the typical four. Phosphorylation of E6 Thr156 disables binding.\",\n      \"method\": \"NMR structure determination; isothermal titration calorimetry; mutagenesis; molecular dynamics simulation\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — NMR structure + ITC + mutagenesis in one study, single lab but multiple rigorous methods\",\n      \"pmids\": [\"17713926\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Dlg1 loss-of-function in mice causes abnormalities in renal/urogenital development (hypoplastic kidneys/ureters, absent vagina and seminal vesicle) associated with impaired epithelial cellular proliferation rather than disruption of cell-cell junctional complexes.\",\n      \"method\": \"Dlgh1 knockout mouse generation; histology; immunostaining for junctional markers; proliferation assays\",\n      \"journal\": \"Development (Cambridge, England)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic knockout with defined phenotypic readout distinguishing proliferation from junction defects, single lab\",\n      \"pmids\": [\"17435047\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"GluR1 binding to SAP97 via its C-terminal 7 aa is required to translocate SAP97 from the cytosol to plasma membranes; GluR1 and SAP97 together at the plasma membrane promote dendrite branching in an activity-dependent manner.\",\n      \"method\": \"GluR1 C-terminal deletion (GluR1Δ7) in vitro and in vivo; membrane fractionation; immunofluorescence; dendritic morphometry\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — specific deletion mutant + fractionation + functional morphological assay, single lab\",\n      \"pmids\": [\"18842882\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Two N-terminal SAP97 isoforms (palmitoylated αSAP97 at PSD; L27-containing βSAP97 at perisynaptic regions) differentially localize GluR1-containing AMPARs within subsynaptic subdomains, directly modulating AMPAR dynamics and synaptic function.\",\n      \"method\": \"Live imaging; electrophysiology; isoform-specific overexpression in hippocampal neurons\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — isoform-specific live imaging + electrophysiology, multiple orthogonal methods, well-controlled experiments\",\n      \"pmids\": [\"19357261\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"SAP97 and CASK together are required for retention and trafficking of NMDARs (NR1/NR2B) through a specialized ER subcompartment in hippocampal neurons that bypasses the somatic Golgi and merges with dendritic Golgi outposts; AMPARs use the conventional somatic Golgi pathway.\",\n      \"method\": \"Live imaging of fluorescently-tagged receptors/adaptors in rat hippocampal neurons; RNAi knockdown of SAP97/CASK; subcellular fractionation\",\n      \"journal\": \"Nature neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — live imaging of trafficking pathway + RNAi functional validation, high-quality mechanistic study\",\n      \"pmids\": [\"19620977\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"SAP97 forms a tripartite complex with Kv4.2/4.3 channels and CaMKII in cardiomyocytes; SAP97 clustering of Kv4.3 at the plasma membrane enhances Ito current and enables CaMKII-dependent regulation. Kv4 channels lacking the SAL sequence no longer respond to CaMKII inhibitors.\",\n      \"method\": \"Pull-down; co-immunoprecipitation from cardiac myocytes; SAP97 shRNA; adenoviral overexpression; patch clamp\",\n      \"journal\": \"Circulation research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — co-IP from native tissue + SAL mutagenesis + RNAi + electrophysiology, multiple orthogonal methods\",\n      \"pmids\": [\"19213956\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Inhibiting SAP97-myosin VI interaction (using a dominant-negative myosin VI construct) reduces synapse number, surface AMPAR expression, and prevents activity-dependent AMPAR recruitment to silent synapses in hippocampal neurons.\",\n      \"method\": \"Dominant-negative construct expression; immunofluorescence; whole-cell patch-clamp recording of mEPSCs\",\n      \"journal\": \"Journal of neurochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — dominant-negative approach + electrophysiology + immunofluorescence, single lab\",\n      \"pmids\": [\"19895665\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"CaMKII preferentially phosphorylates SAP97 splice variant containing I3 and I5 inserts; AKAP79/150 directly and specifically binds only the I3I5-containing SH3-GK region. CaMKII phosphorylation of this splice variant prevents AKAP79/150 association, thereby relieving AKAP79-dependent down-regulation of GluR1 AMPAR currents.\",\n      \"method\": \"In vitro phosphorylation; GST fusion binding assays; immune complex kinase assay; electrophysiology with active CaMKII infusion\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — in vitro binding assays + phosphorylation assays + isoform specificity with GST domain constructs + functional electrophysiology, multiple methods\",\n      \"pmids\": [\"19858198\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"SAP97 via its PDZ domains interacts specifically with the SIV motif at the C-terminus of cardiac sodium channel Nav1.5 at intercalated discs (while dystrophin-syntrophin complex anchors Nav1.5 at lateral membranes). SAP97 silencing reduces Nav1.5 surface expression and sodium current.\",\n      \"method\": \"Pull-down assays; immunostaining; patch clamp; SAP97 siRNA knockdown in HEK293 and cardiomyocytes; mdx mouse comparison\",\n      \"journal\": \"Circulation research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — pull-down with specificity controls + RNAi functional validation + electrophysiology + mutagenesis of SIV motif, multiple orthogonal methods\",\n      \"pmids\": [\"21164104\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Ezrin regulates Dlg1 localization at the immunological synapse, controlling microtubule network organization; ezrin-Dlg1 interaction is required for p38 MAP kinase-dependent NF-AT activation and Erk1/2 downregulation at the immune synapse.\",\n      \"method\": \"Co-immunoprecipitation; RNAi; immunofluorescence; live imaging; TCR signaling assays\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP + RNAi + imaging showing ezrin-Dlg1 functional link, single lab\",\n      \"pmids\": [\"20551903\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Conditional SAP97 deletion in mature neurons causes no deficits in glutamatergic transmission or LTP, indicating functional redundancy with other PSD-MAGUKs; overexpression during early development traffics both AMPARs and NMDARs to synapses and rescues AMPAR deficits in PSD-93/-95 double-KO neurons.\",\n      \"method\": \"Conditional knockout; electrophysiology; overexpression in wild-type and double-KO neurons\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — conditional genetic KO + epistasis rescue experiments + electrophysiology, multiple orthogonal methods\",\n      \"pmids\": [\"20133708\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"During wound-induced migration, Cdc42 acts through Dlg1 to regulate dynein interaction with microtubules at the cell front; Dlg1 interacts with dynein via the scaffolding protein GKAP, and together they control microtubule dynamics and centrosome positioning.\",\n      \"method\": \"Co-immunoprecipitation; RNAi knockdown; live imaging; centrosome positioning assay in wounded monolayers\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — co-IP identifying Dlg1-GKAP-dynein complex + RNAi with centrosome phenotype + live imaging, multiple methods\",\n      \"pmids\": [\"21041448\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"PKCα interacts with DLG1/SAP97 via the third PDZ domain of DLG1 and the C-terminal PDZ-binding motif of PKCα; this scaffolding interaction promotes wound healing/cell migration. PKCα phosphorylates DLG1 at Thr-656 in its SH3-Hook region, which serves as a marker of PKCα activity.\",\n      \"method\": \"PDZ domain proteomic array; co-immunoprecipitation; scratch migration assay with PKCα/DLG1 co-depletion; phosphorylation site identification\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — PDZ array + co-IP + functional migration assay + phosphosite identification, single lab\",\n      \"pmids\": [\"22027822\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"αSAP97 occludes LTP by enhancing postsynaptic AMPAR levels; βSAP97 blocks LTP by reducing synaptic NMDAR localization while restricting extrasynaptic AMPAR pools. Knockdown of endogenous βSAP97 increases synaptic AMPAR and NMDAR levels.\",\n      \"method\": \"Paired whole-cell recordings from synaptically coupled hippocampal neurons; live imaging; RNAi knockdown; isoform-specific overexpression\",\n      \"journal\": \"The Journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — isoform-specific RNAi + paired electrophysiology + live imaging, multiple orthogonal methods\",\n      \"pmids\": [\"21768261\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"CASK binding to SAP97 via L27 domains stabilizes SAP97 in an 'extended' conformation; unbound SAP97 is in a 'compact' conformation. Compact SAP97 preferentially associates with GluA1-AMPARs; CASK-bound extended SAP97 colocalizes with GluN2B-NMDARs, providing a mechanism for differential receptor sorting.\",\n      \"method\": \"Intramolecular FRET sensors; co-IP; isoform expression in HEK cells and hippocampal neurons; colocalization imaging\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — FRET-based conformational sensor + co-IP + cellular colocalization, multiple orthogonal methods in single study\",\n      \"pmids\": [\"23864692\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"DLG1 knockdown decreases surface expression of the glial glutamate transporter EAAT2b (which contains a PDZ ligand) in MDCK cells and astrocytes; DLG1 co-immunoprecipitates with EAAT2b. CaMKII activation disrupts DLG1-EAAT2b interaction and decreases EAAT2b surface expression.\",\n      \"method\": \"Co-immunoprecipitation; shRNA knockdown; surface biotinylation assay; CaMKII pharmacological activation\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP + RNAi + surface expression assay + pharmacological validation, single lab\",\n      \"pmids\": [\"25834051\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"DLG1 is an anchor for the MARCH2 E3 ubiquitin ligase at cell-cell contact sites via PDZ domain interaction; MARCH2 promotes ubiquitination of DLG1 in vivo.\",\n      \"method\": \"Tandem affinity purification + mass spectrometry; co-immunoprecipitation; in vivo ubiquitination assay; immunofluorescence with PDZ-motif deletion\",\n      \"journal\": \"Cellular signalling\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — TAP-MS + co-IP + ubiquitination assay, single lab, multiple methods\",\n      \"pmids\": [\"17980554\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"SAP97 governs ADAM10 trafficking from dendritic Golgi outposts to synaptic membranes in hippocampal neurons; this process requires PKC phosphorylation of SAP97's SH3 domain, which modulates SAP97-ADAM10 association. This mechanism is altered in Alzheimer's disease brains.\",\n      \"method\": \"Co-immunoprecipitation; phosphosite mapping; PKC inhibitor/activator treatment; siRNA knockdown; confocal imaging\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP + phosphosite identification + functional trafficking assay, single lab\",\n      \"pmids\": [\"25429624\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Dlg1 is localized at the basolateral cell cortex during mitosis and directly interacts with LGN, promoting cortical localization of the LGN complex to control planar spindle orientation in the chick neuroepithelium and human cells.\",\n      \"method\": \"Live imaging of spindle movements; RNAi knockdown; co-immunoprecipitation; overexpression on adhesive micropatterns\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct binding assay (co-IP) + live imaging of spindle dynamics + RNAi in multiple systems (chick and human), multiple methods\",\n      \"pmids\": [\"25202028\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Cardiac-specific SAP97 ablation in mice decreases IK1, Ito, and IKur potassium currents and prolongs action potential duration without affecting INa, confirming SAP97's role in regulating potassium channel function in vivo.\",\n      \"method\": \"Cardiac-specific Cre-lox knockout; patch clamp; ECG; immunostaining\",\n      \"journal\": \"Heart rhythm\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic cardiac-specific KO + patch clamp + ECG, multiple orthogonal methods, in vivo model\",\n      \"pmids\": [\"25447080\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Pten recruits Dlg1-Eg5 complexes to pre-mitotic centrosomes via its PDZ-binding domain; Eg5 phosphorylation by Nek9-Nek6 and Cdk1 kinases is required for docking onto Pten-Dlg1. Dlg1 ablation impairs Eg5 loading onto centrosomes and spindle pole motility, causing asymmetric spindles and chromosome missegregation.\",\n      \"method\": \"Co-immunoprecipitation; mouse genetic models (PDZ-BD deletion, Dlg1 ablation); centrosome fractionation; live imaging of spindle poles; aneuploidy assays\",\n      \"journal\": \"Nature cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple genetic models + co-IP + centrosome fractionation + live imaging + functional segregation readout, high-quality multi-method study\",\n      \"pmids\": [\"27240320\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"In Schwann cells, Kif13b kinesin promotes p38γ MAPK-mediated phosphorylation and ubiquitination of Dlg1, downregulating Dlg1 and the PI3K/AKT pathway. In oligodendrocytes, Kif13b negatively regulates Dlg1 stability; Dlg1 in that context enhances AKT activation and myelination.\",\n      \"method\": \"Kif13b conditional knockout mice; immunoprecipitation; phosphorylation and ubiquitination assays; AKT pathway analysis\",\n      \"journal\": \"PLoS biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — conditional KO + biochemical phosphorylation/ubiquitination assays, single lab, cell-type-specific effects\",\n      \"pmids\": [\"27070899\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Vascular endothelial cell-specific loss of Dlg1 impairs β-catenin (canonical Wnt) signaling in the retina. Dlg1 transfection in reporter cells with Dlg1 inactivation enhances β-catenin signaling ~4-fold; the retinal vascular phenotype is rescued by stabilizing β-catenin in ECs.\",\n      \"method\": \"EC-specific Cre-lox knockout; genetic epistasis with β-catenin signaling components; CRISPR/Cas9 inactivation in reporter cells; β-catenin stabilization rescue\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — conditional KO + genetic epistasis + CRISPR reporter cells + rescue experiments, multiple orthogonal methods\",\n      \"pmids\": [\"31066677\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"SGEF forms a ternary complex with Scribble and Dlg1; SGEF targets to apical junctions in a Scribble-dependent manner and regulates actomyosin contractility and barrier function through RhoG activation coordinated by the Scribble-Dlg1 scaffold.\",\n      \"method\": \"Co-immunoprecipitation; RNAi knockdown; 3D cyst assay; immunofluorescence; Scribble-dependent targeting assay\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP confirming ternary complex + RNAi with functional readouts, single lab\",\n      \"pmids\": [\"31248911\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"SAP97 maintains cardiac β1AR signaling integrity by scaffolding β1AR; GRK5 promotes agonist-induced dissociation of SAP97 from β1AR. Loss of SAP97 shifts β1AR toward arrestin2-CaMKII association and activates Epac-dependent CaMKII, causing cardiac remodeling.\",\n      \"method\": \"Cardiac-specific SAP97 deletion; co-immunoprecipitation; CaMKII activity assays; cardiac function measurements; GRK5 deletion epistasis\",\n      \"journal\": \"Circulation research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — cardiac-specific KO + GRK5 epistasis + co-IP + CaMKII activity + functional cardiac phenotype, multiple methods\",\n      \"pmids\": [\"32507058\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"DLG1/SAP97 is a multi-domain MAGUK scaffolding protein that uses its PDZ1, PDZ2, and PDZ3 domains to cluster and traffic ion channels (AMPA/NMDA glutamate receptors, Kv1.5, Kv4.2/4.3, Kir2.x, Nav1.5) and signaling proteins (APC, CASK, GKAP, AKAP79, ADAM10, CRFR1, β1AR) at synapses, epithelial junctions, and cardiomyocyte membrane domains; its N-terminal L27 domain controls CASK-dependent conformational switching between compact (AMPAR-preferring) and extended (NMDAR-preferring) states and mediates multimerization; CaMKII phosphorylation of Ser39 drives SAP97 to the postsynaptic compartment while Ser232 phosphorylation disrupts NR2A binding to trigger receptor insertion; p38γ phosphorylation releases SAP97 from cytoskeletal GKAP tethering; PKCα and PKC phosphorylation at SH3-domain sites regulate cell migration and ADAM10 trafficking, respectively; in dividing cells Dlg1 recruits LGN to the basolateral cortex for planar spindle orientation and recruits Eg5 to centrosomes via Pten-PDZ-BD to establish bipolar spindles; in T cells Dlg1 scaffolds alternative p38-NFAT signaling and coordinates immune synapse actin/TCR organization; and in the heart, cardiac-specific Dlg1 ablation selectively reduces potassium currents and prolongs action potential duration.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"DLG1 (hDlg/SAP97) is a multidomain MAGUK scaffolding protein that organizes membrane signaling microdomains at epithelial junctions, neuronal synapses, the immune synapse, the mitotic cortex, and the cardiomyocyte membrane by clustering and trafficking transmembrane receptors and channels through its three PDZ domains, SH3 region, and a catalytically inactive guanylate kinase-like (GK) domain [#0, #8]. Subcellular targeting and cytoskeletal attachment are governed by an N-terminal region and alternatively spliced inserts: the unique SAP97 N-terminus and the I3 insert direct it to the epithelial lateral membrane and cell-cell contacts via protein 4.1/ERM and the CASK/MPP7-LIN7 L27-domain complexes, while the I2 insert directs nuclear localization [#2, #6, #15, #19, #33]. In neurons, SAP97 binds the AMPA receptor subunit GluA1 (PDZ-dependent) and the NMDA receptor subunit NR2A (PDZ1), and its CASK-controlled monomer-dimer/compact-extended conformational switch sorts these receptors: compact SAP97 favors GluA1-AMPARs while CASK-bound extended SAP97 favors GluN2B-NMDARs [#5, #21, #22, #48]. CaMKII phosphorylation orchestrates this trafficking, driving SAP97 to the postsynaptic compartment via Ser39 and disrupting NR2A binding via Ser232 to trigger receptor insertion [#21, #29]; SAP97 and CASK route NMDARs through a specialized dendritic ER/Golgi-outpost pathway [#38]. Distinct palmitoylated alpha and L27-containing beta isoforms partition AMPARs into subsynaptic domains and exert opposite effects on synaptic potentiation [#37, #47]. In epithelia DLG1 couples to E-cadherin-based junctions, is stabilized by cell contact and degraded by the proteasome, and its release from cytoskeletal GKAP tethering is triggered by p38gamma phosphorylation during osmotic stress [#7, #17, #24]; it further scaffolds Scribble-SGEF-RhoG to control actomyosin contractility and barrier function [#57] and is required for canonical Wnt/beta-catenin signaling in retinal endothelium [#56]. In dividing cells DLG1 localizes to the basolateral cortex and binds LGN to orient the mitotic spindle, and is recruited by PTEN with Eg5 to centrosomes to build bipolar spindles and ensure faithful chromosome segregation [#52, #54]. In T cells DLG1 scaffolds an Lck-Zap70-WASp complex and an alternative p38-NFAT signaling pathway at the immune synapse, dependent on ezrin-controlled localization [#26, #28, #43]. In the heart DLG1 anchors potassium channels (Kv4.x, Kir2.x, Kv1.5) and the sodium channel Nav1.5, and cardiac-specific ablation selectively reduces potassium currents and prolongs action potential duration while leaving INa intact [#39, #42, #53]; it also maintains beta1-adrenergic receptor signaling integrity, with loss shifting beta1AR toward arrestin-CaMKII signaling and cardiac remodeling [#58]. DLG1 is additionally targeted by viral oncoproteins (Ad9 ORF1, HTLV-1 Tax, HPV-18 E6) through PDZ-binding motifs, and Tax binding disrupts the DLG1-APC interaction that underlies DLG1-mediated G0/G1 cell-cycle arrest [#3, #9, #11, #34].\",\n  \"teleology\": [\n    {\n      \"year\": 1994,\n      \"claim\": \"Establishing DLG1's domain architecture and its association with the membrane-cytoskeleton adaptor protein 4.1 defined it as a junction-localized scaffold rather than an enzyme.\",\n      \"evidence\": \"cDNA cloning, in vitro binding with recombinant protein 4.1, and immunolocalization\",\n      \"pmids\": [\"7937897\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Did not define which PDZ domains engage transmembrane partners\", \"No functional consequence of 4.1 binding established\"]\n    },\n    {\n      \"year\": 1996,\n      \"claim\": \"Domain dissection showed that the PDZ1-2 unit and the alternatively spliced I3 insert provide redundant targeting routes binding 4.1/ERM and T/SXV-motif partners, explaining how DLG1 reaches cell-cell contacts.\",\n      \"evidence\": \"In vitro domain binding, domain-deletion localization in permeabilized cells, and co-IP of 4.1 and ezrin\",\n      \"pmids\": [\"8922391\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not identify the physiological transmembrane ligands at junctions\", \"Conformational regulation of targeting unaddressed\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Resolving the unique SAP97 N-terminal 65 residues as the primary lateral-membrane targeting determinant, and demonstrating the GK domain lacks guanylate kinase activity, recast DLG1 as a localization-driven, enzymatically inert scaffold; concurrent identification of GluA1 binding linked it to glutamate receptors.\",\n      \"evidence\": \"Domain-deletion mutagenesis with fractionation/IF; in vitro GK enzymatic assay; co-IP of GluR1 from rat brain with recombinant binding\",\n      \"pmids\": [\"9683631\", \"9523702\", \"9677374\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism coupling the N-terminus to the cytoskeleton not resolved\", \"GluA1 binding specificity vs other AMPAR subunits explained but trafficking role not yet shown\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Discovery that viral oncoproteins (Ad9 ORF1, HTLV-1 Tax, HPV-18 E6) bind DLG1 PDZ domains, and that DLG1 binds APC and arrests the cell cycle, established a tumor-suppressor axis disrupted by viral hijacking.\",\n      \"evidence\": \"Library screen, in vitro/in vivo binding, co-IP from infected T cells, and BrdU/cell-cycle assays with domain mutants\",\n      \"pmids\": [\"9192623\", \"9286858\", \"10557085\", \"10656683\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How APC binding mechanistically blocks G1/S transition not defined\", \"Endogenous (non-viral) regulators of the DLG1-APC axis unknown\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Identifying CASK GUK-SH3 binding and demonstrating that SAP97 retains Kv1 channels in the ER while distinct from PSD-95 revealed DLG1 as a biosynthetic-trafficking scaffold, not merely a surface-clustering one.\",\n      \"evidence\": \"Yeast two-hybrid, GST binding, co-IP, and heterologous channel surface/IF analysis\",\n      \"pmids\": [\"10993877\", \"10629225\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether ER retention reflects a regulated trafficking checkpoint not established\", \"CASK's role in DLG1 conformation not yet probed\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Mapping channel partners (Kir2.x via PDZ2, Kv1.5 via TDL motif) and the conserved CASK L27N-SAP97 N-terminal interaction tied DLG1 to cardiac/epithelial channel localization and defined the L27 module controlling targeting and oligomerization.\",\n      \"evidence\": \"GST pulldown from native tissue, co-IP, mutagenesis, oocyte patch clamp, dominant-negative CASK in MDCK, and Drosophila conservation\",\n      \"pmids\": [\"11181181\", \"11709425\", \"11865057\", \"11723125\", \"11694581\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether PKA regulation of channel binding occurs in vivo not shown\", \"Stoichiometry of the SAP97-CASK-channel complex undefined\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Demonstrating CaMKII phosphorylation of SAP97 Ser232 within PDZ1 disrupts NR2A binding provided the first phosphoregulatory switch coupling kinase activity to receptor release.\",\n      \"evidence\": \"In vitro pulldown, co-IP from synaptosomes, metabolic labeling, CaMKII inhibition, and phosphomimetic mutants\",\n      \"pmids\": [\"12933808\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not connect the switch to receptor surface insertion\", \"Other CaMKII sites and their order unresolved\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Linking the L27-controlled monomer-dimer transition to AMPAR synaptic delivery and LTP, while RNAi knockdown impaired AMPA and NMDA transmission, established SAP97 multimerization as functionally required for synaptic strength.\",\n      \"evidence\": \"Single-particle EM, RNAi, EPSC electrophysiology, L27 mutants, and FRAP\",\n      \"pmids\": [\"15504326\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct structural basis of the compact-extended switch not yet visualized\", \"Redundancy with other PSD-MAGUKs not assessed\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Identifying p38gamma phosphorylation as the trigger releasing SAP97 from GKAP/cytoskeleton, and the Cdc42-Par6-PKCzeta pathway promoting DLG1-APC for migratory microtubule polarization, extended DLG1 regulation to stress responses and directed cell migration.\",\n      \"evidence\": \"In vitro kinase assays, co-IP, phosphosite mapping, osmotic stress, RNAi, and TIRF imaging in astrocytes\",\n      \"pmids\": [\"15729360\", \"16157700\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How GKAP release alters junctional integrity mechanistically not fully defined\", \"Direct kinase-substrate stoichiometry in migration unresolved\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Defining isoform-specific synaptic roles (palmitoylated alpha vs L27 beta) and the requirement of DLG1 for TCR-induced alternative p38-NFAT signaling and immune-synapse organization broadened DLG1 into activity-dependent and immune scaffolding.\",\n      \"evidence\": \"Isoform rescue electrophysiology with CaMKII inhibition; siRNA/mutant rescue with NFAT reporters; Lck/Zap70/WASp co-IP and imaging; AKAP79-beta1AR PKA scaffold co-IP\",\n      \"pmids\": [\"16815335\", \"17187070\", \"15699074\", \"17170109\", \"17156128\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How a single scaffold selectively activates p38-NFAT but not JNK/NF-kB not mechanistically resolved\", \"Isoform expression regulation in vivo unaddressed\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Structural and partner-mapping work (PDZ2-E6 NMR with non-canonical six-residue binding, TACE/ADAM17 via PDZ3, Delta1, MPP7-LIN7 L27 complex) detailed the diverse PDZ/L27 engagement modes underlying DLG1 specificity.\",\n      \"evidence\": \"NMR/ITC, yeast two-hybrid, co-IP, domain deletions, and shedding/migration assays\",\n      \"pmids\": [\"17713926\", \"12668732\", \"15485825\", \"17237226\", \"17435047\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether the non-canonical PDZ2 mode generalizes to endogenous ligands unclear\", \"Knockout urogenital phenotype mechanism (proliferation vs junctions) not molecularly explained\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Defining a specialized SAP97-CASK NMDAR ER/Golgi-outpost trafficking route, the cardiac SAP97-Kv4-CaMKII complex, the AKAP79 splice-variant phosphoswitch, and GluA1-driven membrane translocation integrated DLG1 into compartment-specific receptor and channel delivery.\",\n      \"evidence\": \"Live imaging, RNAi, fractionation, co-IP from cardiomyocytes, patch clamp, GST binding, and dendritic morphometry\",\n      \"pmids\": [\"19620977\", \"19213956\", \"19858198\", \"18842882\", \"19357261\", \"19895665\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular machinery routing cargo to dendritic Golgi outposts not fully defined\", \"Relative contributions of multiple CaMKII sites in vivo unresolved\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Cardiac Nav1.5 anchoring at intercalated discs, the Cdc42-Dlg1-GKAP-dynein control of centrosome positioning, ezrin-dependent immune-synapse localization, and conditional-KO redundancy with PSD-MAGUKs delineated context-specific essential and dispensable roles.\",\n      \"evidence\": \"Pulldown, RNAi, patch clamp, mdx comparison, live imaging, co-IP, and conditional KO with rescue electrophysiology\",\n      \"pmids\": [\"21164104\", \"21041448\", \"20551903\", \"20133708\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Compensating MAGUKs in mature neurons not identified at the molecular level\", \"How DLG1 partitions Nav1.5 between intercalated discs and lateral membrane not resolved\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Direct demonstration that CASK binding stabilizes an extended SAP97 conformation preferring GluN2B-NMDARs while compact SAP97 prefers GluA1-AMPARs provided the conformational logic for differential receptor sorting; parallel work added EAAT2b, MARCH2-mediated ubiquitination, and PKC-dependent ADAM10 trafficking.\",\n      \"evidence\": \"Intramolecular FRET sensors, co-IP, colocalization, surface biotinylation, TAP-MS, and ubiquitination assays\",\n      \"pmids\": [\"23864692\", \"25834051\", \"17980554\", \"25429624\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"What sets the equilibrium between compact and extended states in vivo unclear\", \"Physiological MARCH2-DLG1 turnover regulation not established\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Identifying direct Dlg1-LGN binding for planar spindle orientation established DLG1 as a cortical determinant linking the cell-cortex scaffold to mitotic machinery.\",\n      \"evidence\": \"Live spindle imaging, RNAi in chick and human cells, co-IP, and micropattern overexpression\",\n      \"pmids\": [\"25202028\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Upstream cues localizing Dlg1 to the basolateral cortex during mitosis not defined\", \"Relationship to the PTEN-Eg5 centrosomal role not yet integrated\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Demonstrating PTEN-dependent recruitment of Dlg1-Eg5 to centrosomes for bipolar spindle assembly, and Kif13b/p38gamma-controlled Dlg1 stability regulating PI3K/AKT in glia, expanded DLG1 into centrosomal spindle control and myelination-linked AKT signaling.\",\n      \"evidence\": \"Genetic mouse models, co-IP, centrosome fractionation, live imaging, aneuploidy assays, and conditional Kif13b KO with phospho/ubiquitination analysis\",\n      \"pmids\": [\"27240320\", \"27070899\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How DLG1 mechanically supports spindle-pole motility not fully resolved\", \"Cell-type-specific opposite outcomes of Dlg1 turnover not mechanistically reconciled\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Showing endothelial Dlg1 is required for canonical Wnt/beta-catenin signaling and that Dlg1 scaffolds Scribble-SGEF-RhoG for actomyosin/barrier control connected DLG1 to developmental signaling and junctional contractility.\",\n      \"evidence\": \"EC-specific KO, genetic epistasis, CRISPR reporter cells, beta-catenin rescue, co-IP, and 3D cyst assays\",\n      \"pmids\": [\"31066677\", \"31248911\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct molecular link between Dlg1 and the beta-catenin destruction complex not defined\", \"Whether Scribble-Dlg1-SGEF acts in vivo at endothelial junctions untested\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Cardiac-specific KO work showed SAP97 maintains beta1AR signaling fidelity, with GRK5-driven dissociation shifting beta1AR toward arrestin-CaMKII and Epac-CaMKII activation and pathological remodeling, defining a protective cardiac signaling role.\",\n      \"evidence\": \"Cardiac-specific deletion, GRK5 epistasis, co-IP, CaMKII activity assays, and cardiac function measurements\",\n      \"pmids\": [\"32507058\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How SAP97 biases beta1AR away from arrestin coupling structurally unresolved\", \"Therapeutic exploitability of the SAP97-beta1AR axis untested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How DLG1's conformational state, isoform/splice composition, and phosphorylation code are integrated to select among its many partners within a single cell remains the central open question.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No unified structural model of how PDZ/L27/SH3-GK states combinatorially set partner choice\", \"Quantitative rules governing tissue-specific partner selection not established\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [2, 19, 22, 33, 48]},\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [0, 2, 6, 7, 45]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [12, 18, 20, 30, 58]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [1, 7, 14, 36, 42]},\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [12, 18, 29, 38]},\n      {\"term_id\": \"GO:0005815\", \"supporting_discovery_ids\": [45, 54]},\n      {\"term_id\": \"GO:0005856\", \"supporting_discovery_ids\": [6, 7, 24, 25]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [15]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [5, 22, 27, 38, 48]},\n      {\"term_id\": \"R-HSA-1640170\", \"supporting_discovery_ids\": [11, 52, 54]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [26, 28, 43]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [25, 30, 56, 58]},\n      {\"term_id\": \"R-HSA-397014\", \"supporting_discovery_ids\": [39, 42, 53]},\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [12, 23, 38, 42, 51]}\n    ],\n    \"complexes\": [\n      \"SAP97-CASK-Veli-Mint1 channel trafficking complex\",\n      \"MPP7-LIN7-DLG1 L27 complex\",\n      \"Scribble-Dlg1-SGEF complex\",\n      \"Lck-Dlg1-Zap70-WASp immune synapse complex\"\n    ],\n    \"partners\": [\n      \"CASK\",\n      \"GKAP\",\n      \"GRIA1\",\n      \"GRIN2A\",\n      \"LGN\",\n      \"APC\",\n      \"AKAP79\",\n      \"EZR\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":10,"faith_total":10,"faith_pct":100.0}}