{"gene":"APPL2","run_date":"2026-06-09T22:02:44","timeline":{"discoveries":[{"year":2006,"finding":"APPL2 interacts with FSHR (follicle stimulating hormone receptor) and with APPL1 via the N-terminus/BAR domain of APPL1; unlike APPL1, APPL2 does not associate with Akt2, establishing a functional distinction between the two paralogs.","method":"Co-immunoprecipitation","journal":"Molecular and cellular endocrinology","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — reciprocal Co-IP in single lab, but multiple binding partners tested and a clear negative result (APPL2 does not bind Akt2) distinguishes APPL2 from APPL1","pmids":["17030088"],"is_preprint":false},{"year":2007,"finding":"APPL2 forms homooligomers and heterooligomers with APPL1 through its BAR domain (necessary and sufficient for APPL-APPL interactions); full-length APPL2 binds phosphoinositides via its PH and PTB domains; APPL2-YFP localizes to cytosolic membrane structures that undergo movement, fusion and fission events and recruits endogenous RAB5 to enlarged membrane structures.","method":"Co-immunoprecipitation, yeast two-hybrid, in vitro phosphoinositide-binding assay, live-cell fluorescence imaging","journal":"Traffic (Copenhagen, Denmark)","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (Co-IP, Y2H, in vitro lipid binding, live imaging) in a single study establishing domain-level mechanisms","pmids":["18034774"],"is_preprint":false},{"year":2009,"finding":"APPL2 activates beta-catenin/TCF-mediated transcription by directly interacting with the transcriptional repressor Reptin (via the PH domain of APPL1, mapped for APPL1; APPL2 similarly interacts); APPL2 is present in an endogenous complex containing Reptin, beta-catenin, HDAC1, and HDAC2; overexpression of APPL2 relieves Reptin-dependent repression and reduces amounts of HDACs and beta-catenin associated with Reptin.","method":"Co-immunoprecipitation, reporter assay, siRNA knockdown, chromatin immunoprecipitation","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (Co-IP, reporter assay, siRNA KD, ChIP) in a single study with functional validation","pmids":["19433865"],"is_preprint":false},{"year":2010,"finding":"APPL1 and APPL2 BAR domains interact directly on curved cell membranes in a homotypic (APPL1-APPL1, APPL2-APPL2) and heterotypic (APPL1-APPL2) manner, as demonstrated by FRET.","method":"FRET microscopy (sensitized emission, acceptor photobleaching, sequential acceptor photobleaching) in live cells","journal":"PloS one","confidence":"High","confidence_rationale":"Tier 1 / Strong — three independent FRET methods consistently confirming direct in vivo BAR domain interactions on membranes","pmids":["20814572"],"is_preprint":false},{"year":2012,"finding":"APPL2 knockdown in glioma cells reduces cell survival and enhances apoptosis by upregulating apoptosis-related genes UNC5B and HRK; this prosurvival activity is independent of Akt/GSK3β modulation and of APPL2's endosomal localization.","method":"siRNA/shRNA knockdown, caspase activity assay, colony formation assay, xenograft tumor growth, gene expression analysis","journal":"Molecular oncology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean KD/KO with defined cellular phenotypes and multiple orthogonal readouts, single lab","pmids":["22989406"],"is_preprint":false},{"year":2014,"finding":"APPL2 inhibits insulin-stimulated GLUT4 translocation and glucose uptake in skeletal muscle by interacting with TBC1D1; insulin stimulates TBC1D1 phosphorylation on Ser235, which enhances binding to the BAR domain of APPL2, suppressing subsequent TBC1D1 phosphorylation on Thr596 needed for GLUT4 trafficking. Ser235Ala substitution in TBC1D1 abolishes this inhibitory axis.","method":"Co-immunoprecipitation, site-directed mutagenesis, conditional knockout mice, glucose uptake assay, GLUT4 translocation assay","journal":"Diabetes","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — Co-IP with domain mapping, mutagenesis, conditional KO mice, and multiple functional readouts; mechanistic pathway fully resolved","pmids":["24879834"],"is_preprint":false},{"year":2014,"finding":"APPL2 forms a complex with APPL1 and the PI3K regulatory subunit p85α; in LPS-challenged macrophages, loss of APPL2 enhances PI3K/Akt/NF-κB signaling and increases TNF-α and IL-1β production, whereas loss of APPL1 reduces Akt activation and cytokine production, indicating APPL2 is a negative regulator of innate immune signaling through this complex.","method":"Co-immunoprecipitation, Appl2 knockout mice, LPS challenge, cytokine ELISA, Akt/NF-κB phosphorylation immunoblotting","journal":"Cell & bioscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — Co-IP identifying complex components, KO mice with defined immune phenotype, and multiple molecular readouts in a single study","pmids":["25328665"],"is_preprint":false},{"year":2015,"finding":"Rab31-GTP recruits APPL2 to early-stage phagosomes; siRNA depletion of APPL2 delays the PI(4,5)P2-to-PI(3,4,5)P3 transition, impairs phagocytic cup closure, reduces PI3K/Akt signaling, and enhances p38 signaling from FcγR, thereby reducing FcγR-mediated phagocytosis in macrophages.","method":"siRNA knockdown, fluorescence imaging of phagosome stages, PI3K/Akt and p38 signaling assays","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — siRNA depletion with multiple orthogonal functional readouts (phagocytosis, phosphoinositide dynamics, signaling kinetics) in a single study","pmids":["25568335"],"is_preprint":false},{"year":2015,"finding":"APPL1 and APPL2 double-knockout mouse embryonic fibroblasts exhibit defects in HGF-induced Akt activation, migration, and invasion, while individual knockouts of either protein do not impair development, indicating redundant roles in HGF signaling.","method":"Conditional/constitutive knockout mice, MEF Akt signaling assay, migration/invasion assay","journal":"Journal of cellular physiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean genetic KO (single and double), defined signaling and phenotypic readouts, single lab","pmids":["26445298"],"is_preprint":false},{"year":2016,"finding":"APPL2 localizes to distinct surface and endocytic membrane domains in LPS-activated macrophages; depletion of APPL2 specifically impairs nuclear translocation of NF-κB p65 and constrains secretion of pro- and anti-inflammatory cytokines downstream of TLR4, with APPL2 having opposing regulatory effects to APPL1 on Akt and MAPK signaling.","method":"siRNA depletion, immunofluorescence localization, NF-κB nuclear translocation assay, cytokine secretion assay, Akt/MAPK phosphorylation immunoblotting","journal":"Traffic (Copenhagen, Denmark)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA KD with multiple signaling and functional readouts, single lab","pmids":["27219021"],"is_preprint":false},{"year":2017,"finding":"APPL2 overexpression in transgenic mice enhances glucocorticoid receptor (GR) phosphorylation under basal conditions and impairs hippocampal neurogenesis; this neurogenesis defect is reversed by the GR antagonist RU486, placing APPL2 upstream of GR activity.","method":"APPL2 transgenic mice, GR phosphorylation immunoblotting, hippocampal neurogenesis quantification, pharmacological rescue with RU486","journal":"Molecular neurobiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — transgenic model with pharmacological rescue establishing epistasis, single lab","pmids":["28965332"],"is_preprint":false},{"year":2020,"finding":"APPL2 enhances glucose-stimulated insulin secretion (GSIS) by promoting F-actin depolymerization via Rac1 in pancreatic β-cells; APPL2 interacts with RacGAP1 in a glucose-dependent manner through its BAR-PH domain, suppressing RacGAP1's inhibitory action on Rac1, thereby enabling F-actin remodeling. Concurrent knockdown of RacGAP1 rescues APPL2-deficiency-induced defects in GSIS, F-actin remodeling, and Rac1 activation.","method":"β-cell-specific APPL2 knockout mice, Co-immunoprecipitation with domain mapping, siRNA knockdown, live-cell F-actin imaging, phalloidin staining, Rac1 activation assay, pharmacological rescue","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — conditional KO mice, Co-IP with domain mapping, genetic epistasis (double KD rescue), and multiple orthogonal functional readouts in a single study","pmids":["33122440"],"is_preprint":false},{"year":2020,"finding":"APPL2 interacts with Notch1 and promotes gliogenesis over neurogenesis in adult olfactory bulb neural stem cells; APPL2 overexpression switches NSC fate from neuronal differentiation to gliogenesis, while knockdown promotes neurogenesis, and APPL2 transgenic mice show higher glial cell populations and impaired olfactory discrimination.","method":"Co-immunoprecipitation (APPL2-Notch1), in vitro NSC differentiation assay, APPL2 transgenic mice, immunofluorescence quantification, olfactory behavioral testing","journal":"Neuroscience bulletin","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — Co-IP identifying binding partner, in vitro and in vivo models with phenotypic readouts, single lab","pmids":["32468397"],"is_preprint":false}],"current_model":"APPL2 is a multidomain endosomal adaptor protein (BAR-PH-PTB) that forms homo- and heterooligomers with APPL1 via BAR domains, binds phosphoinositides, and localizes to RAB5/RAB31-positive signaling endosomes, where it scaffolds distinct signaling complexes: it suppresses PI3K/Akt/NF-κB-mediated innate immune signaling by forming a complex with APPL1 and PI3K-p85α, inhibits insulin-stimulated GLUT4 trafficking by sequestering TBC1D1 via its BAR domain, promotes glucose-stimulated insulin secretion in β-cells by binding RacGAP1 (through BAR-PH) to relieve inhibition of Rac1 and enable F-actin remodeling, activates Wnt/beta-catenin transcription by disrupting a Reptin-HDAC repressive complex, regulates NF-κB nuclear translocation and cytokine secretion downstream of TLR4, and controls neural stem cell fate decisions via interaction with Notch1—collectively acting as a context-dependent molecular switch that modulates metabolic, immune, and developmental signaling."},"narrative":{"mechanistic_narrative":"APPL2 is a multidomain endosomal adaptor protein that functions as a context-dependent scaffold modulating metabolic, immune, and developmental signaling [PMID:18034774, PMID:25328665]. It oligomerizes through its BAR domain, forming both homooligomers and heterooligomers with its paralog APPL1, binds phosphoinositides via its PH and PTB domains, and localizes to dynamic cytosolic membrane structures where it recruits RAB5 [PMID:18034774]; direct BAR-domain interactions between APPL1 and APPL2 occur on curved membranes in living cells [PMID:20814572]. Functional divergence from APPL1 is established by APPL2's failure to associate with Akt2 [PMID:17030088]. In innate immunity, APPL2 forms a complex with APPL1 and the PI3K regulatory subunit p85α and acts as a negative regulator of PI3K/Akt/NF-κB signaling, restraining TNF-α and IL-1β production in LPS-challenged macrophages [PMID:25328665], while controlling NF-κB p65 nuclear translocation and cytokine secretion downstream of TLR4 [PMID:27219021]; RAB31-GTP recruits APPL2 to early phagosomes where it drives the PI(4,5)P2-to-PI(3,4,5)P3 transition required for FcγR-mediated phagocytosis [PMID:25568335]. In glucose metabolism, APPL2 inhibits insulin-stimulated GLUT4 translocation in skeletal muscle by binding insulin-induced Ser235-phosphorylated TBC1D1 through its BAR domain [PMID:24879834], yet in pancreatic β-cells it promotes glucose-stimulated insulin secretion by binding RacGAP1 via its BAR-PH domain to relieve inhibition of Rac1 and enable F-actin remodeling [PMID:33122440]. In transcriptional and developmental contexts, APPL2 activates β-catenin/TCF transcription by disrupting a Reptin-HDAC1/2 repressive complex [PMID:19433865], interacts with Notch1 to bias adult neural stem cells toward gliogenesis [PMID:32468397], and acts upstream of glucocorticoid receptor activity to regulate hippocampal neurogenesis [PMID:28965332].","teleology":[{"year":2006,"claim":"Established that APPL2 is functionally distinct from its paralog APPL1, defining the central question of paralog-specific roles.","evidence":"Reciprocal Co-immunoprecipitation testing multiple binding partners, including a negative result for Akt2","pmids":["17030088"],"confidence":"Medium","gaps":["Functional consequence of FSHR binding not resolved","Did not address endosomal or signaling roles"]},{"year":2007,"claim":"Resolved the domain-level basis of APPL2 membrane targeting and oligomerization, showing the BAR domain mediates APPL-APPL interactions and PH/PTB domains bind phosphoinositides.","evidence":"Co-IP, yeast two-hybrid, in vitro phosphoinositide-binding assay, and live-cell imaging of RAB5 recruitment","pmids":["18034774"],"confidence":"High","gaps":["Specific phosphoinositide species preference not fully defined","Physiological cargo of these membrane structures not identified"]},{"year":2009,"claim":"Showed APPL2 has a nuclear/transcriptional function, relieving Reptin-HDAC-mediated repression of β-catenin/TCF targets, extending its role beyond endosomes.","evidence":"Co-IP, reporter assay, siRNA knockdown, and chromatin immunoprecipitation","pmids":["19433865"],"confidence":"High","gaps":["How endosomal APPL2 reaches transcriptional complexes unclear","Direct vs. indirect disruption of Reptin complex not distinguished"]},{"year":2010,"claim":"Confirmed that APPL1-APPL2 BAR-domain interactions occur directly on curved membranes in living cells, validating the structural model in situ.","evidence":"Three independent FRET methods in live cells","pmids":["20814572"],"confidence":"High","gaps":["Stoichiometry of oligomers not determined","Regulation of homo- vs. heterotypic interaction not addressed"]},{"year":2012,"claim":"Identified an endosome- and Akt-independent prosurvival role for APPL2 in glioma cells, indicating functions beyond its canonical scaffolding.","evidence":"siRNA/shRNA knockdown with caspase, colony formation, xenograft, and gene expression readouts","pmids":["22989406"],"confidence":"Medium","gaps":["Mechanism linking APPL2 to UNC5B/HRK regulation unknown","Single lab; cell-type generality untested"]},{"year":2014,"claim":"Defined APPL2 as a negative regulator of insulin-stimulated GLUT4 trafficking via phospho-dependent TBC1D1 sequestration, providing a resolved metabolic mechanism.","evidence":"Co-IP with domain mapping, site-directed mutagenesis, conditional knockout mice, and glucose uptake/GLUT4 translocation assays","pmids":["24879834"],"confidence":"High","gaps":["Kinase responsible for Ser235 phosphorylation not identified in this axis","Tissue-specific contribution to whole-body glucose homeostasis not fully quantified"]},{"year":2014,"claim":"Established APPL2 as a negative regulator of innate immune PI3K/Akt/NF-κB signaling through a complex with APPL1 and p85α, with opposing roles to APPL1.","evidence":"Co-IP, Appl2 knockout mice, LPS challenge, cytokine ELISA, and Akt/NF-κB immunoblotting","pmids":["25328665"],"confidence":"High","gaps":["How APPL2 inhibits p85α/PI3K mechanistically not resolved","Relationship to membrane localization not directly tested here"]},{"year":2015,"claim":"Showed RAB31-GTP recruits APPL2 to phagosomes to drive phosphoinositide conversion and FcγR-mediated phagocytosis, linking its endosomal localization to immune effector function.","evidence":"siRNA knockdown, fluorescence imaging of phagosome stages, and PI3K/Akt and p38 signaling assays","pmids":["25568335"],"confidence":"High","gaps":["Direct enzymatic role in PIP conversion vs. scaffolding unclear","How RAB31 and RAB5 recruitment are coordinated unknown"]},{"year":2015,"claim":"Demonstrated functional redundancy between APPL1 and APPL2 in HGF-induced Akt signaling and cell motility, clarifying when paralog loss produces phenotypes.","evidence":"Single and double knockout mice and MEF Akt signaling, migration, and invasion assays","pmids":["26445298"],"confidence":"Medium","gaps":["Molecular basis of redundancy not dissected","Whether redundancy extends to other pathways untested"]},{"year":2016,"claim":"Refined the TLR4-signaling role of APPL2, showing it is required for NF-κB p65 nuclear translocation and cytokine secretion with effects on Akt/MAPK opposite to APPL1.","evidence":"siRNA depletion, immunofluorescence localization, NF-κB translocation, cytokine secretion, and Akt/MAPK immunoblotting","pmids":["27219021"],"confidence":"Medium","gaps":["Reconciliation with APPL2 as NF-κB suppressor in other contexts unresolved","Direct molecular target controlling p65 translocation not identified"]},{"year":2017,"claim":"Placed APPL2 upstream of glucocorticoid receptor activity in regulating hippocampal neurogenesis, establishing a developmental/neuroendocrine role.","evidence":"APPL2 transgenic mice, GR phosphorylation immunoblotting, neurogenesis quantification, and pharmacological rescue with RU486","pmids":["28965332"],"confidence":"Medium","gaps":["Direct vs. indirect control of GR phosphorylation unknown","Molecular link between APPL2 and GR not mapped"]},{"year":2020,"claim":"Resolved a tissue-opposite metabolic role: in β-cells APPL2 promotes insulin secretion by binding RacGAP1 to relieve Rac1 inhibition and enable F-actin remodeling.","evidence":"β-cell-specific knockout mice, Co-IP with domain mapping, genetic epistasis via RacGAP1 double knockdown, F-actin imaging, and Rac1 activation assays","pmids":["33122440"],"confidence":"High","gaps":["Glucose-dependence of the APPL2-RacGAP1 interaction mechanism unclear","How this reconciles with APPL2's inhibitory role in muscle not integrated"]},{"year":2020,"claim":"Identified APPL2-Notch1 interaction as a determinant of adult neural stem cell fate, biasing toward gliogenesis over neurogenesis.","evidence":"Co-IP, in vitro NSC differentiation, APPL2 transgenic mice, immunofluorescence, and olfactory behavioral testing","pmids":["32468397"],"confidence":"Medium","gaps":["Whether APPL2 modulates Notch1 signaling directly not established","Domain mediating Notch1 interaction not mapped"]},{"year":null,"claim":"How a single endosomal adaptor coordinates its opposing context-dependent outputs across metabolic, immune, transcriptional, and developmental pathways remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unifying mechanism explaining tissue-opposite effects (e.g. muscle vs. β-cell)","Structural basis for differential partner selection by the shared BAR-PH-PTB architecture undefined","No structural model of APPL2-partner complexes"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[1,5,6,11]},{"term_id":"GO:0008289","term_label":"lipid binding","supporting_discovery_ids":[1,7]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[5,6,11]},{"term_id":"GO:0140110","term_label":"transcription regulator activity","supporting_discovery_ids":[2]}],"localization":[{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[1,7]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[1]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[9]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[2,9]}],"pathway":[{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[6,7,9]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[5,6,11]},{"term_id":"R-HSA-74160","term_label":"Gene expression (Transcription)","supporting_discovery_ids":[2]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[10,12]},{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[5,7]}],"complexes":["APPL1-APPL2 BAR oligomer","APPL1-APPL2-p85alpha (PI3K) complex","Reptin-beta-catenin-HDAC1/2 complex"],"partners":["APPL1","TBC1D1","RACGAP1","REPTIN","NOTCH1","FSHR","RAB5","RAB31"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q06481","full_name":"Amyloid beta precursor like protein 2","aliases":["APPH","Amyloid beta (A4) precursor-like protein 2","Amyloid protein homolog","Amyloid-like protein 2","APLP-2","CDEI box-binding protein","CDEBP","Sperm membrane protein YWK-II"],"length_aa":763,"mass_kda":87.0,"function":"May play a role in the regulation of hemostasis. The soluble form may have inhibitory properties towards coagulation factors. May interact with cellular G-protein signaling pathways. May bind to the DNA 5'-GTCACATG-3'(CDEI box). Inhibits trypsin, chymotrypsin, plasmin, factor XIA and plasma and glandular kallikrein. Modulates the Cu/Zn nitric oxide-catalyzed autodegradation of GPC1 heparan sulfate side chains in fibroblasts (By similarity)","subcellular_location":"Cell membrane; Nucleus","url":"https://www.uniprot.org/uniprotkb/Q06481/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/APPL2","classification":"Not Classified","n_dependent_lines":1,"n_total_lines":1208,"dependency_fraction":0.0008278145695364238},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000136044","cell_line_id":"CID000672","localizations":[{"compartment":"cytoplasmic","grade":3},{"compartment":"vesicles","grade":1}],"interactors":[{"gene":"APPL1","stoichiometry":4.0},{"gene":"CLNS1A","stoichiometry":0.2},{"gene":"MYO6","stoichiometry":0.2},{"gene":"POLR2E","stoichiometry":0.2},{"gene":"POLR3B","stoichiometry":0.2},{"gene":"POLR3F","stoichiometry":0.2},{"gene":"POLR3H","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID000672","total_profiled":1310},"omim":[{"mim_id":"606231","title":"ADAPTOR PROTEIN, PHOSPHOTYROSINE INTERACTION, PH DOMAIN, AND LEUCINE ZIPPER-CONTAINING PROTEIN 2; APPL2","url":"https://www.omim.org/entry/606231"},{"mim_id":"604299","title":"ADAPTOR PROTEIN, PHOSPHOTYROSINE INTERACTION, PH DOMAIN, AND LEUCINE ZIPPER-CONTAINING PROTEIN 1; APPL1","url":"https://www.omim.org/entry/604299"},{"mim_id":"179512","title":"RAS-ASSOCIATED PROTEIN RAB5A; RAB5A","url":"https://www.omim.org/entry/179512"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Vesicles","reliability":"Approved"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/APPL2"},"hgnc":{"alias_symbol":["FLJ10659","DIP13B"],"prev_symbol":[]},"alphafold":{"accession":"Q06481","domains":[{"cath_id":"3.90.570.10","chopping":"52-136","consensus_level":"high","plddt":87.6595,"start":52,"end":136},{"cath_id":"3.30.1490.140","chopping":"151-205","consensus_level":"high","plddt":92.8027,"start":151,"end":205},{"cath_id":"4.10.410.10","chopping":"300-364","consensus_level":"high","plddt":88.0675,"start":300,"end":364},{"cath_id":"1.20.120.770","chopping":"374-456","consensus_level":"high","plddt":90.1201,"start":374,"end":456},{"cath_id":"1.20.120.770","chopping":"482-577","consensus_level":"high","plddt":88.3395,"start":482,"end":577}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q06481","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q06481-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q06481-F1-predicted_aligned_error_v6.png","plddt_mean":68.38},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=APPL2","jax_strain_url":"https://www.jax.org/strain/search?query=APPL2"},"sequence":{"accession":"Q06481","fasta_url":"https://rest.uniprot.org/uniprotkb/Q06481.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q06481/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q06481"}},"corpus_meta":[{"pmid":"17030088","id":"PMC_17030088","title":"APPL1, APPL2, Akt2 and FOXO1a interact with FSHR in a potential signaling complex.","date":"2006","source":"Molecular and cellular endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/17030088","citation_count":78,"is_preprint":false},{"pmid":"19433865","id":"PMC_19433865","title":"Endosomal adaptor proteins APPL1 and APPL2 are novel activators of beta-catenin/TCF-mediated transcription.","date":"2009","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/19433865","citation_count":54,"is_preprint":false},{"pmid":"18034774","id":"PMC_18034774","title":"Membrane targeting by APPL1 and APPL2: dynamic scaffolds that oligomerize and bind phosphoinositides.","date":"2007","source":"Traffic (Copenhagen, Denmark)","url":"https://pubmed.ncbi.nlm.nih.gov/18034774","citation_count":45,"is_preprint":false},{"pmid":"29675572","id":"PMC_29675572","title":"Baicalin Modulates APPL2/Glucocorticoid Receptor Signaling Cascade, Promotes Neurogenesis, and Attenuates Emotional and Olfactory Dysfunctions in Chronic Corticosterone-Induced Depression.","date":"2018","source":"Molecular neurobiology","url":"https://pubmed.ncbi.nlm.nih.gov/29675572","citation_count":40,"is_preprint":false},{"pmid":"25568335","id":"PMC_25568335","title":"Rab31 and APPL2 enhance FcγR-mediated phagocytosis through PI3K/Akt signaling in macrophages.","date":"2015","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/25568335","citation_count":37,"is_preprint":false},{"pmid":"33122440","id":"PMC_33122440","title":"The adaptor protein APPL2 controls glucose-stimulated insulin secretion via F-actin remodeling in pancreatic β-cells.","date":"2020","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/33122440","citation_count":30,"is_preprint":false},{"pmid":"24879834","id":"PMC_24879834","title":"The adaptor protein APPL2 inhibits insulin-stimulated glucose uptake by interacting with TBC1D1 in skeletal muscle.","date":"2014","source":"Diabetes","url":"https://pubmed.ncbi.nlm.nih.gov/24879834","citation_count":28,"is_preprint":false},{"pmid":"22989406","id":"PMC_22989406","title":"Multifunctional protein APPL2 contributes to survival of human glioma cells.","date":"2012","source":"Molecular oncology","url":"https://pubmed.ncbi.nlm.nih.gov/22989406","citation_count":17,"is_preprint":false},{"pmid":"20814572","id":"PMC_20814572","title":"APPL proteins FRET at the BAR: direct observation of APPL1 and APPL2 BAR domain-mediated interactions on cell membranes using FRET microscopy.","date":"2010","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/20814572","citation_count":17,"is_preprint":false},{"pmid":"23977033","id":"PMC_23977033","title":"Association of genetic variation in adaptor protein APPL1/APPL2 loci with non-alcoholic fatty liver disease.","date":"2013","source":"PloS 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Denmark)","url":"https://pubmed.ncbi.nlm.nih.gov/27219021","citation_count":13,"is_preprint":false},{"pmid":"25328665","id":"PMC_25328665","title":"Absence of Appl2 sensitizes endotoxin shock through activation of PI3K/Akt pathway.","date":"2014","source":"Cell & bioscience","url":"https://pubmed.ncbi.nlm.nih.gov/25328665","citation_count":12,"is_preprint":false},{"pmid":"30189216","id":"PMC_30189216","title":"The reversal effect of physical exercise on aging-related increases in APPL2 content in skeletal muscle.","date":"2018","source":"Life sciences","url":"https://pubmed.ncbi.nlm.nih.gov/30189216","citation_count":8,"is_preprint":false},{"pmid":"30218350","id":"PMC_30218350","title":"Overexpressed in colorectal carcinoma gene (OCC-1) upregulation and APPL2 gene downregulation in breast cancer specimens.","date":"2018","source":"Molecular biology reports","url":"https://pubmed.ncbi.nlm.nih.gov/30218350","citation_count":4,"is_preprint":false},{"pmid":"32468397","id":"PMC_32468397","title":"APPL2 Negatively Regulates Olfactory Functions by Switching Fate Commitments of Neural Stem Cells in Adult Olfactory Bulb via Interaction with Notch1 Signaling.","date":"2020","source":"Neuroscience bulletin","url":"https://pubmed.ncbi.nlm.nih.gov/32468397","citation_count":1,"is_preprint":false},{"pmid":"38431228","id":"PMC_38431228","title":"Aspongopus chinensis ach-miR-276a-3p induces breast cancer cell cycle arrest by targeting APPL2 to regulate the CDK2-Rb-E2F1 signaling pathway.","date":"2024","source":"Toxicology and applied pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/38431228","citation_count":0,"is_preprint":false},{"pmid":"38927595","id":"PMC_38927595","title":"Lack of T04C9.1, the Homologue of Mammalian APPL2, Leads to Premature Ageing and Shortens Lifespan in Caenorhabditis elegans.","date":"2024","source":"Genes","url":"https://pubmed.ncbi.nlm.nih.gov/38927595","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":12308,"output_tokens":3517,"usd":0.044839,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":11110,"output_tokens":4568,"usd":0.084875,"stage2_stop_reason":"end_turn"},"total_usd":0.129714,"stage1_batch_id":"msgbatch_0179Z2pxRYBsXi2xADneafRw","stage2_batch_id":"msgbatch_01LaY9ZaVdgjWArcZo9eqQE5","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2006,\n      \"finding\": \"APPL2 interacts with FSHR (follicle stimulating hormone receptor) and with APPL1 via the N-terminus/BAR domain of APPL1; unlike APPL1, APPL2 does not associate with Akt2, establishing a functional distinction between the two paralogs.\",\n      \"method\": \"Co-immunoprecipitation\",\n      \"journal\": \"Molecular and cellular endocrinology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — reciprocal Co-IP in single lab, but multiple binding partners tested and a clear negative result (APPL2 does not bind Akt2) distinguishes APPL2 from APPL1\",\n      \"pmids\": [\"17030088\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"APPL2 forms homooligomers and heterooligomers with APPL1 through its BAR domain (necessary and sufficient for APPL-APPL interactions); full-length APPL2 binds phosphoinositides via its PH and PTB domains; APPL2-YFP localizes to cytosolic membrane structures that undergo movement, fusion and fission events and recruits endogenous RAB5 to enlarged membrane structures.\",\n      \"method\": \"Co-immunoprecipitation, yeast two-hybrid, in vitro phosphoinositide-binding assay, live-cell fluorescence imaging\",\n      \"journal\": \"Traffic (Copenhagen, Denmark)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (Co-IP, Y2H, in vitro lipid binding, live imaging) in a single study establishing domain-level mechanisms\",\n      \"pmids\": [\"18034774\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"APPL2 activates beta-catenin/TCF-mediated transcription by directly interacting with the transcriptional repressor Reptin (via the PH domain of APPL1, mapped for APPL1; APPL2 similarly interacts); APPL2 is present in an endogenous complex containing Reptin, beta-catenin, HDAC1, and HDAC2; overexpression of APPL2 relieves Reptin-dependent repression and reduces amounts of HDACs and beta-catenin associated with Reptin.\",\n      \"method\": \"Co-immunoprecipitation, reporter assay, siRNA knockdown, chromatin immunoprecipitation\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (Co-IP, reporter assay, siRNA KD, ChIP) in a single study with functional validation\",\n      \"pmids\": [\"19433865\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"APPL1 and APPL2 BAR domains interact directly on curved cell membranes in a homotypic (APPL1-APPL1, APPL2-APPL2) and heterotypic (APPL1-APPL2) manner, as demonstrated by FRET.\",\n      \"method\": \"FRET microscopy (sensitized emission, acceptor photobleaching, sequential acceptor photobleaching) in live cells\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — three independent FRET methods consistently confirming direct in vivo BAR domain interactions on membranes\",\n      \"pmids\": [\"20814572\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"APPL2 knockdown in glioma cells reduces cell survival and enhances apoptosis by upregulating apoptosis-related genes UNC5B and HRK; this prosurvival activity is independent of Akt/GSK3β modulation and of APPL2's endosomal localization.\",\n      \"method\": \"siRNA/shRNA knockdown, caspase activity assay, colony formation assay, xenograft tumor growth, gene expression analysis\",\n      \"journal\": \"Molecular oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KD/KO with defined cellular phenotypes and multiple orthogonal readouts, single lab\",\n      \"pmids\": [\"22989406\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"APPL2 inhibits insulin-stimulated GLUT4 translocation and glucose uptake in skeletal muscle by interacting with TBC1D1; insulin stimulates TBC1D1 phosphorylation on Ser235, which enhances binding to the BAR domain of APPL2, suppressing subsequent TBC1D1 phosphorylation on Thr596 needed for GLUT4 trafficking. Ser235Ala substitution in TBC1D1 abolishes this inhibitory axis.\",\n      \"method\": \"Co-immunoprecipitation, site-directed mutagenesis, conditional knockout mice, glucose uptake assay, GLUT4 translocation assay\",\n      \"journal\": \"Diabetes\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — Co-IP with domain mapping, mutagenesis, conditional KO mice, and multiple functional readouts; mechanistic pathway fully resolved\",\n      \"pmids\": [\"24879834\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"APPL2 forms a complex with APPL1 and the PI3K regulatory subunit p85α; in LPS-challenged macrophages, loss of APPL2 enhances PI3K/Akt/NF-κB signaling and increases TNF-α and IL-1β production, whereas loss of APPL1 reduces Akt activation and cytokine production, indicating APPL2 is a negative regulator of innate immune signaling through this complex.\",\n      \"method\": \"Co-immunoprecipitation, Appl2 knockout mice, LPS challenge, cytokine ELISA, Akt/NF-κB phosphorylation immunoblotting\",\n      \"journal\": \"Cell & bioscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — Co-IP identifying complex components, KO mice with defined immune phenotype, and multiple molecular readouts in a single study\",\n      \"pmids\": [\"25328665\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Rab31-GTP recruits APPL2 to early-stage phagosomes; siRNA depletion of APPL2 delays the PI(4,5)P2-to-PI(3,4,5)P3 transition, impairs phagocytic cup closure, reduces PI3K/Akt signaling, and enhances p38 signaling from FcγR, thereby reducing FcγR-mediated phagocytosis in macrophages.\",\n      \"method\": \"siRNA knockdown, fluorescence imaging of phagosome stages, PI3K/Akt and p38 signaling assays\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — siRNA depletion with multiple orthogonal functional readouts (phagocytosis, phosphoinositide dynamics, signaling kinetics) in a single study\",\n      \"pmids\": [\"25568335\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"APPL1 and APPL2 double-knockout mouse embryonic fibroblasts exhibit defects in HGF-induced Akt activation, migration, and invasion, while individual knockouts of either protein do not impair development, indicating redundant roles in HGF signaling.\",\n      \"method\": \"Conditional/constitutive knockout mice, MEF Akt signaling assay, migration/invasion assay\",\n      \"journal\": \"Journal of cellular physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean genetic KO (single and double), defined signaling and phenotypic readouts, single lab\",\n      \"pmids\": [\"26445298\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"APPL2 localizes to distinct surface and endocytic membrane domains in LPS-activated macrophages; depletion of APPL2 specifically impairs nuclear translocation of NF-κB p65 and constrains secretion of pro- and anti-inflammatory cytokines downstream of TLR4, with APPL2 having opposing regulatory effects to APPL1 on Akt and MAPK signaling.\",\n      \"method\": \"siRNA depletion, immunofluorescence localization, NF-κB nuclear translocation assay, cytokine secretion assay, Akt/MAPK phosphorylation immunoblotting\",\n      \"journal\": \"Traffic (Copenhagen, Denmark)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA KD with multiple signaling and functional readouts, single lab\",\n      \"pmids\": [\"27219021\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"APPL2 overexpression in transgenic mice enhances glucocorticoid receptor (GR) phosphorylation under basal conditions and impairs hippocampal neurogenesis; this neurogenesis defect is reversed by the GR antagonist RU486, placing APPL2 upstream of GR activity.\",\n      \"method\": \"APPL2 transgenic mice, GR phosphorylation immunoblotting, hippocampal neurogenesis quantification, pharmacological rescue with RU486\",\n      \"journal\": \"Molecular neurobiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — transgenic model with pharmacological rescue establishing epistasis, single lab\",\n      \"pmids\": [\"28965332\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"APPL2 enhances glucose-stimulated insulin secretion (GSIS) by promoting F-actin depolymerization via Rac1 in pancreatic β-cells; APPL2 interacts with RacGAP1 in a glucose-dependent manner through its BAR-PH domain, suppressing RacGAP1's inhibitory action on Rac1, thereby enabling F-actin remodeling. Concurrent knockdown of RacGAP1 rescues APPL2-deficiency-induced defects in GSIS, F-actin remodeling, and Rac1 activation.\",\n      \"method\": \"β-cell-specific APPL2 knockout mice, Co-immunoprecipitation with domain mapping, siRNA knockdown, live-cell F-actin imaging, phalloidin staining, Rac1 activation assay, pharmacological rescue\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — conditional KO mice, Co-IP with domain mapping, genetic epistasis (double KD rescue), and multiple orthogonal functional readouts in a single study\",\n      \"pmids\": [\"33122440\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"APPL2 interacts with Notch1 and promotes gliogenesis over neurogenesis in adult olfactory bulb neural stem cells; APPL2 overexpression switches NSC fate from neuronal differentiation to gliogenesis, while knockdown promotes neurogenesis, and APPL2 transgenic mice show higher glial cell populations and impaired olfactory discrimination.\",\n      \"method\": \"Co-immunoprecipitation (APPL2-Notch1), in vitro NSC differentiation assay, APPL2 transgenic mice, immunofluorescence quantification, olfactory behavioral testing\",\n      \"journal\": \"Neuroscience bulletin\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — Co-IP identifying binding partner, in vitro and in vivo models with phenotypic readouts, single lab\",\n      \"pmids\": [\"32468397\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"APPL2 is a multidomain endosomal adaptor protein (BAR-PH-PTB) that forms homo- and heterooligomers with APPL1 via BAR domains, binds phosphoinositides, and localizes to RAB5/RAB31-positive signaling endosomes, where it scaffolds distinct signaling complexes: it suppresses PI3K/Akt/NF-κB-mediated innate immune signaling by forming a complex with APPL1 and PI3K-p85α, inhibits insulin-stimulated GLUT4 trafficking by sequestering TBC1D1 via its BAR domain, promotes glucose-stimulated insulin secretion in β-cells by binding RacGAP1 (through BAR-PH) to relieve inhibition of Rac1 and enable F-actin remodeling, activates Wnt/beta-catenin transcription by disrupting a Reptin-HDAC repressive complex, regulates NF-κB nuclear translocation and cytokine secretion downstream of TLR4, and controls neural stem cell fate decisions via interaction with Notch1—collectively acting as a context-dependent molecular switch that modulates metabolic, immune, and developmental signaling.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"APPL2 is a multidomain endosomal adaptor protein that functions as a context-dependent scaffold modulating metabolic, immune, and developmental signaling [#1, #6]. It oligomerizes through its BAR domain, forming both homooligomers and heterooligomers with its paralog APPL1, binds phosphoinositides via its PH and PTB domains, and localizes to dynamic cytosolic membrane structures where it recruits RAB5 [#1]; direct BAR-domain interactions between APPL1 and APPL2 occur on curved membranes in living cells [#3]. Functional divergence from APPL1 is established by APPL2's failure to associate with Akt2 [#0]. In innate immunity, APPL2 forms a complex with APPL1 and the PI3K regulatory subunit p85\\u03b1 and acts as a negative regulator of PI3K/Akt/NF-\\u03baB signaling, restraining TNF-\\u03b1 and IL-1\\u03b2 production in LPS-challenged macrophages [#6], while controlling NF-\\u03baB p65 nuclear translocation and cytokine secretion downstream of TLR4 [#9]; RAB31-GTP recruits APPL2 to early phagosomes where it drives the PI(4,5)P2-to-PI(3,4,5)P3 transition required for Fc\\u03b3R-mediated phagocytosis [#7]. In glucose metabolism, APPL2 inhibits insulin-stimulated GLUT4 translocation in skeletal muscle by binding insulin-induced Ser235-phosphorylated TBC1D1 through its BAR domain [#5], yet in pancreatic \\u03b2-cells it promotes glucose-stimulated insulin secretion by binding RacGAP1 via its BAR-PH domain to relieve inhibition of Rac1 and enable F-actin remodeling [#11]. In transcriptional and developmental contexts, APPL2 activates \\u03b2-catenin/TCF transcription by disrupting a Reptin-HDAC1/2 repressive complex [#2], interacts with Notch1 to bias adult neural stem cells toward gliogenesis [#12], and acts upstream of glucocorticoid receptor activity to regulate hippocampal neurogenesis [#10].\",\n  \"teleology\": [\n    {\n      \"year\": 2006,\n      \"claim\": \"Established that APPL2 is functionally distinct from its paralog APPL1, defining the central question of paralog-specific roles.\",\n      \"evidence\": \"Reciprocal Co-immunoprecipitation testing multiple binding partners, including a negative result for Akt2\",\n      \"pmids\": [\"17030088\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of FSHR binding not resolved\", \"Did not address endosomal or signaling roles\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Resolved the domain-level basis of APPL2 membrane targeting and oligomerization, showing the BAR domain mediates APPL-APPL interactions and PH/PTB domains bind phosphoinositides.\",\n      \"evidence\": \"Co-IP, yeast two-hybrid, in vitro phosphoinositide-binding assay, and live-cell imaging of RAB5 recruitment\",\n      \"pmids\": [\"18034774\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specific phosphoinositide species preference not fully defined\", \"Physiological cargo of these membrane structures not identified\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Showed APPL2 has a nuclear/transcriptional function, relieving Reptin-HDAC-mediated repression of \\u03b2-catenin/TCF targets, extending its role beyond endosomes.\",\n      \"evidence\": \"Co-IP, reporter assay, siRNA knockdown, and chromatin immunoprecipitation\",\n      \"pmids\": [\"19433865\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How endosomal APPL2 reaches transcriptional complexes unclear\", \"Direct vs. indirect disruption of Reptin complex not distinguished\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Confirmed that APPL1-APPL2 BAR-domain interactions occur directly on curved membranes in living cells, validating the structural model in situ.\",\n      \"evidence\": \"Three independent FRET methods in live cells\",\n      \"pmids\": [\"20814572\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Stoichiometry of oligomers not determined\", \"Regulation of homo- vs. heterotypic interaction not addressed\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Identified an endosome- and Akt-independent prosurvival role for APPL2 in glioma cells, indicating functions beyond its canonical scaffolding.\",\n      \"evidence\": \"siRNA/shRNA knockdown with caspase, colony formation, xenograft, and gene expression readouts\",\n      \"pmids\": [\"22989406\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism linking APPL2 to UNC5B/HRK regulation unknown\", \"Single lab; cell-type generality untested\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Defined APPL2 as a negative regulator of insulin-stimulated GLUT4 trafficking via phospho-dependent TBC1D1 sequestration, providing a resolved metabolic mechanism.\",\n      \"evidence\": \"Co-IP with domain mapping, site-directed mutagenesis, conditional knockout mice, and glucose uptake/GLUT4 translocation assays\",\n      \"pmids\": [\"24879834\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Kinase responsible for Ser235 phosphorylation not identified in this axis\", \"Tissue-specific contribution to whole-body glucose homeostasis not fully quantified\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Established APPL2 as a negative regulator of innate immune PI3K/Akt/NF-\\u03baB signaling through a complex with APPL1 and p85\\u03b1, with opposing roles to APPL1.\",\n      \"evidence\": \"Co-IP, Appl2 knockout mice, LPS challenge, cytokine ELISA, and Akt/NF-\\u03baB immunoblotting\",\n      \"pmids\": [\"25328665\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How APPL2 inhibits p85\\u03b1/PI3K mechanistically not resolved\", \"Relationship to membrane localization not directly tested here\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Showed RAB31-GTP recruits APPL2 to phagosomes to drive phosphoinositide conversion and Fc\\u03b3R-mediated phagocytosis, linking its endosomal localization to immune effector function.\",\n      \"evidence\": \"siRNA knockdown, fluorescence imaging of phagosome stages, and PI3K/Akt and p38 signaling assays\",\n      \"pmids\": [\"25568335\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct enzymatic role in PIP conversion vs. scaffolding unclear\", \"How RAB31 and RAB5 recruitment are coordinated unknown\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Demonstrated functional redundancy between APPL1 and APPL2 in HGF-induced Akt signaling and cell motility, clarifying when paralog loss produces phenotypes.\",\n      \"evidence\": \"Single and double knockout mice and MEF Akt signaling, migration, and invasion assays\",\n      \"pmids\": [\"26445298\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular basis of redundancy not dissected\", \"Whether redundancy extends to other pathways untested\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Refined the TLR4-signaling role of APPL2, showing it is required for NF-\\u03baB p65 nuclear translocation and cytokine secretion with effects on Akt/MAPK opposite to APPL1.\",\n      \"evidence\": \"siRNA depletion, immunofluorescence localization, NF-\\u03baB translocation, cytokine secretion, and Akt/MAPK immunoblotting\",\n      \"pmids\": [\"27219021\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Reconciliation with APPL2 as NF-\\u03baB suppressor in other contexts unresolved\", \"Direct molecular target controlling p65 translocation not identified\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Placed APPL2 upstream of glucocorticoid receptor activity in regulating hippocampal neurogenesis, establishing a developmental/neuroendocrine role.\",\n      \"evidence\": \"APPL2 transgenic mice, GR phosphorylation immunoblotting, neurogenesis quantification, and pharmacological rescue with RU486\",\n      \"pmids\": [\"28965332\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct vs. indirect control of GR phosphorylation unknown\", \"Molecular link between APPL2 and GR not mapped\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Resolved a tissue-opposite metabolic role: in \\u03b2-cells APPL2 promotes insulin secretion by binding RacGAP1 to relieve Rac1 inhibition and enable F-actin remodeling.\",\n      \"evidence\": \"\\u03b2-cell-specific knockout mice, Co-IP with domain mapping, genetic epistasis via RacGAP1 double knockdown, F-actin imaging, and Rac1 activation assays\",\n      \"pmids\": [\"33122440\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Glucose-dependence of the APPL2-RacGAP1 interaction mechanism unclear\", \"How this reconciles with APPL2's inhibitory role in muscle not integrated\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Identified APPL2-Notch1 interaction as a determinant of adult neural stem cell fate, biasing toward gliogenesis over neurogenesis.\",\n      \"evidence\": \"Co-IP, in vitro NSC differentiation, APPL2 transgenic mice, immunofluorescence, and olfactory behavioral testing\",\n      \"pmids\": [\"32468397\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether APPL2 modulates Notch1 signaling directly not established\", \"Domain mediating Notch1 interaction not mapped\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How a single endosomal adaptor coordinates its opposing context-dependent outputs across metabolic, immune, transcriptional, and developmental pathways remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unifying mechanism explaining tissue-opposite effects (e.g. muscle vs. \\u03b2-cell)\", \"Structural basis for differential partner selection by the shared BAR-PH-PTB architecture undefined\", \"No structural model of APPL2-partner complexes\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [1, 5, 6, 11]},\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [1, 7]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [5, 6, 11]},\n      {\"term_id\": \"GO:0140110\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [1, 7]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [1]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [9]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [2, 9]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [6, 7, 9]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [5, 6, 11]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [10, 12]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [5, 7]}\n    ],\n    \"complexes\": [\n      \"APPL1-APPL2 BAR oligomer\",\n      \"APPL1-APPL2-p85alpha (PI3K) complex\",\n      \"Reptin-beta-catenin-HDAC1/2 complex\"\n    ],\n    \"partners\": [\n      \"APPL1\",\n      \"TBC1D1\",\n      \"RacGAP1\",\n      \"Reptin\",\n      \"Notch1\",\n      \"FSHR\",\n      \"RAB5\",\n      \"RAB31\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":6,"faith_total":6,"faith_pct":100.0}}