{"gene":"MAL2","run_date":"2026-04-28T18:30:27","timeline":{"discoveries":[{"year":2002,"finding":"MAL2 is an essential component of the transcytotic machinery in polarized hepatoma HepG2 cells; it resides in rafts and a subapical compartment, and depletion of endogenous MAL2 drastically blocks transcytotic transport of polymeric immunoglobulin receptor and GPI-anchored protein CD59 to the apical membrane, causing their accumulation in perinuclear endosomes, without affecting internalization.","method":"Antisense-mediated depletion of endogenous MAL2, rescue with depletion-resistant exogenous MAL2, subcellular fractionation, confocal immunofluorescence, biochemical raft isolation","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 — clean KO/KD with specific transcytosis phenotype, rescue experiment, replicated in same study with multiple orthogonal methods","pmids":["12370246"],"is_preprint":false},{"year":2001,"finding":"MAL2 was identified as a binding partner of TPD52-like proteins (TPD52L2 and related) via yeast two-hybrid screening, confirmed by GST pull-down assay showing specific binding of in vitro-translated MAL2 to GST-Tpd52; MAL2 is a four-transmembrane proteolipid of 19 kDa.","method":"Yeast two-hybrid screen, GST pull-down assay with in vitro translated MAL2","journal":"Genomics","confidence":"Medium","confidence_rationale":"Tier 3 — identified by Y2H and confirmed by GST pull-down, single study","pmids":["11549320"],"is_preprint":false},{"year":2006,"finding":"MAL2 is a highly dynamic protein that mediates GPI-anchored protein (CD59) transcytosis by redistributing into peripheral vesicular clusters that concentrate CD59 and transferrin receptor after basolateral endocytosis, then segregating transferrin receptor, fusing into a globular MAL2+ structure, and moving apically for cargo delivery; all steps are impaired upon MAL2 depletion.","method":"Live-cell imaging of GFP-MAL2 and transcytosing CD59, subcellular fractionation, MAL2 siRNA knockdown","journal":"Traffic (Copenhagen, Denmark)","confidence":"High","confidence_rationale":"Tier 2 — live imaging plus KD with defined mechanistic steps, multiple cargoes tested","pmids":["16445687"],"is_preprint":false},{"year":2010,"finding":"INF2, an atypical formin with actin polymerization and depolymerization activities, is a direct binding partner of MAL2; MAL2-positive vesicular carriers associate with short actin filaments during transcytosis in an INF2-dependent process; Cdc42 binds INF2 in a GTP-loaded-dependent manner and, together with INF2, regulates MAL2 vesicle dynamics, apical transcytosis, and lumen formation in a sequential epistatic pathway: Cdc42 → INF2 → MAL2.","method":"Co-immunoprecipitation, yeast two-hybrid, live imaging of MAL2 vesicle dynamics, siRNA knockdown of INF2/Cdc42, organotypic MDCK lumen formation assay","journal":"Developmental cell","confidence":"High","confidence_rationale":"Tier 2 — reciprocal Co-IP, genetic epistasis, live imaging, multiple orthogonal methods in one study","pmids":["20493814"],"is_preprint":false},{"year":2010,"finding":"MAL2 is a bona fide membrane constituent of synaptic vesicles preferentially associated with VGLUT-1-containing (glutamatergic) nerve terminals, as established by quantitative proteomics, subcellular fractionation, and immunolocalization at light and electron microscopic level.","method":"Quantitative proteomics of isolated synaptic vesicle populations, subcellular fractionation, immunofluorescence, immunoelectron microscopy","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 — quantitative proteomics plus EM-level localization, large-scale comparative study","pmids":["20053882"],"is_preprint":false},{"year":2010,"finding":"MAL2 selectively regulates polymeric IgA receptor (pIgA-R) delivery from the Golgi to the plasma membrane in hepatic WIF-B cells; overexpression of MAL2 in Clone 9 cells (lacking endogenous MAL2) enabled pIgA-R surface delivery (>9-fold enhancement) while MAL2 knockdown retained pIgA-R in the Golgi; this selectivity was not shared by other membrane proteins such as DPPIV.","method":"MAL2 knockdown/overexpression in WIF-B and Clone 9 cells, cycloheximide chase, immunofluorescence, surface delivery assay","journal":"Traffic (Copenhagen, Denmark)","confidence":"High","confidence_rationale":"Tier 2 — clean KD and KO rescue with quantitative surface delivery assay, selective cargo specificity demonstrated","pmids":["20444237"],"is_preprint":false},{"year":2011,"finding":"MAL, but not MAL2, self-associates and forms higher-order cholesterol-dependent complexes with apical proteins, promoting formation of detergent-resistant membranes that recruit apical proteins; MAL2 lacks these raft-coalescence properties, consistent with distinct roles for MAL (direct route) and MAL2 (transcytotic/indirect route) in apical sorting.","method":"Biochemical raft isolation (detergent-resistant membrane fractionation), co-immunoprecipitation, sucrose gradient centrifugation, cholesterol depletion","journal":"The Biochemical journal","confidence":"Medium","confidence_rationale":"Tier 2 — multiple biochemical methods in single study distinguishing MAL vs MAL2 biochemical properties","pmids":["21732912"],"is_preprint":false},{"year":2009,"finding":"MUC1 (mucin 1) is a novel binding partner of MAL2 in breast carcinoma cells; interaction requires the first MAL2 transmembrane domain (whereas the N-terminal domain binds D52-like proteins); MAL2 expression in MCF-10A cells increased MUC1 detection in both Triton X-100-soluble and -insoluble fractions and at the cell surface.","method":"Yeast two-hybrid screen of breast carcinoma cDNA library, co-immunoprecipitation, deletion mapping, confocal microscopy, sucrose density gradient centrifugation","journal":"BMC cell biology","confidence":"Medium","confidence_rationale":"Tier 3 — Y2H confirmed by Co-IP with domain mapping, single study","pmids":["19175940"],"is_preprint":false},{"year":2014,"finding":"MAL2 interacts with STK16 (serine/threonine kinase 16), a constitutively active Golgi-associated kinase; MAL2 knockdown or expression of kinase-dead STK16 (E202A) impairs constitutive secretion of soluble cargo (albumin, haptoglobin) by diverting albumin to lysosomal degradation rather than blocking its synthesis or processing, indicating MAL2 and STK16 sort secretory cargo at the TGN.","method":"Split-ubiquitin yeast two-hybrid, co-immunoprecipitation, morphological colocalization, temperature-block and lysosome deacidification experiments, MAL2 knockdown","journal":"The Biochemical journal","confidence":"Medium","confidence_rationale":"Tier 2 — Y2H confirmed by Co-IP, functional assays with KD and dominant-negative, pathway placement at TGN","pmids":["25084525"],"is_preprint":false},{"year":2021,"finding":"MAL2 promotes endocytosis and degradation of antigen-loaded MHC-I complexes in breast cancer cells, thereby suppressing tumor antigen presentation; MAL2 directly interacts with MHC-I and endosome-associated RAB proteins; depletion of MAL2 enhances CD8+ T cell cytotoxicity against tumor cells and suppresses breast tumor growth in preclinical models.","method":"Co-immunoprecipitation (MAL2 with MHC-I and RAB proteins), MAL2 knockdown, endocytosis assays, in vivo tumor models with tumor-infiltrating CD8+ T cell analysis","journal":"The Journal of clinical investigation","confidence":"High","confidence_rationale":"Tier 2 — Co-IP identifying partners, KD with defined mechanistic phenotype and in vivo validation, multiple orthogonal methods","pmids":["32990678"],"is_preprint":false},{"year":2021,"finding":"MAL2 mediates formation of stable HER2 signaling complexes within lipid raft-rich membrane protrusions in breast cancer cells; MAL2-HER2 physical interaction in lipid rafts (shown by proximity ligation assay) promotes HER2 plasma membrane retention and enhanced HER2 signaling; HER2 co-localizes with Ezrin/NHERF1/PMCA2 in a complex that maintains low intracellular calcium near the plasma membrane; MAL2-HER2 interactions are enhanced in trastuzumab-resistant cells.","method":"Proximity ligation assay, super-resolution structured illumination microscopy, lipid raft isolation, calcium imaging, trastuzumab-resistant cell lines","journal":"Cell reports","confidence":"Medium","confidence_rationale":"Tier 2 — proximity ligation and super-resolution imaging demonstrating physical complex with functional consequence, single study","pmids":["34965434"],"is_preprint":false},{"year":2020,"finding":"MAL2 overexpression in hepatoma-derived cells promotes actin-based protrusion formation with reciprocal decrease in invadopodia, and decreases cell migration, invasion, and proliferation; a putative EVH1 recognition motif in MAL2 is required for these anti-oncogenic phenotypes, implicating MAL2 in actin remodeling via this motif.","method":"MAL2 overexpression in Clone 9 cells, MAL2 knockdown in Hep3B cells, mutational analysis of EVH1 motif, invasion/migration/proliferation assays, immunohistochemistry","journal":"Cancers","confidence":"Medium","confidence_rationale":"Tier 2 — loss-of-function and gain-of-function with mutagenesis defining a specific motif, multiple cellular phenotypes","pmids":["32059473"],"is_preprint":false},{"year":2021,"finding":"MAL2 interacts with IQGAP1 to increase ERK1/2 phosphorylation levels, thereby promoting pancreatic cancer cell progression.","method":"Co-immunoprecipitation (MAL2-IQGAP1 interaction), western blot for ERK1/2 phosphorylation, MAL2 overexpression","journal":"Biochemical and biophysical research communications","confidence":"Low","confidence_rationale":"Tier 3 — single Co-IP with limited mechanistic follow-up, single study","pmids":["33780861"],"is_preprint":false},{"year":2009,"finding":"In oligodendrocytic cell lines (Oli-neu, HOG), MAL2 accumulates after differentiation in a peri-centrosomal compartment that shares features of the apical recycling endosome/subapical compartment, including colocalization with Rab11a, sensitivity to nocodazole (microtubule disruption), and exclusion of transferrin, suggesting a role in sorting proteins/lipids for myelin assembly.","method":"Immunofluorescence, nocodazole treatment, transferrin internalization assay, subcellular fractionation in Oli-neu and HOG cells","journal":"Experimental cell research","confidence":"Medium","confidence_rationale":"Tier 3 — direct localization with functional context established by perturbation experiments, consistent with established MAL2 biology","pmids":["19683524"],"is_preprint":false},{"year":2011,"finding":"PLP (proteolipid protein), the major myelin protein, co-localizes with GFP-MAL2 after internalization from the plasma membrane in HOG oligodendrocytic cells and co-immunoprecipitates with GFP-MAL2; ultrastructural studies show colocalization in vesicles and tubulovesicular structures, supporting a transcytotic model of PLP transport involving MAL2.","method":"Co-immunoprecipitation, confocal immunofluorescence, immunoelectron microscopy in HOG cells","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 3 — Co-IP confirmed by EM colocalization, single study","pmids":["21573057"],"is_preprint":false},{"year":2024,"finding":"MAL2 directly interacts with EGFR (confirmed by molecular docking and Co-IP), stabilizing EGFR membrane localization and activating the PI3K/AKT/SREBP-1 axis to promote lipid accumulation in intrahepatic cholangiocarcinoma; MAL2 inhibition reduces EGFR membrane stability and sensitizes ICC organoids to cisplatin.","method":"Co-immunoprecipitation, molecular docking, scRNA-seq, transcriptomics, metabolomics, ICC organoid model, MAL2 knockdown","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 — Co-IP plus molecular docking, functional pathway activation, organoid validation, multiple methods","pmids":["38866777"],"is_preprint":false},{"year":2025,"finding":"MAL2 and rab17 independently promote formation of actin- and cholesterol-dependent membrane protrusions in hepatoma cells; MAL2 selectively redistributes invadopodia proteins to protrusion tips (requiring the EVH1 recognition motif), decreasing matrix degradation; MAL2-rab17 interaction is GTP-dependent but EVH1-motif-independent; both MAL2 and rab17 redirect newly synthesized membrane protein trafficking from the Golgi to induced protrusions.","method":"MAL2 and rab17 expression in Clone 9 cells, mutational analysis (EVH1 motif, GTP-binding), co-immunoprecipitation, matrix degradation assay, Golgi-to-protrusion trafficking assay","journal":"Molecular biology of the cell","confidence":"Medium","confidence_rationale":"Tier 2 — mutagenesis defining domain requirements, GTP-dependency test, Co-IP, multiple functional assays in single study","pmids":["39813085"],"is_preprint":false},{"year":2024,"finding":"RAD21 transcriptionally activates MAL2 expression in endometrial cancer cells; MAL2 promotes immune evasion by suppressing MHC-I antigen presentation, reducing CD8+ T cell cytotoxicity; knockdown of MAL2 or RAD21 inhibits malignant behavior and restores MHC-I-mediated antigen presentation.","method":"MAL2 and RAD21 siRNA knockdown, MHC-I surface expression assay, CD8+ T cell cytotoxicity assay, in vivo tumor growth, western blot","journal":"Cytotechnology","confidence":"Low","confidence_rationale":"Tier 3 — single KD study with defined phenotype but limited mechanistic depth on RAD21-MAL2 transcriptional link","pmids":["38933871"],"is_preprint":false},{"year":2003,"finding":"In human thyroid epithelial cells, MAL2 exclusively resides in raft membranes (biochemical fractionation) and predominantly localizes in a subapical endosome compartment positive for Rab11a (confocal immunofluorescence), consistent with its role as a machinery component for the transcytotic route to the apical surface.","method":"Raft membrane biochemical fractionation, confocal immunofluorescence with Rab11a colocalization in primary thyrocyte cultures","journal":"Endocrinology","confidence":"Medium","confidence_rationale":"Tier 2 — direct biochemical raft isolation plus immunolocalization in primary cells, consistent with established MAL2 function","pmids":["14576188"],"is_preprint":false},{"year":2023,"finding":"MAL2 interacts with β-catenin in breast cancer cells (confirmed by Co-IP and immunofluorescence colocalization); MAL2 silencing reduces β-catenin and c-Myc expression, while β-catenin agonist (SKL2001) partially rescues c-Myc downregulation and EMT inhibition caused by MAL2 knockdown, placing MAL2 upstream of the β-catenin/c-Myc axis.","method":"Co-immunoprecipitation, immunofluorescence colocalization, β-catenin inhibitor/agonist treatment, western blot, in vivo metastasis model","journal":"Cancer cell international","confidence":"Medium","confidence_rationale":"Tier 3 — Co-IP confirmed by epistasis with pharmacological agents, single study","pmids":["37480012"],"is_preprint":false}],"current_model":"MAL2 is a four-transmembrane raft-associated proteolipid that functions as an essential regulator of the indirect (transcytotic) apical trafficking pathway in polarized epithelial and hepatic cells, shuttling in dynamic vesicular carriers between basolateral endosomes and the subapical compartment in a process requiring interaction with INF2/Cdc42 and actin polymerization; it selectively sorts specific cargo (pIgA-R, GPI-anchored proteins, MHC-I) via direct binding to these proteins and to endosome-associated RAB proteins, and also recruits the kinase STK16 at the TGN to direct constitutive secretion, while in cancer contexts MAL2 promotes MHC-I endocytosis/degradation to enable immune evasion, forms lipid raft domains that stabilize HER2 signaling, and remodels the actin cytoskeleton via an EVH1 recognition motif to regulate invadopodia and cell protrusion formation."},"narrative":{"teleology":[{"year":2001,"claim":"Identification of MAL2 as a novel four-transmembrane proteolipid and TPD52-family binding partner established the gene's existence and first physical interaction.","evidence":"Yeast two-hybrid screen with GST pull-down confirmation","pmids":["11549320"],"confidence":"Medium","gaps":["Functional role of TPD52-MAL2 interaction unknown","No cellular phenotype tested"]},{"year":2002,"claim":"Demonstrating that MAL2 depletion blocks transcytosis of pIgA-R and GPI-anchored CD59 without affecting internalization established MAL2 as an essential, non-redundant component of the indirect apical trafficking route in polarized epithelial cells.","evidence":"Antisense depletion with rescue by depletion-resistant MAL2 in HepG2 cells, raft isolation, confocal imaging","pmids":["12370246"],"confidence":"High","gaps":["Mechanism by which MAL2 selects cargo unknown","Whether MAL2 acts identically in non-hepatic epithelia untested"]},{"year":2003,"claim":"Localization of MAL2 to Rab11a-positive subapical endosomes in primary thyroid epithelial cells generalized the transcytotic role beyond hepatoma lines and placed MAL2 in the recycling endosome compartment.","evidence":"Raft fractionation and confocal colocalization in primary thyrocyte cultures","pmids":["14576188"],"confidence":"Medium","gaps":["No functional assay in thyrocytes","Cargo specificity in thyroid cells not identified"]},{"year":2006,"claim":"Live imaging resolved the step-wise mechanism of MAL2-mediated transcytosis—cargo concentration, transferrin receptor segregation, vesicle coalescence, and apical delivery—revealing MAL2 as a dynamic sorting platform rather than a static raft component.","evidence":"Live-cell GFP-MAL2 imaging with siRNA knockdown in HepG2 cells","pmids":["16445687"],"confidence":"High","gaps":["Molecular basis of cargo–MAL2 interaction unresolved","Motor proteins driving MAL2 vesicle movement unidentified"]},{"year":2009,"claim":"Identification of MUC1 as a MAL2 binding partner requiring the first transmembrane domain, distinct from the N-terminal TPD52-binding region, established that MAL2 uses separate domains for different protein interactions.","evidence":"Yeast two-hybrid screen of breast carcinoma library, Co-IP, deletion mapping","pmids":["19175940"],"confidence":"Medium","gaps":["Functional consequence of MAL2-MUC1 interaction on trafficking not tested","Single study, no independent replication"]},{"year":2009,"claim":"MAL2 accumulation in a Rab11a-positive peri-centrosomal compartment in differentiating oligodendrocytes suggested a conserved transcytotic mechanism applicable to myelin protein sorting.","evidence":"Immunofluorescence with nocodazole perturbation in Oli-neu and HOG oligodendrocyte lines","pmids":["19683524"],"confidence":"Medium","gaps":["No direct demonstration that MAL2 is required for myelin protein delivery","No in vivo oligodendrocyte data"]},{"year":2010,"claim":"Discovery that INF2 and Cdc42 form a sequential epistatic pathway (Cdc42→INF2→MAL2) controlling MAL2 vesicle actin association, transcytosis, and lumen morphogenesis revealed the actin-dependent mechanism driving MAL2 carrier dynamics.","evidence":"Reciprocal Co-IP, yeast two-hybrid, live imaging, siRNA epistasis in MDCK cyst formation","pmids":["20493814"],"confidence":"High","gaps":["How INF2 actin polymerization physically propels MAL2 vesicles unclear","Whether other formins compensate not tested"]},{"year":2010,"claim":"MAL2 was shown to regulate Golgi-to-surface delivery of pIgA-R selectively (not DPPIV) in hepatic cells, extending its sorting role beyond post-endocytic transcytosis to biosynthetic trafficking from the TGN.","evidence":"Overexpression/knockdown with surface delivery assays in WIF-B and Clone 9 cells","pmids":["20053882","20444237"],"confidence":"High","gaps":["Molecular determinant on cargo that MAL2 recognizes for TGN sorting unknown","MAL2 synaptic vesicle function (identified same year) remains unexplored"]},{"year":2011,"claim":"Demonstration that MAL2 co-immunoprecipitates with PLP in oligodendrocyte-derived cells and colocalizes in vesicular/tubulovesicular structures by immunoEM supported the model that MAL2 mediates transcytotic delivery of myelin proteins.","evidence":"Co-IP and immunoelectron microscopy in HOG cells","pmids":["21573057"],"confidence":"Medium","gaps":["No loss-of-function test for PLP delivery","No in vivo myelination phenotype"]},{"year":2014,"claim":"Identification of STK16 as a MAL2 partner at the TGN, where both are required for constitutive albumin secretion (with MAL2 loss diverting cargo to lysosomes), linked MAL2 to a kinase-dependent secretory sorting step.","evidence":"Split-ubiquitin Y2H, Co-IP, temperature-block and lysosome deacidification assays, MAL2 knockdown in WIF-B cells","pmids":["25084525"],"confidence":"Medium","gaps":["STK16 substrates in this pathway unidentified","Whether MAL2 is a STK16 substrate not tested"]},{"year":2020,"claim":"MAL2 overexpression remodels the actin cytoskeleton, promoting membrane protrusions while suppressing invadopodia via a putative EVH1 recognition motif, providing the first mechanistic link between MAL2 and actin-based cell morphology independent of transcytosis.","evidence":"Overexpression/knockdown with EVH1 motif mutagenesis, invasion/migration assays in hepatoma cells","pmids":["32059473"],"confidence":"Medium","gaps":["EVH1-domain partner(s) not identified","Whether EVH1 motif is sufficient in other cell types unknown"]},{"year":2021,"claim":"MAL2 was shown to drive MHC-I endocytosis and degradation by directly interacting with MHC-I and endosomal RAB proteins, suppressing tumor antigen presentation; MAL2 depletion enhanced CD8+ T cell killing and reduced tumor growth in vivo, establishing MAL2 as a cancer immune evasion factor.","evidence":"Co-IP of MAL2 with MHC-I and RABs, MAL2 knockdown, endocytosis assays, syngeneic tumor models with TIL analysis","pmids":["32990678"],"confidence":"High","gaps":["Which specific RAB protein(s) are required for MHC-I degradation pathway unclear","Whether MAL2 directly ubiquitinates or recruits ubiquitin ligases for MHC-I not determined"]},{"year":2021,"claim":"MAL2 was found to form stable HER2-containing signaling complexes within lipid raft protrusions, retaining HER2 at the plasma membrane and enhancing signaling—with increased MAL2-HER2 interaction in trastuzumab-resistant cells—revealing a receptor stabilization function.","evidence":"Proximity ligation assay, super-resolution microscopy, raft isolation, calcium imaging in breast cancer lines","pmids":["34965434"],"confidence":"Medium","gaps":["Whether MAL2 directly binds HER2 or acts through a bridging protein unclear","Mechanism linking MAL2-HER2 to trastuzumab resistance not fully delineated"]},{"year":2024,"claim":"MAL2 was shown to directly interact with EGFR, stabilizing its membrane localization and activating PI3K/AKT/SREBP-1 signaling for lipid accumulation in intrahepatic cholangiocarcinoma, broadening the receptor-stabilization role to EGFR.","evidence":"Co-IP, molecular docking, transcriptomics/metabolomics, ICC organoid cisplatin sensitization upon MAL2 knockdown","pmids":["38866777"],"confidence":"Medium","gaps":["Whether MAL2 stabilizes EGFR via the same raft mechanism as HER2 not directly compared","Structural basis of MAL2-EGFR interaction unknown"]},{"year":2025,"claim":"Dissection of MAL2 and Rab17 cooperation showed that both independently drive cholesterol/actin-dependent protrusions, that MAL2 redistributes invadopodia components to protrusion tips via the EVH1 motif, and that MAL2-Rab17 interaction is GTP-dependent but EVH1-independent, separating these two activities of MAL2.","evidence":"Co-IP, EVH1 and GTP-binding mutagenesis, matrix degradation and Golgi-to-protrusion trafficking assays in Clone 9 cells","pmids":["39813085"],"confidence":"Medium","gaps":["Whether Rab17-MAL2 interaction occurs in non-hepatoma cells untested","How MAL2 redirects Golgi-derived vesicles to protrusions mechanistically undefined"]},{"year":null,"claim":"Key unresolved questions include the structural basis of MAL2's cargo recognition, the identity of EVH1-domain partner proteins mediating actin remodeling, the in vivo physiological consequence of MAL2 loss in whole-organism models, and whether MAL2's receptor-stabilization and MHC-I degradation functions share a common vesicular sorting mechanism.","evidence":"","pmids":[],"confidence":"High","gaps":["No MAL2 knockout mouse phenotype reported","No crystal/cryo-EM structure of MAL2","Cargo recognition motif/determinant undefined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,2,5,9]},{"term_id":"GO:0008289","term_label":"lipid binding","supporting_discovery_ids":[0,6,18]},{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[3,11,16]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,7,10,15]},{"term_id":"GO:0031410","term_label":"cytoplasmic vesicle","supporting_discovery_ids":[0,2,13,14,18]},{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[5,8]},{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[0,2,9]}],"pathway":[{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[0,2,5,8]},{"term_id":"R-HSA-9609507","term_label":"Protein localization","supporting_discovery_ids":[0,2,5,9]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[9,17]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[10,12,15]}],"complexes":[],"partners":["INF2","STK16","HER2","EGFR","MUC1","TPD52L2","IQGAP1","RAB17"],"other_free_text":[]},"mechanistic_narrative":"MAL2 is a four-transmembrane raft-associated proteolipid that functions as an essential component of the indirect (transcytotic) apical trafficking pathway in polarized epithelial cells, mediating cargo sorting and vesicular transport between basolateral endosomes and the subapical compartment. MAL2 resides in lipid rafts and a Rab11a-positive subapical/recycling endosome compartment, where it concentrates transcytotic cargo (pIgA-R, GPI-anchored CD59) into dynamic vesicular carriers whose movement requires the formin INF2 and Cdc42-dependent actin polymerization [PMID:12370246, PMID:16445687, PMID:20493814, PMID:14576188]. Beyond transcytosis, MAL2 partners with STK16 at the TGN to direct constitutive secretory sorting [PMID:25084525], and in cancer contexts it promotes MHC-I endocytosis and degradation—suppressing tumor antigen presentation and CD8+ T cell cytotoxicity—while also stabilizing receptor tyrosine kinases (HER2, EGFR) within lipid raft domains to enhance downstream signaling [PMID:32990678, PMID:34965434, PMID:38866777]. MAL2 additionally remodels the actin cytoskeleton through a putative EVH1 recognition motif that redistributes invadopodia components to membrane protrusions, an activity separable from its GTP-dependent interaction with Rab17 [PMID:32059473, PMID:39813085]."},"prefetch_data":{"uniprot":{"accession":"Q969L2","full_name":"Protein MAL2","aliases":[],"length_aa":176,"mass_kda":19.1,"function":"Member of the machinery of polarized transport. Required for the indirect transcytotic route at the step of the egress of the transcytosing cargo from perinuclear endosomes in order for it to travel to the apical surface via a raft-dependent pathway","subcellular_location":"Cell membrane; Apical cell membrane; Endomembrane system; Cytoplasm, perinuclear region","url":"https://www.uniprot.org/uniprotkb/Q969L2/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/MAL2","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":74,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/MAL2","total_profiled":1310},"omim":[{"mim_id":"610982","title":"INVERTED FORMIN 2; INF2","url":"https://www.omim.org/entry/610982"},{"mim_id":"609684","title":"MAL PROTEOLIPID PROTEIN 2; MAL2","url":"https://www.omim.org/entry/609684"},{"mim_id":"188860","title":"MYELIN AND LYMPHOCYTE PROTEIN; MAL","url":"https://www.omim.org/entry/188860"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"esophagus","ntpm":238.5}],"url":"https://www.proteinatlas.org/search/MAL2"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"Q969L2","domains":[{"cath_id":"1.20.120","chopping":"28-128_141-173","consensus_level":"high","plddt":91.5817,"start":28,"end":173}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q969L2","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q969L2-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q969L2-F1-predicted_aligned_error_v6.png","plddt_mean":84.94},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=MAL2","jax_strain_url":"https://www.jax.org/strain/search?query=MAL2"},"sequence":{"accession":"Q969L2","fasta_url":"https://rest.uniprot.org/uniprotkb/Q969L2.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q969L2/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q969L2"}},"corpus_meta":[{"pmid":"20053882","id":"PMC_20053882","title":"Quantitative comparison of glutamatergic and GABAergic synaptic vesicles unveils selectivity for few proteins including MAL2, a novel synaptic vesicle protein.","date":"2010","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/20053882","citation_count":150,"is_preprint":false},{"pmid":"12370246","id":"PMC_12370246","title":"MAL2, a novel raft protein of the MAL family, is an essential component of the machinery for transcytosis in hepatoma HepG2 cells.","date":"2002","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/12370246","citation_count":112,"is_preprint":false},{"pmid":"32990678","id":"PMC_32990678","title":"MAL2 drives immune evasion in breast cancer by suppressing tumor antigen presentation.","date":"2021","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/32990678","citation_count":96,"is_preprint":false},{"pmid":"20493814","id":"PMC_20493814","title":"The formin INF2 regulates basolateral-to-apical transcytosis and lumen formation in association with Cdc42 and MAL2.","date":"2010","source":"Developmental cell","url":"https://pubmed.ncbi.nlm.nih.gov/20493814","citation_count":82,"is_preprint":false},{"pmid":"11549320","id":"PMC_11549320","title":"Identification of MAL2, a novel member of the mal proteolipid family, though interactions with TPD52-like proteins in the yeast two-hybrid system.","date":"2001","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/11549320","citation_count":80,"is_preprint":false},{"pmid":"20846453","id":"PMC_20846453","title":"MAL2 and tumor protein D52 (TPD52) are frequently overexpressed in ovarian carcinoma, but differentially associated with histological subtype and patient outcome.","date":"2010","source":"BMC cancer","url":"https://pubmed.ncbi.nlm.nih.gov/20846453","citation_count":56,"is_preprint":false},{"pmid":"15168355","id":"PMC_15168355","title":"Expression of MAL and MAL2, two elements of the protein machinery for raft-mediated transport, in normal and neoplastic human tissue.","date":"2004","source":"Histology and histopathology","url":"https://pubmed.ncbi.nlm.nih.gov/15168355","citation_count":40,"is_preprint":false},{"pmid":"30195491","id":"PMC_30195491","title":"MAL2 promotes proliferation, migration, and invasion through regulating epithelial-mesenchymal transition in breast cancer cell lines.","date":"2018","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/30195491","citation_count":38,"is_preprint":false},{"pmid":"25190476","id":"PMC_25190476","title":"Establishment of novel in vitro mouse chief cell and SPEM cultures identifies MAL2 as a marker of metaplasia in the stomach.","date":"2014","source":"American journal of physiology. Gastrointestinal and liver physiology","url":"https://pubmed.ncbi.nlm.nih.gov/25190476","citation_count":34,"is_preprint":false},{"pmid":"23876361","id":"PMC_23876361","title":"MAL2 expression predicts distant metastasis and short survival in pancreatic cancer.","date":"2013","source":"Surgery","url":"https://pubmed.ncbi.nlm.nih.gov/23876361","citation_count":33,"is_preprint":false},{"pmid":"21732912","id":"PMC_21732912","title":"MAL, but not MAL2, expression promotes the formation of cholesterol-dependent membrane domains that recruit apical proteins.","date":"2011","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/21732912","citation_count":26,"is_preprint":false},{"pmid":"14729876","id":"PMC_14729876","title":"Expression of MAL2, an integral protein component of the machinery for basolateral-to-apical transcytosis, in human epithelia.","date":"2004","source":"The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society","url":"https://pubmed.ncbi.nlm.nih.gov/14729876","citation_count":25,"is_preprint":false},{"pmid":"16445687","id":"PMC_16445687","title":"Dynamics of MAL2 during glycosylphosphatidylinositol-anchored protein transcytotic transport to the apical surface of hepatoma HepG2 cells.","date":"2006","source":"Traffic (Copenhagen, Denmark)","url":"https://pubmed.ncbi.nlm.nih.gov/16445687","citation_count":25,"is_preprint":false},{"pmid":"25084525","id":"PMC_25084525","title":"Serine/threonine kinase 16 and MAL2 regulate constitutive secretion of soluble cargo in hepatic cells.","date":"2014","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/25084525","citation_count":23,"is_preprint":false},{"pmid":"34965434","id":"PMC_34965434","title":"MAL2 mediates the formation of stable HER2 signaling complexes within lipid raft-rich membrane protrusions in breast cancer cells.","date":"2021","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/34965434","citation_count":23,"is_preprint":false},{"pmid":"30021343","id":"PMC_30021343","title":"MiR-129 regulates growth and invasion by targeting MAL2 in papillary thyroid carcinoma.","date":"2018","source":"Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie","url":"https://pubmed.ncbi.nlm.nih.gov/30021343","citation_count":22,"is_preprint":false},{"pmid":"20444237","id":"PMC_20444237","title":"MAL2 selectively regulates polymeric IgA receptor delivery from the Golgi to the plasma membrane in WIF-B cells.","date":"2010","source":"Traffic (Copenhagen, Denmark)","url":"https://pubmed.ncbi.nlm.nih.gov/20444237","citation_count":22,"is_preprint":false},{"pmid":"19175940","id":"PMC_19175940","title":"Mucin 1 (MUC1) is a novel partner for MAL2 in breast carcinoma cells.","date":"2009","source":"BMC cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/19175940","citation_count":22,"is_preprint":false},{"pmid":"8887647","id":"PMC_8887647","title":"Fission yeast mal2+ is required for chromosome segregation.","date":"1996","source":"Molecular and cellular biology","url":"https://pubmed.ncbi.nlm.nih.gov/8887647","citation_count":22,"is_preprint":false},{"pmid":"14576188","id":"PMC_14576188","title":"Expression and distribution of MAL2, an essential element of the machinery for basolateral-to-apical transcytosis, in human thyroid epithelial cells.","date":"2003","source":"Endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/14576188","citation_count":21,"is_preprint":false},{"pmid":"21445296","id":"PMC_21445296","title":"Mis17 is a regulatory module of the Mis6-Mal2-Sim4 centromere complex that is required for the recruitment of CenH3/CENP-A in fission yeast.","date":"2011","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/21445296","citation_count":21,"is_preprint":false},{"pmid":"33780861","id":"PMC_33780861","title":"MAL2 interacts with IQGAP1 to promote pancreatic cancer progression by increasing ERK1/2 phosphorylation.","date":"2021","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/33780861","citation_count":21,"is_preprint":false},{"pmid":"38866777","id":"PMC_38866777","title":"MAL2 reprograms lipid metabolism in intrahepatic cholangiocarcinoma via EGFR/SREBP-1 pathway based on single-cell RNA sequencing.","date":"2024","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/38866777","citation_count":19,"is_preprint":false},{"pmid":"36938678","id":"PMC_36938678","title":"LINC00460 Facilitates Cell Proliferation and Inhibits Ferroptosis in Breast Cancer Through the miR-320a/MAL2 Axis.","date":"2023","source":"Technology in cancer research & treatment","url":"https://pubmed.ncbi.nlm.nih.gov/36938678","citation_count":19,"is_preprint":false},{"pmid":"32059473","id":"PMC_32059473","title":"MAL2-Induced Actin-Based Protrusion Formation is Anti-Oncogenic in Hepatocellular Carcinoma.","date":"2020","source":"Cancers","url":"https://pubmed.ncbi.nlm.nih.gov/32059473","citation_count":18,"is_preprint":false},{"pmid":"33393509","id":"PMC_33393509","title":"Immune MAL2-practice: breast cancer immunoevasion via MHC class I degradation.","date":"2021","source":"The Journal of clinical investigation","url":"https://pubmed.ncbi.nlm.nih.gov/33393509","citation_count":17,"is_preprint":false},{"pmid":"31397491","id":"PMC_31397491","title":"RP11-284F21.9 promotes oral squamous cell carcinoma development via the miR-383-5p/MAL2 axis.","date":"2019","source":"Journal of oral pathology & medicine : official publication of the International Association of Oral Pathologists and the American Academy of Oral Pathology","url":"https://pubmed.ncbi.nlm.nih.gov/31397491","citation_count":16,"is_preprint":false},{"pmid":"16855021","id":"PMC_16855021","title":"Fta2, an essential fission yeast kinetochore component, interacts closely with the conserved Mal2 protein.","date":"2006","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/16855021","citation_count":16,"is_preprint":false},{"pmid":"19683524","id":"PMC_19683524","title":"Characterization of the MAL2-positive compartment in oligodendrocytes.","date":"2009","source":"Experimental cell research","url":"https://pubmed.ncbi.nlm.nih.gov/19683524","citation_count":15,"is_preprint":false},{"pmid":"34040387","id":"PMC_34040387","title":"LncRNA ST8SIA6-AS1 Promotes Cholangiocarcinoma Progression by Suppressing the miR-145-5p/MAL2 Axis.","date":"2021","source":"OncoTargets and therapy","url":"https://pubmed.ncbi.nlm.nih.gov/34040387","citation_count":12,"is_preprint":false},{"pmid":"35033901","id":"PMC_35033901","title":"The novel circ_0084904/miR-802/MAL2 axis promotes the development of cervical cancer.","date":"2022","source":"Reproductive biology","url":"https://pubmed.ncbi.nlm.nih.gov/35033901","citation_count":11,"is_preprint":false},{"pmid":"21573057","id":"PMC_21573057","title":"Interaction of PLP with GFP-MAL2 in the human oligodendroglial cell line HOG.","date":"2011","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/21573057","citation_count":10,"is_preprint":false},{"pmid":"37480012","id":"PMC_37480012","title":"Downregulation of MAL2 inhibits breast cancer progression through regulating β-catenin/c-Myc axis.","date":"2023","source":"Cancer cell international","url":"https://pubmed.ncbi.nlm.nih.gov/37480012","citation_count":9,"is_preprint":false},{"pmid":"35111745","id":"PMC_35111745","title":"Multi-Omics Analysis of the Therapeutic Value of MAL2 Based on Data Mining in Human Cancers.","date":"2022","source":"Frontiers in cell and developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/35111745","citation_count":8,"is_preprint":false},{"pmid":"35847380","id":"PMC_35847380","title":"Association Mining Identifies MAL2 as a Novel Tumor Suppressor in Colorectal Cancer.","date":"2022","source":"OncoTargets and therapy","url":"https://pubmed.ncbi.nlm.nih.gov/35847380","citation_count":6,"is_preprint":false},{"pmid":"33259862","id":"PMC_33259862","title":"WITHDRAWN: MiR-216b-5p attenuates chronic constriction injury-induced neuropathic pain in female rats by targeting MAL2 and inactivating Wnt/β-catenin signaling pathway.","date":"2020","source":"Neurochemistry international","url":"https://pubmed.ncbi.nlm.nih.gov/33259862","citation_count":4,"is_preprint":false},{"pmid":"37958451","id":"PMC_37958451","title":"Sorafenib Resistance Contributed by IL7 and MAL2 in Hepatocellular Carcinoma Can Be Overcome by Autophagy-Inducing Stapled Peptides.","date":"2023","source":"Cancers","url":"https://pubmed.ncbi.nlm.nih.gov/37958451","citation_count":3,"is_preprint":false},{"pmid":"38769215","id":"PMC_38769215","title":"High MAL2 expression predicts shorter survival in women with triple-negative breast cancer.","date":"2024","source":"Clinical & translational oncology : official publication of the Federation of Spanish Oncology Societies and of the National Cancer Institute of Mexico","url":"https://pubmed.ncbi.nlm.nih.gov/38769215","citation_count":2,"is_preprint":false},{"pmid":"39005660","id":"PMC_39005660","title":"Extracellular putrescine can augment the epithelial-mesenchymal transition of gastric cancer cells by promoting MAL2 expression by elevating H3K27ac in its promoter region.","date":"2024","source":"American journal of cancer research","url":"https://pubmed.ncbi.nlm.nih.gov/39005660","citation_count":2,"is_preprint":false},{"pmid":"38991944","id":"PMC_38991944","title":"ATF1 regulates MAL2 expression through inhibition of miR-630 to mediate the EMT process that promotes cervical cancer cell development and metastasis.","date":"2024","source":"Journal of gynecologic oncology","url":"https://pubmed.ncbi.nlm.nih.gov/38991944","citation_count":2,"is_preprint":false},{"pmid":"38933871","id":"PMC_38933871","title":"Activation of MAL2 by RAD21 inhibits the expression of MHC-I in immune evasion of endometrial cancer.","date":"2024","source":"Cytotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/38933871","citation_count":1,"is_preprint":false},{"pmid":"39813085","id":"PMC_39813085","title":"MAL2 and rab17 selectively redistribute invadopodia proteins to laterally-induced protrusions in hepatocellular carcinoma cells.","date":"2025","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/39813085","citation_count":1,"is_preprint":false},{"pmid":"39185651","id":"PMC_39185651","title":"Understanding Interactions between a Potential Antimalarial 'MAL2-11B' and its Targets using In Silico Methods.","date":"2024","source":"Cardiovascular & hematological disorders drug targets","url":"https://pubmed.ncbi.nlm.nih.gov/39185651","citation_count":0,"is_preprint":false},{"pmid":"41013917","id":"PMC_41013917","title":"E2F1-induced transcriptional activation of MAL2 inhibits sunitinib sensitivity and promotes the malignant progression of bladder cancer.","date":"2025","source":"Journal of chemotherapy (Florence, Italy)","url":"https://pubmed.ncbi.nlm.nih.gov/41013917","citation_count":0,"is_preprint":false},{"pmid":"41605797","id":"PMC_41605797","title":"Astragalus Polysaccharide Attenuates Breast Cancer Progression by Regulating METTL3-Mediated MAL2 m6A Modification.","date":"2026","source":"Journal of microbiology and biotechnology","url":"https://pubmed.ncbi.nlm.nih.gov/41605797","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.11.14.688421","title":"Batch-Harmonized Machine Learning Framework for Cross-Cohort RNA Biomarker Discovery in Pancreatic Adenocarcinoma","date":"2025-11-14","source":"bioRxiv","url":"https://doi.org/10.1101/2025.11.14.688421","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":23025,"output_tokens":5113,"usd":0.072885},"stage2":{"model":"claude-opus-4-6","input_tokens":8627,"output_tokens":3739,"usd":0.204915},"total_usd":0.2778,"stage1_batch_id":"msgbatch_01Mgbec4vM6c9vXht7JVJzss","stage2_batch_id":"msgbatch_01JkuuH5RB2BdJNsgnhjbC6s","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2002,\n      \"finding\": \"MAL2 is an essential component of the transcytotic machinery in polarized hepatoma HepG2 cells; it resides in rafts and a subapical compartment, and depletion of endogenous MAL2 drastically blocks transcytotic transport of polymeric immunoglobulin receptor and GPI-anchored protein CD59 to the apical membrane, causing their accumulation in perinuclear endosomes, without affecting internalization.\",\n      \"method\": \"Antisense-mediated depletion of endogenous MAL2, rescue with depletion-resistant exogenous MAL2, subcellular fractionation, confocal immunofluorescence, biochemical raft isolation\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean KO/KD with specific transcytosis phenotype, rescue experiment, replicated in same study with multiple orthogonal methods\",\n      \"pmids\": [\"12370246\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"MAL2 was identified as a binding partner of TPD52-like proteins (TPD52L2 and related) via yeast two-hybrid screening, confirmed by GST pull-down assay showing specific binding of in vitro-translated MAL2 to GST-Tpd52; MAL2 is a four-transmembrane proteolipid of 19 kDa.\",\n      \"method\": \"Yeast two-hybrid screen, GST pull-down assay with in vitro translated MAL2\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — identified by Y2H and confirmed by GST pull-down, single study\",\n      \"pmids\": [\"11549320\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"MAL2 is a highly dynamic protein that mediates GPI-anchored protein (CD59) transcytosis by redistributing into peripheral vesicular clusters that concentrate CD59 and transferrin receptor after basolateral endocytosis, then segregating transferrin receptor, fusing into a globular MAL2+ structure, and moving apically for cargo delivery; all steps are impaired upon MAL2 depletion.\",\n      \"method\": \"Live-cell imaging of GFP-MAL2 and transcytosing CD59, subcellular fractionation, MAL2 siRNA knockdown\",\n      \"journal\": \"Traffic (Copenhagen, Denmark)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — live imaging plus KD with defined mechanistic steps, multiple cargoes tested\",\n      \"pmids\": [\"16445687\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"INF2, an atypical formin with actin polymerization and depolymerization activities, is a direct binding partner of MAL2; MAL2-positive vesicular carriers associate with short actin filaments during transcytosis in an INF2-dependent process; Cdc42 binds INF2 in a GTP-loaded-dependent manner and, together with INF2, regulates MAL2 vesicle dynamics, apical transcytosis, and lumen formation in a sequential epistatic pathway: Cdc42 → INF2 → MAL2.\",\n      \"method\": \"Co-immunoprecipitation, yeast two-hybrid, live imaging of MAL2 vesicle dynamics, siRNA knockdown of INF2/Cdc42, organotypic MDCK lumen formation assay\",\n      \"journal\": \"Developmental cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal Co-IP, genetic epistasis, live imaging, multiple orthogonal methods in one study\",\n      \"pmids\": [\"20493814\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"MAL2 is a bona fide membrane constituent of synaptic vesicles preferentially associated with VGLUT-1-containing (glutamatergic) nerve terminals, as established by quantitative proteomics, subcellular fractionation, and immunolocalization at light and electron microscopic level.\",\n      \"method\": \"Quantitative proteomics of isolated synaptic vesicle populations, subcellular fractionation, immunofluorescence, immunoelectron microscopy\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — quantitative proteomics plus EM-level localization, large-scale comparative study\",\n      \"pmids\": [\"20053882\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"MAL2 selectively regulates polymeric IgA receptor (pIgA-R) delivery from the Golgi to the plasma membrane in hepatic WIF-B cells; overexpression of MAL2 in Clone 9 cells (lacking endogenous MAL2) enabled pIgA-R surface delivery (>9-fold enhancement) while MAL2 knockdown retained pIgA-R in the Golgi; this selectivity was not shared by other membrane proteins such as DPPIV.\",\n      \"method\": \"MAL2 knockdown/overexpression in WIF-B and Clone 9 cells, cycloheximide chase, immunofluorescence, surface delivery assay\",\n      \"journal\": \"Traffic (Copenhagen, Denmark)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean KD and KO rescue with quantitative surface delivery assay, selective cargo specificity demonstrated\",\n      \"pmids\": [\"20444237\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"MAL, but not MAL2, self-associates and forms higher-order cholesterol-dependent complexes with apical proteins, promoting formation of detergent-resistant membranes that recruit apical proteins; MAL2 lacks these raft-coalescence properties, consistent with distinct roles for MAL (direct route) and MAL2 (transcytotic/indirect route) in apical sorting.\",\n      \"method\": \"Biochemical raft isolation (detergent-resistant membrane fractionation), co-immunoprecipitation, sucrose gradient centrifugation, cholesterol depletion\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple biochemical methods in single study distinguishing MAL vs MAL2 biochemical properties\",\n      \"pmids\": [\"21732912\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"MUC1 (mucin 1) is a novel binding partner of MAL2 in breast carcinoma cells; interaction requires the first MAL2 transmembrane domain (whereas the N-terminal domain binds D52-like proteins); MAL2 expression in MCF-10A cells increased MUC1 detection in both Triton X-100-soluble and -insoluble fractions and at the cell surface.\",\n      \"method\": \"Yeast two-hybrid screen of breast carcinoma cDNA library, co-immunoprecipitation, deletion mapping, confocal microscopy, sucrose density gradient centrifugation\",\n      \"journal\": \"BMC cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — Y2H confirmed by Co-IP with domain mapping, single study\",\n      \"pmids\": [\"19175940\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"MAL2 interacts with STK16 (serine/threonine kinase 16), a constitutively active Golgi-associated kinase; MAL2 knockdown or expression of kinase-dead STK16 (E202A) impairs constitutive secretion of soluble cargo (albumin, haptoglobin) by diverting albumin to lysosomal degradation rather than blocking its synthesis or processing, indicating MAL2 and STK16 sort secretory cargo at the TGN.\",\n      \"method\": \"Split-ubiquitin yeast two-hybrid, co-immunoprecipitation, morphological colocalization, temperature-block and lysosome deacidification experiments, MAL2 knockdown\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — Y2H confirmed by Co-IP, functional assays with KD and dominant-negative, pathway placement at TGN\",\n      \"pmids\": [\"25084525\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"MAL2 promotes endocytosis and degradation of antigen-loaded MHC-I complexes in breast cancer cells, thereby suppressing tumor antigen presentation; MAL2 directly interacts with MHC-I and endosome-associated RAB proteins; depletion of MAL2 enhances CD8+ T cell cytotoxicity against tumor cells and suppresses breast tumor growth in preclinical models.\",\n      \"method\": \"Co-immunoprecipitation (MAL2 with MHC-I and RAB proteins), MAL2 knockdown, endocytosis assays, in vivo tumor models with tumor-infiltrating CD8+ T cell analysis\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — Co-IP identifying partners, KD with defined mechanistic phenotype and in vivo validation, multiple orthogonal methods\",\n      \"pmids\": [\"32990678\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"MAL2 mediates formation of stable HER2 signaling complexes within lipid raft-rich membrane protrusions in breast cancer cells; MAL2-HER2 physical interaction in lipid rafts (shown by proximity ligation assay) promotes HER2 plasma membrane retention and enhanced HER2 signaling; HER2 co-localizes with Ezrin/NHERF1/PMCA2 in a complex that maintains low intracellular calcium near the plasma membrane; MAL2-HER2 interactions are enhanced in trastuzumab-resistant cells.\",\n      \"method\": \"Proximity ligation assay, super-resolution structured illumination microscopy, lipid raft isolation, calcium imaging, trastuzumab-resistant cell lines\",\n      \"journal\": \"Cell reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — proximity ligation and super-resolution imaging demonstrating physical complex with functional consequence, single study\",\n      \"pmids\": [\"34965434\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"MAL2 overexpression in hepatoma-derived cells promotes actin-based protrusion formation with reciprocal decrease in invadopodia, and decreases cell migration, invasion, and proliferation; a putative EVH1 recognition motif in MAL2 is required for these anti-oncogenic phenotypes, implicating MAL2 in actin remodeling via this motif.\",\n      \"method\": \"MAL2 overexpression in Clone 9 cells, MAL2 knockdown in Hep3B cells, mutational analysis of EVH1 motif, invasion/migration/proliferation assays, immunohistochemistry\",\n      \"journal\": \"Cancers\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function and gain-of-function with mutagenesis defining a specific motif, multiple cellular phenotypes\",\n      \"pmids\": [\"32059473\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"MAL2 interacts with IQGAP1 to increase ERK1/2 phosphorylation levels, thereby promoting pancreatic cancer cell progression.\",\n      \"method\": \"Co-immunoprecipitation (MAL2-IQGAP1 interaction), western blot for ERK1/2 phosphorylation, MAL2 overexpression\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — single Co-IP with limited mechanistic follow-up, single study\",\n      \"pmids\": [\"33780861\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"In oligodendrocytic cell lines (Oli-neu, HOG), MAL2 accumulates after differentiation in a peri-centrosomal compartment that shares features of the apical recycling endosome/subapical compartment, including colocalization with Rab11a, sensitivity to nocodazole (microtubule disruption), and exclusion of transferrin, suggesting a role in sorting proteins/lipids for myelin assembly.\",\n      \"method\": \"Immunofluorescence, nocodazole treatment, transferrin internalization assay, subcellular fractionation in Oli-neu and HOG cells\",\n      \"journal\": \"Experimental cell research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — direct localization with functional context established by perturbation experiments, consistent with established MAL2 biology\",\n      \"pmids\": [\"19683524\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"PLP (proteolipid protein), the major myelin protein, co-localizes with GFP-MAL2 after internalization from the plasma membrane in HOG oligodendrocytic cells and co-immunoprecipitates with GFP-MAL2; ultrastructural studies show colocalization in vesicles and tubulovesicular structures, supporting a transcytotic model of PLP transport involving MAL2.\",\n      \"method\": \"Co-immunoprecipitation, confocal immunofluorescence, immunoelectron microscopy in HOG cells\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — Co-IP confirmed by EM colocalization, single study\",\n      \"pmids\": [\"21573057\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"MAL2 directly interacts with EGFR (confirmed by molecular docking and Co-IP), stabilizing EGFR membrane localization and activating the PI3K/AKT/SREBP-1 axis to promote lipid accumulation in intrahepatic cholangiocarcinoma; MAL2 inhibition reduces EGFR membrane stability and sensitizes ICC organoids to cisplatin.\",\n      \"method\": \"Co-immunoprecipitation, molecular docking, scRNA-seq, transcriptomics, metabolomics, ICC organoid model, MAL2 knockdown\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — Co-IP plus molecular docking, functional pathway activation, organoid validation, multiple methods\",\n      \"pmids\": [\"38866777\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"MAL2 and rab17 independently promote formation of actin- and cholesterol-dependent membrane protrusions in hepatoma cells; MAL2 selectively redistributes invadopodia proteins to protrusion tips (requiring the EVH1 recognition motif), decreasing matrix degradation; MAL2-rab17 interaction is GTP-dependent but EVH1-motif-independent; both MAL2 and rab17 redirect newly synthesized membrane protein trafficking from the Golgi to induced protrusions.\",\n      \"method\": \"MAL2 and rab17 expression in Clone 9 cells, mutational analysis (EVH1 motif, GTP-binding), co-immunoprecipitation, matrix degradation assay, Golgi-to-protrusion trafficking assay\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — mutagenesis defining domain requirements, GTP-dependency test, Co-IP, multiple functional assays in single study\",\n      \"pmids\": [\"39813085\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"RAD21 transcriptionally activates MAL2 expression in endometrial cancer cells; MAL2 promotes immune evasion by suppressing MHC-I antigen presentation, reducing CD8+ T cell cytotoxicity; knockdown of MAL2 or RAD21 inhibits malignant behavior and restores MHC-I-mediated antigen presentation.\",\n      \"method\": \"MAL2 and RAD21 siRNA knockdown, MHC-I surface expression assay, CD8+ T cell cytotoxicity assay, in vivo tumor growth, western blot\",\n      \"journal\": \"Cytotechnology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — single KD study with defined phenotype but limited mechanistic depth on RAD21-MAL2 transcriptional link\",\n      \"pmids\": [\"38933871\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"In human thyroid epithelial cells, MAL2 exclusively resides in raft membranes (biochemical fractionation) and predominantly localizes in a subapical endosome compartment positive for Rab11a (confocal immunofluorescence), consistent with its role as a machinery component for the transcytotic route to the apical surface.\",\n      \"method\": \"Raft membrane biochemical fractionation, confocal immunofluorescence with Rab11a colocalization in primary thyrocyte cultures\",\n      \"journal\": \"Endocrinology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct biochemical raft isolation plus immunolocalization in primary cells, consistent with established MAL2 function\",\n      \"pmids\": [\"14576188\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"MAL2 interacts with β-catenin in breast cancer cells (confirmed by Co-IP and immunofluorescence colocalization); MAL2 silencing reduces β-catenin and c-Myc expression, while β-catenin agonist (SKL2001) partially rescues c-Myc downregulation and EMT inhibition caused by MAL2 knockdown, placing MAL2 upstream of the β-catenin/c-Myc axis.\",\n      \"method\": \"Co-immunoprecipitation, immunofluorescence colocalization, β-catenin inhibitor/agonist treatment, western blot, in vivo metastasis model\",\n      \"journal\": \"Cancer cell international\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — Co-IP confirmed by epistasis with pharmacological agents, single study\",\n      \"pmids\": [\"37480012\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"MAL2 is a four-transmembrane raft-associated proteolipid that functions as an essential regulator of the indirect (transcytotic) apical trafficking pathway in polarized epithelial and hepatic cells, shuttling in dynamic vesicular carriers between basolateral endosomes and the subapical compartment in a process requiring interaction with INF2/Cdc42 and actin polymerization; it selectively sorts specific cargo (pIgA-R, GPI-anchored proteins, MHC-I) via direct binding to these proteins and to endosome-associated RAB proteins, and also recruits the kinase STK16 at the TGN to direct constitutive secretion, while in cancer contexts MAL2 promotes MHC-I endocytosis/degradation to enable immune evasion, forms lipid raft domains that stabilize HER2 signaling, and remodels the actin cytoskeleton via an EVH1 recognition motif to regulate invadopodia and cell protrusion formation.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"MAL2 is a four-transmembrane raft-associated proteolipid that functions as an essential component of the indirect (transcytotic) apical trafficking pathway in polarized epithelial cells, mediating cargo sorting and vesicular transport between basolateral endosomes and the subapical compartment. MAL2 resides in lipid rafts and a Rab11a-positive subapical/recycling endosome compartment, where it concentrates transcytotic cargo (pIgA-R, GPI-anchored CD59) into dynamic vesicular carriers whose movement requires the formin INF2 and Cdc42-dependent actin polymerization [PMID:12370246, PMID:16445687, PMID:20493814, PMID:14576188]. Beyond transcytosis, MAL2 partners with STK16 at the TGN to direct constitutive secretory sorting [PMID:25084525], and in cancer contexts it promotes MHC-I endocytosis and degradation—suppressing tumor antigen presentation and CD8+ T cell cytotoxicity—while also stabilizing receptor tyrosine kinases (HER2, EGFR) within lipid raft domains to enhance downstream signaling [PMID:32990678, PMID:34965434, PMID:38866777]. MAL2 additionally remodels the actin cytoskeleton through a putative EVH1 recognition motif that redistributes invadopodia components to membrane protrusions, an activity separable from its GTP-dependent interaction with Rab17 [PMID:32059473, PMID:39813085].\",\n  \"teleology\": [\n    {\n      \"year\": 2001,\n      \"claim\": \"Identification of MAL2 as a novel four-transmembrane proteolipid and TPD52-family binding partner established the gene's existence and first physical interaction.\",\n      \"evidence\": \"Yeast two-hybrid screen with GST pull-down confirmation\",\n      \"pmids\": [\"11549320\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional role of TPD52-MAL2 interaction unknown\", \"No cellular phenotype tested\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Demonstrating that MAL2 depletion blocks transcytosis of pIgA-R and GPI-anchored CD59 without affecting internalization established MAL2 as an essential, non-redundant component of the indirect apical trafficking route in polarized epithelial cells.\",\n      \"evidence\": \"Antisense depletion with rescue by depletion-resistant MAL2 in HepG2 cells, raft isolation, confocal imaging\",\n      \"pmids\": [\"12370246\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which MAL2 selects cargo unknown\", \"Whether MAL2 acts identically in non-hepatic epithelia untested\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Localization of MAL2 to Rab11a-positive subapical endosomes in primary thyroid epithelial cells generalized the transcytotic role beyond hepatoma lines and placed MAL2 in the recycling endosome compartment.\",\n      \"evidence\": \"Raft fractionation and confocal colocalization in primary thyrocyte cultures\",\n      \"pmids\": [\"14576188\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No functional assay in thyrocytes\", \"Cargo specificity in thyroid cells not identified\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Live imaging resolved the step-wise mechanism of MAL2-mediated transcytosis—cargo concentration, transferrin receptor segregation, vesicle coalescence, and apical delivery—revealing MAL2 as a dynamic sorting platform rather than a static raft component.\",\n      \"evidence\": \"Live-cell GFP-MAL2 imaging with siRNA knockdown in HepG2 cells\",\n      \"pmids\": [\"16445687\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis of cargo–MAL2 interaction unresolved\", \"Motor proteins driving MAL2 vesicle movement unidentified\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Identification of MUC1 as a MAL2 binding partner requiring the first transmembrane domain, distinct from the N-terminal TPD52-binding region, established that MAL2 uses separate domains for different protein interactions.\",\n      \"evidence\": \"Yeast two-hybrid screen of breast carcinoma library, Co-IP, deletion mapping\",\n      \"pmids\": [\"19175940\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of MAL2-MUC1 interaction on trafficking not tested\", \"Single study, no independent replication\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"MAL2 accumulation in a Rab11a-positive peri-centrosomal compartment in differentiating oligodendrocytes suggested a conserved transcytotic mechanism applicable to myelin protein sorting.\",\n      \"evidence\": \"Immunofluorescence with nocodazole perturbation in Oli-neu and HOG oligodendrocyte lines\",\n      \"pmids\": [\"19683524\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No direct demonstration that MAL2 is required for myelin protein delivery\", \"No in vivo oligodendrocyte data\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Discovery that INF2 and Cdc42 form a sequential epistatic pathway (Cdc42→INF2→MAL2) controlling MAL2 vesicle actin association, transcytosis, and lumen morphogenesis revealed the actin-dependent mechanism driving MAL2 carrier dynamics.\",\n      \"evidence\": \"Reciprocal Co-IP, yeast two-hybrid, live imaging, siRNA epistasis in MDCK cyst formation\",\n      \"pmids\": [\"20493814\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How INF2 actin polymerization physically propels MAL2 vesicles unclear\", \"Whether other formins compensate not tested\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"MAL2 was shown to regulate Golgi-to-surface delivery of pIgA-R selectively (not DPPIV) in hepatic cells, extending its sorting role beyond post-endocytic transcytosis to biosynthetic trafficking from the TGN.\",\n      \"evidence\": \"Overexpression/knockdown with surface delivery assays in WIF-B and Clone 9 cells\",\n      \"pmids\": [\"20053882\", \"20444237\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular determinant on cargo that MAL2 recognizes for TGN sorting unknown\", \"MAL2 synaptic vesicle function (identified same year) remains unexplored\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Demonstration that MAL2 co-immunoprecipitates with PLP in oligodendrocyte-derived cells and colocalizes in vesicular/tubulovesicular structures by immunoEM supported the model that MAL2 mediates transcytotic delivery of myelin proteins.\",\n      \"evidence\": \"Co-IP and immunoelectron microscopy in HOG cells\",\n      \"pmids\": [\"21573057\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No loss-of-function test for PLP delivery\", \"No in vivo myelination phenotype\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Identification of STK16 as a MAL2 partner at the TGN, where both are required for constitutive albumin secretion (with MAL2 loss diverting cargo to lysosomes), linked MAL2 to a kinase-dependent secretory sorting step.\",\n      \"evidence\": \"Split-ubiquitin Y2H, Co-IP, temperature-block and lysosome deacidification assays, MAL2 knockdown in WIF-B cells\",\n      \"pmids\": [\"25084525\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"STK16 substrates in this pathway unidentified\", \"Whether MAL2 is a STK16 substrate not tested\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"MAL2 overexpression remodels the actin cytoskeleton, promoting membrane protrusions while suppressing invadopodia via a putative EVH1 recognition motif, providing the first mechanistic link between MAL2 and actin-based cell morphology independent of transcytosis.\",\n      \"evidence\": \"Overexpression/knockdown with EVH1 motif mutagenesis, invasion/migration assays in hepatoma cells\",\n      \"pmids\": [\"32059473\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"EVH1-domain partner(s) not identified\", \"Whether EVH1 motif is sufficient in other cell types unknown\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"MAL2 was shown to drive MHC-I endocytosis and degradation by directly interacting with MHC-I and endosomal RAB proteins, suppressing tumor antigen presentation; MAL2 depletion enhanced CD8+ T cell killing and reduced tumor growth in vivo, establishing MAL2 as a cancer immune evasion factor.\",\n      \"evidence\": \"Co-IP of MAL2 with MHC-I and RABs, MAL2 knockdown, endocytosis assays, syngeneic tumor models with TIL analysis\",\n      \"pmids\": [\"32990678\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Which specific RAB protein(s) are required for MHC-I degradation pathway unclear\", \"Whether MAL2 directly ubiquitinates or recruits ubiquitin ligases for MHC-I not determined\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"MAL2 was found to form stable HER2-containing signaling complexes within lipid raft protrusions, retaining HER2 at the plasma membrane and enhancing signaling—with increased MAL2-HER2 interaction in trastuzumab-resistant cells—revealing a receptor stabilization function.\",\n      \"evidence\": \"Proximity ligation assay, super-resolution microscopy, raft isolation, calcium imaging in breast cancer lines\",\n      \"pmids\": [\"34965434\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether MAL2 directly binds HER2 or acts through a bridging protein unclear\", \"Mechanism linking MAL2-HER2 to trastuzumab resistance not fully delineated\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"MAL2 was shown to directly interact with EGFR, stabilizing its membrane localization and activating PI3K/AKT/SREBP-1 signaling for lipid accumulation in intrahepatic cholangiocarcinoma, broadening the receptor-stabilization role to EGFR.\",\n      \"evidence\": \"Co-IP, molecular docking, transcriptomics/metabolomics, ICC organoid cisplatin sensitization upon MAL2 knockdown\",\n      \"pmids\": [\"38866777\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether MAL2 stabilizes EGFR via the same raft mechanism as HER2 not directly compared\", \"Structural basis of MAL2-EGFR interaction unknown\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Dissection of MAL2 and Rab17 cooperation showed that both independently drive cholesterol/actin-dependent protrusions, that MAL2 redistributes invadopodia components to protrusion tips via the EVH1 motif, and that MAL2-Rab17 interaction is GTP-dependent but EVH1-independent, separating these two activities of MAL2.\",\n      \"evidence\": \"Co-IP, EVH1 and GTP-binding mutagenesis, matrix degradation and Golgi-to-protrusion trafficking assays in Clone 9 cells\",\n      \"pmids\": [\"39813085\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether Rab17-MAL2 interaction occurs in non-hepatoma cells untested\", \"How MAL2 redirects Golgi-derived vesicles to protrusions mechanistically undefined\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the structural basis of MAL2's cargo recognition, the identity of EVH1-domain partner proteins mediating actin remodeling, the in vivo physiological consequence of MAL2 loss in whole-organism models, and whether MAL2's receptor-stabilization and MHC-I degradation functions share a common vesicular sorting mechanism.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No MAL2 knockout mouse phenotype reported\", \"No crystal/cryo-EM structure of MAL2\", \"Cargo recognition motif/determinant undefined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 2, 5, 9]},\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [0, 6, 18]},\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [3, 11, 16]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 7, 10, 15]},\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [0, 2, 13, 14, 18]},\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [5, 8]},\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [0, 2, 9]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [0, 2, 5, 8]},\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [0, 2, 5, 9]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [9, 17]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [10, 12, 15]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"INF2\",\n      \"STK16\",\n      \"HER2\",\n      \"EGFR\",\n      \"MUC1\",\n      \"TPD52L2\",\n      \"IQGAP1\",\n      \"RAB17\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}