{"gene":"MADD","run_date":"2026-04-28T18:30:27","timeline":{"discoveries":[{"year":1997,"finding":"MADD (MAP kinase-activating death domain protein) was identified as a novel protein that associates with the death domain of TNFR1 through its own C-terminal death domain, as demonstrated by yeast two-hybrid and co-immunoprecipitation. Overexpression of MADD activates the MAP kinase ERK, and expression of the MADD death domain stimulates both ERK and JNK MAP kinases and induces phosphorylation of cytosolic phospholipase A2, linking TNFR1 to MAP kinase activation and arachidonic acid release.","method":"Yeast two-hybrid, co-immunoprecipitation, overexpression with ERK/JNK kinase activation assays","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — reciprocal co-IP and functional overexpression assays in multiple readouts, foundational paper","pmids":["9115275"],"is_preprint":false},{"year":1996,"finding":"DENN (identical/highly similar to MADD) was identified as a novel human gene encoding a 1287 aa hydrophilic protein with predominant cell membrane localization and some cytoplasmic staining, as shown by immunofluorescent labeling. Western blotting confirmed a 140–145 kDa protein product. An alternative splicing event involving a 129 nt exon was identified.","method":"Western blotting, immunofluorescence localization, Northern blot, RACE cDNA cloning","journal":"DNA sequence : the journal of DNA sequencing and mapping","confidence":"Medium","confidence_rationale":"Tier 3 — direct localization experiment, single lab, foundational characterization","pmids":["8988362"],"is_preprint":false},{"year":1998,"finding":"The DENN gene (virtually identical to MADD) was mapped to chromosome 11p11.21-p11.22 by FISH, comprises 15 exons and 14 introns spanning ~28 kb, and alternative splicing generates two protein isoforms differentially expressed in cells of different lineages. The DENN/MADD protein shows homology to rat Rab3 GEP (a Rab3 GDP/GTP exchange protein) and to C. elegans AEX-3, which interacts with Rab3 to regulate synaptic vesicle release.","method":"FISH, genomic sequencing, Western blotting of subcellular fractions, RT-PCR","journal":"Genome","confidence":"Medium","confidence_rationale":"Tier 2 — direct genomic mapping and subcellular fractionation with functional isoform analysis","pmids":["9796103"],"is_preprint":false},{"year":2001,"finding":"IG20 (MADD splice variant) and DENN-SV (another splice variant of the same gene) exert opposing effects on TNF-alpha-induced apoptosis. All variants interact with TNFR1 and activate ERK and NF-kappaB. However, only IG20-expressing cells show enhanced TNF-alpha-induced caspase-8 and caspase-3 activation, while DENN-SV-expressing cells show reduced or no caspase activation. CrmA maximally inhibited apoptosis in IG20 cells, establishing caspase-8 dependence.","method":"Stable transfection, TNF-alpha treatment, caspase activation assays, co-immunoprecipitation with TNFR1, CrmA inhibitor experiments","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods, epistasis via CrmA, replicated across isoforms","pmids":["11577081"],"is_preprint":false},{"year":2001,"finding":"The DENN domain is structurally larger than previously annotated and is flanked on both sides by conserved domains termed uDENN and dDENN, forming a tripartite module. This tripartite DENN module is present in MADD (MAP kinase activating death domain protein) and other signaling proteins interacting with Rab GTPases or regulating MAPK pathways.","method":"Computational profile-based and bidimensional sequence analysis","journal":"Biochemical and biophysical research communications","confidence":"Low","confidence_rationale":"Tier 4 — computational prediction, no direct experimental validation of MADD specifically","pmids":["11563850"],"is_preprint":false},{"year":2002,"finding":"Antisense silencing of DENN/MADD expression in cancer cell lines (Jurkat, PLC/PRF/5, NS-1) induced marked apoptosis, while DENN/MADD overexpression augmented cellular proliferation and reversed apoptotic effects of antisense treatment or staurosporine, establishing an anti-apoptotic and cell-survival role for DENN/MADD.","method":"Antisense oligodeoxynucleotide treatment, flow cytometry (annexin V, TUNEL, sub-G1), overexpression rescue, electron microscopy","journal":"Molecular carcinogenesis","confidence":"Medium","confidence_rationale":"Tier 2 — loss-of-function and gain-of-function with multiple phenotypic readouts","pmids":["12410563"],"is_preprint":false},{"year":2004,"finding":"DENN/MADD protein expression is significantly reduced in Alzheimer's disease (AD) hippocampus and brain homogenates relative to controls. DENN/MADD and TRADD competitively bind TNFR1 when overexpressed in N2A cells, with DENN/MADD abrogating TNFR1 binding to TRADD. Antisense reduction of endogenous DENN/MADD in rat hippocampal neurons promoted neuronal cell death, indicating DENN/MADD is protective by preventing TRADD-mediated apoptotic signaling.","method":"Immunohistochemistry, Western blotting of brain homogenates, antisense knockdown in primary hippocampal neurons, co-immunoprecipitation competition assay in N2A cells","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods including primary neuron KD with cell death readout and competitive co-IP","pmids":["15007167"],"is_preprint":false},{"year":2004,"finding":"IG20 (pro-apoptotic splice variant of the MADD/IG20 gene) interacts directly with TRAIL death receptors DR4 and DR5, and increases recruitment of FADD and caspase-8 into the TRAIL death-inducing signaling complex (DISC), thereby enhancing TRAIL-induced apoptosis via caspase activation.","method":"Colocalization, co-immunoprecipitation of DR4/DR5 with IG20, DISC assembly assay, caspase inhibitors (p35, CrmA, DN-FADD)","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 2 — co-IP of DISC components, epistasis via dominant-negative FADD and caspase inhibitors, moderate evidence","pmids":["15208670"],"is_preprint":false},{"year":2004,"finding":"DENN/MADD (Rab3GEP) regulates the recycling of Rab3 small G proteins and has an essential role in Ca2+-dependent neurotransmitter release and exocytosis. It is also involved in blocking neuronal cell apoptosis under cytotoxic stress conditions through its interactions with TNFR1 and JNK3.","method":"Review synthesizing prior biochemical and cellular studies","journal":"Trends in molecular medicine","confidence":"Medium","confidence_rationale":"Tier 3 — review synthesizing prior experimental data on Rab3GEP/DENN/MADD identity and dual functions","pmids":["15464446"],"is_preprint":false},{"year":2004,"finding":"Antisense abrogation of DENN/MADD expression in K36 leukemia cells induced apoptosis in vitro and caused tumor regression in vivo. In NFkappaB and TNFR1 knockout cells, antisense treatment caused more pronounced cell death, while TNFalpha and TNFR2 knockouts showed less apoptosis. DENN overexpression stimulated cell proliferation and upregulated TRPM2 and cyclin B1. Antisense treatment altered expression of TNFR2, TRAIL, Fas, TNFalpha, and cyclin D3, placing DENN/MADD in an apoptotic-cell cycle regulatory network.","method":"Antisense oligonucleotide treatment, knockout cell lines, in vivo tumor model, flow cytometry, RT-PCR expression arrays","journal":"International journal of cancer","confidence":"Medium","confidence_rationale":"Tier 2 — multiple KO cell lines for epistasis, in vivo validation, moderate evidence","pmids":["14735464"],"is_preprint":false},{"year":2005,"finding":"Recombinant Rab3 GEP (DENN/MADD) purified from Sf9 cells acts as a GDP/GTP exchange factor active on lipid-modified Rab3A, -3B, -3C, and -3D, but is inactive on lipid-unmodified Rab3A or Rab3A complexed with Rab GDI. Overexpression of Rab3 GEP inhibits Ca2+-dependent exocytosis from PC12 cells.","method":"In vitro GDP/GTP exchange assay with purified recombinant protein, lipid modification requirement test, Rab GDI inhibition assay, PC12 cell overexpression exocytosis assay (human growth hormone coexpression assay)","journal":"Methods in enzymology","confidence":"High","confidence_rationale":"Tier 1 — in vitro enzymatic reconstitution with purified recombinant protein, substrate specificity defined","pmids":["16473592"],"is_preprint":false},{"year":2006,"finding":"Selective knockdown of MADD (but not other IG20 splice variants) using exon-specific shRNA renders HeLa and PA-1 cancer cells susceptible to spontaneous apoptosis without affecting cell proliferation or cell cycle. Re-expression of MADD alone (not DENN-SV) in the absence of endogenous IG20 splice variants was sufficient to rescue cells from spontaneous apoptosis, establishing MADD as necessary and sufficient for cancer cell survival.","method":"Exon-specific shRNA knockdown, rescue with shRNA-resistant MADD expression, flow cytometry apoptosis assay","journal":"Oncogene","confidence":"High","confidence_rationale":"Tier 2 — specific knockdown with rescue experiment, unambiguous assignment of function to MADD isoform","pmids":["16682944"],"is_preprint":false},{"year":2007,"finding":"Endogenous MADD directly interacts with death receptors (DR4/DR5) but not with caspase-8 or FADD, and functions as a negative regulator of caspase-8 activation at death receptors. MADD knockdown leads to caspase-8 activation without increased FADD recruitment, indicating MADD inhibits caspase-8 activation downstream of DISC assembly.","method":"Exon-specific shRNA, immunoprecipitation showing MADD-DR interaction but not MADD-caspase-8 or MADD-FADD, caspase-8 activation assay, CrmA and DN-FADD epistasis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — co-IP with defined binding partners, epistasis via multiple inhibitors, specific knockdown","pmids":["17314102"],"is_preprint":false},{"year":2008,"finding":"KIF1Bbeta and KIF1A motors interact directly with DENN/MADD (Rab3-GEP) through the stalk domain. DENN/MADD binds preferentially to GTP-Rab3 (acting as a Rab3 effector in addition to its GEF role). Sequential genetic perturbations showed KIF1Bbeta and KIF1A are essential for transport of DENN/MADD and Rab3, while DENN/MADD is essential for Rab3 transport. GTP-Rab3 is more effectively transported than GDP-Rab3, indicating nucleotide state regulates axonal transport through preferential interaction with DENN/MADD.","method":"Yeast two-hybrid, co-immunoprecipitation, in vivo axonal transport assays with genetic knockouts, GTP/GDP-Rab3 binding preference assay","journal":"Nature cell biology","confidence":"High","confidence_rationale":"Tier 2 — reciprocal co-IP, sequential genetic knockouts establishing epistasis, in vivo transport assays","pmids":["18849981"],"is_preprint":false},{"year":2008,"finding":"Neural-enriched IG20 splice isoforms KIAA0358 and IG20-SV4 are expressed in human neuroblastoma cells and neural tissues. KIAA0358 exerts a potent antiapoptotic effect while IG20-SV4 has proapoptotic effects directly related to caspase-8 activation in neuroblastoma cells with minimal constitutive caspase-8 expression.","method":"Gain-of-function transfection, siRNA knockdown, caspase-8 activation assay, flow cytometry","journal":"Cancer research","confidence":"Medium","confidence_rationale":"Tier 2 — gain- and loss-of-function with specific molecular readout (caspase-8), single lab","pmids":["18794122"],"is_preprint":false},{"year":2009,"finding":"Endogenous MADD is indispensable for TNF-alpha-induced activation of MAPK (ERK1/2) but not for NF-kappaB activation, JNK or p38. MADD knockdown reduced Grb2 and Sos1/2 recruitment to the TNFR1 complex and decreased Ras and MEKK1/2 activation. Re-expression of shRNA-resistant MADD rescued cells from TNF-alpha-induced apoptosis, establishing the Grb2/Sos1-2/Ras/MEKK pathway as downstream of MADD.","method":"Exon-specific shRNA lentiviral knockdown, pathway activation assays (ERK, JNK, p38, NF-kappaB), co-immunoprecipitation of TNFR1 complex components, Ras activation assay, rescue by re-expression","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — specific knockdown with rescue, multiple orthogonal pathway readouts, co-IP of signaling complex components","pmids":["19289468"],"is_preprint":false},{"year":2010,"finding":"Akt phosphorylates endogenous MADD at three conserved sites. Only phosphorylated MADD can directly interact with the TRAIL receptor DR4, thereby preventing FADD recruitment. TRAIL treatment reduces MADD phosphorylation levels in sensitive cells, causing MADD dissociation from DR4 and allowing DISC formation and apoptosis. Constitutively active Akt rendered TRAIL-sensitive cells resistant; dominant-negative Akt in resistant cells reduced pMADD and sensitized them to TRAIL.","method":"Phosphorylation site mapping (mass spectrometry/mutagenesis), co-immunoprecipitation of pMADD-DR4 interaction, constitutively active and dominant-negative Akt overexpression, TRAIL-induced apoptosis assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — identified specific phosphorylation sites, defined kinase-substrate relationship, epistasis with Akt mutants","pmids":["20484047"],"is_preprint":false},{"year":2010,"finding":"MADD is a GDP/GTP exchange factor (GEF) that activates Rab27A and Rab27B, as part of a systematic characterization of the 17 human DENN domain proteins assigning specific Rab substrates.","method":"Systematic GEF activity screen, localization assays","journal":"The Journal of cell biology","confidence":"Medium","confidence_rationale":"Tier 2 — systematic family-wide screen establishing Rab27A/B as MADD substrates, replicated in later studies","pmids":["20937701"],"is_preprint":false},{"year":2012,"finding":"Alternative splicing changes in DENN/MADD/IG20 (DMI) occur in Alzheimer's disease brains and in SH-SY5Y cells exposed to oligomeric Abeta. Initially, the ratio of DM-SV to IG20 increases in cultures exposed to oAbeta. Knockdown of DMI splice variants including DM-SV with antisense increased cell death, while siRNAs sparing DM-SV increased the DM-SV/IG20 ratio and reduced cell death, suggesting DM-SV (MADD) is required for neuronal survival against oAbeta toxicity.","method":"Antisense DNA knockdown, isoform-specific siRNA, cell viability assay, RT-PCR quantification of splice variant ratios in AD and control brain tissue","journal":"Journal of molecular neuroscience : MN","confidence":"Medium","confidence_rationale":"Tier 2 — isoform-specific knockdown with cell death readout, corroborated in human AD tissue","pmids":["22678883"],"is_preprint":false},{"year":2013,"finding":"MADD/DENN/Rab3GEP functions as a GEF for Rab27 in rat parotid acinar cells. An antibody against the C-terminal 150 amino acids of MADD inhibited IPR-induced amylase release and reduced GTP-Rab27 levels in streptolysin O-permeabilized cells, indicating MADD's GEF activity (GDP/GTP cycling on Rab27) is required for stimulated exocytosis.","method":"Antibody inhibition in permeabilized cells, GTP-Rab27 pull-down assay, amylase release measurement, RT-PCR for DENND family expression","journal":"Archives of biochemistry and biophysics","confidence":"Medium","confidence_rationale":"Tier 2 — functional inhibition assay with direct GTP-loading readout, single lab","pmids":["23702376"],"is_preprint":false},{"year":2013,"finding":"Conditional knockout of IG20/MADD in pancreatic beta-cells (KMA1ko mice) resulted in hyperglycemia, glucose intolerance, and a severe defect in glucose-induced insulin release without defects in insulin processing. KMA1ko beta-cells showed increased insulin accumulation, indicating MADD plays a critical role in insulin secretion (vesicle exocytosis) from beta-cells.","method":"Conditional knockout mouse model, glucose tolerance testing, insulin secretion assay, insulin processing/accumulation measurement","journal":"Diabetes","confidence":"High","confidence_rationale":"Tier 2 — conditional knockout with specific physiological readout (insulin secretion), strong mechanistic link to vesicle trafficking function","pmids":["24379354"],"is_preprint":false},{"year":2014,"finding":"MADD acts as a downstream target of PTEN in TRAIL-induced apoptosis. TRAIL induces reduction of MADD phosphorylation via PTEN upregulation; PTEN knockdown prevented TRAIL-induced reduction in pMADD. Non-phosphorylated MADD translocates from the plasma membrane to the cytoplasm where it binds 14-3-3 and displaces 14-3-3-associated Bax, causing Bax translocation to mitochondria and cytochrome c release.","method":"PTEN siRNA knockdown, subcellular fractionation, co-immunoprecipitation of MADD/14-3-3/Bax, mitochondrial cytochrome c release assay, subcellular localization by immunofluorescence","journal":"Journal of cellular biochemistry","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods including co-IP, fractionation, and epistasis via siRNA, defines a novel PTEN-MADD-Bax pathway","pmids":["24038283"],"is_preprint":false},{"year":2015,"finding":"miR-3151 directly targets MADD (confirmed by luciferase assay) and PIK3R2. Restoration of miR-3151 in CLL cells repressed MADD expression, downregulated MEK/ERK signaling, inhibited proliferation, and enhanced apoptosis, placing MADD as a direct upstream activator of MEK/ERK in CLL cells.","method":"Luciferase reporter assay, miRNA re-expression, Western blotting for MADD/ERK/AKT, cell proliferation and apoptosis assays","journal":"Oncotarget","confidence":"Medium","confidence_rationale":"Tier 3 — luciferase validation of miRNA target site plus downstream signaling, single lab","pmids":["26517243"],"is_preprint":false},{"year":2017,"finding":"miR-181 binds the 3' UTR of DENN/MADD transcripts (validated by luciferase reporter assay) and reduces endogenous DENN/MADD mRNA levels. miR-181 overexpression accentuates mitochondrial membrane potential loss and enhances apoptosis in TNF-alpha-treated L929 cells, linking DENN/MADD suppression to enhanced TNF-alpha pro-death signaling.","method":"Luciferase 3'UTR reporter assay, miRNA overexpression, endogenous mRNA quantification, mitochondrial membrane potential assay, flow cytometry apoptosis","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 3 — luciferase validation plus functional consequence, single lab","pmids":["28323882"],"is_preprint":false},{"year":2019,"finding":"MADD knockdown in anaplastic thyroid cancer cells inhibited proliferation, migration, invasion, and clonogenic capacity, and reduced mitochondrial length and potential. Mechanistically, MADD siRNA inhibited TNFalpha-induced pERK, pGSK3beta, and beta-catenin nuclear translocation, placing MADD upstream of the TNFalpha/ERK/GSK3beta/Wnt axis in ATC. In vivo orthotopic mouse model confirmed tumor regression and decreased lung metastases.","method":"siRNA knockdown, proliferation/invasion/migration assays, mitochondrial function assay, Western blotting for signaling, in vivo orthotopic mouse model","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 — in vitro and in vivo validation with pathway mechanistic analysis, single lab","pmids":["30760700"],"is_preprint":false},{"year":2020,"finding":"Biallelic MADD variants in patients result in loss of MADD protein. Patient-derived fibroblasts show reduced ERK1/2 phosphorylation upon TNF-alpha treatment, enhanced caspase-3/7 activation, increased apoptosis, and defective EGF receptor endocytosis, establishing that MADD deficiency causes simultaneous defects in TNF-alpha-dependent MAPK signaling and vesicular trafficking.","method":"Patient fibroblasts from 23 individuals with MADD variants, Western blotting for MADD protein, TNF-alpha stimulation with ERK phosphorylation assay, caspase-3/7 activity assay, EGF internalization assay, mRNA splice variant analysis","journal":"Brain : a journal of neurology","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal functional assays in patient-derived cells, large cohort corroborating mechanism","pmids":["32761064"],"is_preprint":false},{"year":2021,"finding":"MADD acts as the GDP/GTP exchange factor for Rab27A, Rab3B, and Rab3D in primary human endothelial cells. Rab activity assays showed reduced Rab27A, Rab3B, and Rab3D activation upon MADD silencing. DENN domain-dependent GEF activity (not mere binding) was required for Rab recruitment to Weibel-Palade bodies (WPBs). Artificial mistargeting of MADD abolished Rab27A localization to WPBs in a DENN domain-dependent manner, indicating cytosolic MADD localization is critical. MADD silencing reduced VWF intracellular content and decreased histamine-evoked VWF secretion.","method":"siRNA knockdown, Rab activity (GTP-loading) assay, immunofluorescence localization, MADD-TOMM70 mistargeting construct, DENN domain mutant, VWF secretion assay","journal":"Blood advances","confidence":"High","confidence_rationale":"Tier 1–2 — in-cell GEF activity assay, domain-specific mutant (DENN domain), mistargeting experiment, and functional secretion readout","pmids":["34551092"],"is_preprint":false},{"year":2021,"finding":"A homozygous splice-site variant in MADD (c.2816+1G>A) causes single exon skipping and out-of-frame deletion, resulting in an infantile-lethal syndrome. MADD encodes a Rab GEF that activates RAB3 and RAB27A/27B and is crucial for neuromuscular junction function and endocrine secretory granule release, and also protects cells from caspase-mediated TNF-alpha-induced apoptosis.","method":"Exome sequencing, cDNA analysis confirming exon skipping, segregation analysis, clinical phenotype correlation","journal":"European journal of human genetics : EJHG","confidence":"Medium","confidence_rationale":"Tier 3 — molecular confirmation of splice defect, functional inference from disease phenotype, single study","pmids":["33723354"],"is_preprint":false},{"year":2023,"finding":"CaSR stimulation drives Rab11A-dependent activation of MADD (a Rab11A effector), which then activates Rab27B-regulated secretion of IL-8, CCL2/MCP-1, IL-1beta, and attenuates IL-6 secretion. Rab11A co-immunoprecipitates with MADD, and endosomal PI3-kinases (Vps34 and PI3KC2alpha) promote MADD/Rab27B pathway activation, linking endocytic recycling endosomes to secretory vesicles via MADD.","method":"Co-immunoprecipitation of Rab11A-MADD, PI3K inhibitors, siRNA knockdown of pathway components, secretion assay for cytokines, Rab27B activation assay","journal":"Cellular signalling","confidence":"Medium","confidence_rationale":"Tier 2 — co-IP interaction, functional knockdown, mechanistic pathway placement, single lab","pmids":["37604243"],"is_preprint":false},{"year":2023,"finding":"AML blast-derived exosomes transfer miR-24-3p to T cells, where it directly targets DENN/MADD (validated by direct targeting assay) and alters NF-kappaB, p-JAK/STAT, and p-ERK signaling pathways, increasing T-cell apoptosis and promoting regulatory T-cell development. miR-24-3p overexpression decreased DENN/MADD expression and impaired T-cell function.","method":"Exosome transfer experiments, miRNA overexpression, DENN/MADD expression knockdown, flow cytometry for apoptosis, NF-kappaB/JAK-STAT/ERK signaling assays, direct targeting assay","journal":"Cell communication and signaling : CCS","confidence":"Medium","confidence_rationale":"Tier 2 — direct target validation plus functional consequence in T cells, single lab","pmids":["37735672"],"is_preprint":false},{"year":2024,"finding":"MADD knockout in natural killer cells significantly decreased GTP-bound Rab27a levels in both resting and stimulated NK cells. MADD-deficient NK cells and CD8+ T cells displayed severely reduced degranulation and cytolytic ability comparable to Rab27a deficiency. Although MADD colocalized with Rab27a on lytic granules (LGs) and was enriched at the cytolytic synapse, loss of MADD did not impair Rab27a association with LGs nor their recruitment to the synapse, indicating MADD specifically activates Rab27a without controlling LG docking.","method":"MADD knockout (genetic), GTP-Rab27a pull-down activity assay, degranulation assay, cytolysis assay, immunofluorescence colocalization on lytic granules, synapse recruitment assay","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 — genetic KO with in-cell GTPase activity assay, specific mechanistic dissection of activation vs. docking","pmids":["38506245"],"is_preprint":false},{"year":2024,"finding":"Nucleolin (NCL) is lactylated predominantly at lysine 477 by the acyltransferase P300 in response to hyperactive glycolysis. Lactylated NCL binds the primary transcript of MADD and promotes efficient translation of MADD by circumventing alternative splicing that would otherwise generate a premature termination codon. This NCL lactylation-driven MADD upregulation activates ERK signaling to drive intrahepatic cholangiocarcinoma development.","method":"Proteomics of clinical specimens, mass spectrometry of lactylation sites, P300 acyltransferase identification, RNA binding assay (NCL-MADD pre-mRNA), alternative splicing analysis, xenograft tumor model","journal":"Journal of hepatology","confidence":"High","confidence_rationale":"Tier 1–2 — identified specific PTM site, writer enzyme, RNA-level mechanism, and functional consequence in multiple models","pmids":["38679071"],"is_preprint":false},{"year":2024,"finding":"A homozygous MADD splice site variant causing skipping of exon 30 (in-frame deletion of 36 amino acids, dex30) in patients with diabetes, hypogonadotropic hypogonadism, and growth hormone deficiency reduces insulin content, increases proinsulin-to-insulin ratio, decreases beta-cell numbers in stem cell-derived islets, and decreases luteinizing hormone expression in pituitary gonadotrope cells. The dex30 protein retained intact GDP/GTP exchange activity but showed altered protein-protein interaction profiles affecting multiple signaling pathways.","method":"Patient genetic analysis, MADD exon 30 deletion in hESC-derived pancreatic islets and human beta-cell line EndoC-βH1 and mouse LβT2 gonadotrope cells, insulin/proinsulin content assays, LH expression assay, GDP/GTP exchange activity assay, protein-protein interaction proteomics","journal":"JCI insight","confidence":"High","confidence_rationale":"Tier 1–2 — in vitro GEF activity assay, multiple cellular models, specific domain deletion with defined phenotypes","pmids":["38775154"],"is_preprint":false}],"current_model":"MADD (MAP kinase-activating death domain protein / DENN/Rab3GEP) is a multifunctional cytosolic protein that acts as a GDP/GTP exchange factor (GEF) for Rab3A/B/C/D and Rab27A/B (via its DENN domain, requiring lipid-modified Rab substrates), mediating Ca2+-dependent neurotransmitter/hormone exocytosis and secretory vesicle trafficking; it simultaneously interacts with TNFR1 through its C-terminal death domain to promote ERK/MAPK activation via Grb2/Sos1-2/Ras/MEKK signaling while blocking caspase-8-dependent apoptosis through direct interaction with death receptors (DR4/DR5), and this anti-apoptotic function is regulated by Akt-mediated phosphorylation at three conserved sites that control MADD's membrane localization and DR4 binding; additionally, dephosphorylated MADD translocates to cytoplasm to displace Bax from 14-3-3 and trigger mitochondrial apoptosis downstream of PTEN, establishing MADD as a critical signaling switch governing cell survival, vesicle trafficking, and cytotoxic lymphocyte killing via Rab27a activation."},"narrative":{"teleology":[{"year":1997,"claim":"Identification of MADD as a TNFR1 death-domain interactor that activates MAP kinases established the first molecular link between TNF receptor signaling and ERK/JNK activation through a novel adaptor protein.","evidence":"Yeast two-hybrid screen followed by co-immunoprecipitation and overexpression kinase-activation assays in mammalian cells","pmids":["9115275"],"confidence":"High","gaps":["Endogenous role not yet shown by loss-of-function","Mechanism connecting MADD to MAP kinase cascade unresolved","Physiological context (cell type specificity) unknown"]},{"year":2001,"claim":"Discovery that alternative splice variants (IG20 vs DENN-SV) exert opposing effects on TNF-α-induced caspase-8 activation revealed that the gene's apoptotic function is isoform-specific, resolving apparently contradictory pro- and anti-apoptotic reports.","evidence":"Stable transfection of individual splice variants with caspase activation assays and CrmA epistasis","pmids":["11577081"],"confidence":"High","gaps":["Structural basis for isoform-specific effects unresolved","Endogenous isoform ratios in relevant tissues not defined"]},{"year":2004,"claim":"Demonstration that MADD interacts with TRAIL receptors DR4/DR5 and enhances DISC formation, while competing with TRADD for TNFR1 binding to suppress neuronal apoptosis, established MADD as a dual-receptor signaling node governing cell survival decisions at multiple death receptors.","evidence":"Co-immunoprecipitation of MADD-DR4/DR5 complexes, DISC assembly assays, competitive TNFR1 binding, and antisense knockdown in primary hippocampal neurons","pmids":["15208670","15007167"],"confidence":"High","gaps":["How MADD distinguishes TNFR1 vs DR4/DR5 structurally unknown","Whether MADD competes with TRADD at endogenous expression levels unresolved"]},{"year":2005,"claim":"In vitro reconstitution of MADD/Rab3GEP GEF activity on all four lipid-modified Rab3 isoforms (but not unmodified Rab3 or Rab3-GDI complexes) defined the enzymatic specificity of the DENN domain, establishing MADD as a bona fide Rab3 GEF requiring membrane-anchored substrate.","evidence":"Purified recombinant Rab3GEP from Sf9 cells, in vitro GDP/GTP exchange assay with lipid modification controls","pmids":["16473592"],"confidence":"High","gaps":["Crystal structure of DENN domain–Rab3 interface unavailable","Relative in vivo contribution to each Rab3 family member unresolved"]},{"year":2007,"claim":"Isoform-specific knockdown and rescue experiments established that the MADD isoform specifically is both necessary and sufficient for cancer cell survival by inhibiting caspase-8 activation at death receptors independently of FADD recruitment, defining MADD as a gatekeeper of extrinsic apoptosis.","evidence":"Exon-specific shRNA with shRNA-resistant rescue, co-IP showing MADD binds DR4/DR5 but not caspase-8 or FADD","pmids":["16682944","17314102"],"confidence":"High","gaps":["Structural mechanism by which MADD blocks caspase-8 activation at the receptor unknown","Whether MADD acts stoichiometrically or catalytically at death receptors unresolved"]},{"year":2008,"claim":"Discovery that kinesin motors KIF1Bβ and KIF1A directly bind MADD/Rab3GEP, which in turn preferentially binds GTP-Rab3, established an axonal transport cascade (KIF1B→MADD→Rab3) coupling motor-driven vesicle transport to Rab3 nucleotide state.","evidence":"Yeast two-hybrid, co-immunoprecipitation, in vivo axonal transport assays in genetic knockout backgrounds","pmids":["18849981"],"confidence":"High","gaps":["Whether MADD acts as a GEF during transport or only as an effector/adaptor unresolved","Cargo identity on KIF1B-MADD-Rab3 vesicles not fully defined"]},{"year":2009,"claim":"Endogenous MADD knockdown specifically abolished TNF-α-induced ERK1/2 (but not JNK, p38, or NF-κB) activation by disrupting Grb2/Sos1-2 recruitment to TNFR1 and downstream Ras/MEKK activation, mapping the precise signaling branch controlled by MADD.","evidence":"Lentiviral shRNA knockdown with rescue, co-IP of TNFR1 signaling complex, Ras-GTP pull-down","pmids":["19289468"],"confidence":"High","gaps":["How MADD recruits Grb2 mechanistically (direct or indirect interaction) not defined","Whether this ERK-specific branch operates in non-immune cell types unresolved"]},{"year":2010,"claim":"Identification of three Akt phosphorylation sites on MADD that control its DR4 binding and anti-apoptotic function, and expansion of its GEF substrate range to include Rab27A/B, integrated MADD into both PI3K/Akt survival signaling and lysosomal/secretory granule trafficking.","evidence":"Phosphosite mapping by mass spectrometry/mutagenesis with constitutively active and dominant-negative Akt epistasis; systematic DENN-domain GEF screen for Rab specificity","pmids":["20484047","20937701"],"confidence":"High","gaps":["Phosphatase(s) that dephosphorylate MADD at these sites not identified beyond PTEN pathway","Relative importance of Rab3 vs Rab27 GEF activity in different tissues unclear"]},{"year":2013,"claim":"Conditional knockout of MADD in pancreatic β-cells caused severe glucose-stimulated insulin secretion defects and hyperglycemia without impairing insulin processing, providing the first in vivo genetic proof that MADD's vesicle exocytosis function is physiologically essential for endocrine secretion.","evidence":"Beta-cell-specific conditional knockout mouse, glucose tolerance tests, insulin accumulation and secretion assays","pmids":["24379354"],"confidence":"High","gaps":["Whether Rab3 or Rab27 GEF activity mediates insulin secretion not dissected","Potential compensatory changes in other DENN-domain GEFs not assessed"]},{"year":2014,"claim":"Elucidation of the PTEN-MADD-14-3-3-Bax axis showed that dephosphorylated MADD translocates from the membrane to cytoplasm and displaces Bax from 14-3-3, activating mitochondrial apoptosis, linking MADD phosphorylation status to intrinsic apoptosis in addition to extrinsic pathway regulation.","evidence":"Subcellular fractionation, co-IP of MADD/14-3-3/Bax, cytochrome c release assay, PTEN siRNA epistasis","pmids":["24038283"],"confidence":"High","gaps":["Whether this pathway operates in non-cancer cell types unknown","Direct demonstration that dephosphorylated MADD physically contacts 14-3-3 at endogenous levels not shown"]},{"year":2020,"claim":"Characterization of patient-derived fibroblasts from 23 individuals with biallelic MADD variants confirmed that MADD deficiency simultaneously impairs TNF-α-induced ERK activation, increases caspase-dependent apoptosis, and disrupts EGF receptor endocytosis, validating the dual signaling-trafficking model in a human disease context.","evidence":"Patient fibroblasts with confirmed MADD protein loss, ERK phosphorylation, caspase-3/7 assay, EGF internalization assay","pmids":["32761064"],"confidence":"High","gaps":["Specific Rab substrates affected in patient cells not identified","Whether vesicular trafficking defect is Rab3- or Rab27-dependent not distinguished"]},{"year":2021,"claim":"Demonstration that MADD's DENN-domain GEF activity (not mere Rab binding) is required for Rab27A/Rab3B/Rab3D recruitment to Weibel-Palade bodies and VWF secretion in endothelial cells, and that cytosolic localization of MADD is essential, resolved whether catalytic activation or scaffolding drives Rab targeting.","evidence":"siRNA knockdown, Rab-GTP activity assay, DENN-domain mutant, MADD-TOMM70 mistargeting construct, VWF secretion assay","pmids":["34551092"],"confidence":"High","gaps":["How MADD is recruited to specific vesicle populations remains unknown","Whether MADD GEF activity is regulated by phosphorylation at vesicle membranes not tested"]},{"year":2024,"claim":"MADD knockout in NK cells established that MADD is the principal Rab27a GEF controlling cytotoxic lymphocyte degranulation and killing, activating Rab27a without being required for lytic granule docking at the synapse, dissecting activation from tethering functions.","evidence":"Genetic knockout, GTP-Rab27a pull-down, degranulation and cytolysis assays, immunofluorescence at the cytolytic synapse","pmids":["38506245"],"confidence":"High","gaps":["Post-activation Rab27a effectors downstream of MADD in NK cells not identified","Whether other DENN-domain GEFs partially compensate not assessed"]},{"year":2024,"claim":"Analysis of patients carrying an in-frame MADD exon-30 deletion showed that the mutant protein retains GEF activity but has altered protein-protein interactions, causing diabetes, hypogonadotropic hypogonadism, and GH deficiency, revealing that MADD's non-catalytic interactions are essential for endocrine function independently of GEF activity.","evidence":"Patient genetics, hESC-derived islets, EndoC-βH1, LβT2 gonadotrope cells, GEF activity assay, protein-protein interaction proteomics","pmids":["38775154"],"confidence":"High","gaps":["Specific interactors lost in the dex30 mutant that drive endocrine phenotypes not identified","Whether dex30 affects death-domain-mediated signaling not tested"]},{"year":null,"claim":"How MADD's GEF, death-domain, and scaffolding functions are coordinated in space and time — and which are affected in specific disease contexts — remains unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No high-resolution structure of full-length MADD or DENN–Rab complex available","Whether phosphorylation-dependent membrane/cytoplasm shuttling regulates GEF activity in addition to apoptotic signaling is untested","Tissue-specific isoform expression ratios and their functional consequences are incompletely mapped"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,7,12,15,16]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[10,17,26,30]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[10,17,26,30,32]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[1,21,26]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[1,16,21]},{"term_id":"GO:0031410","term_label":"cytoplasmic vesicle","supporting_discovery_ids":[26,30]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,3,15,16,22,24]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[3,5,7,11,12,21]},{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[10,13,20,26,30]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[29,30]}],"complexes":[],"partners":["TNFRSF1A","TNFRSF10A","TNFRSF10B","RAB27A","RAB3A","KIF1B","RAB11A","GRB2"],"other_free_text":[]},"mechanistic_narrative":"MADD is a multifunctional signaling adaptor and Rab GTPase exchange factor that integrates death receptor signaling with regulated exocytosis. Through its C-terminal death domain, MADD binds TNFR1 and TRAIL receptors DR4/DR5, where Akt-mediated phosphorylation controls its association with DR4 to block FADD recruitment and caspase-8 activation; dephosphorylation by PTEN-dependent mechanisms releases MADD to the cytoplasm, where it displaces Bax from 14-3-3 and triggers mitochondrial apoptosis [PMID:20484047, PMID:24038283, PMID:17314102]. MADD simultaneously functions as the principal GDP/GTP exchange factor for Rab3A–D and Rab27A/B via its tripartite DENN domain, and this GEF activity is essential for Ca²⁺-dependent insulin secretion, von Willebrand factor release from Weibel-Palade bodies, cytokine secretion, and cytotoxic lymphocyte degranulation [PMID:16473592, PMID:24379354, PMID:34551092, PMID:38506245]. Biallelic loss-of-function MADD variants cause a multisystem disorder encompassing defective ERK signaling, enhanced apoptosis, impaired vesicular trafficking, and endocrine dysfunction including diabetes, hypogonadotropic hypogonadism, and growth hormone deficiency [PMID:32761064, PMID:38775154]."},"prefetch_data":{"uniprot":{"accession":"Q8WXG6","full_name":"MAP kinase-activating death domain protein","aliases":["Differentially expressed in normal and neoplastic cells","Insulinoma glucagonoma clone 20","Rab3 GDP/GTP exchange factor","RabGEF","Rab3 GDP/GTP exchange protein","Rab3GEP"],"length_aa":1647,"mass_kda":183.3,"function":"Guanyl-nucleotide exchange factor that regulates small GTPases of the Rab family (PubMed:18559336, PubMed:20937701). Converts GDP-bound inactive form of RAB27A and RAB27B to the GTP-bound active forms (PubMed:18559336, PubMed:20937701). Converts GDP-bound inactive form of RAB3A, RAB3C and RAB3D to the GTP-bound active forms, GTPases involved in synaptic vesicle exocytosis and vesicle secretion (By similarity). Plays a role in synaptic vesicle formation and in vesicle trafficking at the neuromuscular junction (By similarity). Involved in up-regulating a post-docking step of synaptic exocytosis in central synapses (By similarity). Probably by binding to the motor proteins KIF1B and KIF1A, mediates motor-dependent transport of GTP-RAB3A-positive vesicles to the presynaptic nerve terminals (By similarity). Plays a role in TNFA-mediated activation of the MAPK pathway, including ERK1/2 (PubMed:32761064). May link TNFRSF1A with MAP kinase activation (PubMed:9115275). May be involved in the regulation of TNFA-induced apoptosis (PubMed:11577081, PubMed:32761064)","subcellular_location":"Cell membrane; Cytoplasm; Cell projection, axon","url":"https://www.uniprot.org/uniprotkb/Q8WXG6/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/MADD","classification":"Not Classified","n_dependent_lines":2,"n_total_lines":1208,"dependency_fraction":0.0016556291390728477},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"CSNK2B","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/MADD","total_profiled":1310},"omim":[{"mim_id":"619005","title":"NEURODEVELOPMENTAL DISORDER WITH DYSMORPHIC FACIES, IMPAIRED SPEECH, AND HYPOTONIA; NEDDISH","url":"https://www.omim.org/entry/619005"},{"mim_id":"619004","title":"DEEAH SYNDROME; DEEAH","url":"https://www.omim.org/entry/619004"},{"mim_id":"617503","title":"DENN DOMAIN-CONTAINING PROTEIN 3; DENND3","url":"https://www.omim.org/entry/617503"},{"mim_id":"617279","title":"DENN DOMAIN-CONTAINING PROTEIN 5B; DENND5B","url":"https://www.omim.org/entry/617279"},{"mim_id":"617278","title":"DENN DOMAIN-CONTAINING PROTEIN 5A; DENND5A","url":"https://www.omim.org/entry/617278"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Plasma membrane","reliability":"Supported"},{"location":"Cytosol","reliability":"Supported"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"brain","ntpm":101.0}],"url":"https://www.proteinatlas.org/search/MADD"},"hgnc":{"alias_symbol":["DENN","KIAA0358","RAB3GEP","IG20"],"prev_symbol":[]},"alphafold":{"accession":"Q8WXG6","domains":[{"cath_id":"-","chopping":"15-103_171-284_593-606","consensus_level":"high","plddt":85.276,"start":15,"end":606},{"cath_id":"3.40.50.11500","chopping":"299-438_476-502_537-583","consensus_level":"high","plddt":92.2268,"start":299,"end":583},{"cath_id":"-","chopping":"959-1052_1282-1290_1316-1428","consensus_level":"high","plddt":86.0953,"start":959,"end":1428},{"cath_id":"2.30.29.30","chopping":"1440-1533","consensus_level":"high","plddt":81.3988,"start":1440,"end":1533},{"cath_id":"2.30.29.30","chopping":"1546-1633","consensus_level":"high","plddt":82.6607,"start":1546,"end":1633}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8WXG6","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q8WXG6-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q8WXG6-F1-predicted_aligned_error_v6.png","plddt_mean":63.44},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=MADD","jax_strain_url":"https://www.jax.org/strain/search?query=MADD"},"sequence":{"accession":"Q8WXG6","fasta_url":"https://rest.uniprot.org/uniprotkb/Q8WXG6.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q8WXG6/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q8WXG6"}},"corpus_meta":[{"pmid":"20937701","id":"PMC_20937701","title":"Family-wide 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ERK, while expression of the MADD death domain stimulates ERK and JNK and induces phosphorylation of cytosolic phospholipase A2.\",\n      \"method\": \"Yeast two-hybrid, co-immunoprecipitation, overexpression in cell lines\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal co-IP and functional overexpression assays, foundational discovery paper with multiple orthogonal methods\",\n      \"pmids\": [\"9115275\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"MADD (as a splice variant of IG20) and the DENN-SV isoform arise from alternative splicing of a single IG20 gene; all variants interact with TNF receptor 1 and activate ERK and NF-κB, but only IG20 enhances TNF-α-induced caspase-8 and caspase-3 activation, whereas DENN-SV reduces or abolishes caspase activation, conferring resistance to apoptosis.\",\n      \"method\": \"Stable transfection of HeLa cells, caspase activity assays, CrmA inhibition, flow cytometry\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple isoforms tested with orthogonal functional assays, clear mechanistic separation of isoform effects\",\n      \"pmids\": [\"11577081\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"DENN/MADD interacts with both the p55 TNFR1 and JNK3; in competition assays, DENN/MADD abrogates TNFR1 binding to TRADD, suggesting a protective role by blocking TRADD-mediated apoptotic signaling; antisense reduction of DENN/MADD in hippocampal neurons promotes cell death.\",\n      \"method\": \"Co-immunoprecipitation, competition binding in N2A cells, antisense knockdown in primary neurons\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal co-IP, competition binding, and loss-of-function with clear cellular phenotype\",\n      \"pmids\": [\"15007167\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Selective knockdown of the MADD splice variant (but not other IG20 isoforms) renders cancer cells susceptible to spontaneous apoptosis; re-expression of MADD alone (without other isoforms) is sufficient to prevent this apoptosis, establishing MADD as necessary and sufficient for cancer cell survival.\",\n      \"method\": \"Exon-specific shRNA lentiviral knockdown, isoform-specific rescue experiments\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — isoform-selective knockdown with rescue, multiple cell lines tested\",\n      \"pmids\": [\"16682944\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"MADD directly interacts with death receptors DR4/DR5 but not with caspase-8 or FADD, and inhibits caspase-8 activation at death receptors; MADD knockdown leads to caspase-8 activation without increased FADD recruitment to the DISC.\",\n      \"method\": \"Immunoprecipitation, shRNA knockdown, caspase-8 activity assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — direct binding demonstrated by IP, functional mechanism defined by KD with specific caspase readout\",\n      \"pmids\": [\"17314102\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"DENN/MADD (Rab3-GEP) directly interacts with the stalk domain of KIF1Bβ and KIF1A motors; DENN/MADD binds preferentially to GTP-Rab3 (effector function) and is essential for axonal transport of Rab3-carrying vesicles. Sequential genetic perturbations show KIF1A/Bβ are required for DENN/MADD transport, and DENN/MADD is required for Rab3 transport.\",\n      \"method\": \"Direct interaction assays, genetic epistasis in neurons, in vivo transport assays, GTP/GDP-binding pulldowns\",\n      \"journal\": \"Nature cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — multiple orthogonal methods including genetic epistasis and direct binding assays, replicated in vivo\",\n      \"pmids\": [\"18849981\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Endogenous MADD is specifically required for TNF-α-induced MAPK/ERK1/2 activation (but not NF-κB, JNK, or p38 activation, nor EGF-induced MAPK); MADD knockdown reduces Grb2 and Sos1/2 recruitment to the TNFR1 complex and decreases Ras and MEKK1/2 activation; MADD re-expression rescues cells from TNF-α-induced apoptosis.\",\n      \"method\": \"Exon-specific shRNA knockdown, kinase activation assays, co-immunoprecipitation of signaling complex components, rescue experiments\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods, isoform-specific KD with mechanistic pathway dissection and rescue\",\n      \"pmids\": [\"19289468\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"MADD is a GDP/GTP exchange factor (GEF) for Rab27A and Rab27B; among 17 human DENN domain proteins, MADD specifically activates Rab27A/27B in a systematic family-wide characterization.\",\n      \"method\": \"Systematic GEF activity assays across DENN family, localization studies, functional trafficking assays\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct enzymatic GEF assay, systematic family-wide characterization, highly cited foundational study\",\n      \"pmids\": [\"20937701\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Akt phosphorylates MADD at three conserved sites; only phosphorylated MADD directly interacts with the TRAIL receptor DR4, preventing FADD recruitment and DISC formation. TRAIL reduces MADD phosphorylation in sensitive cells, causing MADD dissociation from DR4, FADD association, and apoptosis.\",\n      \"method\": \"In vitro kinase assay, co-immunoprecipitation, phosphorylation-site mutagenesis, flow cytometry apoptosis assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — kinase assay, mutagenesis, co-IP, and functional apoptosis readout in multiple conditions\",\n      \"pmids\": [\"20484047\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"MADD/DENN/Rab3GEP functions as the GEF for Rab27 in rat parotid acinar cells; antibody-mediated inhibition of MADD in permeabilized cells reduces both GTP-Rab27 levels and isoproterenol-induced amylase release, demonstrating that MADD's GEF activity for Rab27 is required for regulated exocytosis.\",\n      \"method\": \"Antibody inhibition in permeabilized cells, Rab27-GTP activity assays, amylase secretion assay\",\n      \"journal\": \"Archives of biochemistry and biophysics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — direct enzymatic inhibition with functional exocytosis readout\",\n      \"pmids\": [\"23702376\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Conditional knockout of IG20/MADD in pancreatic β-cells results in hyperglycemia, glucose intolerance, reduced glucose-induced insulin production, increased insulin accumulation, and severe defect in glucose-induced insulin release, establishing an essential role for MADD in regulated insulin secretion.\",\n      \"method\": \"Conditional knockout mouse model (KMA1ko), glucose tolerance tests, insulin secretion assays\",\n      \"journal\": \"Diabetes\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — conditional KO with defined molecular and physiological phenotype\",\n      \"pmids\": [\"24379354\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"PTEN upregulation in TRAIL-treated cells reduces MADD phosphorylation by Akt; dephosphorylated MADD translocates from the plasma membrane to the cytoplasm where it binds 14-3-3 and displaces 14-3-3-associated Bax, causing Bax translocation to mitochondria and cytochrome c release.\",\n      \"method\": \"PTEN siRNA knockdown, fractionation, co-immunoprecipitation of MADD with 14-3-3 and Bax, cytochrome c release assay\",\n      \"journal\": \"Journal of cellular biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — co-IP and fractionation with functional readout, single lab, moderate mechanistic depth\",\n      \"pmids\": [\"24038283\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Purified Rab3 GEP (DENN/MADD) is active on lipid-modified Rab3A, 3B, 3C, and 3D but inactive on lipid-unmodified Rab3A or Rab3A complexed with Rab GDI; overexpression of Rab3 GEP inhibits Ca2+-dependent exocytosis from PC12 cells.\",\n      \"method\": \"Protein purification from Sf9 cells, in vitro GEF assay with lipid-modified substrates, PC12 cell exocytosis assay\",\n      \"journal\": \"Methods in enzymology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct in vitro enzymatic reconstitution with defined substrate specificity requirements and functional cellular assay\",\n      \"pmids\": [\"16473592\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"MADD acts as the GEF for Rab27A, Rab3B, and Rab3D in primary human endothelial cells; MADD silencing reduces GTP-loading of all three Rabs, decreases their recruitment to Weibel-Palade bodies, reduces VWF content, and impairs histamine-evoked VWF secretion. Rab activation (but not binding) requires the DENN domain, and MADD must be in its normal cytosolic localization to function.\",\n      \"method\": \"MADD siRNA knockdown, Rab activity assays (GTP-pulldown), immunofluorescence, artificial mistargeting with TOMM70 tag, VWF secretion assay\",\n      \"journal\": \"Blood advances\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods including Rab activity assays, domain-function mapping, and physiological secretion readout\",\n      \"pmids\": [\"34551092\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Patient-derived fibroblasts with biallelic loss-of-function MADD variants show: reduced ERK1/2 phosphorylation in response to TNF-α, enhanced caspase-3/7 activation, increased apoptosis, and a defect in epidermal growth factor receptor endocytosis, confirming that MADD is required for TNF-α-dependent MAPK signaling and endocytic vesicle trafficking.\",\n      \"method\": \"Patient-derived fibroblasts, TNF-α stimulation with ERK phosphorylation assay, caspase activity assay, EGF internalization assay\",\n      \"journal\": \"Brain : a journal of neurology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function in human patient cells with multiple orthogonal mechanistic readouts\",\n      \"pmids\": [\"32761064\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"MADD regulates natural killer (NK) cell degranulation through activation of Rab27a; MADD knockout significantly decreases GTP-bound Rab27a in resting and stimulated NK cells, and MADD-deficient NK cells and CD8+ T cells display severely reduced degranulation and cytolytic ability. MADD co-localizes with Rab27a on lytic granules and is enriched at the cytolytic synapse, but loss of MADD does not impair Rab27a association with granules or their recruitment to the synapse.\",\n      \"method\": \"CRISPR knockout, Rab27a-GTP pulldown assay, degranulation assay, cytolytic killing assay, immunofluorescence colocalization\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO with direct GTPase activity assay and functional cytolytic readout, multiple cell types tested\",\n      \"pmids\": [\"38506245\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Rab11A interacts with and activates MADD (a GEF for Rab27A/B), linking recycling endosomes to secretory vesicles; CaSR stimulation drives a Rab11A-dependent, endosomal PI3K-mediated activation of a MADD/Rab27B pathway to promote secretion of inflammatory factors (IL-8, CCL2, IL-1β).\",\n      \"method\": \"Co-immunoprecipitation of Rab11A with MADD, Rab27B activity assays, PI3K inhibitor experiments, cytokine secretion assays\",\n      \"journal\": \"Cellular signalling\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — co-IP and functional secretion assays, single lab, moderate mechanistic depth for MADD-specific function\",\n      \"pmids\": [\"37604243\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Lactylated nucleolin (NCL) binds the primary MADD transcript and promotes efficient translation of MADD by suppressing alternative splicing that generates a premature termination codon; this mechanism drives ERK activation and promotes intrahepatic cholangiocarcinoma development.\",\n      \"method\": \"Mass spectrometry for lactylation sites, macromolecule interaction assays, RNA splicing analysis, xenograft tumor model\",\n      \"journal\": \"Journal of hepatology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — mechanistic RNA splicing link identified with in vivo validation, but MADD as downstream effector only\",\n      \"pmids\": [\"38679071\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"A MADD exon 30 deletion (dex30) reduces insulin content, increases proinsulin-to-insulin ratio in stem cell-derived islets, decreases insulin expression in human β cell lines, and decreases luteinizing hormone expression in gonadotropes, while the GDP/GTP exchange activity of dex30 MADD remains intact — indicating a GEF-independent function of exon 30 in hormone expression.\",\n      \"method\": \"CRISPR exon deletion, stem cell-derived pancreatic islet differentiation, protein-protein interaction mapping, GEF activity assay, hormone expression assays\",\n      \"journal\": \"JCI insight\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — genetic exon deletion with multiple cellular models, GEF assay to dissect domain function, multiple orthogonal hormone readouts\",\n      \"pmids\": [\"38775154\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"IG20 (a MADD splice variant) interacts with TRAIL death receptors DR4 and DR5 by co-immunoprecipitation and colocalization, and increases FADD and caspase-8 recruitment into the TRAIL DISC, enhancing TRAIL-induced apoptosis in a FADD- and caspase-dependent manner.\",\n      \"method\": \"Co-immunoprecipitation, colocalization, dominant-negative FADD and caspase inhibitor experiments, caspase activity assays\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — single co-IP with functional apoptosis readout, single lab\",\n      \"pmids\": [\"15208670\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"MADD (also known as DENN/Rab3GEP/IG20) is a multifunctional protein that acts as a GDP/GTP exchange factor (GEF) activating Rab3A/B/C/D, Rab27A, and Rab27B to regulate Ca2+-dependent exocytosis, axonal vesicle transport, and immune cell degranulation; it also associates with TNFR1 through its death domain to specifically activate MAPK/ERK signaling via Grb2/Sos1/2/Ras recruitment while blocking pro-apoptotic TRADD binding and caspase-8-mediated apoptosis at death receptors, with its pro-survival function dependent on Akt-mediated phosphorylation that tethers it to DR4 and prevents DISC formation.\"\n}\n```\n\n--- ROUND 2 (R2/R3, augmented corpus) ---\n\nI'll systematically classify each paper and extract discoveries only from KEEP papers.\n\n**Classification logic:**\n- Papers about MADD (MAP kinase-activating death domain protein / DENN domain Rab-GEF) = KEEP\n- Papers about MADD = Multiple Acyl-CoA Dehydrogenase Deficiency (metabolic disease) = EXCLUDE (alias collision)\n- Papers about MADD-2, MADD-3, MADD-4 in C. elegans (different proteins) = EXCLUDE (symbol collision)\n- Papers about general DENN domain proteins without specific MADD focus = contextual\n- Papers from gene2pubmed list that are large-scale proteomics/interaction studies = KEEP only if they specifically report MADD findings\n\n**KEEP papers:** 8, 9, 10, 11, 12, 16, 20, 21, 24, 26, 27, 28, 30, 31, 32, 36, 37, 39, 40, 43, 44, 45, 50, 51, 52, 54, 55, 60, 64, 66, 67, 84, 87, 88, 89, 91, 1(main list), 4(main), 5(main)\n\nLet me be more precise:\n\n**KEEP** (canonical MADD protein): Papers 8, 9, 11, 12, 16, 20, 21, 24, 26, 27, 28, 30, 31, 32, 36, 37, 39, 40, 43, 44, 45, 50, 51, 52, 54, 55, 60, 64, 66, 67, 84, 87, 88, 89, 91\n\n**EXCLUDE** (MADD = metabolic disease): 6, 13, 18, 22, 25, 33, 34, 42, 46, 47, 53, 58, 61, 63, 65, 69, 70, 72, 74, 75, 79, 80, 81, 82, 92, 95, 97, 98 + gene2pubmed papers 28, 30\n\n**EXCLUDE** (C. elegans MADD-2/3/4 - different proteins): 14, 15, 23, 29, 48, 62, 71, 76, 77, 78, 99\n\n**EXCLUDE** (general DENN family, not MADD-specific): 1(partially relevant as context), 2, 3, 4, 7, 17, 38, 49, 56\n\n**EXCLUDE** (symbol collision - IG20 glycolipid): 100\n\n**EXCLUDE** (large-scale studies, gene2pubmed): most of gene2pubmed list unless MADD-specific\n\n```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1997,\n      \"finding\": \"MADD (MAP kinase-activating death domain protein) was identified as a novel protein that associates with the death domain of TNFR1 through its own C-terminal death domain, as demonstrated by yeast two-hybrid and co-immunoprecipitation. Overexpression of MADD activates the MAP kinase ERK, and expression of the MADD death domain stimulates both ERK and JNK MAP kinases and induces phosphorylation of cytosolic phospholipase A2, linking TNFR1 to MAP kinase activation and arachidonic acid release.\",\n      \"method\": \"Yeast two-hybrid, co-immunoprecipitation, overexpression with ERK/JNK kinase activation assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal co-IP and functional overexpression assays in multiple readouts, foundational paper\",\n      \"pmids\": [\"9115275\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"DENN (identical/highly similar to MADD) was identified as a novel human gene encoding a 1287 aa hydrophilic protein with predominant cell membrane localization and some cytoplasmic staining, as shown by immunofluorescent labeling. Western blotting confirmed a 140–145 kDa protein product. An alternative splicing event involving a 129 nt exon was identified.\",\n      \"method\": \"Western blotting, immunofluorescence localization, Northern blot, RACE cDNA cloning\",\n      \"journal\": \"DNA sequence : the journal of DNA sequencing and mapping\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — direct localization experiment, single lab, foundational characterization\",\n      \"pmids\": [\"8988362\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"The DENN gene (virtually identical to MADD) was mapped to chromosome 11p11.21-p11.22 by FISH, comprises 15 exons and 14 introns spanning ~28 kb, and alternative splicing generates two protein isoforms differentially expressed in cells of different lineages. The DENN/MADD protein shows homology to rat Rab3 GEP (a Rab3 GDP/GTP exchange protein) and to C. elegans AEX-3, which interacts with Rab3 to regulate synaptic vesicle release.\",\n      \"method\": \"FISH, genomic sequencing, Western blotting of subcellular fractions, RT-PCR\",\n      \"journal\": \"Genome\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct genomic mapping and subcellular fractionation with functional isoform analysis\",\n      \"pmids\": [\"9796103\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"IG20 (MADD splice variant) and DENN-SV (another splice variant of the same gene) exert opposing effects on TNF-alpha-induced apoptosis. All variants interact with TNFR1 and activate ERK and NF-kappaB. However, only IG20-expressing cells show enhanced TNF-alpha-induced caspase-8 and caspase-3 activation, while DENN-SV-expressing cells show reduced or no caspase activation. CrmA maximally inhibited apoptosis in IG20 cells, establishing caspase-8 dependence.\",\n      \"method\": \"Stable transfection, TNF-alpha treatment, caspase activation assays, co-immunoprecipitation with TNFR1, CrmA inhibitor experiments\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods, epistasis via CrmA, replicated across isoforms\",\n      \"pmids\": [\"11577081\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"The DENN domain is structurally larger than previously annotated and is flanked on both sides by conserved domains termed uDENN and dDENN, forming a tripartite module. This tripartite DENN module is present in MADD (MAP kinase activating death domain protein) and other signaling proteins interacting with Rab GTPases or regulating MAPK pathways.\",\n      \"method\": \"Computational profile-based and bidimensional sequence analysis\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 — computational prediction, no direct experimental validation of MADD specifically\",\n      \"pmids\": [\"11563850\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Antisense silencing of DENN/MADD expression in cancer cell lines (Jurkat, PLC/PRF/5, NS-1) induced marked apoptosis, while DENN/MADD overexpression augmented cellular proliferation and reversed apoptotic effects of antisense treatment or staurosporine, establishing an anti-apoptotic and cell-survival role for DENN/MADD.\",\n      \"method\": \"Antisense oligodeoxynucleotide treatment, flow cytometry (annexin V, TUNEL, sub-G1), overexpression rescue, electron microscopy\",\n      \"journal\": \"Molecular carcinogenesis\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — loss-of-function and gain-of-function with multiple phenotypic readouts\",\n      \"pmids\": [\"12410563\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"DENN/MADD protein expression is significantly reduced in Alzheimer's disease (AD) hippocampus and brain homogenates relative to controls. DENN/MADD and TRADD competitively bind TNFR1 when overexpressed in N2A cells, with DENN/MADD abrogating TNFR1 binding to TRADD. Antisense reduction of endogenous DENN/MADD in rat hippocampal neurons promoted neuronal cell death, indicating DENN/MADD is protective by preventing TRADD-mediated apoptotic signaling.\",\n      \"method\": \"Immunohistochemistry, Western blotting of brain homogenates, antisense knockdown in primary hippocampal neurons, co-immunoprecipitation competition assay in N2A cells\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods including primary neuron KD with cell death readout and competitive co-IP\",\n      \"pmids\": [\"15007167\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"IG20 (pro-apoptotic splice variant of the MADD/IG20 gene) interacts directly with TRAIL death receptors DR4 and DR5, and increases recruitment of FADD and caspase-8 into the TRAIL death-inducing signaling complex (DISC), thereby enhancing TRAIL-induced apoptosis via caspase activation.\",\n      \"method\": \"Colocalization, co-immunoprecipitation of DR4/DR5 with IG20, DISC assembly assay, caspase inhibitors (p35, CrmA, DN-FADD)\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — co-IP of DISC components, epistasis via dominant-negative FADD and caspase inhibitors, moderate evidence\",\n      \"pmids\": [\"15208670\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"DENN/MADD (Rab3GEP) regulates the recycling of Rab3 small G proteins and has an essential role in Ca2+-dependent neurotransmitter release and exocytosis. It is also involved in blocking neuronal cell apoptosis under cytotoxic stress conditions through its interactions with TNFR1 and JNK3.\",\n      \"method\": \"Review synthesizing prior biochemical and cellular studies\",\n      \"journal\": \"Trends in molecular medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — review synthesizing prior experimental data on Rab3GEP/DENN/MADD identity and dual functions\",\n      \"pmids\": [\"15464446\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Antisense abrogation of DENN/MADD expression in K36 leukemia cells induced apoptosis in vitro and caused tumor regression in vivo. In NFkappaB and TNFR1 knockout cells, antisense treatment caused more pronounced cell death, while TNFalpha and TNFR2 knockouts showed less apoptosis. DENN overexpression stimulated cell proliferation and upregulated TRPM2 and cyclin B1. Antisense treatment altered expression of TNFR2, TRAIL, Fas, TNFalpha, and cyclin D3, placing DENN/MADD in an apoptotic-cell cycle regulatory network.\",\n      \"method\": \"Antisense oligonucleotide treatment, knockout cell lines, in vivo tumor model, flow cytometry, RT-PCR expression arrays\",\n      \"journal\": \"International journal of cancer\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple KO cell lines for epistasis, in vivo validation, moderate evidence\",\n      \"pmids\": [\"14735464\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Recombinant Rab3 GEP (DENN/MADD) purified from Sf9 cells acts as a GDP/GTP exchange factor active on lipid-modified Rab3A, -3B, -3C, and -3D, but is inactive on lipid-unmodified Rab3A or Rab3A complexed with Rab GDI. Overexpression of Rab3 GEP inhibits Ca2+-dependent exocytosis from PC12 cells.\",\n      \"method\": \"In vitro GDP/GTP exchange assay with purified recombinant protein, lipid modification requirement test, Rab GDI inhibition assay, PC12 cell overexpression exocytosis assay (human growth hormone coexpression assay)\",\n      \"journal\": \"Methods in enzymology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro enzymatic reconstitution with purified recombinant protein, substrate specificity defined\",\n      \"pmids\": [\"16473592\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Selective knockdown of MADD (but not other IG20 splice variants) using exon-specific shRNA renders HeLa and PA-1 cancer cells susceptible to spontaneous apoptosis without affecting cell proliferation or cell cycle. Re-expression of MADD alone (not DENN-SV) in the absence of endogenous IG20 splice variants was sufficient to rescue cells from spontaneous apoptosis, establishing MADD as necessary and sufficient for cancer cell survival.\",\n      \"method\": \"Exon-specific shRNA knockdown, rescue with shRNA-resistant MADD expression, flow cytometry apoptosis assay\",\n      \"journal\": \"Oncogene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — specific knockdown with rescue experiment, unambiguous assignment of function to MADD isoform\",\n      \"pmids\": [\"16682944\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Endogenous MADD directly interacts with death receptors (DR4/DR5) but not with caspase-8 or FADD, and functions as a negative regulator of caspase-8 activation at death receptors. MADD knockdown leads to caspase-8 activation without increased FADD recruitment, indicating MADD inhibits caspase-8 activation downstream of DISC assembly.\",\n      \"method\": \"Exon-specific shRNA, immunoprecipitation showing MADD-DR interaction but not MADD-caspase-8 or MADD-FADD, caspase-8 activation assay, CrmA and DN-FADD epistasis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — co-IP with defined binding partners, epistasis via multiple inhibitors, specific knockdown\",\n      \"pmids\": [\"17314102\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"KIF1Bbeta and KIF1A motors interact directly with DENN/MADD (Rab3-GEP) through the stalk domain. DENN/MADD binds preferentially to GTP-Rab3 (acting as a Rab3 effector in addition to its GEF role). Sequential genetic perturbations showed KIF1Bbeta and KIF1A are essential for transport of DENN/MADD and Rab3, while DENN/MADD is essential for Rab3 transport. GTP-Rab3 is more effectively transported than GDP-Rab3, indicating nucleotide state regulates axonal transport through preferential interaction with DENN/MADD.\",\n      \"method\": \"Yeast two-hybrid, co-immunoprecipitation, in vivo axonal transport assays with genetic knockouts, GTP/GDP-Rab3 binding preference assay\",\n      \"journal\": \"Nature cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal co-IP, sequential genetic knockouts establishing epistasis, in vivo transport assays\",\n      \"pmids\": [\"18849981\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Neural-enriched IG20 splice isoforms KIAA0358 and IG20-SV4 are expressed in human neuroblastoma cells and neural tissues. KIAA0358 exerts a potent antiapoptotic effect while IG20-SV4 has proapoptotic effects directly related to caspase-8 activation in neuroblastoma cells with minimal constitutive caspase-8 expression.\",\n      \"method\": \"Gain-of-function transfection, siRNA knockdown, caspase-8 activation assay, flow cytometry\",\n      \"journal\": \"Cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — gain- and loss-of-function with specific molecular readout (caspase-8), single lab\",\n      \"pmids\": [\"18794122\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Endogenous MADD is indispensable for TNF-alpha-induced activation of MAPK (ERK1/2) but not for NF-kappaB activation, JNK or p38. MADD knockdown reduced Grb2 and Sos1/2 recruitment to the TNFR1 complex and decreased Ras and MEKK1/2 activation. Re-expression of shRNA-resistant MADD rescued cells from TNF-alpha-induced apoptosis, establishing the Grb2/Sos1-2/Ras/MEKK pathway as downstream of MADD.\",\n      \"method\": \"Exon-specific shRNA lentiviral knockdown, pathway activation assays (ERK, JNK, p38, NF-kappaB), co-immunoprecipitation of TNFR1 complex components, Ras activation assay, rescue by re-expression\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — specific knockdown with rescue, multiple orthogonal pathway readouts, co-IP of signaling complex components\",\n      \"pmids\": [\"19289468\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Akt phosphorylates endogenous MADD at three conserved sites. Only phosphorylated MADD can directly interact with the TRAIL receptor DR4, thereby preventing FADD recruitment. TRAIL treatment reduces MADD phosphorylation levels in sensitive cells, causing MADD dissociation from DR4 and allowing DISC formation and apoptosis. Constitutively active Akt rendered TRAIL-sensitive cells resistant; dominant-negative Akt in resistant cells reduced pMADD and sensitized them to TRAIL.\",\n      \"method\": \"Phosphorylation site mapping (mass spectrometry/mutagenesis), co-immunoprecipitation of pMADD-DR4 interaction, constitutively active and dominant-negative Akt overexpression, TRAIL-induced apoptosis assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — identified specific phosphorylation sites, defined kinase-substrate relationship, epistasis with Akt mutants\",\n      \"pmids\": [\"20484047\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"MADD is a GDP/GTP exchange factor (GEF) that activates Rab27A and Rab27B, as part of a systematic characterization of the 17 human DENN domain proteins assigning specific Rab substrates.\",\n      \"method\": \"Systematic GEF activity screen, localization assays\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — systematic family-wide screen establishing Rab27A/B as MADD substrates, replicated in later studies\",\n      \"pmids\": [\"20937701\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Alternative splicing changes in DENN/MADD/IG20 (DMI) occur in Alzheimer's disease brains and in SH-SY5Y cells exposed to oligomeric Abeta. Initially, the ratio of DM-SV to IG20 increases in cultures exposed to oAbeta. Knockdown of DMI splice variants including DM-SV with antisense increased cell death, while siRNAs sparing DM-SV increased the DM-SV/IG20 ratio and reduced cell death, suggesting DM-SV (MADD) is required for neuronal survival against oAbeta toxicity.\",\n      \"method\": \"Antisense DNA knockdown, isoform-specific siRNA, cell viability assay, RT-PCR quantification of splice variant ratios in AD and control brain tissue\",\n      \"journal\": \"Journal of molecular neuroscience : MN\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — isoform-specific knockdown with cell death readout, corroborated in human AD tissue\",\n      \"pmids\": [\"22678883\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"MADD/DENN/Rab3GEP functions as a GEF for Rab27 in rat parotid acinar cells. An antibody against the C-terminal 150 amino acids of MADD inhibited IPR-induced amylase release and reduced GTP-Rab27 levels in streptolysin O-permeabilized cells, indicating MADD's GEF activity (GDP/GTP cycling on Rab27) is required for stimulated exocytosis.\",\n      \"method\": \"Antibody inhibition in permeabilized cells, GTP-Rab27 pull-down assay, amylase release measurement, RT-PCR for DENND family expression\",\n      \"journal\": \"Archives of biochemistry and biophysics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — functional inhibition assay with direct GTP-loading readout, single lab\",\n      \"pmids\": [\"23702376\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Conditional knockout of IG20/MADD in pancreatic beta-cells (KMA1ko mice) resulted in hyperglycemia, glucose intolerance, and a severe defect in glucose-induced insulin release without defects in insulin processing. KMA1ko beta-cells showed increased insulin accumulation, indicating MADD plays a critical role in insulin secretion (vesicle exocytosis) from beta-cells.\",\n      \"method\": \"Conditional knockout mouse model, glucose tolerance testing, insulin secretion assay, insulin processing/accumulation measurement\",\n      \"journal\": \"Diabetes\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — conditional knockout with specific physiological readout (insulin secretion), strong mechanistic link to vesicle trafficking function\",\n      \"pmids\": [\"24379354\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"MADD acts as a downstream target of PTEN in TRAIL-induced apoptosis. TRAIL induces reduction of MADD phosphorylation via PTEN upregulation; PTEN knockdown prevented TRAIL-induced reduction in pMADD. Non-phosphorylated MADD translocates from the plasma membrane to the cytoplasm where it binds 14-3-3 and displaces 14-3-3-associated Bax, causing Bax translocation to mitochondria and cytochrome c release.\",\n      \"method\": \"PTEN siRNA knockdown, subcellular fractionation, co-immunoprecipitation of MADD/14-3-3/Bax, mitochondrial cytochrome c release assay, subcellular localization by immunofluorescence\",\n      \"journal\": \"Journal of cellular biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods including co-IP, fractionation, and epistasis via siRNA, defines a novel PTEN-MADD-Bax pathway\",\n      \"pmids\": [\"24038283\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"miR-3151 directly targets MADD (confirmed by luciferase assay) and PIK3R2. Restoration of miR-3151 in CLL cells repressed MADD expression, downregulated MEK/ERK signaling, inhibited proliferation, and enhanced apoptosis, placing MADD as a direct upstream activator of MEK/ERK in CLL cells.\",\n      \"method\": \"Luciferase reporter assay, miRNA re-expression, Western blotting for MADD/ERK/AKT, cell proliferation and apoptosis assays\",\n      \"journal\": \"Oncotarget\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — luciferase validation of miRNA target site plus downstream signaling, single lab\",\n      \"pmids\": [\"26517243\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"miR-181 binds the 3' UTR of DENN/MADD transcripts (validated by luciferase reporter assay) and reduces endogenous DENN/MADD mRNA levels. miR-181 overexpression accentuates mitochondrial membrane potential loss and enhances apoptosis in TNF-alpha-treated L929 cells, linking DENN/MADD suppression to enhanced TNF-alpha pro-death signaling.\",\n      \"method\": \"Luciferase 3'UTR reporter assay, miRNA overexpression, endogenous mRNA quantification, mitochondrial membrane potential assay, flow cytometry apoptosis\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — luciferase validation plus functional consequence, single lab\",\n      \"pmids\": [\"28323882\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"MADD knockdown in anaplastic thyroid cancer cells inhibited proliferation, migration, invasion, and clonogenic capacity, and reduced mitochondrial length and potential. Mechanistically, MADD siRNA inhibited TNFalpha-induced pERK, pGSK3beta, and beta-catenin nuclear translocation, placing MADD upstream of the TNFalpha/ERK/GSK3beta/Wnt axis in ATC. In vivo orthotopic mouse model confirmed tumor regression and decreased lung metastases.\",\n      \"method\": \"siRNA knockdown, proliferation/invasion/migration assays, mitochondrial function assay, Western blotting for signaling, in vivo orthotopic mouse model\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vitro and in vivo validation with pathway mechanistic analysis, single lab\",\n      \"pmids\": [\"30760700\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Biallelic MADD variants in patients result in loss of MADD protein. Patient-derived fibroblasts show reduced ERK1/2 phosphorylation upon TNF-alpha treatment, enhanced caspase-3/7 activation, increased apoptosis, and defective EGF receptor endocytosis, establishing that MADD deficiency causes simultaneous defects in TNF-alpha-dependent MAPK signaling and vesicular trafficking.\",\n      \"method\": \"Patient fibroblasts from 23 individuals with MADD variants, Western blotting for MADD protein, TNF-alpha stimulation with ERK phosphorylation assay, caspase-3/7 activity assay, EGF internalization assay, mRNA splice variant analysis\",\n      \"journal\": \"Brain : a journal of neurology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal functional assays in patient-derived cells, large cohort corroborating mechanism\",\n      \"pmids\": [\"32761064\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"MADD acts as the GDP/GTP exchange factor for Rab27A, Rab3B, and Rab3D in primary human endothelial cells. Rab activity assays showed reduced Rab27A, Rab3B, and Rab3D activation upon MADD silencing. DENN domain-dependent GEF activity (not mere binding) was required for Rab recruitment to Weibel-Palade bodies (WPBs). Artificial mistargeting of MADD abolished Rab27A localization to WPBs in a DENN domain-dependent manner, indicating cytosolic MADD localization is critical. MADD silencing reduced VWF intracellular content and decreased histamine-evoked VWF secretion.\",\n      \"method\": \"siRNA knockdown, Rab activity (GTP-loading) assay, immunofluorescence localization, MADD-TOMM70 mistargeting construct, DENN domain mutant, VWF secretion assay\",\n      \"journal\": \"Blood advances\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — in-cell GEF activity assay, domain-specific mutant (DENN domain), mistargeting experiment, and functional secretion readout\",\n      \"pmids\": [\"34551092\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"A homozygous splice-site variant in MADD (c.2816+1G>A) causes single exon skipping and out-of-frame deletion, resulting in an infantile-lethal syndrome. MADD encodes a Rab GEF that activates RAB3 and RAB27A/27B and is crucial for neuromuscular junction function and endocrine secretory granule release, and also protects cells from caspase-mediated TNF-alpha-induced apoptosis.\",\n      \"method\": \"Exome sequencing, cDNA analysis confirming exon skipping, segregation analysis, clinical phenotype correlation\",\n      \"journal\": \"European journal of human genetics : EJHG\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — molecular confirmation of splice defect, functional inference from disease phenotype, single study\",\n      \"pmids\": [\"33723354\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"CaSR stimulation drives Rab11A-dependent activation of MADD (a Rab11A effector), which then activates Rab27B-regulated secretion of IL-8, CCL2/MCP-1, IL-1beta, and attenuates IL-6 secretion. Rab11A co-immunoprecipitates with MADD, and endosomal PI3-kinases (Vps34 and PI3KC2alpha) promote MADD/Rab27B pathway activation, linking endocytic recycling endosomes to secretory vesicles via MADD.\",\n      \"method\": \"Co-immunoprecipitation of Rab11A-MADD, PI3K inhibitors, siRNA knockdown of pathway components, secretion assay for cytokines, Rab27B activation assay\",\n      \"journal\": \"Cellular signalling\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — co-IP interaction, functional knockdown, mechanistic pathway placement, single lab\",\n      \"pmids\": [\"37604243\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"AML blast-derived exosomes transfer miR-24-3p to T cells, where it directly targets DENN/MADD (validated by direct targeting assay) and alters NF-kappaB, p-JAK/STAT, and p-ERK signaling pathways, increasing T-cell apoptosis and promoting regulatory T-cell development. miR-24-3p overexpression decreased DENN/MADD expression and impaired T-cell function.\",\n      \"method\": \"Exosome transfer experiments, miRNA overexpression, DENN/MADD expression knockdown, flow cytometry for apoptosis, NF-kappaB/JAK-STAT/ERK signaling assays, direct targeting assay\",\n      \"journal\": \"Cell communication and signaling : CCS\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct target validation plus functional consequence in T cells, single lab\",\n      \"pmids\": [\"37735672\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"MADD knockout in natural killer cells significantly decreased GTP-bound Rab27a levels in both resting and stimulated NK cells. MADD-deficient NK cells and CD8+ T cells displayed severely reduced degranulation and cytolytic ability comparable to Rab27a deficiency. Although MADD colocalized with Rab27a on lytic granules (LGs) and was enriched at the cytolytic synapse, loss of MADD did not impair Rab27a association with LGs nor their recruitment to the synapse, indicating MADD specifically activates Rab27a without controlling LG docking.\",\n      \"method\": \"MADD knockout (genetic), GTP-Rab27a pull-down activity assay, degranulation assay, cytolysis assay, immunofluorescence colocalization on lytic granules, synapse recruitment assay\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — genetic KO with in-cell GTPase activity assay, specific mechanistic dissection of activation vs. docking\",\n      \"pmids\": [\"38506245\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Nucleolin (NCL) is lactylated predominantly at lysine 477 by the acyltransferase P300 in response to hyperactive glycolysis. Lactylated NCL binds the primary transcript of MADD and promotes efficient translation of MADD by circumventing alternative splicing that would otherwise generate a premature termination codon. This NCL lactylation-driven MADD upregulation activates ERK signaling to drive intrahepatic cholangiocarcinoma development.\",\n      \"method\": \"Proteomics of clinical specimens, mass spectrometry of lactylation sites, P300 acyltransferase identification, RNA binding assay (NCL-MADD pre-mRNA), alternative splicing analysis, xenograft tumor model\",\n      \"journal\": \"Journal of hepatology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — identified specific PTM site, writer enzyme, RNA-level mechanism, and functional consequence in multiple models\",\n      \"pmids\": [\"38679071\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"A homozygous MADD splice site variant causing skipping of exon 30 (in-frame deletion of 36 amino acids, dex30) in patients with diabetes, hypogonadotropic hypogonadism, and growth hormone deficiency reduces insulin content, increases proinsulin-to-insulin ratio, decreases beta-cell numbers in stem cell-derived islets, and decreases luteinizing hormone expression in pituitary gonadotrope cells. The dex30 protein retained intact GDP/GTP exchange activity but showed altered protein-protein interaction profiles affecting multiple signaling pathways.\",\n      \"method\": \"Patient genetic analysis, MADD exon 30 deletion in hESC-derived pancreatic islets and human beta-cell line EndoC-βH1 and mouse LβT2 gonadotrope cells, insulin/proinsulin content assays, LH expression assay, GDP/GTP exchange activity assay, protein-protein interaction proteomics\",\n      \"journal\": \"JCI insight\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 — in vitro GEF activity assay, multiple cellular models, specific domain deletion with defined phenotypes\",\n      \"pmids\": [\"38775154\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"MADD (MAP kinase-activating death domain protein / DENN/Rab3GEP) is a multifunctional cytosolic protein that acts as a GDP/GTP exchange factor (GEF) for Rab3A/B/C/D and Rab27A/B (via its DENN domain, requiring lipid-modified Rab substrates), mediating Ca2+-dependent neurotransmitter/hormone exocytosis and secretory vesicle trafficking; it simultaneously interacts with TNFR1 through its C-terminal death domain to promote ERK/MAPK activation via Grb2/Sos1-2/Ras/MEKK signaling while blocking caspase-8-dependent apoptosis through direct interaction with death receptors (DR4/DR5), and this anti-apoptotic function is regulated by Akt-mediated phosphorylation at three conserved sites that control MADD's membrane localization and DR4 binding; additionally, dephosphorylated MADD translocates to cytoplasm to displace Bax from 14-3-3 and trigger mitochondrial apoptosis downstream of PTEN, establishing MADD as a critical signaling switch governing cell survival, vesicle trafficking, and cytotoxic lymphocyte killing via Rab27a activation.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"MADD is a multifunctional scaffolding protein that serves as a guanine nucleotide exchange factor (GEF) for Rab3A/B/C/D and Rab27A/B, coupling vesicle maturation to regulated exocytosis in diverse secretory cell types including pancreatic β-cells, endothelial cells, parotid acinar cells, and cytolytic lymphocytes [PMID:16473592, PMID:20937701, PMID:24379354, PMID:34551092, PMID:38506245]. Through its C-terminal death domain, MADD binds TNFR1 and TRAIL receptors DR4/DR5, where it specifically promotes MAPK/ERK signaling via Grb2/Sos/Ras recruitment while competitively excluding TRADD and blocking caspase-8-dependent apoptosis; this anti-apoptotic function requires Akt-mediated phosphorylation that tethers MADD to death receptors and prevents DISC formation [PMID:9115275, PMID:15007167, PMID:19289468, PMID:20484047]. MADD also functions as a Rab3 effector that bridges kinesin motors (KIF1A/KIF1Bβ) to Rab3-carrying vesicles for axonal transport, and possesses a GEF-independent role in hormone biosynthesis mediated by its exon 30-encoded region [PMID:18849981, PMID:38775154]. Biallelic loss-of-function MADD variants cause a neurodevelopmental disorder with impaired TNF-α-induced ERK signaling, enhanced apoptosis, and defective endocytic trafficking [PMID:32761064].\",\n  \"teleology\": [\n    {\n      \"year\": 1997,\n      \"claim\": \"Identification of MADD as a TNFR1 death domain interactor that activates MAPK/ERK established the first molecular link between death receptors and pro-survival kinase signaling rather than apoptosis.\",\n      \"evidence\": \"Yeast two-hybrid screen, co-immunoprecipitation with TNFR1, overexpression-driven ERK/JNK activation in cell lines\",\n      \"pmids\": [\"9115275\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Endogenous MADD-TNFR1 complex stoichiometry undefined\", \"Pathway selectivity for ERK versus JNK not resolved\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Discovery that alternative splicing of the IG20/MADD gene produces isoforms with opposing effects on caspase activation revealed how a single locus encodes both pro- and anti-apoptotic functions.\",\n      \"evidence\": \"Stable transfection of HeLa cells with individual splice variants, caspase-8/3 activity assays, CrmA inhibition\",\n      \"pmids\": [\"11577081\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Tissue-specific splicing regulation unknown\", \"Structural basis for isoform-specific caspase modulation unresolved\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Demonstration that MADD competitively blocks TRADD binding to TNFR1 and that its loss promotes neuronal death established MADD as a molecular switch that diverts death receptor signaling from apoptosis to survival.\",\n      \"evidence\": \"Competition binding assays in N2A cells, antisense knockdown in primary hippocampal neurons\",\n      \"pmids\": [\"15007167\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether MADD and TRADD compete at the same binding surface not structurally resolved\", \"In vivo neuronal requirement not tested genetically\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Biochemical reconstitution of MADD's GEF activity showed it activates lipid-modified Rab3A/B/C/D but not GDI-complexed Rab3, defining the membrane-dependent substrate specificity of its catalytic function.\",\n      \"evidence\": \"Purified recombinant protein from Sf9 cells, in vitro GEF assay with lipid-modified versus unmodified substrates, PC12 exocytosis assay\",\n      \"pmids\": [\"16473592\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural mechanism of lipid-modification sensing unknown\", \"Overexpression inhibited exocytosis, suggesting dosage sensitivity not fully explained\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Isoform-selective knockdown and rescue showed that the MADD splice variant specifically—not IG20 or DENN-SV—is both necessary and sufficient for cancer cell survival, pinpointing a therapeutic target among IG20 gene products.\",\n      \"evidence\": \"Exon-specific shRNA lentiviral knockdown with isoform-specific rescue in multiple cancer cell lines\",\n      \"pmids\": [\"16682944\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Downstream survival pathway (ERK versus anti-apoptotic) mediating this effect not fully dissected\", \"In vivo tumor dependency not shown\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"MADD was shown to act as both a Rab3 GEF and a GTP-Rab3 effector that physically bridges kinesin motors KIF1A/KIF1Bβ to Rab3-carrying vesicles, establishing its dual role in vesicle maturation and axonal transport.\",\n      \"evidence\": \"Direct interaction assays, genetic epistasis in neurons, in vivo vesicle transport imaging, GTP/GDP-binding pulldowns\",\n      \"pmids\": [\"18849981\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How GEF and effector activities are temporally coordinated on the same vesicle unknown\", \"Whether MADD bridges other kinesins in non-neuronal cells untested\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Dissection of endogenous MADD function in TNFR1 signaling revealed it is specifically required for ERK1/2 activation (not NF-κB, JNK, or p38) through recruitment of Grb2/Sos1/2 and Ras, resolving pathway selectivity.\",\n      \"evidence\": \"Exon-specific shRNA knockdown, kinase activation panel, co-IP of signaling complex, rescue with MADD re-expression\",\n      \"pmids\": [\"19289468\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis for selective Grb2/Sos recruitment unknown\", \"Whether MADD functions similarly at other TNF superfamily receptors not systematically tested\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Two key advances: systematic DENN-family screening identified MADD as the specific GEF for Rab27A/B, and Akt-dependent phosphorylation of MADD was shown to tether it to DR4 to prevent DISC assembly, linking PI3K/Akt survival signaling to death receptor regulation.\",\n      \"evidence\": \"Family-wide GEF activity profiling for Rab27; in vitro Akt kinase assay, phosphosite mutagenesis, co-IP with DR4, apoptosis assays\",\n      \"pmids\": [\"20937701\", \"20484047\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether Rab27 GEF and death receptor functions are coordinated or independent in the same cell unclear\", \"Phosphorylation dynamics at endogenous levels not tracked\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Conditional β-cell knockout of MADD demonstrated its essential role in glucose-stimulated insulin secretion in vivo, and antibody-mediated MADD inhibition in acinar cells showed its GEF activity for Rab27 is required for regulated exocytosis, generalizing its secretory function across endocrine and exocrine systems.\",\n      \"evidence\": \"Conditional KO mouse with glucose tolerance and insulin secretion phenotyping; antibody inhibition in permeabilized parotid acinar cells with Rab27-GTP and amylase secretion assays\",\n      \"pmids\": [\"24379354\", \"23702376\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether the insulin secretion defect is entirely Rab27-dependent or involves Rab3 contributions not resolved\", \"Compensatory mechanisms in other secretory tissues not explored\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"TRAIL-induced PTEN upregulation was shown to dephosphorylate MADD, causing its cytoplasmic redistribution where it displaces Bax from 14-3-3, triggering mitochondrial apoptosis—revealing a second pro-apoptotic mechanism beyond DISC formation.\",\n      \"evidence\": \"PTEN siRNA, subcellular fractionation, co-IP of MADD/14-3-3/Bax, cytochrome c release\",\n      \"pmids\": [\"24038283\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether MADD directly binds 14-3-3 or the interaction is indirect not fully demonstrated\", \"Physiological relevance of this pathway versus DISC-mediated apoptosis not compared\", \"Single-lab finding awaits independent confirmation\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Biallelic loss-of-function MADD variants in patients confirmed its requirement for TNF-α-induced ERK signaling and endocytic trafficking in human cells, establishing MADD deficiency as a cause of neurodevelopmental disease.\",\n      \"evidence\": \"Patient-derived fibroblasts with ERK phosphorylation, caspase-3/7, and EGF receptor endocytosis assays\",\n      \"pmids\": [\"32761064\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Which MADD functions (GEF, death receptor, vesicle transport) most contribute to the neurological phenotype unknown\", \"Full clinical spectrum and genotype-phenotype correlations not established\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"MADD was shown to be the GEF for Rab27A, Rab3B, and Rab3D on Weibel-Palade bodies in endothelial cells, with its DENN domain required for Rab activation but not binding, and cytosolic localization essential for function—extending its secretory role to hemostatic VWF release.\",\n      \"evidence\": \"siRNA knockdown, GTP-pulldown for three Rabs, TOMM70-mistargeting, VWF secretion assay in primary HUVECs\",\n      \"pmids\": [\"34551092\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether MADD regulates all WPB-associated Rabs simultaneously or sequentially unknown\", \"Structural basis for DENN domain discriminating activation from binding unresolved\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Three studies expanded MADD's functional repertoire: MADD-mediated Rab27a activation is required for NK cell and CD8+ T cell degranulation; Rab11A activates MADD to link recycling endosomes to Rab27B-dependent inflammatory secretion; and exon 30 of MADD has a GEF-independent role in insulin and LH hormone expression.\",\n      \"evidence\": \"CRISPR KO with Rab27a-GTP pulldown and cytolytic assays in NK/T cells; co-IP of Rab11A-MADD with cytokine secretion; CRISPR exon deletion in stem cell-derived islets with intact GEF activity\",\n      \"pmids\": [\"38506245\", \"37604243\", \"38775154\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How exon 30 regulates hormone biosynthesis at the molecular level is unknown\", \"Whether Rab11A-MADD interaction is direct and what domain mediates it is unresolved\", \"Post-translational regulation of MADD in immune cells not explored\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"No structural model of full-length MADD exists; how its DENN/GEF domain, death domain, and exon 30-encoded region are coordinately regulated within a single polypeptide—and whether its vesicle trafficking and death receptor functions are coupled in vivo—remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No crystal or cryo-EM structure of MADD or its DENN domain bound to Rab substrates\", \"Coordination of GEF and death receptor scaffold functions in the same cell not addressed\", \"Tissue-specific alternative splicing regulation controlling isoform balance unexplored\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [7, 9, 12, 13, 15]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 2, 4, 5, 6, 8]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [11, 13]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [8, 11]},\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [5, 13, 15]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 2, 6, 8, 14]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [1, 3, 4, 8, 11]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [5, 9, 10, 13, 15]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [15]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"TNFRSF1A\",\n      \"TNFRSF10A\",\n      \"TNFRSF10B\",\n      \"RAB27A\",\n      \"RAB3A\",\n      \"KIF1A\",\n      \"KIF1B\",\n      \"GRB2\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```\n\n--- ROUND 2 (R2/R3, augmented corpus) ---\n\n```json\n{\n  \"mechanistic_narrative\": \"MADD is a multifunctional signaling adaptor and Rab GTPase exchange factor that integrates death receptor signaling with regulated exocytosis. Through its C-terminal death domain, MADD binds TNFR1 and TRAIL receptors DR4/DR5, where Akt-mediated phosphorylation controls its association with DR4 to block FADD recruitment and caspase-8 activation; dephosphorylation by PTEN-dependent mechanisms releases MADD to the cytoplasm, where it displaces Bax from 14-3-3 and triggers mitochondrial apoptosis [PMID:20484047, PMID:24038283, PMID:17314102]. MADD simultaneously functions as the principal GDP/GTP exchange factor for Rab3A–D and Rab27A/B via its tripartite DENN domain, and this GEF activity is essential for Ca²⁺-dependent insulin secretion, von Willebrand factor release from Weibel-Palade bodies, cytokine secretion, and cytotoxic lymphocyte degranulation [PMID:16473592, PMID:24379354, PMID:34551092, PMID:38506245]. Biallelic loss-of-function MADD variants cause a multisystem disorder encompassing defective ERK signaling, enhanced apoptosis, impaired vesicular trafficking, and endocrine dysfunction including diabetes, hypogonadotropic hypogonadism, and growth hormone deficiency [PMID:32761064, PMID:38775154].\",\n  \"teleology\": [\n    {\n      \"year\": 1997,\n      \"claim\": \"Identification of MADD as a TNFR1 death-domain interactor that activates MAP kinases established the first molecular link between TNF receptor signaling and ERK/JNK activation through a novel adaptor protein.\",\n      \"evidence\": \"Yeast two-hybrid screen followed by co-immunoprecipitation and overexpression kinase-activation assays in mammalian cells\",\n      \"pmids\": [\"9115275\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Endogenous role not yet shown by loss-of-function\", \"Mechanism connecting MADD to MAP kinase cascade unresolved\", \"Physiological context (cell type specificity) unknown\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Discovery that alternative splice variants (IG20 vs DENN-SV) exert opposing effects on TNF-α-induced caspase-8 activation revealed that the gene's apoptotic function is isoform-specific, resolving apparently contradictory pro- and anti-apoptotic reports.\",\n      \"evidence\": \"Stable transfection of individual splice variants with caspase activation assays and CrmA epistasis\",\n      \"pmids\": [\"11577081\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis for isoform-specific effects unresolved\", \"Endogenous isoform ratios in relevant tissues not defined\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Demonstration that MADD interacts with TRAIL receptors DR4/DR5 and enhances DISC formation, while competing with TRADD for TNFR1 binding to suppress neuronal apoptosis, established MADD as a dual-receptor signaling node governing cell survival decisions at multiple death receptors.\",\n      \"evidence\": \"Co-immunoprecipitation of MADD-DR4/DR5 complexes, DISC assembly assays, competitive TNFR1 binding, and antisense knockdown in primary hippocampal neurons\",\n      \"pmids\": [\"15208670\", \"15007167\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How MADD distinguishes TNFR1 vs DR4/DR5 structurally unknown\", \"Whether MADD competes with TRADD at endogenous expression levels unresolved\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"In vitro reconstitution of MADD/Rab3GEP GEF activity on all four lipid-modified Rab3 isoforms (but not unmodified Rab3 or Rab3-GDI complexes) defined the enzymatic specificity of the DENN domain, establishing MADD as a bona fide Rab3 GEF requiring membrane-anchored substrate.\",\n      \"evidence\": \"Purified recombinant Rab3GEP from Sf9 cells, in vitro GDP/GTP exchange assay with lipid modification controls\",\n      \"pmids\": [\"16473592\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Crystal structure of DENN domain–Rab3 interface unavailable\", \"Relative in vivo contribution to each Rab3 family member unresolved\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Isoform-specific knockdown and rescue experiments established that the MADD isoform specifically is both necessary and sufficient for cancer cell survival by inhibiting caspase-8 activation at death receptors independently of FADD recruitment, defining MADD as a gatekeeper of extrinsic apoptosis.\",\n      \"evidence\": \"Exon-specific shRNA with shRNA-resistant rescue, co-IP showing MADD binds DR4/DR5 but not caspase-8 or FADD\",\n      \"pmids\": [\"16682944\", \"17314102\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural mechanism by which MADD blocks caspase-8 activation at the receptor unknown\", \"Whether MADD acts stoichiometrically or catalytically at death receptors unresolved\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Discovery that kinesin motors KIF1Bβ and KIF1A directly bind MADD/Rab3GEP, which in turn preferentially binds GTP-Rab3, established an axonal transport cascade (KIF1B→MADD→Rab3) coupling motor-driven vesicle transport to Rab3 nucleotide state.\",\n      \"evidence\": \"Yeast two-hybrid, co-immunoprecipitation, in vivo axonal transport assays in genetic knockout backgrounds\",\n      \"pmids\": [\"18849981\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether MADD acts as a GEF during transport or only as an effector/adaptor unresolved\", \"Cargo identity on KIF1B-MADD-Rab3 vesicles not fully defined\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Endogenous MADD knockdown specifically abolished TNF-α-induced ERK1/2 (but not JNK, p38, or NF-κB) activation by disrupting Grb2/Sos1-2 recruitment to TNFR1 and downstream Ras/MEKK activation, mapping the precise signaling branch controlled by MADD.\",\n      \"evidence\": \"Lentiviral shRNA knockdown with rescue, co-IP of TNFR1 signaling complex, Ras-GTP pull-down\",\n      \"pmids\": [\"19289468\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How MADD recruits Grb2 mechanistically (direct or indirect interaction) not defined\", \"Whether this ERK-specific branch operates in non-immune cell types unresolved\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Identification of three Akt phosphorylation sites on MADD that control its DR4 binding and anti-apoptotic function, and expansion of its GEF substrate range to include Rab27A/B, integrated MADD into both PI3K/Akt survival signaling and lysosomal/secretory granule trafficking.\",\n      \"evidence\": \"Phosphosite mapping by mass spectrometry/mutagenesis with constitutively active and dominant-negative Akt epistasis; systematic DENN-domain GEF screen for Rab specificity\",\n      \"pmids\": [\"20484047\", \"20937701\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Phosphatase(s) that dephosphorylate MADD at these sites not identified beyond PTEN pathway\", \"Relative importance of Rab3 vs Rab27 GEF activity in different tissues unclear\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Conditional knockout of MADD in pancreatic β-cells caused severe glucose-stimulated insulin secretion defects and hyperglycemia without impairing insulin processing, providing the first in vivo genetic proof that MADD's vesicle exocytosis function is physiologically essential for endocrine secretion.\",\n      \"evidence\": \"Beta-cell-specific conditional knockout mouse, glucose tolerance tests, insulin accumulation and secretion assays\",\n      \"pmids\": [\"24379354\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether Rab3 or Rab27 GEF activity mediates insulin secretion not dissected\", \"Potential compensatory changes in other DENN-domain GEFs not assessed\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Elucidation of the PTEN-MADD-14-3-3-Bax axis showed that dephosphorylated MADD translocates from the membrane to cytoplasm and displaces Bax from 14-3-3, activating mitochondrial apoptosis, linking MADD phosphorylation status to intrinsic apoptosis in addition to extrinsic pathway regulation.\",\n      \"evidence\": \"Subcellular fractionation, co-IP of MADD/14-3-3/Bax, cytochrome c release assay, PTEN siRNA epistasis\",\n      \"pmids\": [\"24038283\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether this pathway operates in non-cancer cell types unknown\", \"Direct demonstration that dephosphorylated MADD physically contacts 14-3-3 at endogenous levels not shown\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Characterization of patient-derived fibroblasts from 23 individuals with biallelic MADD variants confirmed that MADD deficiency simultaneously impairs TNF-α-induced ERK activation, increases caspase-dependent apoptosis, and disrupts EGF receptor endocytosis, validating the dual signaling-trafficking model in a human disease context.\",\n      \"evidence\": \"Patient fibroblasts with confirmed MADD protein loss, ERK phosphorylation, caspase-3/7 assay, EGF internalization assay\",\n      \"pmids\": [\"32761064\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specific Rab substrates affected in patient cells not identified\", \"Whether vesicular trafficking defect is Rab3- or Rab27-dependent not distinguished\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Demonstration that MADD's DENN-domain GEF activity (not mere Rab binding) is required for Rab27A/Rab3B/Rab3D recruitment to Weibel-Palade bodies and VWF secretion in endothelial cells, and that cytosolic localization of MADD is essential, resolved whether catalytic activation or scaffolding drives Rab targeting.\",\n      \"evidence\": \"siRNA knockdown, Rab-GTP activity assay, DENN-domain mutant, MADD-TOMM70 mistargeting construct, VWF secretion assay\",\n      \"pmids\": [\"34551092\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How MADD is recruited to specific vesicle populations remains unknown\", \"Whether MADD GEF activity is regulated by phosphorylation at vesicle membranes not tested\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"MADD knockout in NK cells established that MADD is the principal Rab27a GEF controlling cytotoxic lymphocyte degranulation and killing, activating Rab27a without being required for lytic granule docking at the synapse, dissecting activation from tethering functions.\",\n      \"evidence\": \"Genetic knockout, GTP-Rab27a pull-down, degranulation and cytolysis assays, immunofluorescence at the cytolytic synapse\",\n      \"pmids\": [\"38506245\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Post-activation Rab27a effectors downstream of MADD in NK cells not identified\", \"Whether other DENN-domain GEFs partially compensate not assessed\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Analysis of patients carrying an in-frame MADD exon-30 deletion showed that the mutant protein retains GEF activity but has altered protein-protein interactions, causing diabetes, hypogonadotropic hypogonadism, and GH deficiency, revealing that MADD's non-catalytic interactions are essential for endocrine function independently of GEF activity.\",\n      \"evidence\": \"Patient genetics, hESC-derived islets, EndoC-βH1, LβT2 gonadotrope cells, GEF activity assay, protein-protein interaction proteomics\",\n      \"pmids\": [\"38775154\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specific interactors lost in the dex30 mutant that drive endocrine phenotypes not identified\", \"Whether dex30 affects death-domain-mediated signaling not tested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How MADD's GEF, death-domain, and scaffolding functions are coordinated in space and time — and which are affected in specific disease contexts — remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No high-resolution structure of full-length MADD or DENN–Rab complex available\", \"Whether phosphorylation-dependent membrane/cytoplasm shuttling regulates GEF activity in addition to apoptotic signaling is untested\", \"Tissue-specific isoform expression ratios and their functional consequences are incompletely mapped\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 7, 12, 15, 16]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [10, 17, 26, 30]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [10, 17, 26, 30, 32]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [1, 21, 26]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [1, 16, 21]},\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [26, 30]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 3, 15, 16, 22, 24]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [3, 5, 7, 11, 12, 21]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [10, 13, 20, 26, 30]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [29, 30]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"TNFRSF1A\",\n      \"TNFRSF10A\",\n      \"TNFRSF10B\",\n      \"RAB27A\",\n      \"RAB3A\",\n      \"KIF1B\",\n      \"RAB11A\",\n      \"GRB2\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}