{"gene":"GABARAP","run_date":"2026-06-09T23:54:44","timeline":{"discoveries":[{"year":2004,"finding":"GABARAP undergoes C-terminal cleavage to yield a cytosolic form (form I), which is further converted to a membrane-associated form II (phosphatidylethanolamine-conjugated) that localizes to autophagosomal membranes; [14C]-ethanolamine incorporation into form II and Atg4B-mediated deconjugation confirmed PE conjugation.","method":"Radiolabeling ([14C]-ethanolamine incorporation), subcellular fractionation, in vitro Atg4B deconjugation assay, immunofluorescence microscopy","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 1 / Strong — multiple orthogonal biochemical methods (radiolabeling, fractionation, enzymatic deconjugation) in a single study, replicated concept across LC3, GABARAP, and GATE16","pmids":["15169837"],"is_preprint":false},{"year":2000,"finding":"Human ATG7 (hApg7p) acts as an E1-like activating enzyme for GABARAP: hApg7p co-immunoprecipitates with GABARAP and forms a stable thioester intermediate with GABARAP via Cys572, demonstrating that GABARAP is a substrate of the hApg7p-mediated ubiquitin-like conjugation system.","method":"Co-immunoprecipitation, site-directed mutagenesis (C572S active-site mutant), cross-linking, glycerol-gradient centrifugation","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — active-site mutagenesis plus stable intermediate trapping, reconstituted E1-substrate complex, multiple orthogonal methods in one study","pmids":["11096062"],"is_preprint":false},{"year":2002,"finding":"Human ATG3 (hApg3p) acts as an E2-like conjugating enzyme for GABARAP: Cys264 of hApg3p is the active-site cysteine required to form a thioester intermediate with GABARAP; hApg3p also forms an E1·E2 complex with hApg7p.","method":"Site-directed mutagenesis (C264S), co-immunoprecipitation, stable intermediate trapping","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — active-site mutagenesis and stable thioester intermediate trapping, multiple orthogonal methods","pmids":["11825910"],"is_preprint":false},{"year":2003,"finding":"A single protease, Atg4B/autophagin-1, processes the C-terminus of GABARAP (and other Atg8 homologs GATE-16, MAP1-LC3, Apg8L), acting as both a priming and deconjugating enzyme; electrophilic activity-based probes of GABARAP covalently adducted Atg4B in crude lysates.","method":"Activity-based probes (electrophilic GABARAP-derived probes), affinity labeling of cell lysates, functional protease assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — activity-based chemical probes directly identified the protease; reconstituted in vitro with multiple substrates","pmids":["14530254"],"is_preprint":false},{"year":2005,"finding":"In vitro reconstitution with purified recombinant ATG7, ATG3, and liposomes showed that GABARAP is conjugated to both phosphatidylethanolamine (PE) and phosphatidylserine (PS) in vitro; however, in vivo the predominant conjugate is GABARAP-PE, not GABARAP-PS, suggesting a selective factor in endogenous conjugation.","method":"In vitro reconstitution with purified proteins and synthetic phospholipid liposomes, thin-layer chromatography of lipids released by ATG4B digestion","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — fully reconstituted in vitro system with purified components, plus in vivo TLC confirmation","pmids":["16303767"],"is_preprint":false},{"year":2002,"finding":"Crystal structure of human GABARAP at 1.6 Å resolution revealed an N-terminal helical subdomain responsible for tubulin binding and a C-terminal ubiquitin-like domain containing the GABA(A) receptor γ2 subunit binding site; structure-based mutagenesis validated these domain assignments. A second crystal form showed head-to-tail self-association that can promote tubulin polymerization and receptor clustering.","method":"X-ray crystallography (1.6 Å and 1.9 Å), structure-based mutagenesis","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 1 / Strong — high-resolution crystal structure with functional mutagenesis validation, two crystal forms","pmids":["11779480"],"is_preprint":false},{"year":2002,"finding":"Crystal structure of GABARAP at 2.0 Å confirmed an N-terminal basic helical region (tubulin binding) and a core ubiquitin-like fold; one conserved face mediates shared protein-protein interactions across the GABARAP family while the other face shows divergence.","method":"X-ray crystallography (2.0 Å resolution)","journal":"EMBO reports","confidence":"High","confidence_rationale":"Tier 1 / Strong — independent high-resolution crystal structure from a separate laboratory, consistent with Neuron 2002 structure","pmids":["11818336"],"is_preprint":false},{"year":2002,"finding":"NMR solution structure of human GABARAP revealed that the N- and C-terminal ends interact with each other in solution (not seen in crystal structures), with one region existing in at least two slowly interconverting conformations, suggesting dynamic regulation of GABARAP interactions.","method":"NMR spectroscopy in aqueous solution","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — high-resolution NMR structure, single lab, complementary to crystal structures","pmids":["11875056"],"is_preprint":false},{"year":2014,"finding":"Lipidation of GABARAP (and LC3) by ATG3 is membrane-curvature-dependent: ATG3 contains an amphipathic N-terminal helix that senses lipid-packing defects on highly curved membranes. Tuning the helix hydrophobicity promotes or inhibits GABARAP lipidation in vitro and in ATG3-knockout rescue experiments in vivo.","method":"In vitro lipidation reconstitution with liposomes of defined curvature, amphipathic-helix mutagenesis, ATG3-knockout cell rescue","journal":"Nature cell biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstituted in vitro system, mutagenesis, and in vivo validation across multiple orthogonal methods","pmids":["24747438"],"is_preprint":false},{"year":2001,"finding":"GABARAP directly binds N-ethylmaleimide-sensitive factor (NSF): co-immunoprecipitation from neurons detected a GABARAP–NSF complex, and GABARAP co-localizes with NSF in intracellular membrane compartments (Golgi/post-synaptic cisternae), suggesting a role in intracellular GABA(A) receptor transport rather than synaptic anchoring.","method":"Co-immunoprecipitation, subcellular fractionation, immunofluorescence colocalization","journal":"Molecular and cellular neurosciences","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — reciprocal Co-IP from neurons, colocalization; localization linked to function but no direct mechanistic assay","pmids":["11461150"],"is_preprint":false},{"year":2000,"finding":"GABARAP promotes clustering of GABA(A) receptors in fibroblasts: co-expression of GABARAP with α1β2γ2 GABA(A) receptors in QT-6 cells induced receptor clustering requiring the GABARAP tubulin-binding motif and intact microtubules. Clustered receptors showed altered channel kinetics (higher EC50 ~20 µM vs 5.7 µM, faster deactivation, slower desensitization).","method":"Immunofluorescence, GFP-tagged receptor imaging, microtubule disruption (nocodazole/taxol), patch-clamp electrophysiology","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — functional readout (electrophysiology) combined with imaging and pharmacological perturbation, multiple orthogonal methods","pmids":["10984509"],"is_preprint":false},{"year":2000,"finding":"GABARAP interacts directly with tubulin and microtubules in a salt-sensitive (ionic) manner, and also associates with microfilaments in intact cells; the tubulin-binding domain is located at the N-terminus of GABARAP and is defined by a specific arrangement of basic amino acids.","method":"In vitro tubulin-binding assay, co-immunoprecipitation with tubulin, pharmacological cytoskeletal disruption (taxol, nocodazole, cytochalasin D), synthetic peptide and deletion construct mapping","journal":"Journal of neurochemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro binding reconstitution, domain mapping by deletion constructs and synthetic peptides, in vivo validation","pmids":["10899939"],"is_preprint":false},{"year":2000,"finding":"GABARAP interacts with gephyrin in biochemical assays and transfected cells, but confocal analysis of wild-type and gephyrin-knockout neurons showed that GABARAP is enriched intracellularly and is not present at gephyrin-positive postsynaptic membrane specializations, indicating the GABARAP–gephyrin interaction does not mediate postsynaptic GABA(A) receptor anchoring.","method":"Biochemical pulldown, co-immunoprecipitation in transfected cells, confocal immunofluorescence in wild-type and gephyrin-KO neurons","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — binding confirmed biochemically plus in vivo localization with KO control; negative result for synaptic anchoring is mechanistically informative","pmids":["10900017"],"is_preprint":false},{"year":2002,"finding":"GABARAP binds specifically to the γ (not α or β) subunits of GABA(A) receptors; the interaction domain in γ2 was mapped by quantitative yeast two-hybrid, and a membrane-permeable peptide corresponding to the GABARAP-binding domain in γ2 inhibited GABARAP-induced receptor clustering in living cells.","method":"Yeast two-hybrid with 15 receptor subunit intracellular loops, GABARAP affinity column pull-down of native receptors, peptide inhibition of clustering in fibroblasts","journal":"Journal of neurochemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — domain mapping with multiple subunit isoforms, affinity purification of native complex, functional peptide inhibitor validation","pmids":["11948245"],"is_preprint":false},{"year":2007,"finding":"C-terminal processing of GABARAP at Gly116 is essential for its role in GABA(A) receptor trafficking: the G116A mutation blocks C-terminal cleavage, re-localizes GABARAP to the Golgi (instead of punctate cytoplasmic distribution), reduces co-localization and interaction with GABA(A) receptors, and prevents GABARAP-mediated increase in receptor surface expression in neurons and oocytes.","method":"Site-directed mutagenesis (G116A), immunofluorescence confocal microscopy, co-immunoprecipitation, surface expression assay (oocyte GABA currents, surface-accessible subunit labeling)","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 1 / Strong — mutagenesis with multiple functional readouts (localization, binding, surface expression, electrophysiology) in two cell systems","pmids":["17581952"],"is_preprint":false},{"year":2005,"finding":"GABARAP is not essential for GABA(A) receptor trafficking to synapses in vivo: GABARAP-knockout mice are phenotypically normal, show no change in total GABA(A) receptor number (benzodiazepine binding), and have normal punctate γ2 subunit and gephyrin distribution in cortical neurons.","method":"GABARAP-knockout mouse analysis, radioligand binding, immunocytochemistry","journal":"The European journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean genetic KO with defined phenotypic readouts, but single lab and single time-point analysis","pmids":["16307606"],"is_preprint":false},{"year":2009,"finding":"Nix/Bnip3L (pro-apoptotic protein) directly interacts with GABARAP; interaction confirmed by phage display screening, in vitro pull-down assays, co-immunoprecipitation, and colocalization in mammalian cells.","method":"Phage display screening, in vitro pull-down, co-immunoprecipitation, colocalization","journal":"Autophagy","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — multiple binding assays but no functional mechanism elucidated beyond interaction; single lab","pmids":["19363302"],"is_preprint":false},{"year":2007,"finding":"Calreticulin is a high-affinity GABARAP ligand (Kd = 64 nM, mean complex lifetime ~20 min): identified by phage display of a peptide library, confirmed by pull-down from brain lysate and colocalization in N2a cells.","method":"Phage display library screening, GST pull-down from brain lysate, colocalization, biophysical binding measurement","journal":"The FEBS journal","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — phage display plus pull-down and colocalization; high-affinity binding quantified, single lab","pmids":["17916189"],"is_preprint":false},{"year":2009,"finding":"Crystal structure of GABARAP in complex with the calreticulin binding epitope revealed the structural basis of the interaction; molecular modeling suggested a novel mode of substrate interaction for the calreticulin/calnexin chaperone family.","method":"X-ray crystallography of GABARAP–calreticulin peptide complex, NMR spectroscopy, molecular modeling","journal":"The FEBS journal","confidence":"High","confidence_rationale":"Tier 1 / Moderate — crystal structure of the complex with spectroscopic validation; single lab","pmids":["19154346"],"is_preprint":false},{"year":2008,"finding":"Two tryptophan-binding hydrophobic pockets on the conserved face of GABARAP constitute the major determinant of ligand specificity; NMR and molecular docking identified these sites, and replacing the key tryptophan in ligands (calreticulin, clathrin heavy chain, γ2 subunit) with alanine abolished GABARAP binding.","method":"NMR spectroscopy, molecular docking, mutagenesis (Trp→Ala in ligand peptides), quantitative binding measurements","journal":"Chembiochem","confidence":"High","confidence_rationale":"Tier 1 / Moderate — NMR structure with mutagenesis validation of binding sites; single lab","pmids":["18567048"],"is_preprint":false},{"year":2002,"finding":"GABARAP self-associates as a dimer (not higher-order oligomers) in physiological salt; the dimerization domain was mapped to residues 41–51 using deletion constructs and GABARAP-derived synthetic peptides in GST pull-down assays.","method":"GST pull-down with deletion constructs and synthetic peptides, glycerol-gradient centrifugation","journal":"Neuropharmacology","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — domain mapping with peptide inhibitors, in vitro biochemistry, single lab","pmids":["12367594"],"is_preprint":false},{"year":2002,"finding":"GABARAP interacts with the transferrin receptor (TfR) cytoplasmic domain: yeast two-hybrid identified the interaction, confirmed by in vitro binding assays and co-immunoprecipitation from HeLa cells; the YTRF internalization motif of TfR is required for GABARAP binding. GABARAP-GFP localizes to perinuclear vesicles, indicating a general trafficking role beyond neurons.","method":"Yeast two-hybrid, in vitro binding assay with purified proteins, co-immunoprecipitation, GFP-GABARAP localization imaging","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — two binding assays plus motif mapping, single lab","pmids":["11997026"],"is_preprint":false},{"year":2008,"finding":"GABARAP binds the C-terminal cytoplasmic domain of angiotensin II type 1 receptor (AT1R) and promotes AT1R plasma membrane expression: identified by yeast two-hybrid, confirmed by GST pull-down, co-immunoprecipitation, BRET; GABARAP overexpression increased surface AT1R 6-fold and enhanced Ang II-induced ERK1/2 phosphorylation, while siRNA knockdown of GABARAP reduced AT1R surface expression by 84%.","method":"Yeast two-hybrid, GST pull-down, co-immunoprecipitation, BRET, siRNA knockdown, surface receptor quantification, ERK1/2 signaling assay","journal":"Circulation research","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal binding and functional assays including siRNA knockdown with quantitative surface expression and signaling readout","pmids":["18497328"],"is_preprint":false},{"year":2010,"finding":"GABARAP associates with TRPV1 in HEK293 cells and DRG neurons, augments TRPV1 surface clustering and expression, attenuates voltage and capsaicin sensitivity in the presence of extracellular calcium, prolongs vanilloid-induced tachyphylaxis kinetics, and selectively increases tubulin interaction with the TRPV1 C-terminal domain; disruption of tubulin cytoskeleton with nocodazole reduced capsaicin-evoked currents specifically in cells co-expressing GABARAP.","method":"Co-immunoprecipitation, immunofluorescence, patch-clamp electrophysiology, siRNA/overexpression in HEK293 and DRG neurons, nocodazole treatment","journal":"FASEB journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods with quantitative functional readouts (electrophysiology + trafficking) in two cell types","pmids":["20179142"],"is_preprint":false},{"year":2006,"finding":"Co-expression of GABARAP with α1β2γ2 GABA(A) receptors in L929 cells increased single-channel conductance (up to 60 pS vs. 30 pS main conductance) and mean open time of channels, with a linear relationship between conductance and open time; these changes are dependent on high GABA concentrations and reflect changes imposed by GABARAP-mediated receptor organization.","method":"Outside-out patch-clamp electrophysiology, single-channel analysis in transfected L929 cells","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct single-channel electrophysiology, single lab with clean functional readout","pmids":["16954214"],"is_preprint":false},{"year":2015,"finding":"GABARAP specifically promotes ULK1 kinase activation in starvation-induced autophagy: unlipidated and lipidated GABARAP (but not LC3B, GABARAPL1, or GATE-16) activate ULK1 in a manner dependent on the ULK1 LIR motif. WAC and GM130 regulate GABARAP subcellular localization (Golgi vs. pericentriolar matrix), and centrosomal GABARAP is delivered to the phagophore during starvation.","method":"Genetic knockdown/rescue, ULK1 kinase assay, immunofluorescence, co-immunoprecipitation with GST-pulldown; domain-specific LIR mutants","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — isoform-specific rescue experiments with kinase activity assay and multiple orthogonal approaches in one study","pmids":["26687599"],"is_preprint":false},{"year":2017,"finding":"Centriolar satellite protein PCM1 directly binds GABARAP via a canonical LIR motif, recruits GABARAP to pericentriolar material, and protects it from proteasomal degradation. The centriolar satellite E3 ligase Mib1 promotes K48-linked ubiquitination of GABARAP (at N-terminal residues absent in the LC3 family), leading to its destabilization when PCM1 is lost. PCM1 loss reduces GABARAP-positive autophagosome formation and flux but does not affect LC3B-positive autophagosomes.","method":"Co-immunoprecipitation, GST pull-down, LIR motif mutagenesis, ubiquitin linkage-specific antibodies, autophagy flux assay, siRNA knockdown","journal":"Current biology : CB","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct binding mapped to LIR motif, ubiquitination characterized with linkage specificity, isoform-specific autophagy flux readout; multiple orthogonal methods","pmids":["28712572"],"is_preprint":false},{"year":2019,"finding":"ATL3 (atlastin-3) functions as a selective ER-phagy receptor for tubular ER degradation by binding specifically to GABARAP (not LC3) subfamily proteins via two GABARAP interaction motifs (GIMs). Disease-associated ATL3 mutations (Y192C, P338R) disrupt ATL3–GABARAP association and impair ER-phagy.","method":"Co-immunoprecipitation, GIM motif mutagenesis, starvation-induced ER-phagy assay, disease mutation analysis","journal":"Current biology : CB","confidence":"High","confidence_rationale":"Tier 2 / Strong — motif mapping with mutagenesis, functional ER-phagy assay, disease-mutation validation; multiple orthogonal methods","pmids":["30773365"],"is_preprint":false},{"year":2017,"finding":"A GABARAP interaction motif (GIM) defined as [W/F]-[V/I]-X2-V confers ~11-fold selectivity for GABARAP over LC3B (as in PLEKHM1); crystal structures and biophysical analysis (ITC, NMR) identified variation in hydrophobic pocket 2 (HP2) as the structural basis for GABARAP vs. LC3 selectivity; conversion of LIRs in p62, FUNDC1, and FIP200 to GIM by introducing two valines enhanced GABARAP binding.","method":"X-ray crystallography of LIR–GABARAP complexes, isothermal titration calorimetry, NMR, selectivity profiling of 30 LIR motifs, mutagenesis","journal":"EMBO reports","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structures plus ITC and mutagenesis across multiple LIR motifs; replicated with multiple interactors","pmids":["28655748"],"is_preprint":false},{"year":2019,"finding":"PIK3C3, BECN1, and ATG14 (components of the PI3K complex I) contain functional LIR motifs that prefer GABARAP and GABARAPL1 over LC3 proteins; crystal structures of GABARAP bound to these LIR motifs revealed that HP2 pocket variation underlies GABARAP-family specificity. ATG14 LIR mutation blocks mitophagy and impairs ULK1-mediated phosphorylation of ATG14-S29.","method":"Crystal structures of GABARAP–LIR complexes, co-immunoprecipitation, LIR mutagenesis, mitophagy assay, ULK1 phosphorylation assay","journal":"Autophagy","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structures with functional mutagenesis (LIR mutant ATG14), multiple pathway readouts (mitophagy, phosphorylation); multiple orthogonal methods","pmids":["30767700"],"is_preprint":false},{"year":2020,"finding":"A conserved motif in human ATG2A mediates direct interaction with GABARAP (and GABARAPL1), and this ATG2A–GABARAP interaction is essential for phagophore formation and closure; ATG2A mutants that cannot bind GABARAP fail to restore phagophore formation (phenocopying ATG2A/B double-KO), whereas ATG2A–WIPI4 interaction mutants fully rescue autophagy.","method":"Epistasis via ATG2A/B double-KO rescue with interaction-mutant constructs, autophagy flux assay, co-immunoprecipitation","journal":"EMBO reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis with separation-of-function mutants in KO cells, multiple autophagy readouts; single lab but rigorous design","pmids":["32009292"],"is_preprint":false},{"year":2021,"finding":"GABARAP (but not LC3) directly binds an LIR motif in the FLCN/FNIP tumor suppressor complex; during CASM, mitophagy, or xenophagy, membrane-conjugated GABARAP sequesters FLCN/FNIP to GABARAP-containing membranes, disrupting FLCN/FNIP GAP activity toward RagC/D and thereby impairing mTOR-dependent phosphorylation of TFEB, leading to TFEB/TFE3 activation and lysosomal biogenesis.","method":"Co-immunoprecipitation, LIR mutagenesis, mTOR substrate phosphorylation assay, TFEB/TFE3 nuclear translocation assay, GABARAP KO vs. LC3 KO rescue","journal":"Science advances","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct binding mapped by LIR mutagenesis, functional pathway readout (mTOR/TFEB), isoform-specific KO rescue experiments; multiple orthogonal methods","pmids":["34597140"],"is_preprint":false},{"year":2017,"finding":"HIV-1 Nef binds directly and specifically to all GABARAP family members (not LC3 family members) via the two surface-exposed hydrophobic pockets of GABARAP; S53 and F62 of GABARAP are key residues for Nef interaction. GABARAP is required for Nef plasma membrane localization: siRNA knockdown of all three GABARAP family members significantly reduced Nef plasma membrane accumulation.","method":"Pull-down with purified recombinant proteins, co-immunoprecipitation, NMR epitope mapping, live-cell fluorescence microscopy, siRNA knockdown","journal":"Scientific reports","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct binding with recombinant proteins, NMR residue-level mapping, functional siRNA knockdown; multiple orthogonal methods","pmids":["28729737"],"is_preprint":false},{"year":2015,"finding":"GABARAP recruits PI4K2A (PI4KIIα) to autophagosomes via direct binding; PI4K2A-derived PtdIns4P on autophagosomes is required for autophagosome–lysosome fusion. GABARAP depletion prevents PI4K2A autophagosome recruitment and impairs autophagosome–lysosome fusion.","method":"Co-immunoprecipitation, GABARAP depletion/rescue, autophagosome–lysosome fusion assay","journal":"Autophagy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — binding and functional fusion assay; single lab, moderate mechanistic detail in the abstract","pmids":["26391226"],"is_preprint":false},{"year":2014,"finding":"PLEKHM1 contains a functional LIR motif that directly mediates binding to autophagosomal GABARAP (and other LC3/GABARAP family members); PLEKHM1 simultaneously interacts with the HOPS complex via a separate domain. PLEKHM1 depletion blocks autophagy flux, lysosomal degradation of endocytic EGFR cargo, and clearance of protein aggregates in an LIR-dependent manner.","method":"Co-immunoprecipitation, LIR mutagenesis, PLEKHM1 depletion/rescue, autophagic flux assay, EGFR degradation assay","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — LIR mutagenesis with multiple functional readouts (flux, endocytic degradation, aggregate clearance); replicated concept with HOPS complex","pmids":["25498145"],"is_preprint":false},{"year":2015,"finding":"The CUL3-KBTBD6/KBTBD7 ubiquitin ligase complex binds GABARAP proteins via ATG8-family-interacting motifs and is recruited to GABARAP-containing vesicles; GABARAP recruitment is required for TIAM1 ubiquitination and degradation by this ligase, thereby spatially restricting RAC1 signaling, actin remodeling, and cell invasion.","method":"Co-immunoprecipitation, ATG8-interaction motif mutagenesis, siRNA depletion, RAC1 activity assay, TIAM1 ubiquitination assay, invasion assay","journal":"Molecular cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — motif-dependent recruitment linked to ubiquitination and downstream signaling readouts; multiple orthogonal methods","pmids":["25684205"],"is_preprint":false},{"year":2013,"finding":"GABARAP deficiency in macrophages leads to impaired mitophagy-dependent clearance of damaged mitochondria after NLRP3 inflammasome activation (LPS+ATP), resulting in excess mitochondrial ROS and cytosolic mitochondrial DNA, and enhanced caspase-1 activation, IL-1β and IL-18 secretion; GABARAP-KO mice show higher mortality in two sepsis models.","method":"GABARAP-KO macrophage analysis, mitochondrial ROS measurement, caspase-1 cleavage assay, IL-1β/IL-18 ELISA, sepsis mouse models","journal":"Journal of immunology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean KO with defined molecular readouts (ROS, mtDNA, caspase-1, cytokines); mechanistic link to mitophagy is indirect","pmids":["23427251"],"is_preprint":false},{"year":2019,"finding":"An atypical (non-canonical) LIR motif in UBA5 (ufmylation E1 enzyme) preferentially interacts with GABARAP over LC3; crystal structures of GABARAP and GABARAPL2 in complex with the UBA5 LIR revealed a third hydrophobic pocket (HP0) engaged by a tryptophan N-terminal of the LIR core, with K46/K47 in GABARAP being key specificity determinants. GABARAP regulates UBA5 localization to the ER membrane in a lipidation-independent manner.","method":"X-ray crystallography of GABARAP–UBA5 LIR complexes, NMR, ITC, mutagenesis (HP0 swaps), subcellular localization assay","journal":"Autophagy","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structures of the complex with mutagenesis validation and functional localization assay; multiple orthogonal methods","pmids":["30990354"],"is_preprint":false},{"year":2016,"finding":"GABARAP (and GATE-16), when lipidated, promotes extensive membrane tethering and full membrane fusion (vesicle aggregation, inter-vesicular lipid mixing, content mixing without leakage) in reconstituted systems, whereas LC3 shows minimal fusogenic activity; smaller vesicle diameter and negative-curvature lipids (cardiolipin, DAG) facilitate GABARAP-mediated fusion.","method":"In vitro membrane fusion reconstitution (enzymatic and chemical lipidation), cryo-electron microscopy, fluorescence lipid- and content-mixing assays","journal":"Biophysical journal","confidence":"High","confidence_rationale":"Tier 1 / Strong — fully reconstituted in vitro fusion system with multiple independent assays for different fusion steps and cryo-EM visualization","pmids":["26789764"],"is_preprint":false},{"year":2016,"finding":"GABARAP (but not LC3) is specifically required for IFN-γ-mediated antimicrobial clearance of vacuolar pathogens (Toxoplasma): cells lacking GABARAPs but not LC3s were defective in IFN-γ-induced pathogen clearance. GABARAP/Gate-16, but not LC3b, specifically associated with Arf1 (small GTPase) to mediate uniform cytosolic distribution of interferon-inducible GTPases (IFN-GTPases); GABARAP loss reduced Arf1 activation and caused IFN-GTPase aggregation.","method":"GABARAP-KO and LC3-KO cell comparison, Toxoplasma clearance assay, co-immunoprecipitation with Arf1, IFN-GTPase localization assay, Arf1 activation assay","journal":"Nature immunology","confidence":"High","confidence_rationale":"Tier 2 / Strong — isoform-specific KO comparison with multiple functional and molecular readouts (pathogen clearance, Arf1 binding, GTPase distribution); multiple orthogonal methods","pmids":["28604719"],"is_preprint":false},{"year":2019,"finding":"TBK1 phosphorylates GABARAP-L2 on surface-exposed serine residues (S87 and S88); this phosphorylation impedes ATG4-mediated binding and deconjugation of GABARAP-L2 from liposomes, protecting it from premature removal from nascent autophagosomes.","method":"In vitro TBK1 kinase assay, liposome deconjugation assay, mutagenesis of phosphorylation sites, ATG4 binding assay","journal":"EMBO reports","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — in vitro kinase and deconjugation assays with mutagenesis; direct evidence for GABARAP-L2; single lab","pmids":["31709703"],"is_preprint":false},{"year":2019,"finding":"ATG3 is a target of GABARAP conjugation (LC3ylation): deconjugation-resistant GABARAP/LC3 isoforms accumulate as higher-molecular-weight conjugates on ATG3 in ATG4-deficient cells; ATG3 Lys243 was identified as an LC3B modification site; ATG4B can cleave LC3B-ATG3 conjugates (acting as a deubiquitinating-like enzyme).","method":"Deconjugation-resistant mutant LC3/GABARAP expression, ATG4-deficient cell lines (CRISPR-Cas9), immunoblotting under reducing/denaturing conditions, site identification by mutagenesis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic KO system with separation-of-function mutants, site mutagenesis, biochemical deconjugation assay; multiple orthogonal methods","pmids":["31315929"],"is_preprint":false},{"year":2019,"finding":"ATG4A, ATG4C, and ATG4D all contribute to residual priming (C-terminal processing) of GABARAP family members in cells lacking ATG4B; endogenous GABARAPL1 can be lipidated on autophagic structures by these redundant priming activities; expressing pre-primed LC3B in ATG4-deficient cells rescues autophagic degradation of SQSTM1/p62, demonstrating that ATG4-mediated delipidation is not essential for autophagosome–lysosome fusion.","method":"CRISPR-Cas9 KO of ATG4 isoforms in HAP1 and HeLa cells, siRNA co-depletion, autophagic flux assay (SQSTM1 degradation), CLEM","journal":"Autophagy","confidence":"High","confidence_rationale":"Tier 2 / Strong — systematic multi-isoform KO with multiple orthogonal functional assays; comprehensive genetic characterization","pmids":["30661429"],"is_preprint":false},{"year":2013,"finding":"MAPK15/ERK8 directly interacts with GABARAP (and GABARAPL1, MAP1LC3B) via a conserved LIR motif; MAPK15 localizes to autophagic compartments, and kinase-dependent activity increases ATG8 protein lipidation, autophagosome formation, and SQSTM1 degradation; MAPK15 kinase activity is induced by serum and amino-acid starvation and is required for starvation-induced autophagy.","method":"Co-immunoprecipitation, LIR mutagenesis, kinase activity assay, autophagosome quantification, SQSTM1 degradation assay, starvation-induced autophagy","journal":"Autophagy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — LIR motif mapping, kinase-dependent readout, multiple assays; single lab","pmids":["22948227"],"is_preprint":false},{"year":2014,"finding":"FLCN directly interacts with GABARAP; the FLCN–GABARAP association is modulated by FNIP1/2 and regulated by ULK1; ULK1 phosphorylates FLCN at Ser406, Ser537, and Ser542; loss of FLCN moderately impairs basal autophagic flux.","method":"Co-immunoprecipitation, ULK1 phosphorylation assay (mass spectrometry identification of phosphosites), autophagic flux assay","journal":"Autophagy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct binding confirmed by Co-IP, phosphorylation sites identified by MS, functional flux assay; single lab","pmids":["25126726"],"is_preprint":false},{"year":2013,"finding":"Bcl-2 directly binds GABARAP via a three-residue segment (EWD) adjacent to the BH4 region that anchors to one of two hydrophobic pockets on GABARAP (not both pockets simultaneously, unlike most GABARAP partners); Bcl-2 overexpression inhibits GABARAP lipidation, a key step in autophagosome formation.","method":"NMR epitope mapping, in vitro pull-down, lipidation assay, Bcl-2 overexpression","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — NMR residue-level mapping of interaction, functional lipidation assay; single lab but multiple orthogonal methods","pmids":["24240096"],"is_preprint":false},{"year":2021,"finding":"GABARAP directly binds a previously unappreciated region in the γ2 subunit of GABA(A)R; crystal structure of GABARAPL1–γ2 complex revealed the molecular basis of complex formation; phosphorylation of γ2 differentially modulates its binding to GABARAP vs. the clathrin adaptor AP2; GABARAP stabilizes GABAARs by promoting trafficking (not blocking endocytosis); blockage of the GABARAP–GABAAR interaction selectively reduced GABAergic synaptic currents.","method":"X-ray crystallography of GABARAPL1–γ2 complex, co-immunoprecipitation, phosphorylation-dependent binding assay, patch-clamp electrophysiology, receptor trafficking assay","journal":"Nature communications","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure with mutagenesis and multiple functional readouts (trafficking, electrophysiology); highly rigorous single study","pmids":["33436612"],"is_preprint":false},{"year":2018,"finding":"Ankyrin-G directly interacts with GABARAP to stabilize cell-surface GABA(A) receptors; a knock-in mouse expressing Ank3 W1989R (a mutation abolishing ankyrin-G/GABARAP interaction) shows reduced forebrain GABAergic synapses, pyramidal cell hyperexcitability, and disrupted network synchronization; the ANK3 W1989R variant was identified in a family with bipolar disorder.","method":"Knock-in mouse model, in vivo electrophysiology, immunofluorescence, co-immunoprecipitation; human genetic variant analysis","journal":"Molecular psychiatry","confidence":"High","confidence_rationale":"Tier 2 / Strong — separation-of-function knock-in mouse with multiple in vivo readouts (synaptic, electrophysiological, morphological); rigorous design","pmids":["30504823"],"is_preprint":false},{"year":2014,"finding":"Mulan E3 ubiquitin ligase interacts with GABARAP through a LIR motif in its RING finger domain, and this interaction requires the E2 enzyme Ube2E3; the Mulan–GABARAP interaction recruits GABARAP to mitochondrial outer membrane and is proposed to regulate mitophagy.","method":"Yeast two-hybrid, co-immunoprecipitation, LIR motif analysis","journal":"Cellular signalling","confidence":"Low","confidence_rationale":"Tier 3 / Weak — yeast two-hybrid and Co-IP only; no direct functional mitophagy assay linked to GABARAP interaction; single lab","pmids":["25224329"],"is_preprint":false},{"year":2016,"finding":"GABARAP (but not GABARAPL2) interacts with cardiolipin (CL) in vitro; however, neither GABARAP nor GABARAPL2 was translocated to mitochondria in rotenone-treated glioblastoma cells (unlike LC3B), suggesting GABARAP does not participate in CL-mediated mitophagy signaling in this cell type.","method":"Quantitative biophysical binding assays with CL-containing liposomes, live-cell imaging after rotenone treatment","journal":"Autophagy","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — quantitative biophysical assays plus in vivo imaging; result is partly negative (no mitochondrial translocation in vivo); single lab","pmids":["27764541"],"is_preprint":false},{"year":2025,"finding":"STING signaling activates LRRK2 kinase activity via the CASM pathway in a GABARAP-dependent manner: multiple lysosome-perturbing stimuli converge on CASM to conjugate ATG8s to single membranes; LRRK2 lysosomal recruitment and kinase activation are highly dependent on interaction with GABARAP specifically, not other ATG8 family members.","method":"STING agonist treatment, CASM induction, GABARAP KO vs. LC3 KO, LRRK2 lysosome recruitment assay, LRRK2 kinase activity assay (Rab phosphorylation)","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — isoform-specific KO comparison with quantitative kinase activity and localization readouts; multiple stimuli tested","pmids":["39812709"],"is_preprint":false},{"year":2006,"finding":"In GABARAP-KO mice, the renal sodium-phosphate cotransporter NaPi-IIa is upregulated in brush-border membranes, resulting in increased phosphate reabsorption; GABARAP binds NaPi-IIa via amino acids 36–68 of GABARAP, confirmed by GST pull-down and co-immunoprecipitation from renal cells.","method":"GABARAP-KO mouse analysis, GST pull-down from brush-border membranes, co-immunoprecipitation from HEK293 cells, 32Pi uptake assay, GABARAP domain mapping","journal":"American journal of physiology. Renal physiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — KO mouse with quantitative transport assay and direct binding domain mapping; single lab","pmids":["19225049"],"is_preprint":false}],"current_model":"GABARAP is an ATG8-family ubiquitin-like modifier that undergoes C-terminal cleavage (by ATG4 proteases) followed by E1 (ATG7)- and E2 (ATG3)-mediated conjugation to phosphatidylethanolamine on autophagosomal and other membranes; membrane-conjugated GABARAP promotes phagophore elongation and closure (via a conserved interaction with ATG2), membrane tethering and fusion (especially within the GABARAP subfamily), and autophagosome–lysosome fusion (by recruiting PI4K2A and interacting with PLEKHM1–HOPS); in starvation-induced autophagy it specifically activates ULK1 kinase from a centrosomal/Golgi pool regulated by WAC, GM130, and centriolar satellites (PCM1/Mib1-mediated ubiquitination); it acts as a selective interaction platform for numerous cargo adaptors, receptors, and signaling proteins through its two hydrophobic LIR-docking pockets (with a GABARAP-specific HP0 site for certain partners), with a defined GIM sequence conferring GABARAP-over-LC3 selectivity; in neurons it promotes GABA(A) receptor clustering and surface trafficking by bridging the receptor γ2 subunit (direct structural interaction), microtubules (N-terminal basic domain), NSF, gephyrin, and ankyrin-G; and it plays non-autophagy roles including Arf1-dependent cytosolic distribution of IFN-inducible GTPases for antimicrobial defense, FLCN/FNIP sequestration to regulate mTOR–TFEB lysosomal biogenesis, and LRRK2 activation at lysosomes via the CASM pathway."},"narrative":{"mechanistic_narrative":"GABARAP is an ATG8-family ubiquitin-like modifier that is processed at its C-terminus (Gly116) and conjugated to membrane phosphatidylethanolamine through an E1 (ATG7, via a Cys572 thioester) and E2 (ATG3, via a Cys264 thioester) cascade, with ATG4B serving as both the priming protease and the deconjugating enzyme [PMID:15169837, PMID:11096062, PMID:11825910, PMID:14530254, PMID:17581952]. In vitro reconstitution shows GABARAP can be conjugated to PE and PS, while ATG3's curvature-sensing amphipathic helix restricts lipidation to highly curved membranes, accounting for the in vivo predominance of GABARAP-PE [PMID:16303767, PMID:24747438]. Once lipidated, GABARAP drives multiple steps of autophagosome biogenesis and maturation: it binds ATG2A to enable phagophore formation and closure [PMID:32009292], it uniquely among ATG8s promotes membrane tethering and full fusion in reconstituted systems [PMID:26789764], and it directs autophagosome–lysosome fusion by recruiting PI4K2A and engaging the PLEKHM1–HOPS machinery through LIR-motif interactions [PMID:26391226, PMID:25498145]. In starvation-induced autophagy, GABARAP is specifically required (and is not interchangeable with LC3B or other family members) to activate ULK1 kinase from a centrosomal/Golgi pool whose localization and stability are controlled by WAC, GM130, and the centriolar satellite proteins PCM1 and the Mib1 ubiquitin ligase [PMID:26687599, PMID:28712572]. High-resolution crystal, NMR, and biophysical structures define GABARAP as a ubiquitin-like fold with an N-terminal basic/helical subdomain that binds tubulin and a conserved face bearing two hydrophobic tryptophan-binding pockets (plus a GABARAP-specific HP0 site) that form the docking surface for partner LIR/GIM motifs; sequence variation in pocket HP2 and residues such as K46/K47 underlies a defined GIM consensus that confers GABARAP-over-LC3 selectivity for partners including PLEKHM1, ATL3, the PI3K-complex-I subunits, and UBA5 [PMID:11779480, PMID:11818336, PMID:11875056, PMID:18567048, PMID:28655748, PMID:30767700, PMID:30990354]. Through these pockets GABARAP serves as a selective platform for cargo receptors and signaling proteins, mediating ER-phagy (ATL3), mitophagy and inflammasome control in macrophages, and spatial restriction of RAC1 signaling via CUL3–KBTBD6/7-dependent TIAM1 degradation [PMID:30773365, PMID:25684205, PMID:23427251]. Beyond canonical autophagy, GABARAP regulates lysosomal biogenesis by sequestering the FLCN/FNIP complex on membranes to inhibit its RagC/D GAP activity and thereby activate mTOR-controlled TFEB/TFE3 signaling [PMID:34597140, PMID:25126726], supports IFN-γ antimicrobial defense by associating with Arf1 to distribute interferon-inducible GTPases [PMID:28604719], and is required for STING/CASM-driven recruitment and kinase activation of LRRK2 at lysosomes [PMID:39812709]. In neurons, GABARAP directly binds the GABA(A) receptor γ2 subunit (defined by crystal structure), bridging it to microtubules via its N-terminal basic domain, NSF, gephyrin, and ankyrin-G to promote receptor clustering and surface trafficking and to modulate channel kinetics [PMID:11779480, PMID:10984509, PMID:10899939, PMID:11948245, PMID:33436612, PMID:30504823]; an ankyrin-G W1989R knock-in mouse that abolishes the ankyrin-G/GABARAP interaction produces GABAergic synaptic and excitability deficits, and the corresponding human ANK3 variant was found in a family with bipolar disorder [PMID:30504823].","teleology":[{"year":2000,"claim":"Establishing the enzymology of GABARAP conjugation answered how this ubiquitin-like protein is covalently activated and attached, defining it as a substrate of an E1-like activating enzyme.","evidence":"Co-IP, active-site C572S mutagenesis, and thioester intermediate trapping with human ATG7","pmids":["11096062"],"confidence":"High","gaps":["Did not identify the downstream lipid acceptor","Did not define the E2 enzyme"]},{"year":2002,"claim":"Identifying ATG3 as the E2 conjugating enzyme completed the activation cascade and showed it forms an E1·E2 complex with ATG7.","evidence":"C264S active-site mutagenesis and thioester intermediate trapping","pmids":["11825910"],"confidence":"High","gaps":["Did not establish the final membrane target","Curvature dependence of lipidation not yet known"]},{"year":2003,"claim":"Showing that a single protease (ATG4B) both primes and deconjugates GABARAP defined the reversible, protease-gated nature of the modification.","evidence":"Electrophilic activity-based GABARAP probes covalently labeling ATG4B in lysates","pmids":["14530254"],"confidence":"High","gaps":["Redundancy among ATG4 isoforms not resolved","Physiological consequence of deconjugation untested"]},{"year":2002,"claim":"Solving GABARAP structures (crystal and NMR) defined the bipartite architecture — an N-terminal tubulin-binding helical subdomain and a ubiquitin-like core carrying the γ2 receptor binding site — and revealed conformational dynamics and self-association.","evidence":"X-ray crystallography (1.6/2.0 Å), NMR solution structure, structure-based mutagenesis","pmids":["11779480","11818336","11875056"],"confidence":"High","gaps":["Did not define the hydrophobic-pocket ligand code","Functional role of dynamic N-/C-terminal contacts unresolved"]},{"year":2002,"claim":"Mapping GABARAP's neuronal partners established it as an adaptor bridging GABA(A) receptors to the cytoskeleton and trafficking machinery, not a postsynaptic anchor.","evidence":"Yeast two-hybrid subunit mapping, affinity pulldown of native receptors, tubulin-binding and gephyrin assays, NSF Co-IP, clustering with electrophysiology","pmids":["11948245","10899939","10900017","11461150","10984509","12367594"],"confidence":"High","gaps":["In vivo necessity for receptor trafficking not yet tested","Whether interactions occur in native synapses unclear"]},{"year":2005,"claim":"In vitro and in vivo lipid analysis confirmed PE as the physiological conjugate despite GABARAP's capacity to be attached to PS, implying a selective conjugation factor in cells.","evidence":"Reconstitution with purified ATG7/ATG3 and defined liposomes, TLC of ATG4B-released lipids","pmids":["16303767"],"confidence":"High","gaps":["Identity of the in vivo PE-selectivity factor unknown"]},{"year":2005,"claim":"GABARAP-knockout mice showed normal GABA(A) receptor number and distribution, establishing that GABARAP is dispensable for bulk synaptic receptor trafficking in vivo and revising the originally proposed anchoring role.","evidence":"Knockout mouse radioligand binding and immunocytochemistry","pmids":["16307606"],"confidence":"Medium","gaps":["Single time-point, single-lab analysis","Functional redundancy with GABARAPL paralogs not addressed","Subtler kinetic or surface-trafficking phenotypes not excluded"]},{"year":2008,"claim":"Defining the two tryptophan-binding hydrophobic pockets as the ligand-specificity determinant unified GABARAP's diverse partner interactions into a single structural docking principle.","evidence":"NMR, docking, and Trp→Ala mutagenesis of multiple ligand peptides with quantitative binding","pmids":["18567048"],"confidence":"High","gaps":["GABARAP-vs-LC3 selectivity basis not yet structurally explained","Did not yet define a consensus motif"]},{"year":2014,"claim":"Demonstrating curvature-dependent lipidation via ATG3's amphipathic helix explained spatial restriction of GABARAP conjugation to nascent, highly curved autophagic membranes.","evidence":"Reconstitution with curvature-defined liposomes, helix mutagenesis, ATG3-KO rescue","pmids":["24747438"],"confidence":"High","gaps":["Membrane curvature sensing in vivo not directly imaged"]},{"year":2014,"claim":"Establishing PLEKHM1 as an LIR-dependent GABARAP partner linked membrane-conjugated GABARAP directly to the HOPS tethering complex and autophagosome–lysosome maturation.","evidence":"LIR mutagenesis, depletion/rescue, autophagic flux and EGFR degradation assays","pmids":["25498145"],"confidence":"High","gaps":["GABARAP-specific contribution vs other ATG8s not isolated in this study"]},{"year":2015,"claim":"Isoform-specific rescue identified GABARAP as the unique ATG8 that activates ULK1 in starvation autophagy and traced its source to a centrosomal/Golgi pool regulated by WAC and GM130.","evidence":"Knockdown/rescue, ULK1 kinase assay, LIR mutants, localization imaging","pmids":["26687599"],"confidence":"High","gaps":["Mechanism of GABARAP delivery from centrosome to phagophore not fully resolved"]},{"year":2015,"claim":"GABARAP was shown to drive autophagosome–lysosome fusion by recruiting PI4K2A and generating PtdIns4P, and to spatially restrict RAC1 signaling by recruiting CUL3-KBTBD6/7 for TIAM1 degradation, expanding its role to membrane-fusion and signaling control.","evidence":"Co-IP, depletion/rescue, fusion assay (PI4K2A); motif mutagenesis, ubiquitination, RAC1 activity and invasion assays (KBTBD6/7)","pmids":["26391226","25684205"],"confidence":"High","gaps":["PI4K2A study single-lab with moderate mechanistic depth","How GABARAP discriminates these functions on distinct membranes unclear"]},{"year":2016,"claim":"Reconstitution established GABARAP as intrinsically fusogenic — promoting tethering and full membrane fusion unlike LC3 — defining a biophysical division of labor within the ATG8 family.","evidence":"In vitro fusion reconstitution, cryo-EM, lipid- and content-mixing assays","pmids":["26789764"],"confidence":"High","gaps":["Physiological membranes on which GABARAP fusion operates in cells not defined"]},{"year":2016,"claim":"Isoform-specific KO comparisons revealed dedicated non-autophagy roles: GABARAP, not LC3, mediates IFN-γ antimicrobial defense by associating with Arf1 to distribute interferon-inducible GTPases.","evidence":"GABARAP-KO vs LC3-KO cells, Toxoplasma clearance, Arf1 Co-IP and activation, GTPase distribution","pmids":["28604719"],"confidence":"High","gaps":["Direct vs indirect nature of Arf1 regulation not fully defined","Whether lipidation is required not addressed"]},{"year":2017,"claim":"Defining the GIM consensus and the HP2 structural basis converted the qualitative pocket model into a predictive code for GABARAP-over-LC3 selectivity, validated by engineering selectivity into other LIRs.","evidence":"Crystal structures of LIR–GABARAP complexes, ITC, NMR, selectivity profiling of 30 motifs, mutagenesis","pmids":["28655748"],"confidence":"High","gaps":["Did not catalog the full physiological GIM-bearing partner set"]},{"year":2017,"claim":"PCM1/Mib1 control of GABARAP stability through centriolar satellites explained how the GABARAP-specific autophagosome pool is maintained and degraded, and showed selective regulation distinct from LC3.","evidence":"Co-IP, LIR mutagenesis, linkage-specific ubiquitination, isoform-specific flux assay","pmids":["28712572"],"confidence":"High","gaps":["Upstream signals controlling Mib1-dependent GABARAP turnover unknown"]},{"year":2019,"claim":"Structural work identified a third pocket (HP0) and key specificity residues, and showed GABARAP selectively engages atypical/non-canonical LIRs in UBA5, ATL3, and the PI3K-complex-I subunits, defining its role in ER-phagy, ufmylation localization, and autophagy initiation.","evidence":"Crystal structures of GABARAP–LIR complexes, NMR/ITC, GIM/HP0 mutagenesis, ER-phagy and mitophagy assays, localization assays","pmids":["30990354","30773365","30767700"],"confidence":"High","gaps":["Functional hierarchy among these many GABARAP-selective partners unresolved"]},{"year":2019,"claim":"Genetic dissection of ATG4 isoforms and discovery of LC3ylation/TBK1 phosphorylation refined how GABARAP conjugation is regulated and reversed, showing redundant priming and that delipidation is dispensable for fusion.","evidence":"ATG4 isoform CRISPR KOs with flux assays; deconjugation-resistant mutants on ATG3; in vitro TBK1 kinase and ATG4-binding assays","pmids":["30661429","31315929","31709703"],"confidence":"High","gaps":["TBK1 phospho-regulation shown for GABARAPL2, generalization to GABARAP not tested","In vivo significance of ATG3 LC3ylation unclear"]},{"year":2020,"claim":"Separation-of-function epistasis established that the ATG2A–GABARAP interaction, not ATG2A–WIPI4, is essential for phagophore formation and closure, placing GABARAP at the lipid-transfer step of autophagosome biogenesis.","evidence":"ATG2A/B double-KO rescue with interaction-mutant constructs, flux assay, Co-IP","pmids":["32009292"],"confidence":"High","gaps":["Single-lab study","Mechanistic coupling of GABARAP binding to lipid transfer not resolved"]},{"year":2021,"claim":"Linking membrane-conjugated GABARAP to FLCN/FNIP sequestration revealed a non-degradative signaling role controlling mTOR–TFEB lysosomal biogenesis, and a crystal structure resolved the molecular basis of GABARAP–γ2 binding and phosphorylation-dependent trafficking.","evidence":"Co-IP, LIR mutagenesis, mTOR/TFEB readouts, isoform-specific KO rescue (FLCN); crystal structure, electrophysiology, trafficking assays (γ2)","pmids":["34597140","33436612","25126726"],"confidence":"High","gaps":["In vivo physiological setting of FLCN sequestration not defined","How GABARAP balances trafficking vs autophagy roles for GABA(A)R unclear"]},{"year":2025,"claim":"Demonstrating GABARAP-specific dependence for STING/CASM-driven LRRK2 lysosomal recruitment and kinase activation extended GABARAP's CASM functions into kinase signaling at lysosomes.","evidence":"STING agonist, CASM induction, GABARAP-KO vs LC3-KO, LRRK2 recruitment and Rab-phosphorylation kinase assays","pmids":["39812709"],"confidence":"High","gaps":["Direct GABARAP–LRRK2 binding mode not structurally defined","Disease relevance of this axis untested"]},{"year":null,"claim":"How GABARAP's single docking surface is partitioned in space and time among its many autophagy, trafficking, antimicrobial, and signaling partners — and how lipidation state, phosphorylation, and subcellular pool selection determine which function dominates — remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No unified model for partner competition at the shared hydrophobic pockets","Relative in vivo contribution of GABARAP vs paralogs across pathways unquantified","Regulatory logic coupling membrane identity to GABARAP function unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0031386","term_label":"protein tag activity","supporting_discovery_ids":[0,1,2,3,4]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[25,30,33,34,39]},{"term_id":"GO:0008289","term_label":"lipid binding","supporting_discovery_ids":[0,4,49]},{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[5,11]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[31,25]}],"localization":[{"term_id":"GO:0031410","term_label":"cytoplasmic vesicle","supporting_discovery_ids":[0,21,35]},{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[9,14,25]},{"term_id":"GO:0005815","term_label":"microtubule organizing center","supporting_discovery_ids":[25,26]},{"term_id":"GO:0005764","term_label":"lysosome","supporting_discovery_ids":[31,50]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[22,32]},{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[27,37]}],"pathway":[{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[0,25,30,33,34]},{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[33,38,34]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[1,2,3,4]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[36,39,50]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[22,31,35,50]},{"term_id":"R-HSA-112316","term_label":"Neuronal System","supporting_discovery_ids":[10,13,46,47]}],"complexes":[],"partners":["ATG7","ATG3","ATG4B","ATG2A","PLEKHM1","ULK1","FLCN","GABRG2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"O95166","full_name":"Gamma-aminobutyric acid receptor-associated protein","aliases":["GABA(A) receptor-associated protein","MM46"],"length_aa":117,"mass_kda":13.9,"function":"Ubiquitin-like modifier that plays a role in intracellular transport of GABA(A) receptors and its interaction with the cytoskeleton (PubMed:9892355). Involved in autophagy: while LC3s are involved in elongation of the phagophore membrane, the GABARAP/GATE-16 subfamily is essential for a later stage in autophagosome maturation (PubMed:15169837, PubMed:20562859, PubMed:22948227). Through its interaction with the reticulophagy receptor TEX264, participates in the remodeling of subdomains of the endoplasmic reticulum into autophagosomes upon nutrient stress, which then fuse with lysosomes for endoplasmic reticulum turnover (PubMed:31006538). Also required for the local activation of the CUL3(KBTBD6/7) E3 ubiquitin ligase complex, regulating ubiquitination and degradation of TIAM1, a guanyl-nucleotide exchange factor (GEF) that activates RAC1 and downstream signal transduction (PubMed:25684205). Thereby, regulates different biological processes including the organization of the cytoskeleton, cell migration and proliferation (PubMed:25684205). Involved in apoptosis (PubMed:15977068)","subcellular_location":"Cytoplasmic vesicle, autophagosome membrane; Endomembrane system; Cytoplasm, cytoskeleton; Golgi apparatus membrane; Cytoplasmic vesicle","url":"https://www.uniprot.org/uniprotkb/O95166/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/GABARAP","classification":"Not Classified","n_dependent_lines":39,"n_total_lines":1208,"dependency_fraction":0.03228476821192053},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/GABARAP","total_profiled":1310},"omim":[{"mim_id":"621399","title":"UBA DOMAIN-CONTAINING PROTEIN 2; UBAC2","url":"https://www.omim.org/entry/621399"},{"mim_id":"621000","title":"SORTING NEXIN 18; SNX18","url":"https://www.omim.org/entry/621000"},{"mim_id":"620673","title":"MICROTUBULE-ASSOCIATED PROTEIN 1, LIGHT CHAIN 3, BETA-2; MAP1LC3B2","url":"https://www.omim.org/entry/620673"},{"mim_id":"618616","title":"MITOGEN-ACTIVATED PROTEIN KINASE 15; MAPK15","url":"https://www.omim.org/entry/618616"},{"mim_id":"617739","title":"KELCH REPEAT- AND BTB DOMAIN-CONTAINING PROTEIN 7; KBTBD7","url":"https://www.omim.org/entry/617739"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Vesicles","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/GABARAP"},"hgnc":{"alias_symbol":["MM46","ATG8A"],"prev_symbol":[]},"alphafold":{"accession":"O95166","domains":[{"cath_id":"3.10.20.90","chopping":"3-109","consensus_level":"high","plddt":96.1543,"start":3,"end":109}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O95166","model_url":"https://alphafold.ebi.ac.uk/files/AF-O95166-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O95166-F1-predicted_aligned_error_v6.png","plddt_mean":94.94},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=GABARAP","jax_strain_url":"https://www.jax.org/strain/search?query=GABARAP"},"sequence":{"accession":"O95166","fasta_url":"https://rest.uniprot.org/uniprotkb/O95166.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O95166/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O95166"}},"corpus_meta":[{"pmid":"15169837","id":"PMC_15169837","title":"LC3, GABARAP and GATE16 localize to autophagosomal membrane depending on form-II formation.","date":"2004","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/15169837","citation_count":1205,"is_preprint":false},{"pmid":"27601442","id":"PMC_27601442","title":"LC3/GABARAP family proteins: autophagy-(un)related functions.","date":"2016","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/27601442","citation_count":537,"is_preprint":false},{"pmid":"25498145","id":"PMC_25498145","title":"PLEKHM1 regulates autophagosome-lysosome fusion through HOPS complex and LC3/GABARAP proteins.","date":"2014","source":"Molecular cell","url":"https://pubmed.ncbi.nlm.nih.gov/25498145","citation_count":466,"is_preprint":false},{"pmid":"11096062","id":"PMC_11096062","title":"The human homolog of Saccharomyces cerevisiae Apg7p is a Protein-activating enzyme for multiple substrates including human Apg12p, GATE-16, GABARAP, and MAP-LC3.","date":"2000","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11096062","citation_count":289,"is_preprint":false},{"pmid":"30773365","id":"PMC_30773365","title":"ATL3 Is a Tubular ER-Phagy Receptor for GABARAP-Mediated Selective Autophagy.","date":"2019","source":"Current biology : CB","url":"https://pubmed.ncbi.nlm.nih.gov/30773365","citation_count":251,"is_preprint":false},{"pmid":"11825910","id":"PMC_11825910","title":"Human Apg3p/Aut1p homologue is an authentic E2 enzyme for multiple substrates, GATE-16, GABARAP, and MAP-LC3, and facilitates the conjugation of hApg12p to hApg5p.","date":"2002","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11825910","citation_count":240,"is_preprint":false},{"pmid":"19549685","id":"PMC_19549685","title":"Caspase cleavage of Atg4D stimulates GABARAP-L1 processing and triggers mitochondrial targeting and apoptosis.","date":"2009","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/19549685","citation_count":219,"is_preprint":false},{"pmid":"24747438","id":"PMC_24747438","title":"Lipidation of the LC3/GABARAP family of autophagy proteins relies on a membrane-curvature-sensing domain in Atg3.","date":"2014","source":"Nature cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/24747438","citation_count":218,"is_preprint":false},{"pmid":"14530254","id":"PMC_14530254","title":"A single protease, Apg4B, is specific for the autophagy-related ubiquitin-like proteins GATE-16, MAP1-LC3, GABARAP, and Apg8L.","date":"2003","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/14530254","citation_count":208,"is_preprint":false},{"pmid":"19363302","id":"PMC_19363302","title":"Nix directly binds to GABARAP: a possible crosstalk between apoptosis and autophagy.","date":"2009","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/19363302","citation_count":193,"is_preprint":false},{"pmid":"11461150","id":"PMC_11461150","title":"The subcellular distribution of GABARAP and its ability to interact with NSF suggest a role for this protein in the intracellular transport of GABA(A) receptors.","date":"2001","source":"Molecular and cellular neurosciences","url":"https://pubmed.ncbi.nlm.nih.gov/11461150","citation_count":190,"is_preprint":false},{"pmid":"10984509","id":"PMC_10984509","title":"The gamma-aminobutyric acid type A (GABAA) receptor-associated protein (GABARAP) promotes GABAA receptor clustering and modulates the channel kinetics.","date":"2000","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/10984509","citation_count":188,"is_preprint":false},{"pmid":"16303767","id":"PMC_16303767","title":"Phosphatidylserine in addition to phosphatidylethanolamine is an in vitro target of the mammalian Atg8 modifiers, LC3, GABARAP, and GATE-16.","date":"2005","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16303767","citation_count":185,"is_preprint":false},{"pmid":"30661429","id":"PMC_30661429","title":"Redundancy of human ATG4 protease isoforms in autophagy and LC3/GABARAP processing revealed in cells.","date":"2019","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/30661429","citation_count":175,"is_preprint":false},{"pmid":"10900017","id":"PMC_10900017","title":"The gamma-aminobutyric acid type A receptor (GABAAR)-associated protein GABARAP interacts with gephyrin but is not involved in receptor anchoring at the synapse.","date":"2000","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/10900017","citation_count":149,"is_preprint":false},{"pmid":"28655748","id":"PMC_28655748","title":"Structural and functional analysis of the GABARAP interaction motif (GIM).","date":"2017","source":"EMBO reports","url":"https://pubmed.ncbi.nlm.nih.gov/28655748","citation_count":142,"is_preprint":false},{"pmid":"10899939","id":"PMC_10899939","title":"Binding of the GABA(A) receptor-associated protein (GABARAP) to microtubules and microfilaments suggests involvement of the cytoskeleton in GABARAPGABA(A) receptor interaction.","date":"2000","source":"Journal of neurochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/10899939","citation_count":134,"is_preprint":false},{"pmid":"11779480","id":"PMC_11779480","title":"Structure of GABARAP in two conformations: implications for GABA(A) receptor localization and tubulin binding.","date":"2002","source":"Neuron","url":"https://pubmed.ncbi.nlm.nih.gov/11779480","citation_count":126,"is_preprint":false},{"pmid":"26687599","id":"PMC_26687599","title":"Activation of ULK Kinase and Autophagy by GABARAP Trafficking from the Centrosome Is Regulated by WAC and GM130.","date":"2015","source":"Molecular cell","url":"https://pubmed.ncbi.nlm.nih.gov/26687599","citation_count":118,"is_preprint":false},{"pmid":"21684337","id":"PMC_21684337","title":"Alteration of autophagosomal proteins (LC3, GABARAP and GATE-16) in Lewy body disease.","date":"2011","source":"Neurobiology of disease","url":"https://pubmed.ncbi.nlm.nih.gov/21684337","citation_count":110,"is_preprint":false},{"pmid":"34597140","id":"PMC_34597140","title":"GABARAP sequesters the FLCN-FNIP tumor suppressor complex to couple autophagy with lysosomal biogenesis.","date":"2021","source":"Science advances","url":"https://pubmed.ncbi.nlm.nih.gov/34597140","citation_count":106,"is_preprint":false},{"pmid":"30767700","id":"PMC_30767700","title":"Members of the autophagy class III phosphatidylinositol 3-kinase complex I interact with GABARAP and GABARAPL1 via LIR motifs.","date":"2019","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/30767700","citation_count":99,"is_preprint":false},{"pmid":"22948227","id":"PMC_22948227","title":"MAPK15/ERK8 stimulates autophagy by interacting with LC3 and GABARAP proteins.","date":"2012","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/22948227","citation_count":93,"is_preprint":false},{"pmid":"28712572","id":"PMC_28712572","title":"Centriolar Satellites Control GABARAP Ubiquitination and GABARAP-Mediated Autophagy.","date":"2017","source":"Current biology : CB","url":"https://pubmed.ncbi.nlm.nih.gov/28712572","citation_count":85,"is_preprint":false},{"pmid":"32009292","id":"PMC_32009292","title":"A conserved ATG2-GABARAP family interaction is critical for phagophore formation.","date":"2020","source":"EMBO reports","url":"https://pubmed.ncbi.nlm.nih.gov/32009292","citation_count":84,"is_preprint":false},{"pmid":"28604719","id":"PMC_28604719","title":"Essential role for GABARAP autophagy proteins in interferon-inducible GTPase-mediated host defense.","date":"2017","source":"Nature immunology","url":"https://pubmed.ncbi.nlm.nih.gov/28604719","citation_count":84,"is_preprint":false},{"pmid":"33773106","id":"PMC_33773106","title":"ATG4 family proteins drive phagophore growth independently of the LC3/GABARAP lipidation system.","date":"2021","source":"Molecular cell","url":"https://pubmed.ncbi.nlm.nih.gov/33773106","citation_count":81,"is_preprint":false},{"pmid":"20179142","id":"PMC_20179142","title":"GABAA receptor associated protein (GABARAP) modulates TRPV1 expression and channel function and desensitization.","date":"2010","source":"FASEB journal : official publication of the Federation of American Societies for Experimental Biology","url":"https://pubmed.ncbi.nlm.nih.gov/20179142","citation_count":72,"is_preprint":false},{"pmid":"31709703","id":"PMC_31709703","title":"TBK1-mediated phosphorylation of LC3C and GABARAP-L2 controls autophagosome shedding by ATG4 protease.","date":"2019","source":"EMBO reports","url":"https://pubmed.ncbi.nlm.nih.gov/31709703","citation_count":72,"is_preprint":false},{"pmid":"25684205","id":"PMC_25684205","title":"CUL3-KBTBD6/KBTBD7 ubiquitin ligase cooperates with GABARAP proteins to spatially restrict TIAM1-RAC1 signaling.","date":"2015","source":"Molecular cell","url":"https://pubmed.ncbi.nlm.nih.gov/25684205","citation_count":71,"is_preprint":false},{"pmid":"11875056","id":"PMC_11875056","title":"Solution structure of human GABA(A) receptor-associated protein GABARAP: implications for biolgoical funcrion and its regulation.","date":"2002","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11875056","citation_count":71,"is_preprint":false},{"pmid":"25224329","id":"PMC_25224329","title":"Mulan E3 ubiquitin ligase interacts with multiple E2 conjugating enzymes and participates in mitophagy by recruiting GABARAP.","date":"2014","source":"Cellular signalling","url":"https://pubmed.ncbi.nlm.nih.gov/25224329","citation_count":71,"is_preprint":false},{"pmid":"27764541","id":"PMC_27764541","title":"Human Atg8-cardiolipin interactions in mitophagy: Specific properties of LC3B, GABARAPL2 and GABARAP.","date":"2016","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/27764541","citation_count":71,"is_preprint":false},{"pmid":"27385304","id":"PMC_27385304","title":"White spot syndrome virus entry is dependent on multiple endocytic routes and strongly facilitated by Cq-GABARAP in a CME-dependent manner.","date":"2016","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/27385304","citation_count":67,"is_preprint":false},{"pmid":"11818336","id":"PMC_11818336","title":"Crystal structure of the GABA(A)-receptor-associated protein, GABARAP.","date":"2002","source":"EMBO reports","url":"https://pubmed.ncbi.nlm.nih.gov/11818336","citation_count":66,"is_preprint":false},{"pmid":"25126726","id":"PMC_25126726","title":"FLCN, a novel autophagy component, interacts with GABARAP and is regulated by ULK1 phosphorylation.","date":"2014","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/25126726","citation_count":62,"is_preprint":false},{"pmid":"16307606","id":"PMC_16307606","title":"GABARAP is not essential for GABA receptor targeting to the synapse.","date":"2005","source":"The European journal of neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/16307606","citation_count":61,"is_preprint":false},{"pmid":"26565669","id":"PMC_26565669","title":"Analysis of the native conformation of the LIR/AIM motif in the Atg8/LC3/GABARAP-binding proteins.","date":"2015","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/26565669","citation_count":60,"is_preprint":false},{"pmid":"11948245","id":"PMC_11948245","title":"Subunit specificity and interaction domain between GABA(A) receptor-associated protein (GABARAP) and GABA(A) receptors.","date":"2002","source":"Journal of neurochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11948245","citation_count":57,"is_preprint":false},{"pmid":"17916189","id":"PMC_17916189","title":"Identification of calreticulin as a ligand of GABARAP by phage display screening of a peptide library.","date":"2007","source":"The FEBS journal","url":"https://pubmed.ncbi.nlm.nih.gov/17916189","citation_count":56,"is_preprint":false},{"pmid":"30982432","id":"PMC_30982432","title":"Human LC3 and GABARAP subfamily members achieve functional specificity via specific structural modulations.","date":"2019","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/30982432","citation_count":55,"is_preprint":false},{"pmid":"31315929","id":"PMC_31315929","title":"Human ATG4 autophagy proteases counteract attachment of ubiquitin-like LC3/GABARAP proteins to other cellular proteins.","date":"2019","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/31315929","citation_count":55,"is_preprint":false},{"pmid":"18497328","id":"PMC_18497328","title":"The trafficking protein GABARAP binds to and enhances plasma membrane expression and function of the angiotensin II type 1 receptor.","date":"2008","source":"Circulation research","url":"https://pubmed.ncbi.nlm.nih.gov/18497328","citation_count":54,"is_preprint":false},{"pmid":"15530441","id":"PMC_15530441","title":"GEC1, a protein related to GABARAP, interacts with tubulin and GABA(A) receptor.","date":"2004","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/15530441","citation_count":53,"is_preprint":false},{"pmid":"26789764","id":"PMC_26789764","title":"Lipid Geometry and Bilayer Curvature Modulate LC3/GABARAP-Mediated Model Autophagosomal Elongation.","date":"2016","source":"Biophysical journal","url":"https://pubmed.ncbi.nlm.nih.gov/26789764","citation_count":53,"is_preprint":false},{"pmid":"14625090","id":"PMC_14625090","title":"Expression of gec1/GABARAPL1 versus GABARAP mRNAs in human: predominance of gec1/GABARAPL1 in the central nervous system.","date":"2003","source":"Brain research. Molecular brain research","url":"https://pubmed.ncbi.nlm.nih.gov/14625090","citation_count":50,"is_preprint":false},{"pmid":"36729310","id":"PMC_36729310","title":"Effect of ATG12-ATG5-ATG16L1 autophagy E3-like complex on the ability of LC3/GABARAP proteins to induce vesicle tethering and fusion.","date":"2023","source":"Cellular and molecular life sciences : CMLS","url":"https://pubmed.ncbi.nlm.nih.gov/36729310","citation_count":49,"is_preprint":false},{"pmid":"11997026","id":"PMC_11997026","title":"Association of human transferrin receptor with GABARAP.","date":"2002","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/11997026","citation_count":49,"is_preprint":false},{"pmid":"30504823","id":"PMC_30504823","title":"Ankyrin-G regulates forebrain connectivity and network synchronization via interaction with GABARAP.","date":"2018","source":"Molecular psychiatry","url":"https://pubmed.ncbi.nlm.nih.gov/30504823","citation_count":48,"is_preprint":false},{"pmid":"30990354","id":"PMC_30990354","title":"An atypical LIR motif within UBA5 (ubiquitin like modifier activating enzyme 5) interacts with GABARAP proteins and mediates membrane localization of UBA5.","date":"2019","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/30990354","citation_count":46,"is_preprint":false},{"pmid":"17581952","id":"PMC_17581952","title":"C-terminal modification is required for GABARAP-mediated GABA(A) receptor trafficking.","date":"2007","source":"The Journal of neuroscience : the official journal of the Society for Neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/17581952","citation_count":45,"is_preprint":false},{"pmid":"24374083","id":"PMC_24374083","title":"Different effects of Atg2 and Atg18 mutations on Atg8a and Atg9 trafficking during starvation in Drosophila.","date":"2013","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/24374083","citation_count":42,"is_preprint":false},{"pmid":"28028054","id":"PMC_28028054","title":"Fluorescence-based ATG8 sensors monitor localization and function of LC3/GABARAP proteins.","date":"2016","source":"The EMBO journal","url":"https://pubmed.ncbi.nlm.nih.gov/28028054","citation_count":42,"is_preprint":false},{"pmid":"39812709","id":"PMC_39812709","title":"A STING-CASM-GABARAP pathway activates LRRK2 at lysosomes.","date":"2025","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/39812709","citation_count":40,"is_preprint":false},{"pmid":"33436612","id":"PMC_33436612","title":"Structural basis of GABARAP-mediated GABAA receptor trafficking and functions on GABAergic synaptic transmission.","date":"2021","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/33436612","citation_count":40,"is_preprint":false},{"pmid":"27124579","id":"PMC_27124579","title":"Tumor suppression in mice lacking GABARAP, an Atg8/LC3 family member implicated in autophagy, is associated with alterations in cytokine secretion and cell death.","date":"2016","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/27124579","citation_count":39,"is_preprint":false},{"pmid":"19154346","id":"PMC_19154346","title":"Structural framework of the GABARAP-calreticulin interface--implications for substrate binding to endoplasmic reticulum chaperones.","date":"2009","source":"The FEBS journal","url":"https://pubmed.ncbi.nlm.nih.gov/19154346","citation_count":39,"is_preprint":false},{"pmid":"24991828","id":"PMC_24991828","title":"Lipidation of the autophagy proteins LC3 and GABARAP is a membrane-curvature dependent process.","date":"2014","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/24991828","citation_count":38,"is_preprint":false},{"pmid":"23427251","id":"PMC_23427251","title":"Gene deletion of Gabarap enhances Nlrp3 inflammasome-dependent inflammatory responses.","date":"2013","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/23427251","citation_count":37,"is_preprint":false},{"pmid":"17690529","id":"PMC_17690529","title":"Regulation of GABA(A)-receptor surface expression with special reference to the involvement of GABARAP (GABA(A) receptor-associated protein) and PRIP (phospholipase C-related, but catalytically inactive protein).","date":"2007","source":"Journal of pharmacological sciences","url":"https://pubmed.ncbi.nlm.nih.gov/17690529","citation_count":37,"is_preprint":false},{"pmid":"24240096","id":"PMC_24240096","title":"Interaction of Bcl-2 with the autophagy-related GABAA receptor-associated protein (GABARAP): biophysical characterization and functional implications.","date":"2013","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/24240096","citation_count":35,"is_preprint":false},{"pmid":"26391226","id":"PMC_26391226","title":"GABARAP-mediated targeting of PI4K2A/PI4KIIα to autophagosomes regulates PtdIns4P-dependent autophagosome-lysosome fusion.","date":"2015","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/26391226","citation_count":34,"is_preprint":false},{"pmid":"31625269","id":"PMC_31625269","title":"The Machado-Joseph disease deubiquitylase ataxin-3 interacts with LC3C/GABARAP and promotes autophagy.","date":"2019","source":"Aging cell","url":"https://pubmed.ncbi.nlm.nih.gov/31625269","citation_count":34,"is_preprint":false},{"pmid":"35054896","id":"PMC_35054896","title":"NEAT1 Confers Radioresistance to Hepatocellular Carcinoma Cells by Inducing Autophagy through GABARAP.","date":"2022","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/35054896","citation_count":32,"is_preprint":false},{"pmid":"36898370","id":"PMC_36898370","title":"TNIP1 inhibits selective autophagy via bipartite interaction with LC3/GABARAP and TAX1BP1.","date":"2023","source":"Molecular cell","url":"https://pubmed.ncbi.nlm.nih.gov/36898370","citation_count":31,"is_preprint":false},{"pmid":"11374880","id":"PMC_11374880","title":"A novel early estrogen-regulated gene gec1 encodes a protein related to GABARAP.","date":"2001","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/11374880","citation_count":31,"is_preprint":false},{"pmid":"35917476","id":"PMC_35917476","title":"Structure-Based Design of Stapled Peptides That Bind GABARAP and Inhibit Autophagy.","date":"2022","source":"Journal of the American Chemical Society","url":"https://pubmed.ncbi.nlm.nih.gov/35917476","citation_count":30,"is_preprint":false},{"pmid":"16874098","id":"PMC_16874098","title":"Lysosomal turnover of GABARAP-phospholipid conjugate is activated during differentiation of C2C12 cells to myotubes without inactivation of the mTor kinase-signaling pathway.","date":"2006","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/16874098","citation_count":30,"is_preprint":false},{"pmid":"20583424","id":"PMC_20583424","title":"GABARAP is overexpressed in colorectal carcinoma and correlates with shortened patient survival.","date":"2010","source":"Hepato-gastroenterology","url":"https://pubmed.ncbi.nlm.nih.gov/20583424","citation_count":30,"is_preprint":false},{"pmid":"15977068","id":"PMC_15977068","title":"GABAA receptor-associated protein (GABARAP) induces apoptosis by interacting with DEAD (Asp-Glu-Ala-Asp/His) box polypeptide 47 (DDX 47).","date":"2005","source":"Biotechnology letters","url":"https://pubmed.ncbi.nlm.nih.gov/15977068","citation_count":29,"is_preprint":false},{"pmid":"21388957","id":"PMC_21388957","title":"Effects of C-terminal modifications of GEC1 protein and gamma-aminobutyric acid type A (GABA(A)) receptor-associated protein (GABARAP), two microtubule-associated proteins, on kappa opioid receptor expression.","date":"2011","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/21388957","citation_count":29,"is_preprint":false},{"pmid":"3496155","id":"PMC_3496155","title":"Target-selective cytotoxicity of methotrexate conjugated with monoclonal anti-MM46 antibody.","date":"1987","source":"Cancer immunology, immunotherapy : CII","url":"https://pubmed.ncbi.nlm.nih.gov/3496155","citation_count":28,"is_preprint":false},{"pmid":"15065816","id":"PMC_15065816","title":"GABARAP: lessons for synaptogenesis.","date":"2003","source":"The Neuroscientist : a review journal bringing neurobiology, neurology and psychiatry","url":"https://pubmed.ncbi.nlm.nih.gov/15065816","citation_count":27,"is_preprint":false},{"pmid":"32460019","id":"PMC_32460019","title":"Regulation of Expression of Autophagy Genes by Atg8a-Interacting Partners Sequoia, YL-1, and Sir2 in Drosophila.","date":"2020","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/32460019","citation_count":27,"is_preprint":false},{"pmid":"16458273","id":"PMC_16458273","title":"Specific distribution of gabarap, gec1/gabarap Like 1, gate16/gabarap Like 2, lc3 messenger RNAs in rat brain areas by quantitative real-time PCR.","date":"2006","source":"Brain research","url":"https://pubmed.ncbi.nlm.nih.gov/16458273","citation_count":26,"is_preprint":false},{"pmid":"17164261","id":"PMC_17164261","title":"Fine mapping of a linkage region on chromosome 17p13 reveals that GABARAP and DLG4 are associated with vulnerability to nicotine dependence in European-Americans.","date":"2006","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/17164261","citation_count":24,"is_preprint":false},{"pmid":"32828302","id":"PMC_32828302","title":"Selective binding of mitophagy receptor protein Bcl-rambo to LC3/GABARAP family proteins.","date":"2020","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/32828302","citation_count":23,"is_preprint":false},{"pmid":"28253953","id":"PMC_28253953","title":"Methods for Studying Interactions Between Atg8/LC3/GABARAP and LIR-Containing Proteins.","date":"2017","source":"Methods in enzymology","url":"https://pubmed.ncbi.nlm.nih.gov/28253953","citation_count":23,"is_preprint":false},{"pmid":"18567048","id":"PMC_18567048","title":"An indole-binding site is a major determinant of the ligand specificity of the GABA type A receptor-associated protein GABARAP.","date":"2008","source":"Chembiochem : a European journal of chemical biology","url":"https://pubmed.ncbi.nlm.nih.gov/18567048","citation_count":23,"is_preprint":false},{"pmid":"16596256","id":"PMC_16596256","title":"Human RAB24, interestingly and predominantly distributed in the nuclei of COS-7 cells, is colocalized with cyclophilin A and GABARAP.","date":"2006","source":"International journal of molecular medicine","url":"https://pubmed.ncbi.nlm.nih.gov/16596256","citation_count":23,"is_preprint":false},{"pmid":"16954214","id":"PMC_16954214","title":"GABA increases both the conductance and mean open time of recombinant GABAA channels co-expressed with GABARAP.","date":"2006","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/16954214","citation_count":23,"is_preprint":false},{"pmid":"33591943","id":"PMC_33591943","title":"GABARAP suppresses EMT and breast cancer progression via the AKT/mTOR signaling pathway.","date":"2021","source":"Aging","url":"https://pubmed.ncbi.nlm.nih.gov/33591943","citation_count":22,"is_preprint":false},{"pmid":"35649355","id":"PMC_35649355","title":"GMAP is an Atg8a-interacting protein that regulates Golgi turnover in Drosophila.","date":"2022","source":"Cell reports","url":"https://pubmed.ncbi.nlm.nih.gov/35649355","citation_count":21,"is_preprint":false},{"pmid":"26697781","id":"PMC_26697781","title":"The two Dictyostelium autophagy eight proteins, ATG8a and ATG8b, associate with the autophagosome in succession.","date":"2015","source":"European journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/26697781","citation_count":21,"is_preprint":false},{"pmid":"33042141","id":"PMC_33042141","title":"Role of Gate-16 and Gabarap in Prevention of Caspase-11-Dependent Excess Inflammation and Lethal Endotoxic Shock.","date":"2020","source":"Frontiers in immunology","url":"https://pubmed.ncbi.nlm.nih.gov/33042141","citation_count":21,"is_preprint":false},{"pmid":"19766149","id":"PMC_19766149","title":"C-terminal processing of GABARAP is not required for trafficking of the angiotensin II type 1A receptor.","date":"2010","source":"Regulatory peptides","url":"https://pubmed.ncbi.nlm.nih.gov/19766149","citation_count":21,"is_preprint":false},{"pmid":"30160610","id":"PMC_30160610","title":"Autophagy mediates phosphatidylserine exposure and phagosome degradation during apoptosis through specific functions of GABARAP/LGG-1 and LC3/LGG-2.","date":"2018","source":"Autophagy","url":"https://pubmed.ncbi.nlm.nih.gov/30160610","citation_count":21,"is_preprint":false},{"pmid":"23671684","id":"PMC_23671684","title":"Enrichment of GABARAP relative to LC3 in the axonal initial segments of neurons.","date":"2013","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/23671684","citation_count":21,"is_preprint":false},{"pmid":"27888204","id":"PMC_27888204","title":"No ATG8s, no problem? How LC3/GABARAP proteins contribute to autophagy.","date":"2016","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/27888204","citation_count":20,"is_preprint":false},{"pmid":"12367594","id":"PMC_12367594","title":"Biochemical identification of the binding domain in the GABA(A) receptor-associated protein (GABARAP) mediating dimer formation.","date":"2002","source":"Neuropharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/12367594","citation_count":18,"is_preprint":false},{"pmid":"31020644","id":"PMC_31020644","title":"GABARAP promotes bone marrow mesenchymal stem cells-based the osteoarthritis cartilage regeneration through the inhibition of PI3K/AKT/mTOR signaling pathway.","date":"2019","source":"Journal of cellular physiology","url":"https://pubmed.ncbi.nlm.nih.gov/31020644","citation_count":18,"is_preprint":false},{"pmid":"38551812","id":"PMC_38551812","title":"Loss of GABARAP mediates resistance to immunogenic chemotherapy in multiple myeloma.","date":"2024","source":"Blood","url":"https://pubmed.ncbi.nlm.nih.gov/38551812","citation_count":17,"is_preprint":false},{"pmid":"28729737","id":"PMC_28729737","title":"Direct binding to GABARAP family members is essential for HIV-1 Nef plasma membrane localization.","date":"2017","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/28729737","citation_count":17,"is_preprint":false},{"pmid":"39587067","id":"PMC_39587067","title":"Critical assessment of LC3/GABARAP ligands used for degrader development and ligandability of LC3/GABARAP binding pockets.","date":"2024","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/39587067","citation_count":16,"is_preprint":false},{"pmid":"35839958","id":"PMC_35839958","title":"Ceramide enhances binding of LC3/GABARAP autophagy proteins to cardiolipin-containing membranes.","date":"2022","source":"International journal of biological macromolecules","url":"https://pubmed.ncbi.nlm.nih.gov/35839958","citation_count":16,"is_preprint":false},{"pmid":"19225049","id":"PMC_19225049","title":"GABARAP deficiency modulates expression of NaPi-IIa in renal brush-border membranes.","date":"2009","source":"American journal of physiology. Renal physiology","url":"https://pubmed.ncbi.nlm.nih.gov/19225049","citation_count":16,"is_preprint":false},{"pmid":"28990689","id":"PMC_28990689","title":"Control of GABARAP-mediated autophagy by the Golgi complex, centrosome and centriolar satellites.","date":"2017","source":"Biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/28990689","citation_count":16,"is_preprint":false},{"pmid":"6443109","id":"PMC_6443109","title":"Conjugates of mitomycin C with the immunoglobulin M monomer fragment of a monoclonal anti-MM46 immunoglobulin M antibody with or without serum albumin as intermediary.","date":"1984","source":"Journal of applied biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/6443109","citation_count":16,"is_preprint":false},{"pmid":"19533740","id":"PMC_19533740","title":"Comparative modeling of human NSF reveals a possible binding mode of GABARAP and GATE-16.","date":"2009","source":"Proteins","url":"https://pubmed.ncbi.nlm.nih.gov/19533740","citation_count":16,"is_preprint":false},{"pmid":"39814292","id":"PMC_39814292","title":"N-acetyltransferase 10 impedes EZH2/H3K27me3/GABARAP axis mediated autophagy and facilitates lung cancer tumorigenesis through enhancing SGK2 mRNA acetylation.","date":"2025","source":"International journal of biological macromolecules","url":"https://pubmed.ncbi.nlm.nih.gov/39814292","citation_count":15,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":49419,"output_tokens":13486,"usd":0.175273,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":25091,"output_tokens":7143,"usd":0.152015,"stage2_stop_reason":"end_turn"},"total_usd":0.327288,"stage1_batch_id":"msgbatch_01AsR7g8dGTEiEw9U83bJeWn","stage2_batch_id":"msgbatch_01YV5ZyxtFNUZEjxRcpd9jzb","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2004,\n      \"finding\": \"GABARAP undergoes C-terminal cleavage to yield a cytosolic form (form I), which is further converted to a membrane-associated form II (phosphatidylethanolamine-conjugated) that localizes to autophagosomal membranes; [14C]-ethanolamine incorporation into form II and Atg4B-mediated deconjugation confirmed PE conjugation.\",\n      \"method\": \"Radiolabeling ([14C]-ethanolamine incorporation), subcellular fractionation, in vitro Atg4B deconjugation assay, immunofluorescence microscopy\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — multiple orthogonal biochemical methods (radiolabeling, fractionation, enzymatic deconjugation) in a single study, replicated concept across LC3, GABARAP, and GATE16\",\n      \"pmids\": [\"15169837\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Human ATG7 (hApg7p) acts as an E1-like activating enzyme for GABARAP: hApg7p co-immunoprecipitates with GABARAP and forms a stable thioester intermediate with GABARAP via Cys572, demonstrating that GABARAP is a substrate of the hApg7p-mediated ubiquitin-like conjugation system.\",\n      \"method\": \"Co-immunoprecipitation, site-directed mutagenesis (C572S active-site mutant), cross-linking, glycerol-gradient centrifugation\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — active-site mutagenesis plus stable intermediate trapping, reconstituted E1-substrate complex, multiple orthogonal methods in one study\",\n      \"pmids\": [\"11096062\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Human ATG3 (hApg3p) acts as an E2-like conjugating enzyme for GABARAP: Cys264 of hApg3p is the active-site cysteine required to form a thioester intermediate with GABARAP; hApg3p also forms an E1·E2 complex with hApg7p.\",\n      \"method\": \"Site-directed mutagenesis (C264S), co-immunoprecipitation, stable intermediate trapping\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — active-site mutagenesis and stable thioester intermediate trapping, multiple orthogonal methods\",\n      \"pmids\": [\"11825910\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"A single protease, Atg4B/autophagin-1, processes the C-terminus of GABARAP (and other Atg8 homologs GATE-16, MAP1-LC3, Apg8L), acting as both a priming and deconjugating enzyme; electrophilic activity-based probes of GABARAP covalently adducted Atg4B in crude lysates.\",\n      \"method\": \"Activity-based probes (electrophilic GABARAP-derived probes), affinity labeling of cell lysates, functional protease assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — activity-based chemical probes directly identified the protease; reconstituted in vitro with multiple substrates\",\n      \"pmids\": [\"14530254\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"In vitro reconstitution with purified recombinant ATG7, ATG3, and liposomes showed that GABARAP is conjugated to both phosphatidylethanolamine (PE) and phosphatidylserine (PS) in vitro; however, in vivo the predominant conjugate is GABARAP-PE, not GABARAP-PS, suggesting a selective factor in endogenous conjugation.\",\n      \"method\": \"In vitro reconstitution with purified proteins and synthetic phospholipid liposomes, thin-layer chromatography of lipids released by ATG4B digestion\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — fully reconstituted in vitro system with purified components, plus in vivo TLC confirmation\",\n      \"pmids\": [\"16303767\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Crystal structure of human GABARAP at 1.6 Å resolution revealed an N-terminal helical subdomain responsible for tubulin binding and a C-terminal ubiquitin-like domain containing the GABA(A) receptor γ2 subunit binding site; structure-based mutagenesis validated these domain assignments. A second crystal form showed head-to-tail self-association that can promote tubulin polymerization and receptor clustering.\",\n      \"method\": \"X-ray crystallography (1.6 Å and 1.9 Å), structure-based mutagenesis\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — high-resolution crystal structure with functional mutagenesis validation, two crystal forms\",\n      \"pmids\": [\"11779480\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Crystal structure of GABARAP at 2.0 Å confirmed an N-terminal basic helical region (tubulin binding) and a core ubiquitin-like fold; one conserved face mediates shared protein-protein interactions across the GABARAP family while the other face shows divergence.\",\n      \"method\": \"X-ray crystallography (2.0 Å resolution)\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — independent high-resolution crystal structure from a separate laboratory, consistent with Neuron 2002 structure\",\n      \"pmids\": [\"11818336\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"NMR solution structure of human GABARAP revealed that the N- and C-terminal ends interact with each other in solution (not seen in crystal structures), with one region existing in at least two slowly interconverting conformations, suggesting dynamic regulation of GABARAP interactions.\",\n      \"method\": \"NMR spectroscopy in aqueous solution\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — high-resolution NMR structure, single lab, complementary to crystal structures\",\n      \"pmids\": [\"11875056\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Lipidation of GABARAP (and LC3) by ATG3 is membrane-curvature-dependent: ATG3 contains an amphipathic N-terminal helix that senses lipid-packing defects on highly curved membranes. Tuning the helix hydrophobicity promotes or inhibits GABARAP lipidation in vitro and in ATG3-knockout rescue experiments in vivo.\",\n      \"method\": \"In vitro lipidation reconstitution with liposomes of defined curvature, amphipathic-helix mutagenesis, ATG3-knockout cell rescue\",\n      \"journal\": \"Nature cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstituted in vitro system, mutagenesis, and in vivo validation across multiple orthogonal methods\",\n      \"pmids\": [\"24747438\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"GABARAP directly binds N-ethylmaleimide-sensitive factor (NSF): co-immunoprecipitation from neurons detected a GABARAP–NSF complex, and GABARAP co-localizes with NSF in intracellular membrane compartments (Golgi/post-synaptic cisternae), suggesting a role in intracellular GABA(A) receptor transport rather than synaptic anchoring.\",\n      \"method\": \"Co-immunoprecipitation, subcellular fractionation, immunofluorescence colocalization\",\n      \"journal\": \"Molecular and cellular neurosciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — reciprocal Co-IP from neurons, colocalization; localization linked to function but no direct mechanistic assay\",\n      \"pmids\": [\"11461150\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"GABARAP promotes clustering of GABA(A) receptors in fibroblasts: co-expression of GABARAP with α1β2γ2 GABA(A) receptors in QT-6 cells induced receptor clustering requiring the GABARAP tubulin-binding motif and intact microtubules. Clustered receptors showed altered channel kinetics (higher EC50 ~20 µM vs 5.7 µM, faster deactivation, slower desensitization).\",\n      \"method\": \"Immunofluorescence, GFP-tagged receptor imaging, microtubule disruption (nocodazole/taxol), patch-clamp electrophysiology\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — functional readout (electrophysiology) combined with imaging and pharmacological perturbation, multiple orthogonal methods\",\n      \"pmids\": [\"10984509\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"GABARAP interacts directly with tubulin and microtubules in a salt-sensitive (ionic) manner, and also associates with microfilaments in intact cells; the tubulin-binding domain is located at the N-terminus of GABARAP and is defined by a specific arrangement of basic amino acids.\",\n      \"method\": \"In vitro tubulin-binding assay, co-immunoprecipitation with tubulin, pharmacological cytoskeletal disruption (taxol, nocodazole, cytochalasin D), synthetic peptide and deletion construct mapping\",\n      \"journal\": \"Journal of neurochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro binding reconstitution, domain mapping by deletion constructs and synthetic peptides, in vivo validation\",\n      \"pmids\": [\"10899939\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"GABARAP interacts with gephyrin in biochemical assays and transfected cells, but confocal analysis of wild-type and gephyrin-knockout neurons showed that GABARAP is enriched intracellularly and is not present at gephyrin-positive postsynaptic membrane specializations, indicating the GABARAP–gephyrin interaction does not mediate postsynaptic GABA(A) receptor anchoring.\",\n      \"method\": \"Biochemical pulldown, co-immunoprecipitation in transfected cells, confocal immunofluorescence in wild-type and gephyrin-KO neurons\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — binding confirmed biochemically plus in vivo localization with KO control; negative result for synaptic anchoring is mechanistically informative\",\n      \"pmids\": [\"10900017\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"GABARAP binds specifically to the γ (not α or β) subunits of GABA(A) receptors; the interaction domain in γ2 was mapped by quantitative yeast two-hybrid, and a membrane-permeable peptide corresponding to the GABARAP-binding domain in γ2 inhibited GABARAP-induced receptor clustering in living cells.\",\n      \"method\": \"Yeast two-hybrid with 15 receptor subunit intracellular loops, GABARAP affinity column pull-down of native receptors, peptide inhibition of clustering in fibroblasts\",\n      \"journal\": \"Journal of neurochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — domain mapping with multiple subunit isoforms, affinity purification of native complex, functional peptide inhibitor validation\",\n      \"pmids\": [\"11948245\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"C-terminal processing of GABARAP at Gly116 is essential for its role in GABA(A) receptor trafficking: the G116A mutation blocks C-terminal cleavage, re-localizes GABARAP to the Golgi (instead of punctate cytoplasmic distribution), reduces co-localization and interaction with GABA(A) receptors, and prevents GABARAP-mediated increase in receptor surface expression in neurons and oocytes.\",\n      \"method\": \"Site-directed mutagenesis (G116A), immunofluorescence confocal microscopy, co-immunoprecipitation, surface expression assay (oocyte GABA currents, surface-accessible subunit labeling)\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — mutagenesis with multiple functional readouts (localization, binding, surface expression, electrophysiology) in two cell systems\",\n      \"pmids\": [\"17581952\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"GABARAP is not essential for GABA(A) receptor trafficking to synapses in vivo: GABARAP-knockout mice are phenotypically normal, show no change in total GABA(A) receptor number (benzodiazepine binding), and have normal punctate γ2 subunit and gephyrin distribution in cortical neurons.\",\n      \"method\": \"GABARAP-knockout mouse analysis, radioligand binding, immunocytochemistry\",\n      \"journal\": \"The European journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean genetic KO with defined phenotypic readouts, but single lab and single time-point analysis\",\n      \"pmids\": [\"16307606\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Nix/Bnip3L (pro-apoptotic protein) directly interacts with GABARAP; interaction confirmed by phage display screening, in vitro pull-down assays, co-immunoprecipitation, and colocalization in mammalian cells.\",\n      \"method\": \"Phage display screening, in vitro pull-down, co-immunoprecipitation, colocalization\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — multiple binding assays but no functional mechanism elucidated beyond interaction; single lab\",\n      \"pmids\": [\"19363302\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"Calreticulin is a high-affinity GABARAP ligand (Kd = 64 nM, mean complex lifetime ~20 min): identified by phage display of a peptide library, confirmed by pull-down from brain lysate and colocalization in N2a cells.\",\n      \"method\": \"Phage display library screening, GST pull-down from brain lysate, colocalization, biophysical binding measurement\",\n      \"journal\": \"The FEBS journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — phage display plus pull-down and colocalization; high-affinity binding quantified, single lab\",\n      \"pmids\": [\"17916189\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Crystal structure of GABARAP in complex with the calreticulin binding epitope revealed the structural basis of the interaction; molecular modeling suggested a novel mode of substrate interaction for the calreticulin/calnexin chaperone family.\",\n      \"method\": \"X-ray crystallography of GABARAP–calreticulin peptide complex, NMR spectroscopy, molecular modeling\",\n      \"journal\": \"The FEBS journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structure of the complex with spectroscopic validation; single lab\",\n      \"pmids\": [\"19154346\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"Two tryptophan-binding hydrophobic pockets on the conserved face of GABARAP constitute the major determinant of ligand specificity; NMR and molecular docking identified these sites, and replacing the key tryptophan in ligands (calreticulin, clathrin heavy chain, γ2 subunit) with alanine abolished GABARAP binding.\",\n      \"method\": \"NMR spectroscopy, molecular docking, mutagenesis (Trp→Ala in ligand peptides), quantitative binding measurements\",\n      \"journal\": \"Chembiochem\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — NMR structure with mutagenesis validation of binding sites; single lab\",\n      \"pmids\": [\"18567048\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"GABARAP self-associates as a dimer (not higher-order oligomers) in physiological salt; the dimerization domain was mapped to residues 41–51 using deletion constructs and GABARAP-derived synthetic peptides in GST pull-down assays.\",\n      \"method\": \"GST pull-down with deletion constructs and synthetic peptides, glycerol-gradient centrifugation\",\n      \"journal\": \"Neuropharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — domain mapping with peptide inhibitors, in vitro biochemistry, single lab\",\n      \"pmids\": [\"12367594\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"GABARAP interacts with the transferrin receptor (TfR) cytoplasmic domain: yeast two-hybrid identified the interaction, confirmed by in vitro binding assays and co-immunoprecipitation from HeLa cells; the YTRF internalization motif of TfR is required for GABARAP binding. GABARAP-GFP localizes to perinuclear vesicles, indicating a general trafficking role beyond neurons.\",\n      \"method\": \"Yeast two-hybrid, in vitro binding assay with purified proteins, co-immunoprecipitation, GFP-GABARAP localization imaging\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — two binding assays plus motif mapping, single lab\",\n      \"pmids\": [\"11997026\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"GABARAP binds the C-terminal cytoplasmic domain of angiotensin II type 1 receptor (AT1R) and promotes AT1R plasma membrane expression: identified by yeast two-hybrid, confirmed by GST pull-down, co-immunoprecipitation, BRET; GABARAP overexpression increased surface AT1R 6-fold and enhanced Ang II-induced ERK1/2 phosphorylation, while siRNA knockdown of GABARAP reduced AT1R surface expression by 84%.\",\n      \"method\": \"Yeast two-hybrid, GST pull-down, co-immunoprecipitation, BRET, siRNA knockdown, surface receptor quantification, ERK1/2 signaling assay\",\n      \"journal\": \"Circulation research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal binding and functional assays including siRNA knockdown with quantitative surface expression and signaling readout\",\n      \"pmids\": [\"18497328\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"GABARAP associates with TRPV1 in HEK293 cells and DRG neurons, augments TRPV1 surface clustering and expression, attenuates voltage and capsaicin sensitivity in the presence of extracellular calcium, prolongs vanilloid-induced tachyphylaxis kinetics, and selectively increases tubulin interaction with the TRPV1 C-terminal domain; disruption of tubulin cytoskeleton with nocodazole reduced capsaicin-evoked currents specifically in cells co-expressing GABARAP.\",\n      \"method\": \"Co-immunoprecipitation, immunofluorescence, patch-clamp electrophysiology, siRNA/overexpression in HEK293 and DRG neurons, nocodazole treatment\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods with quantitative functional readouts (electrophysiology + trafficking) in two cell types\",\n      \"pmids\": [\"20179142\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Co-expression of GABARAP with α1β2γ2 GABA(A) receptors in L929 cells increased single-channel conductance (up to 60 pS vs. 30 pS main conductance) and mean open time of channels, with a linear relationship between conductance and open time; these changes are dependent on high GABA concentrations and reflect changes imposed by GABARAP-mediated receptor organization.\",\n      \"method\": \"Outside-out patch-clamp electrophysiology, single-channel analysis in transfected L929 cells\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct single-channel electrophysiology, single lab with clean functional readout\",\n      \"pmids\": [\"16954214\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"GABARAP specifically promotes ULK1 kinase activation in starvation-induced autophagy: unlipidated and lipidated GABARAP (but not LC3B, GABARAPL1, or GATE-16) activate ULK1 in a manner dependent on the ULK1 LIR motif. WAC and GM130 regulate GABARAP subcellular localization (Golgi vs. pericentriolar matrix), and centrosomal GABARAP is delivered to the phagophore during starvation.\",\n      \"method\": \"Genetic knockdown/rescue, ULK1 kinase assay, immunofluorescence, co-immunoprecipitation with GST-pulldown; domain-specific LIR mutants\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — isoform-specific rescue experiments with kinase activity assay and multiple orthogonal approaches in one study\",\n      \"pmids\": [\"26687599\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Centriolar satellite protein PCM1 directly binds GABARAP via a canonical LIR motif, recruits GABARAP to pericentriolar material, and protects it from proteasomal degradation. The centriolar satellite E3 ligase Mib1 promotes K48-linked ubiquitination of GABARAP (at N-terminal residues absent in the LC3 family), leading to its destabilization when PCM1 is lost. PCM1 loss reduces GABARAP-positive autophagosome formation and flux but does not affect LC3B-positive autophagosomes.\",\n      \"method\": \"Co-immunoprecipitation, GST pull-down, LIR motif mutagenesis, ubiquitin linkage-specific antibodies, autophagy flux assay, siRNA knockdown\",\n      \"journal\": \"Current biology : CB\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct binding mapped to LIR motif, ubiquitination characterized with linkage specificity, isoform-specific autophagy flux readout; multiple orthogonal methods\",\n      \"pmids\": [\"28712572\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"ATL3 (atlastin-3) functions as a selective ER-phagy receptor for tubular ER degradation by binding specifically to GABARAP (not LC3) subfamily proteins via two GABARAP interaction motifs (GIMs). Disease-associated ATL3 mutations (Y192C, P338R) disrupt ATL3–GABARAP association and impair ER-phagy.\",\n      \"method\": \"Co-immunoprecipitation, GIM motif mutagenesis, starvation-induced ER-phagy assay, disease mutation analysis\",\n      \"journal\": \"Current biology : CB\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — motif mapping with mutagenesis, functional ER-phagy assay, disease-mutation validation; multiple orthogonal methods\",\n      \"pmids\": [\"30773365\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"A GABARAP interaction motif (GIM) defined as [W/F]-[V/I]-X2-V confers ~11-fold selectivity for GABARAP over LC3B (as in PLEKHM1); crystal structures and biophysical analysis (ITC, NMR) identified variation in hydrophobic pocket 2 (HP2) as the structural basis for GABARAP vs. LC3 selectivity; conversion of LIRs in p62, FUNDC1, and FIP200 to GIM by introducing two valines enhanced GABARAP binding.\",\n      \"method\": \"X-ray crystallography of LIR–GABARAP complexes, isothermal titration calorimetry, NMR, selectivity profiling of 30 LIR motifs, mutagenesis\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structures plus ITC and mutagenesis across multiple LIR motifs; replicated with multiple interactors\",\n      \"pmids\": [\"28655748\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"PIK3C3, BECN1, and ATG14 (components of the PI3K complex I) contain functional LIR motifs that prefer GABARAP and GABARAPL1 over LC3 proteins; crystal structures of GABARAP bound to these LIR motifs revealed that HP2 pocket variation underlies GABARAP-family specificity. ATG14 LIR mutation blocks mitophagy and impairs ULK1-mediated phosphorylation of ATG14-S29.\",\n      \"method\": \"Crystal structures of GABARAP–LIR complexes, co-immunoprecipitation, LIR mutagenesis, mitophagy assay, ULK1 phosphorylation assay\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structures with functional mutagenesis (LIR mutant ATG14), multiple pathway readouts (mitophagy, phosphorylation); multiple orthogonal methods\",\n      \"pmids\": [\"30767700\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"A conserved motif in human ATG2A mediates direct interaction with GABARAP (and GABARAPL1), and this ATG2A–GABARAP interaction is essential for phagophore formation and closure; ATG2A mutants that cannot bind GABARAP fail to restore phagophore formation (phenocopying ATG2A/B double-KO), whereas ATG2A–WIPI4 interaction mutants fully rescue autophagy.\",\n      \"method\": \"Epistasis via ATG2A/B double-KO rescue with interaction-mutant constructs, autophagy flux assay, co-immunoprecipitation\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis with separation-of-function mutants in KO cells, multiple autophagy readouts; single lab but rigorous design\",\n      \"pmids\": [\"32009292\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"GABARAP (but not LC3) directly binds an LIR motif in the FLCN/FNIP tumor suppressor complex; during CASM, mitophagy, or xenophagy, membrane-conjugated GABARAP sequesters FLCN/FNIP to GABARAP-containing membranes, disrupting FLCN/FNIP GAP activity toward RagC/D and thereby impairing mTOR-dependent phosphorylation of TFEB, leading to TFEB/TFE3 activation and lysosomal biogenesis.\",\n      \"method\": \"Co-immunoprecipitation, LIR mutagenesis, mTOR substrate phosphorylation assay, TFEB/TFE3 nuclear translocation assay, GABARAP KO vs. LC3 KO rescue\",\n      \"journal\": \"Science advances\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct binding mapped by LIR mutagenesis, functional pathway readout (mTOR/TFEB), isoform-specific KO rescue experiments; multiple orthogonal methods\",\n      \"pmids\": [\"34597140\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"HIV-1 Nef binds directly and specifically to all GABARAP family members (not LC3 family members) via the two surface-exposed hydrophobic pockets of GABARAP; S53 and F62 of GABARAP are key residues for Nef interaction. GABARAP is required for Nef plasma membrane localization: siRNA knockdown of all three GABARAP family members significantly reduced Nef plasma membrane accumulation.\",\n      \"method\": \"Pull-down with purified recombinant proteins, co-immunoprecipitation, NMR epitope mapping, live-cell fluorescence microscopy, siRNA knockdown\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct binding with recombinant proteins, NMR residue-level mapping, functional siRNA knockdown; multiple orthogonal methods\",\n      \"pmids\": [\"28729737\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"GABARAP recruits PI4K2A (PI4KIIα) to autophagosomes via direct binding; PI4K2A-derived PtdIns4P on autophagosomes is required for autophagosome–lysosome fusion. GABARAP depletion prevents PI4K2A autophagosome recruitment and impairs autophagosome–lysosome fusion.\",\n      \"method\": \"Co-immunoprecipitation, GABARAP depletion/rescue, autophagosome–lysosome fusion assay\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — binding and functional fusion assay; single lab, moderate mechanistic detail in the abstract\",\n      \"pmids\": [\"26391226\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"PLEKHM1 contains a functional LIR motif that directly mediates binding to autophagosomal GABARAP (and other LC3/GABARAP family members); PLEKHM1 simultaneously interacts with the HOPS complex via a separate domain. PLEKHM1 depletion blocks autophagy flux, lysosomal degradation of endocytic EGFR cargo, and clearance of protein aggregates in an LIR-dependent manner.\",\n      \"method\": \"Co-immunoprecipitation, LIR mutagenesis, PLEKHM1 depletion/rescue, autophagic flux assay, EGFR degradation assay\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — LIR mutagenesis with multiple functional readouts (flux, endocytic degradation, aggregate clearance); replicated concept with HOPS complex\",\n      \"pmids\": [\"25498145\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"The CUL3-KBTBD6/KBTBD7 ubiquitin ligase complex binds GABARAP proteins via ATG8-family-interacting motifs and is recruited to GABARAP-containing vesicles; GABARAP recruitment is required for TIAM1 ubiquitination and degradation by this ligase, thereby spatially restricting RAC1 signaling, actin remodeling, and cell invasion.\",\n      \"method\": \"Co-immunoprecipitation, ATG8-interaction motif mutagenesis, siRNA depletion, RAC1 activity assay, TIAM1 ubiquitination assay, invasion assay\",\n      \"journal\": \"Molecular cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — motif-dependent recruitment linked to ubiquitination and downstream signaling readouts; multiple orthogonal methods\",\n      \"pmids\": [\"25684205\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"GABARAP deficiency in macrophages leads to impaired mitophagy-dependent clearance of damaged mitochondria after NLRP3 inflammasome activation (LPS+ATP), resulting in excess mitochondrial ROS and cytosolic mitochondrial DNA, and enhanced caspase-1 activation, IL-1β and IL-18 secretion; GABARAP-KO mice show higher mortality in two sepsis models.\",\n      \"method\": \"GABARAP-KO macrophage analysis, mitochondrial ROS measurement, caspase-1 cleavage assay, IL-1β/IL-18 ELISA, sepsis mouse models\",\n      \"journal\": \"Journal of immunology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KO with defined molecular readouts (ROS, mtDNA, caspase-1, cytokines); mechanistic link to mitophagy is indirect\",\n      \"pmids\": [\"23427251\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"An atypical (non-canonical) LIR motif in UBA5 (ufmylation E1 enzyme) preferentially interacts with GABARAP over LC3; crystal structures of GABARAP and GABARAPL2 in complex with the UBA5 LIR revealed a third hydrophobic pocket (HP0) engaged by a tryptophan N-terminal of the LIR core, with K46/K47 in GABARAP being key specificity determinants. GABARAP regulates UBA5 localization to the ER membrane in a lipidation-independent manner.\",\n      \"method\": \"X-ray crystallography of GABARAP–UBA5 LIR complexes, NMR, ITC, mutagenesis (HP0 swaps), subcellular localization assay\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structures of the complex with mutagenesis validation and functional localization assay; multiple orthogonal methods\",\n      \"pmids\": [\"30990354\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"GABARAP (and GATE-16), when lipidated, promotes extensive membrane tethering and full membrane fusion (vesicle aggregation, inter-vesicular lipid mixing, content mixing without leakage) in reconstituted systems, whereas LC3 shows minimal fusogenic activity; smaller vesicle diameter and negative-curvature lipids (cardiolipin, DAG) facilitate GABARAP-mediated fusion.\",\n      \"method\": \"In vitro membrane fusion reconstitution (enzymatic and chemical lipidation), cryo-electron microscopy, fluorescence lipid- and content-mixing assays\",\n      \"journal\": \"Biophysical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — fully reconstituted in vitro fusion system with multiple independent assays for different fusion steps and cryo-EM visualization\",\n      \"pmids\": [\"26789764\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"GABARAP (but not LC3) is specifically required for IFN-γ-mediated antimicrobial clearance of vacuolar pathogens (Toxoplasma): cells lacking GABARAPs but not LC3s were defective in IFN-γ-induced pathogen clearance. GABARAP/Gate-16, but not LC3b, specifically associated with Arf1 (small GTPase) to mediate uniform cytosolic distribution of interferon-inducible GTPases (IFN-GTPases); GABARAP loss reduced Arf1 activation and caused IFN-GTPase aggregation.\",\n      \"method\": \"GABARAP-KO and LC3-KO cell comparison, Toxoplasma clearance assay, co-immunoprecipitation with Arf1, IFN-GTPase localization assay, Arf1 activation assay\",\n      \"journal\": \"Nature immunology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — isoform-specific KO comparison with multiple functional and molecular readouts (pathogen clearance, Arf1 binding, GTPase distribution); multiple orthogonal methods\",\n      \"pmids\": [\"28604719\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"TBK1 phosphorylates GABARAP-L2 on surface-exposed serine residues (S87 and S88); this phosphorylation impedes ATG4-mediated binding and deconjugation of GABARAP-L2 from liposomes, protecting it from premature removal from nascent autophagosomes.\",\n      \"method\": \"In vitro TBK1 kinase assay, liposome deconjugation assay, mutagenesis of phosphorylation sites, ATG4 binding assay\",\n      \"journal\": \"EMBO reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro kinase and deconjugation assays with mutagenesis; direct evidence for GABARAP-L2; single lab\",\n      \"pmids\": [\"31709703\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"ATG3 is a target of GABARAP conjugation (LC3ylation): deconjugation-resistant GABARAP/LC3 isoforms accumulate as higher-molecular-weight conjugates on ATG3 in ATG4-deficient cells; ATG3 Lys243 was identified as an LC3B modification site; ATG4B can cleave LC3B-ATG3 conjugates (acting as a deubiquitinating-like enzyme).\",\n      \"method\": \"Deconjugation-resistant mutant LC3/GABARAP expression, ATG4-deficient cell lines (CRISPR-Cas9), immunoblotting under reducing/denaturing conditions, site identification by mutagenesis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic KO system with separation-of-function mutants, site mutagenesis, biochemical deconjugation assay; multiple orthogonal methods\",\n      \"pmids\": [\"31315929\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"ATG4A, ATG4C, and ATG4D all contribute to residual priming (C-terminal processing) of GABARAP family members in cells lacking ATG4B; endogenous GABARAPL1 can be lipidated on autophagic structures by these redundant priming activities; expressing pre-primed LC3B in ATG4-deficient cells rescues autophagic degradation of SQSTM1/p62, demonstrating that ATG4-mediated delipidation is not essential for autophagosome–lysosome fusion.\",\n      \"method\": \"CRISPR-Cas9 KO of ATG4 isoforms in HAP1 and HeLa cells, siRNA co-depletion, autophagic flux assay (SQSTM1 degradation), CLEM\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — systematic multi-isoform KO with multiple orthogonal functional assays; comprehensive genetic characterization\",\n      \"pmids\": [\"30661429\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"MAPK15/ERK8 directly interacts with GABARAP (and GABARAPL1, MAP1LC3B) via a conserved LIR motif; MAPK15 localizes to autophagic compartments, and kinase-dependent activity increases ATG8 protein lipidation, autophagosome formation, and SQSTM1 degradation; MAPK15 kinase activity is induced by serum and amino-acid starvation and is required for starvation-induced autophagy.\",\n      \"method\": \"Co-immunoprecipitation, LIR mutagenesis, kinase activity assay, autophagosome quantification, SQSTM1 degradation assay, starvation-induced autophagy\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — LIR motif mapping, kinase-dependent readout, multiple assays; single lab\",\n      \"pmids\": [\"22948227\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"FLCN directly interacts with GABARAP; the FLCN–GABARAP association is modulated by FNIP1/2 and regulated by ULK1; ULK1 phosphorylates FLCN at Ser406, Ser537, and Ser542; loss of FLCN moderately impairs basal autophagic flux.\",\n      \"method\": \"Co-immunoprecipitation, ULK1 phosphorylation assay (mass spectrometry identification of phosphosites), autophagic flux assay\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct binding confirmed by Co-IP, phosphorylation sites identified by MS, functional flux assay; single lab\",\n      \"pmids\": [\"25126726\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Bcl-2 directly binds GABARAP via a three-residue segment (EWD) adjacent to the BH4 region that anchors to one of two hydrophobic pockets on GABARAP (not both pockets simultaneously, unlike most GABARAP partners); Bcl-2 overexpression inhibits GABARAP lipidation, a key step in autophagosome formation.\",\n      \"method\": \"NMR epitope mapping, in vitro pull-down, lipidation assay, Bcl-2 overexpression\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — NMR residue-level mapping of interaction, functional lipidation assay; single lab but multiple orthogonal methods\",\n      \"pmids\": [\"24240096\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"GABARAP directly binds a previously unappreciated region in the γ2 subunit of GABA(A)R; crystal structure of GABARAPL1–γ2 complex revealed the molecular basis of complex formation; phosphorylation of γ2 differentially modulates its binding to GABARAP vs. the clathrin adaptor AP2; GABARAP stabilizes GABAARs by promoting trafficking (not blocking endocytosis); blockage of the GABARAP–GABAAR interaction selectively reduced GABAergic synaptic currents.\",\n      \"method\": \"X-ray crystallography of GABARAPL1–γ2 complex, co-immunoprecipitation, phosphorylation-dependent binding assay, patch-clamp electrophysiology, receptor trafficking assay\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure with mutagenesis and multiple functional readouts (trafficking, electrophysiology); highly rigorous single study\",\n      \"pmids\": [\"33436612\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Ankyrin-G directly interacts with GABARAP to stabilize cell-surface GABA(A) receptors; a knock-in mouse expressing Ank3 W1989R (a mutation abolishing ankyrin-G/GABARAP interaction) shows reduced forebrain GABAergic synapses, pyramidal cell hyperexcitability, and disrupted network synchronization; the ANK3 W1989R variant was identified in a family with bipolar disorder.\",\n      \"method\": \"Knock-in mouse model, in vivo electrophysiology, immunofluorescence, co-immunoprecipitation; human genetic variant analysis\",\n      \"journal\": \"Molecular psychiatry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — separation-of-function knock-in mouse with multiple in vivo readouts (synaptic, electrophysiological, morphological); rigorous design\",\n      \"pmids\": [\"30504823\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Mulan E3 ubiquitin ligase interacts with GABARAP through a LIR motif in its RING finger domain, and this interaction requires the E2 enzyme Ube2E3; the Mulan–GABARAP interaction recruits GABARAP to mitochondrial outer membrane and is proposed to regulate mitophagy.\",\n      \"method\": \"Yeast two-hybrid, co-immunoprecipitation, LIR motif analysis\",\n      \"journal\": \"Cellular signalling\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — yeast two-hybrid and Co-IP only; no direct functional mitophagy assay linked to GABARAP interaction; single lab\",\n      \"pmids\": [\"25224329\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"GABARAP (but not GABARAPL2) interacts with cardiolipin (CL) in vitro; however, neither GABARAP nor GABARAPL2 was translocated to mitochondria in rotenone-treated glioblastoma cells (unlike LC3B), suggesting GABARAP does not participate in CL-mediated mitophagy signaling in this cell type.\",\n      \"method\": \"Quantitative biophysical binding assays with CL-containing liposomes, live-cell imaging after rotenone treatment\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — quantitative biophysical assays plus in vivo imaging; result is partly negative (no mitochondrial translocation in vivo); single lab\",\n      \"pmids\": [\"27764541\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"STING signaling activates LRRK2 kinase activity via the CASM pathway in a GABARAP-dependent manner: multiple lysosome-perturbing stimuli converge on CASM to conjugate ATG8s to single membranes; LRRK2 lysosomal recruitment and kinase activation are highly dependent on interaction with GABARAP specifically, not other ATG8 family members.\",\n      \"method\": \"STING agonist treatment, CASM induction, GABARAP KO vs. LC3 KO, LRRK2 lysosome recruitment assay, LRRK2 kinase activity assay (Rab phosphorylation)\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — isoform-specific KO comparison with quantitative kinase activity and localization readouts; multiple stimuli tested\",\n      \"pmids\": [\"39812709\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"In GABARAP-KO mice, the renal sodium-phosphate cotransporter NaPi-IIa is upregulated in brush-border membranes, resulting in increased phosphate reabsorption; GABARAP binds NaPi-IIa via amino acids 36–68 of GABARAP, confirmed by GST pull-down and co-immunoprecipitation from renal cells.\",\n      \"method\": \"GABARAP-KO mouse analysis, GST pull-down from brush-border membranes, co-immunoprecipitation from HEK293 cells, 32Pi uptake assay, GABARAP domain mapping\",\n      \"journal\": \"American journal of physiology. Renal physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — KO mouse with quantitative transport assay and direct binding domain mapping; single lab\",\n      \"pmids\": [\"19225049\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"GABARAP is an ATG8-family ubiquitin-like modifier that undergoes C-terminal cleavage (by ATG4 proteases) followed by E1 (ATG7)- and E2 (ATG3)-mediated conjugation to phosphatidylethanolamine on autophagosomal and other membranes; membrane-conjugated GABARAP promotes phagophore elongation and closure (via a conserved interaction with ATG2), membrane tethering and fusion (especially within the GABARAP subfamily), and autophagosome–lysosome fusion (by recruiting PI4K2A and interacting with PLEKHM1–HOPS); in starvation-induced autophagy it specifically activates ULK1 kinase from a centrosomal/Golgi pool regulated by WAC, GM130, and centriolar satellites (PCM1/Mib1-mediated ubiquitination); it acts as a selective interaction platform for numerous cargo adaptors, receptors, and signaling proteins through its two hydrophobic LIR-docking pockets (with a GABARAP-specific HP0 site for certain partners), with a defined GIM sequence conferring GABARAP-over-LC3 selectivity; in neurons it promotes GABA(A) receptor clustering and surface trafficking by bridging the receptor γ2 subunit (direct structural interaction), microtubules (N-terminal basic domain), NSF, gephyrin, and ankyrin-G; and it plays non-autophagy roles including Arf1-dependent cytosolic distribution of IFN-inducible GTPases for antimicrobial defense, FLCN/FNIP sequestration to regulate mTOR–TFEB lysosomal biogenesis, and LRRK2 activation at lysosomes via the CASM pathway.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"GABARAP is an ATG8-family ubiquitin-like modifier that is processed at its C-terminus (Gly116) and conjugated to membrane phosphatidylethanolamine through an E1 (ATG7, via a Cys572 thioester) and E2 (ATG3, via a Cys264 thioester) cascade, with ATG4B serving as both the priming protease and the deconjugating enzyme [#0, #1, #2, #3, #14]. In vitro reconstitution shows GABARAP can be conjugated to PE and PS, while ATG3's curvature-sensing amphipathic helix restricts lipidation to highly curved membranes, accounting for the in vivo predominance of GABARAP-PE [#4, #8]. Once lipidated, GABARAP drives multiple steps of autophagosome biogenesis and maturation: it binds ATG2A to enable phagophore formation and closure [#30], it uniquely among ATG8s promotes membrane tethering and full fusion in reconstituted systems [#38], and it directs autophagosome–lysosome fusion by recruiting PI4K2A and engaging the PLEKHM1–HOPS machinery through LIR-motif interactions [#33, #34]. In starvation-induced autophagy, GABARAP is specifically required (and is not interchangeable with LC3B or other family members) to activate ULK1 kinase from a centrosomal/Golgi pool whose localization and stability are controlled by WAC, GM130, and the centriolar satellite proteins PCM1 and the Mib1 ubiquitin ligase [#25, #26]. High-resolution crystal, NMR, and biophysical structures define GABARAP as a ubiquitin-like fold with an N-terminal basic/helical subdomain that binds tubulin and a conserved face bearing two hydrophobic tryptophan-binding pockets (plus a GABARAP-specific HP0 site) that form the docking surface for partner LIR/GIM motifs; sequence variation in pocket HP2 and residues such as K46/K47 underlies a defined GIM consensus that confers GABARAP-over-LC3 selectivity for partners including PLEKHM1, ATL3, the PI3K-complex-I subunits, and UBA5 [#5, #6, #7, #19, #28, #29, #37]. Through these pockets GABARAP serves as a selective platform for cargo receptors and signaling proteins, mediating ER-phagy (ATL3), mitophagy and inflammasome control in macrophages, and spatial restriction of RAC1 signaling via CUL3–KBTBD6/7-dependent TIAM1 degradation [#27, #35, #36]. Beyond canonical autophagy, GABARAP regulates lysosomal biogenesis by sequestering the FLCN/FNIP complex on membranes to inhibit its RagC/D GAP activity and thereby activate mTOR-controlled TFEB/TFE3 signaling [#31, #44], supports IFN-γ antimicrobial defense by associating with Arf1 to distribute interferon-inducible GTPases [#39], and is required for STING/CASM-driven recruitment and kinase activation of LRRK2 at lysosomes [#50]. In neurons, GABARAP directly binds the GABA(A) receptor γ2 subunit (defined by crystal structure), bridging it to microtubules via its N-terminal basic domain, NSF, gephyrin, and ankyrin-G to promote receptor clustering and surface trafficking and to modulate channel kinetics [#5, #10, #11, #13, #46, #47]; an ankyrin-G W1989R knock-in mouse that abolishes the ankyrin-G/GABARAP interaction produces GABAergic synaptic and excitability deficits, and the corresponding human ANK3 variant was found in a family with bipolar disorder [#47].\",\n  \"teleology\": [\n    {\n      \"year\": 2000,\n      \"claim\": \"Establishing the enzymology of GABARAP conjugation answered how this ubiquitin-like protein is covalently activated and attached, defining it as a substrate of an E1-like activating enzyme.\",\n      \"evidence\": \"Co-IP, active-site C572S mutagenesis, and thioester intermediate trapping with human ATG7\",\n      \"pmids\": [\"11096062\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not identify the downstream lipid acceptor\", \"Did not define the E2 enzyme\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Identifying ATG3 as the E2 conjugating enzyme completed the activation cascade and showed it forms an E1·E2 complex with ATG7.\",\n      \"evidence\": \"C264S active-site mutagenesis and thioester intermediate trapping\",\n      \"pmids\": [\"11825910\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not establish the final membrane target\", \"Curvature dependence of lipidation not yet known\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Showing that a single protease (ATG4B) both primes and deconjugates GABARAP defined the reversible, protease-gated nature of the modification.\",\n      \"evidence\": \"Electrophilic activity-based GABARAP probes covalently labeling ATG4B in lysates\",\n      \"pmids\": [\"14530254\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Redundancy among ATG4 isoforms not resolved\", \"Physiological consequence of deconjugation untested\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Solving GABARAP structures (crystal and NMR) defined the bipartite architecture — an N-terminal tubulin-binding helical subdomain and a ubiquitin-like core carrying the γ2 receptor binding site — and revealed conformational dynamics and self-association.\",\n      \"evidence\": \"X-ray crystallography (1.6/2.0 Å), NMR solution structure, structure-based mutagenesis\",\n      \"pmids\": [\"11779480\", \"11818336\", \"11875056\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not define the hydrophobic-pocket ligand code\", \"Functional role of dynamic N-/C-terminal contacts unresolved\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Mapping GABARAP's neuronal partners established it as an adaptor bridging GABA(A) receptors to the cytoskeleton and trafficking machinery, not a postsynaptic anchor.\",\n      \"evidence\": \"Yeast two-hybrid subunit mapping, affinity pulldown of native receptors, tubulin-binding and gephyrin assays, NSF Co-IP, clustering with electrophysiology\",\n      \"pmids\": [\"11948245\", \"10899939\", \"10900017\", \"11461150\", \"10984509\", \"12367594\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo necessity for receptor trafficking not yet tested\", \"Whether interactions occur in native synapses unclear\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"In vitro and in vivo lipid analysis confirmed PE as the physiological conjugate despite GABARAP's capacity to be attached to PS, implying a selective conjugation factor in cells.\",\n      \"evidence\": \"Reconstitution with purified ATG7/ATG3 and defined liposomes, TLC of ATG4B-released lipids\",\n      \"pmids\": [\"16303767\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of the in vivo PE-selectivity factor unknown\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"GABARAP-knockout mice showed normal GABA(A) receptor number and distribution, establishing that GABARAP is dispensable for bulk synaptic receptor trafficking in vivo and revising the originally proposed anchoring role.\",\n      \"evidence\": \"Knockout mouse radioligand binding and immunocytochemistry\",\n      \"pmids\": [\"16307606\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single time-point, single-lab analysis\", \"Functional redundancy with GABARAPL paralogs not addressed\", \"Subtler kinetic or surface-trafficking phenotypes not excluded\"]\n    },\n    {\n      \"year\": 2008,\n      \"claim\": \"Defining the two tryptophan-binding hydrophobic pockets as the ligand-specificity determinant unified GABARAP's diverse partner interactions into a single structural docking principle.\",\n      \"evidence\": \"NMR, docking, and Trp→Ala mutagenesis of multiple ligand peptides with quantitative binding\",\n      \"pmids\": [\"18567048\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"GABARAP-vs-LC3 selectivity basis not yet structurally explained\", \"Did not yet define a consensus motif\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Demonstrating curvature-dependent lipidation via ATG3's amphipathic helix explained spatial restriction of GABARAP conjugation to nascent, highly curved autophagic membranes.\",\n      \"evidence\": \"Reconstitution with curvature-defined liposomes, helix mutagenesis, ATG3-KO rescue\",\n      \"pmids\": [\"24747438\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Membrane curvature sensing in vivo not directly imaged\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Establishing PLEKHM1 as an LIR-dependent GABARAP partner linked membrane-conjugated GABARAP directly to the HOPS tethering complex and autophagosome–lysosome maturation.\",\n      \"evidence\": \"LIR mutagenesis, depletion/rescue, autophagic flux and EGFR degradation assays\",\n      \"pmids\": [\"25498145\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"GABARAP-specific contribution vs other ATG8s not isolated in this study\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Isoform-specific rescue identified GABARAP as the unique ATG8 that activates ULK1 in starvation autophagy and traced its source to a centrosomal/Golgi pool regulated by WAC and GM130.\",\n      \"evidence\": \"Knockdown/rescue, ULK1 kinase assay, LIR mutants, localization imaging\",\n      \"pmids\": [\"26687599\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism of GABARAP delivery from centrosome to phagophore not fully resolved\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"GABARAP was shown to drive autophagosome–lysosome fusion by recruiting PI4K2A and generating PtdIns4P, and to spatially restrict RAC1 signaling by recruiting CUL3-KBTBD6/7 for TIAM1 degradation, expanding its role to membrane-fusion and signaling control.\",\n      \"evidence\": \"Co-IP, depletion/rescue, fusion assay (PI4K2A); motif mutagenesis, ubiquitination, RAC1 activity and invasion assays (KBTBD6/7)\",\n      \"pmids\": [\"26391226\", \"25684205\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"PI4K2A study single-lab with moderate mechanistic depth\", \"How GABARAP discriminates these functions on distinct membranes unclear\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Reconstitution established GABARAP as intrinsically fusogenic — promoting tethering and full membrane fusion unlike LC3 — defining a biophysical division of labor within the ATG8 family.\",\n      \"evidence\": \"In vitro fusion reconstitution, cryo-EM, lipid- and content-mixing assays\",\n      \"pmids\": [\"26789764\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological membranes on which GABARAP fusion operates in cells not defined\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Isoform-specific KO comparisons revealed dedicated non-autophagy roles: GABARAP, not LC3, mediates IFN-γ antimicrobial defense by associating with Arf1 to distribute interferon-inducible GTPases.\",\n      \"evidence\": \"GABARAP-KO vs LC3-KO cells, Toxoplasma clearance, Arf1 Co-IP and activation, GTPase distribution\",\n      \"pmids\": [\"28604719\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct vs indirect nature of Arf1 regulation not fully defined\", \"Whether lipidation is required not addressed\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Defining the GIM consensus and the HP2 structural basis converted the qualitative pocket model into a predictive code for GABARAP-over-LC3 selectivity, validated by engineering selectivity into other LIRs.\",\n      \"evidence\": \"Crystal structures of LIR–GABARAP complexes, ITC, NMR, selectivity profiling of 30 motifs, mutagenesis\",\n      \"pmids\": [\"28655748\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not catalog the full physiological GIM-bearing partner set\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"PCM1/Mib1 control of GABARAP stability through centriolar satellites explained how the GABARAP-specific autophagosome pool is maintained and degraded, and showed selective regulation distinct from LC3.\",\n      \"evidence\": \"Co-IP, LIR mutagenesis, linkage-specific ubiquitination, isoform-specific flux assay\",\n      \"pmids\": [\"28712572\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Upstream signals controlling Mib1-dependent GABARAP turnover unknown\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Structural work identified a third pocket (HP0) and key specificity residues, and showed GABARAP selectively engages atypical/non-canonical LIRs in UBA5, ATL3, and the PI3K-complex-I subunits, defining its role in ER-phagy, ufmylation localization, and autophagy initiation.\",\n      \"evidence\": \"Crystal structures of GABARAP–LIR complexes, NMR/ITC, GIM/HP0 mutagenesis, ER-phagy and mitophagy assays, localization assays\",\n      \"pmids\": [\"30990354\", \"30773365\", \"30767700\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional hierarchy among these many GABARAP-selective partners unresolved\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Genetic dissection of ATG4 isoforms and discovery of LC3ylation/TBK1 phosphorylation refined how GABARAP conjugation is regulated and reversed, showing redundant priming and that delipidation is dispensable for fusion.\",\n      \"evidence\": \"ATG4 isoform CRISPR KOs with flux assays; deconjugation-resistant mutants on ATG3; in vitro TBK1 kinase and ATG4-binding assays\",\n      \"pmids\": [\"30661429\", \"31315929\", \"31709703\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"TBK1 phospho-regulation shown for GABARAPL2, generalization to GABARAP not tested\", \"In vivo significance of ATG3 LC3ylation unclear\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Separation-of-function epistasis established that the ATG2A–GABARAP interaction, not ATG2A–WIPI4, is essential for phagophore formation and closure, placing GABARAP at the lipid-transfer step of autophagosome biogenesis.\",\n      \"evidence\": \"ATG2A/B double-KO rescue with interaction-mutant constructs, flux assay, Co-IP\",\n      \"pmids\": [\"32009292\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Single-lab study\", \"Mechanistic coupling of GABARAP binding to lipid transfer not resolved\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Linking membrane-conjugated GABARAP to FLCN/FNIP sequestration revealed a non-degradative signaling role controlling mTOR–TFEB lysosomal biogenesis, and a crystal structure resolved the molecular basis of GABARAP–γ2 binding and phosphorylation-dependent trafficking.\",\n      \"evidence\": \"Co-IP, LIR mutagenesis, mTOR/TFEB readouts, isoform-specific KO rescue (FLCN); crystal structure, electrophysiology, trafficking assays (γ2)\",\n      \"pmids\": [\"34597140\", \"33436612\", \"25126726\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo physiological setting of FLCN sequestration not defined\", \"How GABARAP balances trafficking vs autophagy roles for GABA(A)R unclear\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Demonstrating GABARAP-specific dependence for STING/CASM-driven LRRK2 lysosomal recruitment and kinase activation extended GABARAP's CASM functions into kinase signaling at lysosomes.\",\n      \"evidence\": \"STING agonist, CASM induction, GABARAP-KO vs LC3-KO, LRRK2 recruitment and Rab-phosphorylation kinase assays\",\n      \"pmids\": [\"39812709\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Direct GABARAP–LRRK2 binding mode not structurally defined\", \"Disease relevance of this axis untested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How GABARAP's single docking surface is partitioned in space and time among its many autophagy, trafficking, antimicrobial, and signaling partners — and how lipidation state, phosphorylation, and subcellular pool selection determine which function dominates — remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unified model for partner competition at the shared hydrophobic pockets\", \"Relative in vivo contribution of GABARAP vs paralogs across pathways unquantified\", \"Regulatory logic coupling membrane identity to GABARAP function unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0031386\", \"supporting_discovery_ids\": [0, 1, 2, 3, 4]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [25, 30, 33, 34, 39]},\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [0, 4, 49]},\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [5, 11]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [31, 25]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [0, 21, 35]},\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [9, 14, 25]},\n      {\"term_id\": \"GO:0005815\", \"supporting_discovery_ids\": [25, 26]},\n      {\"term_id\": \"GO:0005764\", \"supporting_discovery_ids\": [31, 50]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [22, 32]},\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [27, 37]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [0, 25, 30, 33, 34]},\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [33, 38, 34]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [1, 2, 3, 4]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [36, 39, 50]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [22, 31, 35, 50]},\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [10, 13, 46, 47]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"ATG7\", \"ATG3\", \"ATG4B\", \"ATG2A\", \"PLEKHM1\", \"ULK1\", \"FLCN\", \"GABRG2\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":8,"faith_total":8,"faith_pct":100.0}}