{"gene":"GGA1","run_date":"2026-06-10T01:55:21","timeline":{"discoveries":[{"year":2002,"finding":"X-ray crystal structure of the GGA1 VHS domain alone and in complex with the cation-independent mannose 6-phosphate receptor (CI-MPR) C-terminal peptide containing an acidic-cluster dileucine (ACLL) sequence revealed that the VHS domain forms a super-helix of eight alpha-helices; recognition of ACLL motifs involves unidirectional movements of helices α6 and α8 creating electrostatic and hydrophobic interactions.","method":"X-ray crystallography (crystal structures of apo and peptide-bound VHS domain)","journal":"Nature","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structures of both apo and ligand-bound forms with detailed structural analysis; foundational mechanistic paper replicated by subsequent structural and biochemical work","pmids":["11859376"],"is_preprint":false},{"year":2002,"finding":"Full-length cytoplasmic GGA1 (and GGA3 but not GGA2) is autoinhibited in its ability to bind the CI-MPR because an acidic-cluster dileucine (AC-LL) sequence in the hinge segment binds to the VHS domain ligand-binding site; this autoinhibition depends on phosphorylation of a serine three residues upstream of the AC-LL motif by casein kinase 2.","method":"In vitro binding assays with full-length and truncated GGA constructs, site-directed mutagenesis, in vitro casein kinase 2 phosphorylation assay, substitution of GGA1 inhibitory sequence into GGA2","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution with mutagenesis, kinase assays, and domain-swap experiments; multiple orthogonal approaches in one study","pmids":["12060753"],"is_preprint":false},{"year":2002,"finding":"The VHS domains of GGA1 and GGA2 bind the cytosolic domain of memapsin 2 (beta-secretase/BACE); Asp496, Leu499, and Leu500 in the memapsin 2 cytosolic tail are essential for this interaction, mirroring the spacing found in mannose-6-phosphate receptor cytosolic domains.","method":"Gel-immobilized VHS domain pulldown from cell lysates, site-directed mutagenesis of memapsin 2 cytosolic tail","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — reciprocal pulldown with mutagenesis confirmation; single lab but two complementary methods","pmids":["12135764"],"is_preprint":false},{"year":2002,"finding":"The cytoplasmic domain of the Vps10p-domain receptor sorLA binds GGA1 and GGA2 via three critical C-terminal residues that conform to a minimal GGA-binding motif (ψ-ψ-X-X-φ) that lacks a classical acidic cluster or dileucine.","method":"In vitro binding assays, mutagenesis of sorLA cytoplasmic tail","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct binding assay with mutagenesis; single lab, two methods","pmids":["11821067"],"is_preprint":false},{"year":2003,"finding":"Live-cell fluorescence imaging showed that GGA1, clathrin, and AP-1 colocalize at the TGN and on pleomorphic vesicular-tubular carriers (up to 10 µm displacement at ~1 µm/s) that bud from the TGN; GGA1 and clathrin cycle on and off membranes with half-times of 10–20 s independently of vesicle budding.","method":"Live fluorescence imaging with GFP-tagged GGA1, clathrin, and AP-1; FRAP","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — live-cell imaging with multiple spectral variants and FRAP; directly demonstrates GGA1 dynamics and carrier morphology in cells","pmids":["12686608"],"is_preprint":false},{"year":2003,"finding":"Crystal structure of the GGA1 GAT domain at 2.4 Å revealed a three-helix bundle with a long N-terminal helical extension; the ARF-binding site resides in the N-terminal extension, and the core three-helix bundle shares structural homology with the N-terminal domain of syntaxin 1a.","method":"X-ray crystallography at 2.4 Å resolution","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Strong — high-resolution crystal structure confirmed by two independent groups (PMID 12668765 and 12767220)","pmids":["12668765"],"is_preprint":false},{"year":2003,"finding":"The 2.8 Å crystal structure of the GGA1 GAT domain revealed four helices; the conserved N-terminal helix-loop-helix motif harbors a hydrophobic ARF-binding patch, and the C-terminal three-helix bundle is responsible for rabaptin-5 binding, as confirmed by structure-based mutagenesis.","method":"X-ray crystallography at 2.8 Å, structure-based mutagenesis and biochemical binding assays","journal":"Biochemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure combined with mutagenesis-biochemical validation; consistent with independent structural study (PMID 12668765)","pmids":["12767220"],"is_preprint":false},{"year":2003,"finding":"The C-terminal three-helix bundle of the GGA1 GAT domain mediates binding to the coiled-coil region of Rabaptin-5 through a hydrophobic surface patch; the GGA1-specific residue N284 (vs. S293 in GGA3) accounts for the differential Rabaptin-5 binding among GGA family members, and GAT–Rabaptin-5 binding is independent of ARF binding.","method":"Site-directed mutagenesis, in vitro pulldown/binding assays, crystal-structure-guided interpretation","journal":"Biochemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — mutagenesis of both GGA1 and GGA3 with biochemical validation; structural context from solved crystal structure","pmids":["14636058"],"is_preprint":false},{"year":2004,"finding":"The BACE cytosolic DISLL motif is recognized by the GGA1 VHS domain; phosphorylation of the serine in this motif enhances binding affinity ~3-fold. The crystal structure of the GGA1 VHS domain bound to the phosphorylated BACE peptide showed that phospho-serine alters the lysine side chain and backbone, creating an additional hydrogen bond and stronger electrostatic interaction.","method":"X-ray crystallography of VHS–BACE peptide complex, quantitative binding assays with phosphorylated and unphosphorylated peptides","journal":"Traffic (Copenhagen, Denmark)","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure of complex plus quantitative binding measurements; mechanistically explains phosphoregulation","pmids":["15117318"],"is_preprint":false},{"year":2004,"finding":"Fluorescence lifetime imaging microscopy (FLIM/FRET) in intact cells demonstrated that GGA1 interacts with phosphorylated BACE in juxtanuclear compartments; serine phosphorylation of BACE regulates its interaction with GGA1 in cells, and non-phosphorylatable or pseudo-phosphorylated BACE mutants remain colocalized with GGA1 at the Golgi.","method":"FLIM-FRET in live/fixed cells, phosphomimetic and non-phosphorylatable BACE mutants","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 2 / Strong — FRET-based proximity assay in intact cells with phosphomutants; directly validates phosphoregulation of GGA1–BACE interaction in cellular context","pmids":["15466887"],"is_preprint":false},{"year":2004,"finding":"GGA1 interacts with the AP-1 gamma-ear through a WNSF sequence (W382-N383-S384-F385) in its hinge region; Trp and Phe are critical residues; this WXXF-type motif competes with Rabaptin-5 FXXPhi-type binding for the same or overlapping site on the AP-1 gamma-ear.","method":"In vitro binding assays, competitive inhibition with peptides, site-directed mutagenesis of GGA1 hinge and AP-1 gamma-ear","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal mutagenesis in both GGA1 and AP-1 with competitive binding assays; multiple orthogonal experiments","pmids":["14973137"],"is_preprint":false},{"year":2004,"finding":"Glu58 and Glu59 of the CD-MPR CK2 acidic cluster site are essential for high-affinity GGA1 binding in vitro; phosphorylation of Ser57 does not influence GGA1 binding to CD-MPR. The binding affinity of GGA1 to CD-MPR is 2.4-fold higher than that of AP-1.","method":"In vitro binding assays with phosphopeptides and mutant CD-MPR cytoplasmic tail peptides, quantitative affinity measurements","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — quantitative binding assays with systematic mutagenesis; single lab","pmids":["15044437"],"is_preprint":false},{"year":2004,"finding":"GGA1 phosphorylation at S268 and T270 in the GAT domain (identified by tandem mass spectrometry) causes redistribution from Golgi/TGN to cytoplasmic puncta when phosphomimetic mutations are introduced; this phosphorylation regulates the rate of GGA1 coat dissociation from vesicles.","method":"Tandem mass spectrometry to identify phosphorylation sites, expression of phosphomimetic HA-GGA1 mutants in mammalian cells, quantitative colocalization with Golgi/TGN markers","journal":"Traffic (Copenhagen, Denmark)","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — MS identification of phosphosites combined with functional mutagenesis and quantitative localization; single lab","pmids":["14690499"],"is_preprint":false},{"year":2006,"finding":"GGA1 overexpression in cultured cells increased APP C-terminal fragment from beta-cleavage but reduced Abeta production; FRET analysis showed GGA1 confines APP to the Golgi where the two proteins come into close proximity; the GAT domain integrity is required for these effects, and direct GGA1–BACE binding is not required.","method":"Overexpression and dominant-negative constructs, FRET, subcellular fractionation, domain deletion/mutation analysis","journal":"The Journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — FRET plus domain-deletion analysis, single lab; mechanistically shows GGA1 acts as a spatial switch for APP processing at the Golgi","pmids":["17005855"],"is_preprint":false},{"year":2006,"finding":"GGA1 overexpression reduces Abeta secretion while RNAi-mediated knockdown increases Abeta secretion; GGA1 modulates APP processing by affecting subcellular trafficking of BACE1, independent of direct GGA1–APP interaction, and without altering total cellular BACE1 activity.","method":"GGA1 overexpression and siRNA knockdown in cultured cells, Abeta ELISA, APP processing assays","journal":"The Journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function and gain-of-function with defined biochemical readout; single lab","pmids":["17151287"],"is_preprint":false},{"year":2007,"finding":"GGA1 promotes assembly of clathrin in vitro; full-length GGA1 polymerizes clathrin into both baskets and tubules (~180 nm long, ~50 nm wide); the hinge+GAE fragment assembles clathrin only into baskets; maximum clathrin assembly occurs at one GGA1 per heavy chain.","method":"In vitro clathrin assembly assay with purified components, electron microscopy to determine structure of assembled complexes","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with purified proteins, EM structural validation, domain dissection; single lab but multiple orthogonal approaches","pmids":["17344219"],"is_preprint":false},{"year":2007,"finding":"The GGA1 GAE domain crystal structure in complex with its own hinge WNSF peptide revealed that the two aromatic residues fit into a hydrophobic groove of the GAE domain; the hinge region competes with accessory proteins and AP-1 for GAE binding, establishing an autoregulatory mechanism for GGA1 in clathrin-mediated trafficking.","method":"X-ray crystallography of GAE–hinge peptide complex, fluorescence quenching competition assays","journal":"Traffic (Copenhagen, Denmark)","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure combined with quantitative competition binding assays; extends autoinhibition model established for VHS domain","pmids":["17506864"],"is_preprint":false},{"year":2012,"finding":"GGA1 silencing potentiates BACE1 elevation induced by GGA3 deletion in neurons in vitro, indicating that GGA1 and GGA3 synergistically regulate BACE1 levels; GGA1 is a caspase-3 substrate that is depleted after traumatic brain injury.","method":"siRNA knockdown in primary neurons, caspase-3 cleavage assays, mouse TBI model, immunoblotting","journal":"The Journal of neuroscience","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vitro caspase-3 substrate assay plus neuronal knockdown with defined biochemical readout; single lab","pmids":["22836275"],"is_preprint":false},{"year":2012,"finding":"siRNA knockdown of GGA1 (but not GGA2 or GGA3) disrupts LR11/SorLA endosomal trafficking and prevents LR11-mediated and BACE1-mediated modulation of APP processing to Abeta; GGA1 is specifically required for LR11 endocytic traffic.","method":"siRNA knockdown of individual GGA family members, APP processing assays, BACE1 mutagenesis (S498A), subcellular localization by immunofluorescence","journal":"Molecular biology of the cell","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA specificity demonstrated across three GGA paralogs with defined biochemical readout and mutagenesis; single lab","pmids":["22621900"],"is_preprint":false},{"year":2014,"finding":"GGA1 functions in a Rabep1/GGA1/Arl3-dependent ciliary targeting mechanism at the TGN; GGA1 couples the polycystin-1/polycystin-2 complex (identified by yeast two-hybrid) to an Arl3-based ciliary trafficking module, enabling trafficking of these large membrane proteins to cilia.","method":"Yeast two-hybrid screening, candidate approach, co-immunoprecipitation, siRNA knockdown with ciliary localization readout","journal":"Nature communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — yeast two-hybrid plus Co-IP plus functional knockdown with defined localization phenotype; single lab","pmids":["25405894"],"is_preprint":false},{"year":2017,"finding":"GGA1 mediates rapid trafficking of phosphorylated BACE1 (phospho-S498, DISLL motif) from early endosomes to recycling endosomes; the phosphomimetic S498D mutant exits early endosomes faster and shows reduced APP processing and Abeta production; retromer cooperates with GGA1 in this pathway.","method":"Phosphomimetic/non-phosphorylatable BACE1 mutants, siRNA knockdown of GGA1 and retromer, quantitative endosomal trafficking assays, Abeta ELISA, primary neuron experiments","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple phosphomutants, loss-of-function of two pathway components (GGA1 and retromer), trafficking kinetics measured, validated in primary neurons","pmids":["29142073"],"is_preprint":false},{"year":2016,"finding":"GGA1 and GGA2 are required for cell surface transport of α2B-adrenergic receptor (α2B-AR); knockdown of GGA1 arrests α2B-AR in the perinuclear region and attenuates ERK1/2 activation and cAMP inhibition; the GGA1 hinge region directly interacts with the third intracellular loop of α2B-AR.","method":"shRNA/siRNA knockdown, cell surface ELISA, receptor-mediated signaling assays, co-immunoprecipitation, domain mapping","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function with signaling readout and Co-IP domain mapping; single lab","pmids":["27901063"],"is_preprint":false},{"year":2019,"finding":"A naturally occurring truncated splice variant of GGA1 (GGA1t), lacking the N-terminal hinge portion, acts as a dominant-negative inhibitor of α2B-AR cell surface export; GGA1t forms homodimers and heterodimers with full-length GGA1, is unable to bind cargo α2B-AR, and cannot recruit clathrin to the TGN.","method":"Overexpression of GGA1t, cell surface receptor assays, Co-IP for dimerization, clathrin recruitment assay at TGN","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — gain-of-function with mechanistic domain analysis and functional cargo/clathrin recruitment assays; single lab","pmids":["31316103"],"is_preprint":false},{"year":2018,"finding":"GGA1 is required for myotube formation in C2C12 myoblasts; Gga1 depletion by RNAi prevents formation of large multi-nucleated myotubes; GGA1 is involved in cell surface expression and sorting of the insulin receptor, as inhibition of lysosomal proteases in GGA1-knockdown cells increased insulin receptor levels.","method":"siRNA knockdown in C2C12 cells, morphological analysis of myotube formation, lysosomal protease inhibition, insulin receptor immunoblotting","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — RNAi loss-of-function with defined morphological and biochemical readouts; single lab","pmids":["30440034"],"is_preprint":false},{"year":2024,"finding":"GGA1 interacts with the endosomal Na+/H+ exchanger NHE6 (and organellar NHEs 6, 7, 9 but not surface NHEs 1 and 5) via the NHE6 cytoplasmic tail; GGA1 knockout causes NHE6 mislocalization — less NHE6 in endosomes, more in lysosomes and Golgi, with increased surface exocytosis — and alkalinization of Golgi luminal pH.","method":"Yeast two-hybrid screening, reciprocal co-immunoprecipitation (overexpressed and endogenous), hybrid NHE1/NHE6 domain-swap constructs, subcellular fractionation in GGA1 KO cells, super-resolution microscopy co-localization, luminal pH measurement","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (Y2H, endogenous Co-IP, domain-swap, KO fractionation, pH measurement, super-resolution imaging); single lab but comprehensive","pmids":["39002678"],"is_preprint":false},{"year":2025,"finding":"In GIST cells, a constitutively active KIT mutant activates the PLCγ2–PKD2–PLD2 cascade, which promotes association of γ-adaptin with GGA1 at the Golgi/TGN; PLD activity is required for GGA1-dependent Golgi/TGN retention of KIT mutant, and PLD inhibition releases KIT mutant from the Golgi for lysosomal degradation.","method":"PLD inhibitor treatment, siRNA knockdown of PLD1/PLD2, co-immunoprecipitation of γ-adaptin with GGA1, subcellular localization assays","journal":"bioRxiv","confidence":"Low","confidence_rationale":"Tier 3 / Weak — preprint, single lab, Co-IP with inhibitor/knockdown; mechanistic pathway only partially defined","pmids":["bio_10.1101_2025.03.02.640696"],"is_preprint":true},{"year":2005,"finding":"In vitro biochemical characterization combined with the GAT–Rabaptin-5 complex crystal structure established that the binding mode between the GGA1 GAT domain and Rabaptin-5 is helix-bundle-to-helix-bundle in nature.","method":"In vitro binding assays, crystal structure of GGA1 GAT–Rabaptin-5 complex","journal":"Methods in enzymology","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — crystal structure plus biochemical assays; consistent with earlier structural and mutagenesis data from same group","pmids":["16473621"],"is_preprint":false}],"current_model":"GGA1 is a modular TGN-to-endosome adaptor protein whose VHS domain recognizes acidic-cluster dileucine (ACLL/DXXLL) motifs on sorting receptors (CI-MPR, sorLA, LR11, BACE1/memapsin 2, NHE6) with affinity enhanced by phosphorylation of the cargo motif; its GAT domain binds ARF-GTP for TGN recruitment and Rabaptin-5 for endosome targeting via a helix-bundle interaction; its hinge region mediates autoinhibition of the VHS domain (via a phospho-regulated intramolecular AC-LL interaction), recruits AP-1 through a WNSF motif, and directly contacts GPCR cargo; its GAE domain autoregulates GGA1 by binding the hinge WNSF sequence competitively with accessory proteins; GGA1 assembles clathrin into both baskets and tubules; multiple phosphorylation events in the GAT domain regulate Golgi membrane association; and GGA1 controls subcellular trafficking of BACE1, APP, LR11, α2B-adrenergic receptor, NHE6, and ciliary membrane proteins (polycystins), with key roles in regulating amyloid-β production, endosome pH homeostasis, and cell-surface receptor targeting."},"narrative":{"mechanistic_narrative":"GGA1 is a modular monomeric clathrin adaptor that sorts transmembrane cargo between the trans-Golgi network (TGN) and the endosomal system, dynamically cycling on and off TGN membranes and clathrin-coated vesicular-tubular carriers together with clathrin and AP-1 [PMID:12686608]. Its N-terminal VHS domain is the cargo-recognition module: a super-helix of eight alpha-helices that binds acidic-cluster dileucine (ACLL/DXXLL) motifs in the cytosolic tails of sorting receptors such as the cation-independent mannose-6-phosphate receptor, with helices α6 and α8 forming the electrostatic and hydrophobic contacts [PMID:11859376], and it engages a structurally related class of cargo including BACE/memapsin 2 and the Vps10p-domain receptor sorLA [PMID:12135764, PMID:11821067]. Cargo binding is tuned by phosphorylation: phospho-serine in the BACE DISLL motif strengthens VHS engagement by creating an additional hydrogen bond and electrostatic contact [PMID:15117318, PMID:15466887], while an intramolecular acidic-cluster dileucine sequence in the hinge, when phosphorylated by casein kinase 2, folds back onto the VHS ligand site to autoinhibit cargo binding [PMID:12060753]. The GAT domain is a helix bundle whose N-terminal extension binds ARF for TGN recruitment and whose C-terminal three-helix bundle binds the Rabaptin-5 coiled-coil through a hydrophobic patch in an ARF-independent, helix-bundle-to-helix-bundle mode [PMID:12668765, PMID:12767220, PMID:14636058, PMID:16473621]; phosphorylation within the GAT domain at S268/T270 controls Golgi membrane association and coat dissociation [PMID:14690499]. The hinge recruits AP-1 via a WNSF motif that competes with Rabaptin-5 for the γ-ear [PMID:14973137], and the GAE domain binds this same hinge WNSF sequence competitively with accessory proteins to provide a further autoregulatory layer [PMID:17506864]; GGA1 also drives clathrin polymerization into both baskets and tubules [PMID:17344219]. Through these activities GGA1 governs the subcellular itinerary of multiple cargoes: it confines APP and BACE1 to the Golgi and routes phospho-BACE1 from early to recycling endosomes in cooperation with retromer, thereby lowering amyloid-β production [PMID:17005855, PMID:17151287, PMID:29142073], directs cell-surface delivery of the α2B-adrenergic receptor via a direct hinge–third-intracellular-loop contact [PMID:27901063], maintains endosomal localization and luminal pH homeostasis through the Na+/H+ exchanger NHE6 [PMID:39002678], and couples the polycystin-1/2 complex to an Arl3-dependent ciliary targeting module [PMID:25405894]. GGA1 and GGA3 act synergistically to restrain neuronal BACE1 levels, and GGA1 is a caspase-3 substrate depleted after traumatic brain injury [PMID:22836275].","teleology":[{"year":2002,"claim":"Established the structural basis of GGA1 cargo recognition, answering how the VHS domain reads acidic-cluster dileucine sorting signals.","evidence":"X-ray structures of apo and CI-MPR peptide-bound VHS domain","pmids":["11859376"],"confidence":"High","gaps":["Did not address how full-length GGA1 is regulated","Limited to one cargo peptide"]},{"year":2002,"claim":"Revealed that GGA1 cargo binding is autoinhibited, answering how the adaptor is switched off when not engaged at the TGN.","evidence":"In vitro binding with truncations, domain-swap into GGA2, and CK2 phosphorylation assays","pmids":["12060753"],"confidence":"High","gaps":["In vivo trigger for relief of autoinhibition not defined","Structural detail of the hinge-VHS contact came later"]},{"year":2002,"claim":"Broadened the cargo repertoire beyond MPRs, showing GGA1 binds the beta-secretase BACE/memapsin 2 and the receptor sorLA, linking the adaptor to amyloidogenic and Vps10p-domain cargo.","evidence":"VHS-domain pulldowns and cytosolic-tail mutagenesis of memapsin 2 and sorLA","pmids":["12135764","11821067"],"confidence":"Medium","gaps":["Single-lab biochemistry without cellular trafficking readout","sorLA motif lacks classic acidic cluster, leaving binding mode unresolved"]},{"year":2003,"claim":"Demonstrated GGA1 dynamics in cells, answering whether GGA1 acts as a stable coat or a rapidly cycling adaptor at the TGN.","evidence":"Live multicolor fluorescence imaging and FRAP of GFP-GGA1, clathrin, and AP-1","pmids":["12686608"],"confidence":"High","gaps":["Molecular determinants of the rapid on/off cycling not defined","Cargo dependence of carrier budding not resolved"]},{"year":2003,"claim":"Solved the GAT domain structure and partitioned its ARF- and Rabaptin-5-binding surfaces, explaining how GGA1 is recruited to TGN versus endosomal membranes.","evidence":"Crystal structures of the GAT domain plus structure-based mutagenesis and binding assays","pmids":["12668765","12767220","14636058","16473621"],"confidence":"High","gaps":["Functional consequence of simultaneous ARF and Rabaptin-5 engagement unresolved","In-cell timing of the two interactions not established"]},{"year":2004,"claim":"Showed phosphorylation tunes cargo affinity, answering how cells regulate GGA1 binding to BACE in space and time.","evidence":"Crystal structure of VHS bound to phospho-BACE peptide, quantitative binding, and FLIM-FRET with phosphomutants in cells","pmids":["15117318","15466887"],"confidence":"High","gaps":["Kinase responsible for BACE motif phosphorylation in neurons not identified","Quantitative contribution to net Abeta output not measured here"]},{"year":2004,"claim":"Mapped the hinge WNSF motif to the AP-1 gamma-ear and showed it competes with Rabaptin-5, defining a shared interaction surface for accessory recruitment.","evidence":"Reciprocal mutagenesis and competitive peptide binding for GGA1 hinge and AP-1 gamma-ear","pmids":["14973137"],"confidence":"High","gaps":["Functional outcome of GGA1-AP-1 handoff in cargo sorting not directly tested","Stoichiometry of competition in cells unknown"]},{"year":2004,"claim":"Identified GAT-domain phosphosites controlling membrane association, linking post-translational modification to coat dissociation kinetics.","evidence":"Mass spectrometry phosphosite mapping plus phosphomimetic localization analysis","pmids":["14690499"],"confidence":"Medium","gaps":["Responsible kinase not identified","Effect on cargo delivery not measured"]},{"year":2007,"claim":"Demonstrated GGA1 directly assembles clathrin and resolved an additional GAE-hinge autoregulatory loop, completing the modular regulatory picture.","evidence":"In vitro clathrin assembly with EM, plus GAE-hinge peptide crystal structure and competition assays","pmids":["17344219","17506864"],"confidence":"High","gaps":["Physiological balance between basket and tubule assembly unknown","How hinge autoregulation integrates with cargo loading in cells not resolved"]},{"year":2006,"claim":"Established GGA1 as a spatial regulator of amyloidogenic processing, showing it confines APP/BACE1 to the Golgi to suppress Abeta production.","evidence":"Overexpression, RNAi, FRET, and domain-deletion analysis with Abeta ELISA","pmids":["17005855","17151287"],"confidence":"Medium","gaps":["Direct GGA1-APP binding not required, leaving exact spatial mechanism inferential","Single-lab cellular system"]},{"year":2012,"claim":"Defined paralog-specific roles, showing GGA1 alone is required for LR11/SorLA endocytic traffic and that GGA1 and GGA3 synergistically restrain neuronal BACE1.","evidence":"Isoform-specific siRNA across three GGAs, APP processing assays, caspase-3 cleavage, and mouse TBI model","pmids":["22621900","22836275"],"confidence":"Medium","gaps":["Molecular basis of GGA1 specificity for LR11 not defined","In vivo consequence of caspase-mediated GGA1 loss not established"]},{"year":2017,"claim":"Resolved the directionality of BACE1 sorting, showing GGA1 moves phospho-BACE1 from early to recycling endosomes with retromer to lower Abeta.","evidence":"BACE1 phosphomutants, GGA1 and retromer siRNA, endosomal trafficking kinetics, Abeta ELISA in primary neurons","pmids":["29142073"],"confidence":"High","gaps":["Precise GGA1-retromer molecular coupling not defined","Generalizability to other phospho-cargo unknown"]},{"year":2016,"claim":"Extended GGA1 function to GPCR surface delivery, showing the hinge directly contacts the alpha2B-adrenergic receptor third intracellular loop to enable export and downstream signaling.","evidence":"Knockdown, surface ELISA, signaling assays, Co-IP and domain mapping","pmids":["27901063"],"confidence":"Medium","gaps":["Hinge-loop binding interface not structurally defined","Generality across GPCRs untested"]},{"year":2019,"claim":"Identified a dominant-negative GGA1 splice variant, showing isoform diversity can block adaptor function via dimerization and loss of cargo/clathrin binding.","evidence":"GGA1t overexpression, surface receptor assays, Co-IP dimerization, TGN clathrin recruitment assay","pmids":["31316103"],"confidence":"Medium","gaps":["Endogenous expression and physiological role of GGA1t not established","Single cargo system"]},{"year":2018,"claim":"Linked GGA1 to myogenesis and insulin receptor sorting, broadening its cargo and developmental relevance.","evidence":"siRNA in C2C12 myoblasts, myotube morphology, lysosomal protease inhibition, insulin receptor immunoblot","pmids":["30440034"],"confidence":"Medium","gaps":["Direct GGA1-insulin receptor interaction not demonstrated","Mechanism linking sorting to myotube fusion unresolved"]},{"year":2024,"claim":"Defined GGA1 control of organellar pH, showing it binds the NHE6 tail to maintain endosomal localization and Golgi luminal pH.","evidence":"Y2H, endogenous Co-IP, domain-swaps, KO fractionation, super-resolution imaging, luminal pH measurement","pmids":["39002678"],"confidence":"High","gaps":["VHS motif within the NHE6 tail not precisely mapped","Physiological consequence of pH dysregulation not tested in vivo"]},{"year":2014,"claim":"Placed GGA1 in ciliary trafficking, showing it couples the polycystin complex to an Arl3-dependent module at the TGN.","evidence":"Yeast two-hybrid, Co-IP, and siRNA with ciliary localization readout","pmids":["25405894"],"confidence":"Medium","gaps":["Direct GGA1-polycystin interface not mapped","Relationship to canonical ACLL cargo recognition unclear"]},{"year":2025,"claim":"Proposed a signaling input retaining oncogenic KIT at the Golgi via GGA1, but the pathway is only partially defined.","evidence":"PLD inhibitor and PLD1/2 siRNA, gamma-adaptin-GGA1 Co-IP, localization assays (preprint)","pmids":["bio_10.1101_2025.03.02.640696"],"confidence":"Low","gaps":["Preprint, not peer-reviewed","Direct GGA1-KIT interaction not shown","Mechanism by which PLD activity controls GGA1 recruitment incomplete"]},{"year":null,"claim":"How the layered autoregulation, cargo phosphorylation, and signaling inputs are integrated in vivo to set cargo-specific GGA1 sorting decisions remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No whole-organism loss-of-function phenotype in the corpus","Quantitative model linking autoinhibition relief to cargo selection lacking","How GGA1 chooses among competing cargo at the TGN unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[0,4,10,15]},{"term_id":"GO:0038024","term_label":"cargo receptor activity","supporting_discovery_ids":[0,2,3,8,24]},{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[15]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[1,16]}],"localization":[{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[4,12,13,24]},{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[20,24,19]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[1,12]},{"term_id":"GO:0031410","term_label":"cytoplasmic vesicle","supporting_discovery_ids":[4,15]}],"pathway":[{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[4,15,20,24]},{"term_id":"R-HSA-9609507","term_label":"Protein 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Mediates the ARF-dependent recruitment of clathrin to the TGN and binds ubiquitinated proteins and membrane cargo molecules with a cytosolic acidic cluster-dileucine (DXXLL) motif (PubMed:11301005, PubMed:15886016). Mediates export of the GPCR receptor ADRA2B to the cell surface (PubMed:27901063). Required for targeting PKD1:PKD2 complex from the trans-Golgi network to the cilium membrane (By similarity). Regulates retrograde transport of proteins such as phosphorylated form of BACE1 from endosomes to the trans-Golgi network (PubMed:15615712, PubMed:15886016)","subcellular_location":"Golgi apparatus, trans-Golgi network membrane; Endosome membrane; Early endosome membrane","url":"https://www.uniprot.org/uniprotkb/Q9UJY5/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/GGA1","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/GGA1","total_profiled":1310},"omim":[{"mim_id":"617366","title":"COILED-COIL DOMAIN-CONTAINING PROTEIN 91; CCDC91","url":"https://www.omim.org/entry/617366"},{"mim_id":"613439","title":"CONSORTIN; CNST","url":"https://www.omim.org/entry/613439"},{"mim_id":"609700","title":"RAB GUANINE NUCLEOTIDE EXCHANGE FACTOR 1; RABGEF1","url":"https://www.omim.org/entry/609700"},{"mim_id":"606006","title":"GOLGI-ASSOCIATED, GAMMA-ADAPTIN EAR-CONTAINING, ARF-BINDING PROTEIN 3; GGA3","url":"https://www.omim.org/entry/606006"},{"mim_id":"606005","title":"GOLGI-ASSOCIATED, GAMMA-ADAPTIN EAR-CONTAINING, ARF-BINDING PROTEIN 2; GGA2","url":"https://www.omim.org/entry/606005"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Golgi apparatus","reliability":"Supported"},{"location":"Vesicles","reliability":"Supported"},{"location":"Nucleoplasm","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"testis","ntpm":176.9}],"url":"https://www.proteinatlas.org/search/GGA1"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"Q9UJY5","domains":[{"cath_id":"1.25.40.90","chopping":"11-156","consensus_level":"high","plddt":88.842,"start":11,"end":156},{"cath_id":"1.20.58.160","chopping":"175-302","consensus_level":"medium","plddt":88.3482,"start":175,"end":302},{"cath_id":"2.60.40.1230","chopping":"505-628","consensus_level":"high","plddt":90.3073,"start":505,"end":628}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9UJY5","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9UJY5-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9UJY5-F1-predicted_aligned_error_v6.png","plddt_mean":73.44},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=GGA1","jax_strain_url":"https://www.jax.org/strain/search?query=GGA1"},"sequence":{"accession":"Q9UJY5","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9UJY5.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9UJY5/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9UJY5"}},"corpus_meta":[{"pmid":"11859376","id":"PMC_11859376","title":"Structural 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unidirectional movements of helices α6 and α8 creating electrostatic and hydrophobic interactions.\",\n      \"method\": \"X-ray crystallography (crystal structures of apo and peptide-bound VHS domain)\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structures of both apo and ligand-bound forms with detailed structural analysis; foundational mechanistic paper replicated by subsequent structural and biochemical work\",\n      \"pmids\": [\"11859376\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Full-length cytoplasmic GGA1 (and GGA3 but not GGA2) is autoinhibited in its ability to bind the CI-MPR because an acidic-cluster dileucine (AC-LL) sequence in the hinge segment binds to the VHS domain ligand-binding site; this autoinhibition depends on phosphorylation of a serine three residues upstream of the AC-LL motif by casein kinase 2.\",\n      \"method\": \"In vitro binding assays with full-length and truncated GGA constructs, site-directed mutagenesis, in vitro casein kinase 2 phosphorylation assay, substitution of GGA1 inhibitory sequence into GGA2\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution with mutagenesis, kinase assays, and domain-swap experiments; multiple orthogonal approaches in one study\",\n      \"pmids\": [\"12060753\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"The VHS domains of GGA1 and GGA2 bind the cytosolic domain of memapsin 2 (beta-secretase/BACE); Asp496, Leu499, and Leu500 in the memapsin 2 cytosolic tail are essential for this interaction, mirroring the spacing found in mannose-6-phosphate receptor cytosolic domains.\",\n      \"method\": \"Gel-immobilized VHS domain pulldown from cell lysates, site-directed mutagenesis of memapsin 2 cytosolic tail\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal pulldown with mutagenesis confirmation; single lab but two complementary methods\",\n      \"pmids\": [\"12135764\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"The cytoplasmic domain of the Vps10p-domain receptor sorLA binds GGA1 and GGA2 via three critical C-terminal residues that conform to a minimal GGA-binding motif (ψ-ψ-X-X-φ) that lacks a classical acidic cluster or dileucine.\",\n      \"method\": \"In vitro binding assays, mutagenesis of sorLA cytoplasmic tail\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct binding assay with mutagenesis; single lab, two methods\",\n      \"pmids\": [\"11821067\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Live-cell fluorescence imaging showed that GGA1, clathrin, and AP-1 colocalize at the TGN and on pleomorphic vesicular-tubular carriers (up to 10 µm displacement at ~1 µm/s) that bud from the TGN; GGA1 and clathrin cycle on and off membranes with half-times of 10–20 s independently of vesicle budding.\",\n      \"method\": \"Live fluorescence imaging with GFP-tagged GGA1, clathrin, and AP-1; FRAP\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — live-cell imaging with multiple spectral variants and FRAP; directly demonstrates GGA1 dynamics and carrier morphology in cells\",\n      \"pmids\": [\"12686608\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Crystal structure of the GGA1 GAT domain at 2.4 Å revealed a three-helix bundle with a long N-terminal helical extension; the ARF-binding site resides in the N-terminal extension, and the core three-helix bundle shares structural homology with the N-terminal domain of syntaxin 1a.\",\n      \"method\": \"X-ray crystallography at 2.4 Å resolution\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — high-resolution crystal structure confirmed by two independent groups (PMID 12668765 and 12767220)\",\n      \"pmids\": [\"12668765\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"The 2.8 Å crystal structure of the GGA1 GAT domain revealed four helices; the conserved N-terminal helix-loop-helix motif harbors a hydrophobic ARF-binding patch, and the C-terminal three-helix bundle is responsible for rabaptin-5 binding, as confirmed by structure-based mutagenesis.\",\n      \"method\": \"X-ray crystallography at 2.8 Å, structure-based mutagenesis and biochemical binding assays\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure combined with mutagenesis-biochemical validation; consistent with independent structural study (PMID 12668765)\",\n      \"pmids\": [\"12767220\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"The C-terminal three-helix bundle of the GGA1 GAT domain mediates binding to the coiled-coil region of Rabaptin-5 through a hydrophobic surface patch; the GGA1-specific residue N284 (vs. S293 in GGA3) accounts for the differential Rabaptin-5 binding among GGA family members, and GAT–Rabaptin-5 binding is independent of ARF binding.\",\n      \"method\": \"Site-directed mutagenesis, in vitro pulldown/binding assays, crystal-structure-guided interpretation\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — mutagenesis of both GGA1 and GGA3 with biochemical validation; structural context from solved crystal structure\",\n      \"pmids\": [\"14636058\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"The BACE cytosolic DISLL motif is recognized by the GGA1 VHS domain; phosphorylation of the serine in this motif enhances binding affinity ~3-fold. The crystal structure of the GGA1 VHS domain bound to the phosphorylated BACE peptide showed that phospho-serine alters the lysine side chain and backbone, creating an additional hydrogen bond and stronger electrostatic interaction.\",\n      \"method\": \"X-ray crystallography of VHS–BACE peptide complex, quantitative binding assays with phosphorylated and unphosphorylated peptides\",\n      \"journal\": \"Traffic (Copenhagen, Denmark)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure of complex plus quantitative binding measurements; mechanistically explains phosphoregulation\",\n      \"pmids\": [\"15117318\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Fluorescence lifetime imaging microscopy (FLIM/FRET) in intact cells demonstrated that GGA1 interacts with phosphorylated BACE in juxtanuclear compartments; serine phosphorylation of BACE regulates its interaction with GGA1 in cells, and non-phosphorylatable or pseudo-phosphorylated BACE mutants remain colocalized with GGA1 at the Golgi.\",\n      \"method\": \"FLIM-FRET in live/fixed cells, phosphomimetic and non-phosphorylatable BACE mutants\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — FRET-based proximity assay in intact cells with phosphomutants; directly validates phosphoregulation of GGA1–BACE interaction in cellular context\",\n      \"pmids\": [\"15466887\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"GGA1 interacts with the AP-1 gamma-ear through a WNSF sequence (W382-N383-S384-F385) in its hinge region; Trp and Phe are critical residues; this WXXF-type motif competes with Rabaptin-5 FXXPhi-type binding for the same or overlapping site on the AP-1 gamma-ear.\",\n      \"method\": \"In vitro binding assays, competitive inhibition with peptides, site-directed mutagenesis of GGA1 hinge and AP-1 gamma-ear\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal mutagenesis in both GGA1 and AP-1 with competitive binding assays; multiple orthogonal experiments\",\n      \"pmids\": [\"14973137\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Glu58 and Glu59 of the CD-MPR CK2 acidic cluster site are essential for high-affinity GGA1 binding in vitro; phosphorylation of Ser57 does not influence GGA1 binding to CD-MPR. The binding affinity of GGA1 to CD-MPR is 2.4-fold higher than that of AP-1.\",\n      \"method\": \"In vitro binding assays with phosphopeptides and mutant CD-MPR cytoplasmic tail peptides, quantitative affinity measurements\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — quantitative binding assays with systematic mutagenesis; single lab\",\n      \"pmids\": [\"15044437\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"GGA1 phosphorylation at S268 and T270 in the GAT domain (identified by tandem mass spectrometry) causes redistribution from Golgi/TGN to cytoplasmic puncta when phosphomimetic mutations are introduced; this phosphorylation regulates the rate of GGA1 coat dissociation from vesicles.\",\n      \"method\": \"Tandem mass spectrometry to identify phosphorylation sites, expression of phosphomimetic HA-GGA1 mutants in mammalian cells, quantitative colocalization with Golgi/TGN markers\",\n      \"journal\": \"Traffic (Copenhagen, Denmark)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — MS identification of phosphosites combined with functional mutagenesis and quantitative localization; single lab\",\n      \"pmids\": [\"14690499\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"GGA1 overexpression in cultured cells increased APP C-terminal fragment from beta-cleavage but reduced Abeta production; FRET analysis showed GGA1 confines APP to the Golgi where the two proteins come into close proximity; the GAT domain integrity is required for these effects, and direct GGA1–BACE binding is not required.\",\n      \"method\": \"Overexpression and dominant-negative constructs, FRET, subcellular fractionation, domain deletion/mutation analysis\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — FRET plus domain-deletion analysis, single lab; mechanistically shows GGA1 acts as a spatial switch for APP processing at the Golgi\",\n      \"pmids\": [\"17005855\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"GGA1 overexpression reduces Abeta secretion while RNAi-mediated knockdown increases Abeta secretion; GGA1 modulates APP processing by affecting subcellular trafficking of BACE1, independent of direct GGA1–APP interaction, and without altering total cellular BACE1 activity.\",\n      \"method\": \"GGA1 overexpression and siRNA knockdown in cultured cells, Abeta ELISA, APP processing assays\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function and gain-of-function with defined biochemical readout; single lab\",\n      \"pmids\": [\"17151287\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"GGA1 promotes assembly of clathrin in vitro; full-length GGA1 polymerizes clathrin into both baskets and tubules (~180 nm long, ~50 nm wide); the hinge+GAE fragment assembles clathrin only into baskets; maximum clathrin assembly occurs at one GGA1 per heavy chain.\",\n      \"method\": \"In vitro clathrin assembly assay with purified components, electron microscopy to determine structure of assembled complexes\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with purified proteins, EM structural validation, domain dissection; single lab but multiple orthogonal approaches\",\n      \"pmids\": [\"17344219\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"The GGA1 GAE domain crystal structure in complex with its own hinge WNSF peptide revealed that the two aromatic residues fit into a hydrophobic groove of the GAE domain; the hinge region competes with accessory proteins and AP-1 for GAE binding, establishing an autoregulatory mechanism for GGA1 in clathrin-mediated trafficking.\",\n      \"method\": \"X-ray crystallography of GAE–hinge peptide complex, fluorescence quenching competition assays\",\n      \"journal\": \"Traffic (Copenhagen, Denmark)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure combined with quantitative competition binding assays; extends autoinhibition model established for VHS domain\",\n      \"pmids\": [\"17506864\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"GGA1 silencing potentiates BACE1 elevation induced by GGA3 deletion in neurons in vitro, indicating that GGA1 and GGA3 synergistically regulate BACE1 levels; GGA1 is a caspase-3 substrate that is depleted after traumatic brain injury.\",\n      \"method\": \"siRNA knockdown in primary neurons, caspase-3 cleavage assays, mouse TBI model, immunoblotting\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vitro caspase-3 substrate assay plus neuronal knockdown with defined biochemical readout; single lab\",\n      \"pmids\": [\"22836275\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"siRNA knockdown of GGA1 (but not GGA2 or GGA3) disrupts LR11/SorLA endosomal trafficking and prevents LR11-mediated and BACE1-mediated modulation of APP processing to Abeta; GGA1 is specifically required for LR11 endocytic traffic.\",\n      \"method\": \"siRNA knockdown of individual GGA family members, APP processing assays, BACE1 mutagenesis (S498A), subcellular localization by immunofluorescence\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA specificity demonstrated across three GGA paralogs with defined biochemical readout and mutagenesis; single lab\",\n      \"pmids\": [\"22621900\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"GGA1 functions in a Rabep1/GGA1/Arl3-dependent ciliary targeting mechanism at the TGN; GGA1 couples the polycystin-1/polycystin-2 complex (identified by yeast two-hybrid) to an Arl3-based ciliary trafficking module, enabling trafficking of these large membrane proteins to cilia.\",\n      \"method\": \"Yeast two-hybrid screening, candidate approach, co-immunoprecipitation, siRNA knockdown with ciliary localization readout\",\n      \"journal\": \"Nature communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — yeast two-hybrid plus Co-IP plus functional knockdown with defined localization phenotype; single lab\",\n      \"pmids\": [\"25405894\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"GGA1 mediates rapid trafficking of phosphorylated BACE1 (phospho-S498, DISLL motif) from early endosomes to recycling endosomes; the phosphomimetic S498D mutant exits early endosomes faster and shows reduced APP processing and Abeta production; retromer cooperates with GGA1 in this pathway.\",\n      \"method\": \"Phosphomimetic/non-phosphorylatable BACE1 mutants, siRNA knockdown of GGA1 and retromer, quantitative endosomal trafficking assays, Abeta ELISA, primary neuron experiments\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple phosphomutants, loss-of-function of two pathway components (GGA1 and retromer), trafficking kinetics measured, validated in primary neurons\",\n      \"pmids\": [\"29142073\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"GGA1 and GGA2 are required for cell surface transport of α2B-adrenergic receptor (α2B-AR); knockdown of GGA1 arrests α2B-AR in the perinuclear region and attenuates ERK1/2 activation and cAMP inhibition; the GGA1 hinge region directly interacts with the third intracellular loop of α2B-AR.\",\n      \"method\": \"shRNA/siRNA knockdown, cell surface ELISA, receptor-mediated signaling assays, co-immunoprecipitation, domain mapping\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function with signaling readout and Co-IP domain mapping; single lab\",\n      \"pmids\": [\"27901063\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"A naturally occurring truncated splice variant of GGA1 (GGA1t), lacking the N-terminal hinge portion, acts as a dominant-negative inhibitor of α2B-AR cell surface export; GGA1t forms homodimers and heterodimers with full-length GGA1, is unable to bind cargo α2B-AR, and cannot recruit clathrin to the TGN.\",\n      \"method\": \"Overexpression of GGA1t, cell surface receptor assays, Co-IP for dimerization, clathrin recruitment assay at TGN\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — gain-of-function with mechanistic domain analysis and functional cargo/clathrin recruitment assays; single lab\",\n      \"pmids\": [\"31316103\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"GGA1 is required for myotube formation in C2C12 myoblasts; Gga1 depletion by RNAi prevents formation of large multi-nucleated myotubes; GGA1 is involved in cell surface expression and sorting of the insulin receptor, as inhibition of lysosomal proteases in GGA1-knockdown cells increased insulin receptor levels.\",\n      \"method\": \"siRNA knockdown in C2C12 cells, morphological analysis of myotube formation, lysosomal protease inhibition, insulin receptor immunoblotting\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — RNAi loss-of-function with defined morphological and biochemical readouts; single lab\",\n      \"pmids\": [\"30440034\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"GGA1 interacts with the endosomal Na+/H+ exchanger NHE6 (and organellar NHEs 6, 7, 9 but not surface NHEs 1 and 5) via the NHE6 cytoplasmic tail; GGA1 knockout causes NHE6 mislocalization — less NHE6 in endosomes, more in lysosomes and Golgi, with increased surface exocytosis — and alkalinization of Golgi luminal pH.\",\n      \"method\": \"Yeast two-hybrid screening, reciprocal co-immunoprecipitation (overexpressed and endogenous), hybrid NHE1/NHE6 domain-swap constructs, subcellular fractionation in GGA1 KO cells, super-resolution microscopy co-localization, luminal pH measurement\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (Y2H, endogenous Co-IP, domain-swap, KO fractionation, pH measurement, super-resolution imaging); single lab but comprehensive\",\n      \"pmids\": [\"39002678\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"In GIST cells, a constitutively active KIT mutant activates the PLCγ2–PKD2–PLD2 cascade, which promotes association of γ-adaptin with GGA1 at the Golgi/TGN; PLD activity is required for GGA1-dependent Golgi/TGN retention of KIT mutant, and PLD inhibition releases KIT mutant from the Golgi for lysosomal degradation.\",\n      \"method\": \"PLD inhibitor treatment, siRNA knockdown of PLD1/PLD2, co-immunoprecipitation of γ-adaptin with GGA1, subcellular localization assays\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — preprint, single lab, Co-IP with inhibitor/knockdown; mechanistic pathway only partially defined\",\n      \"pmids\": [\"bio_10.1101_2025.03.02.640696\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"In vitro biochemical characterization combined with the GAT–Rabaptin-5 complex crystal structure established that the binding mode between the GGA1 GAT domain and Rabaptin-5 is helix-bundle-to-helix-bundle in nature.\",\n      \"method\": \"In vitro binding assays, crystal structure of GGA1 GAT–Rabaptin-5 complex\",\n      \"journal\": \"Methods in enzymology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structure plus biochemical assays; consistent with earlier structural and mutagenesis data from same group\",\n      \"pmids\": [\"16473621\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"GGA1 is a modular TGN-to-endosome adaptor protein whose VHS domain recognizes acidic-cluster dileucine (ACLL/DXXLL) motifs on sorting receptors (CI-MPR, sorLA, LR11, BACE1/memapsin 2, NHE6) with affinity enhanced by phosphorylation of the cargo motif; its GAT domain binds ARF-GTP for TGN recruitment and Rabaptin-5 for endosome targeting via a helix-bundle interaction; its hinge region mediates autoinhibition of the VHS domain (via a phospho-regulated intramolecular AC-LL interaction), recruits AP-1 through a WNSF motif, and directly contacts GPCR cargo; its GAE domain autoregulates GGA1 by binding the hinge WNSF sequence competitively with accessory proteins; GGA1 assembles clathrin into both baskets and tubules; multiple phosphorylation events in the GAT domain regulate Golgi membrane association; and GGA1 controls subcellular trafficking of BACE1, APP, LR11, α2B-adrenergic receptor, NHE6, and ciliary membrane proteins (polycystins), with key roles in regulating amyloid-β production, endosome pH homeostasis, and cell-surface receptor targeting.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"GGA1 is a modular monomeric clathrin adaptor that sorts transmembrane cargo between the trans-Golgi network (TGN) and the endosomal system, dynamically cycling on and off TGN membranes and clathrin-coated vesicular-tubular carriers together with clathrin and AP-1 [#4]. Its N-terminal VHS domain is the cargo-recognition module: a super-helix of eight alpha-helices that binds acidic-cluster dileucine (ACLL/DXXLL) motifs in the cytosolic tails of sorting receptors such as the cation-independent mannose-6-phosphate receptor, with helices \\u03b16 and \\u03b18 forming the electrostatic and hydrophobic contacts [#0], and it engages a structurally related class of cargo including BACE/memapsin 2 and the Vps10p-domain receptor sorLA [#2, #3]. Cargo binding is tuned by phosphorylation: phospho-serine in the BACE DISLL motif strengthens VHS engagement by creating an additional hydrogen bond and electrostatic contact [#8, #9], while an intramolecular acidic-cluster dileucine sequence in the hinge, when phosphorylated by casein kinase 2, folds back onto the VHS ligand site to autoinhibit cargo binding [#1]. The GAT domain is a helix bundle whose N-terminal extension binds ARF for TGN recruitment and whose C-terminal three-helix bundle binds the Rabaptin-5 coiled-coil through a hydrophobic patch in an ARF-independent, helix-bundle-to-helix-bundle mode [#5, #6, #7, #26]; phosphorylation within the GAT domain at S268/T270 controls Golgi membrane association and coat dissociation [#12]. The hinge recruits AP-1 via a WNSF motif that competes with Rabaptin-5 for the \\u03b3-ear [#10], and the GAE domain binds this same hinge WNSF sequence competitively with accessory proteins to provide a further autoregulatory layer [#16]; GGA1 also drives clathrin polymerization into both baskets and tubules [#15]. Through these activities GGA1 governs the subcellular itinerary of multiple cargoes: it confines APP and BACE1 to the Golgi and routes phospho-BACE1 from early to recycling endosomes in cooperation with retromer, thereby lowering amyloid-\\u03b2 production [#13, #14, #20], directs cell-surface delivery of the \\u03b12B-adrenergic receptor via a direct hinge\\u2013third-intracellular-loop contact [#21], maintains endosomal localization and luminal pH homeostasis through the Na+/H+ exchanger NHE6 [#24], and couples the polycystin-1/2 complex to an Arl3-dependent ciliary targeting module [#19]. GGA1 and GGA3 act synergistically to restrain neuronal BACE1 levels, and GGA1 is a caspase-3 substrate depleted after traumatic brain injury [#17].\",\n  \"teleology\": [\n    {\n      \"year\": 2002,\n      \"claim\": \"Established the structural basis of GGA1 cargo recognition, answering how the VHS domain reads acidic-cluster dileucine sorting signals.\",\n      \"evidence\": \"X-ray structures of apo and CI-MPR peptide-bound VHS domain\",\n      \"pmids\": [\"11859376\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Did not address how full-length GGA1 is regulated\", \"Limited to one cargo peptide\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Revealed that GGA1 cargo binding is autoinhibited, answering how the adaptor is switched off when not engaged at the TGN.\",\n      \"evidence\": \"In vitro binding with truncations, domain-swap into GGA2, and CK2 phosphorylation assays\",\n      \"pmids\": [\"12060753\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo trigger for relief of autoinhibition not defined\", \"Structural detail of the hinge-VHS contact came later\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Broadened the cargo repertoire beyond MPRs, showing GGA1 binds the beta-secretase BACE/memapsin 2 and the receptor sorLA, linking the adaptor to amyloidogenic and Vps10p-domain cargo.\",\n      \"evidence\": \"VHS-domain pulldowns and cytosolic-tail mutagenesis of memapsin 2 and sorLA\",\n      \"pmids\": [\"12135764\", \"11821067\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab biochemistry without cellular trafficking readout\", \"sorLA motif lacks classic acidic cluster, leaving binding mode unresolved\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Demonstrated GGA1 dynamics in cells, answering whether GGA1 acts as a stable coat or a rapidly cycling adaptor at the TGN.\",\n      \"evidence\": \"Live multicolor fluorescence imaging and FRAP of GFP-GGA1, clathrin, and AP-1\",\n      \"pmids\": [\"12686608\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular determinants of the rapid on/off cycling not defined\", \"Cargo dependence of carrier budding not resolved\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Solved the GAT domain structure and partitioned its ARF- and Rabaptin-5-binding surfaces, explaining how GGA1 is recruited to TGN versus endosomal membranes.\",\n      \"evidence\": \"Crystal structures of the GAT domain plus structure-based mutagenesis and binding assays\",\n      \"pmids\": [\"12668765\", \"12767220\", \"14636058\", \"16473621\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of simultaneous ARF and Rabaptin-5 engagement unresolved\", \"In-cell timing of the two interactions not established\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Showed phosphorylation tunes cargo affinity, answering how cells regulate GGA1 binding to BACE in space and time.\",\n      \"evidence\": \"Crystal structure of VHS bound to phospho-BACE peptide, quantitative binding, and FLIM-FRET with phosphomutants in cells\",\n      \"pmids\": [\"15117318\", \"15466887\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Kinase responsible for BACE motif phosphorylation in neurons not identified\", \"Quantitative contribution to net Abeta output not measured here\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Mapped the hinge WNSF motif to the AP-1 gamma-ear and showed it competes with Rabaptin-5, defining a shared interaction surface for accessory recruitment.\",\n      \"evidence\": \"Reciprocal mutagenesis and competitive peptide binding for GGA1 hinge and AP-1 gamma-ear\",\n      \"pmids\": [\"14973137\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional outcome of GGA1-AP-1 handoff in cargo sorting not directly tested\", \"Stoichiometry of competition in cells unknown\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Identified GAT-domain phosphosites controlling membrane association, linking post-translational modification to coat dissociation kinetics.\",\n      \"evidence\": \"Mass spectrometry phosphosite mapping plus phosphomimetic localization analysis\",\n      \"pmids\": [\"14690499\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Responsible kinase not identified\", \"Effect on cargo delivery not measured\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Demonstrated GGA1 directly assembles clathrin and resolved an additional GAE-hinge autoregulatory loop, completing the modular regulatory picture.\",\n      \"evidence\": \"In vitro clathrin assembly with EM, plus GAE-hinge peptide crystal structure and competition assays\",\n      \"pmids\": [\"17344219\", \"17506864\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological balance between basket and tubule assembly unknown\", \"How hinge autoregulation integrates with cargo loading in cells not resolved\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Established GGA1 as a spatial regulator of amyloidogenic processing, showing it confines APP/BACE1 to the Golgi to suppress Abeta production.\",\n      \"evidence\": \"Overexpression, RNAi, FRET, and domain-deletion analysis with Abeta ELISA\",\n      \"pmids\": [\"17005855\", \"17151287\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct GGA1-APP binding not required, leaving exact spatial mechanism inferential\", \"Single-lab cellular system\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Defined paralog-specific roles, showing GGA1 alone is required for LR11/SorLA endocytic traffic and that GGA1 and GGA3 synergistically restrain neuronal BACE1.\",\n      \"evidence\": \"Isoform-specific siRNA across three GGAs, APP processing assays, caspase-3 cleavage, and mouse TBI model\",\n      \"pmids\": [\"22621900\", \"22836275\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Molecular basis of GGA1 specificity for LR11 not defined\", \"In vivo consequence of caspase-mediated GGA1 loss not established\"]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Resolved the directionality of BACE1 sorting, showing GGA1 moves phospho-BACE1 from early to recycling endosomes with retromer to lower Abeta.\",\n      \"evidence\": \"BACE1 phosphomutants, GGA1 and retromer siRNA, endosomal trafficking kinetics, Abeta ELISA in primary neurons\",\n      \"pmids\": [\"29142073\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Precise GGA1-retromer molecular coupling not defined\", \"Generalizability to other phospho-cargo unknown\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Extended GGA1 function to GPCR surface delivery, showing the hinge directly contacts the alpha2B-adrenergic receptor third intracellular loop to enable export and downstream signaling.\",\n      \"evidence\": \"Knockdown, surface ELISA, signaling assays, Co-IP and domain mapping\",\n      \"pmids\": [\"27901063\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Hinge-loop binding interface not structurally defined\", \"Generality across GPCRs untested\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Identified a dominant-negative GGA1 splice variant, showing isoform diversity can block adaptor function via dimerization and loss of cargo/clathrin binding.\",\n      \"evidence\": \"GGA1t overexpression, surface receptor assays, Co-IP dimerization, TGN clathrin recruitment assay\",\n      \"pmids\": [\"31316103\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Endogenous expression and physiological role of GGA1t not established\", \"Single cargo system\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Linked GGA1 to myogenesis and insulin receptor sorting, broadening its cargo and developmental relevance.\",\n      \"evidence\": \"siRNA in C2C12 myoblasts, myotube morphology, lysosomal protease inhibition, insulin receptor immunoblot\",\n      \"pmids\": [\"30440034\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct GGA1-insulin receptor interaction not demonstrated\", \"Mechanism linking sorting to myotube fusion unresolved\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Defined GGA1 control of organellar pH, showing it binds the NHE6 tail to maintain endosomal localization and Golgi luminal pH.\",\n      \"evidence\": \"Y2H, endogenous Co-IP, domain-swaps, KO fractionation, super-resolution imaging, luminal pH measurement\",\n      \"pmids\": [\"39002678\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"VHS motif within the NHE6 tail not precisely mapped\", \"Physiological consequence of pH dysregulation not tested in vivo\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Placed GGA1 in ciliary trafficking, showing it couples the polycystin complex to an Arl3-dependent module at the TGN.\",\n      \"evidence\": \"Yeast two-hybrid, Co-IP, and siRNA with ciliary localization readout\",\n      \"pmids\": [\"25405894\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct GGA1-polycystin interface not mapped\", \"Relationship to canonical ACLL cargo recognition unclear\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Proposed a signaling input retaining oncogenic KIT at the Golgi via GGA1, but the pathway is only partially defined.\",\n      \"evidence\": \"PLD inhibitor and PLD1/2 siRNA, gamma-adaptin-GGA1 Co-IP, localization assays (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.03.02.640696\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Preprint, not peer-reviewed\", \"Direct GGA1-KIT interaction not shown\", \"Mechanism by which PLD activity controls GGA1 recruitment incomplete\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How the layered autoregulation, cargo phosphorylation, and signaling inputs are integrated in vivo to set cargo-specific GGA1 sorting decisions remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No whole-organism loss-of-function phenotype in the corpus\", \"Quantitative model linking autoinhibition relief to cargo selection lacking\", \"How GGA1 chooses among competing cargo at the TGN unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 4, 10, 15]},\n      {\"term_id\": \"GO:0038024\", \"supporting_discovery_ids\": [0, 2, 3, 8, 24]},\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [15]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [1, 16]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [4, 12, 13, 24]},\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [20, 24, 19]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [1, 12]},\n      {\"term_id\": \"GO:0031410\", \"supporting_discovery_ids\": [4, 15]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [4, 15, 20, 24]},\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [19, 21, 24]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [13, 14, 20]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"CI-MPR\", \"BACE1\", \"SORL1\", \"Rabaptin-5\", \"AP-1\", \"ARF\", \"NHE6\", \"ADRA2B\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}