{"gene":"NSF","run_date":"2026-06-10T05:19:52","timeline":{"discoveries":[{"year":1988,"finding":"SEC18 (yeast NSF) is essential for yeast cell growth and is required for secretory protein transport between the ER and Golgi complex. The protein is hydrophilic, lacks signal sequence or transmembrane anchor, resides in the cytoplasm, and associates transiently with a 100,000 x g pellet fraction consistent with small vesicles.","method":"Gene cloning by complementation, gene disruption, subcellular fractionation, in vitro transcription/translation","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — gene disruption with growth phenotype, biochemical fractionation, replicated in subsequent studies","pmids":["3054509"],"is_preprint":false},{"year":1990,"finding":"Three soluble NSF attachment proteins (alpha-, beta-, gamma-SNAP) were purified from bovine brain cytosol and shown to bind NSF to Golgi membranes, forming a SNAP-NSF-membrane complex required for the membrane fusion stage of intra-Golgi transport. Yeast SEC17 encodes a functional homolog of alpha-SNAP, establishing evolutionary conservation of the NSF/SNAP fusion mechanism.","method":"Protein purification, in vitro Golgi transport assay, complementation with yeast sec17 mutant cytosol","journal":"Cell","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstituted in vitro transport, purified components, cross-species complementation, replicated widely","pmids":["2111733"],"is_preprint":false},{"year":1991,"finding":"Yeast Sec18p/NSF function is required sequentially for protein transport from the ER to the Golgi, through multiple Golgi compartments, and from the Golgi to the cell surface, defining at least three functionally distinct Golgi compartments.","method":"Temperature-shift experiments with sec18 and sec23 yeast mutants tracking transport of alpha-factor and CPY biosynthetic intermediates","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic loss-of-function with defined transport phenotypes at multiple pathway steps, replicated with multiple substrates","pmids":["2071670"],"is_preprint":false},{"year":1992,"finding":"NSF and alpha-SNAP are required during the formation of functional transport vesicles from Golgi membranes, not only at the attachment/fusion step; after vesicle formation, the NEM-sensitive function of NSF is no longer required.","method":"Cell-free Golgi transport assay measuring functional vesicle formation; immunodepletion of NSF/SNAP","journal":"The Journal of cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — cell-free reconstitution assay, single lab, dissection of step-specific requirements","pmids":["1522110"],"is_preprint":false},{"year":1993,"finding":"Alpha- and gamma-SNAP are ubiquitously expressed and act synergistically in intra-Golgi transport; beta-SNAP is a brain-specific isoform of alpha-SNAP. SNAPs enable NSF to bind to target membranes, and their action at specific fusion sites is controlled by SNARE receptors particular to the membranes being fused.","method":"cDNA cloning, in vitro Golgi transport assay, tissue expression analysis","journal":"Nature","confidence":"High","confidence_rationale":"Tier 1 / Strong — biochemical reconstitution, cloning with functional assay, replicated across labs","pmids":["8455721"],"is_preprint":false},{"year":1994,"finding":"NSF ATPase activity is regulated by alpha- and gamma-SNAPs. Immobilized (but not soluble) SNAPs enhance NSF ATPase activity in a dose-dependent manner, primarily by decreasing the Km of the low-affinity ATPase site ~100-fold, thereby acting as a molecular switch to activate NSF at physiological ATP concentrations.","method":"In vitro ATPase assay with recombinant His6-tagged NSF and SNAPs; enzyme kinetics analysis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro enzymatic assay with purified recombinant proteins, kinetic analysis of both ATPase domains","pmids":["7961908"],"is_preprint":false},{"year":1995,"finding":"NSF mediates basolateral (but not apical) transport from the trans-Golgi network to the plasma membrane in MDCK epithelial cells. Anti-NSF antibodies and alpha-SNAP inhibit/stimulate basolateral transport, while apical transport is insensitive to NSF, Rab-GDI, and neurotoxins.","method":"In vitro transport assay with streptolysin O-permeabilized MDCK cells; anti-NSF antibodies; toxin inhibition","journal":"Cell","confidence":"High","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal inhibitors (antibody, alpha-SNAP, neurotoxins, Rab-GDI) in cell-free system, single lab","pmids":["7758111"],"is_preprint":false},{"year":1995,"finding":"NSF together with SNAPs and p115 (a vesicle docking protein) restores cisternal regrowth from mitotic Golgi fragments in a cell-free system, while p97 (an NSF-like ATPase) also restores regrowth but produces morphologically distinct cisternae, indicating distinct roles in rebuilding Golgi after mitosis.","method":"Cell-free Golgi reassembly assay; NEM or salt-washing inhibition; reconstitution with purified proteins","journal":"Cell","confidence":"High","confidence_rationale":"Tier 1 / Moderate — cell-free reconstitution with purified proteins, morphological readout, comparison of NSF vs p97","pmids":["7553851"],"is_preprint":false},{"year":1995,"finding":"Alpha- and gamma-SNAP stimulate Ca2+-dependent exocytosis in digitonin-permeabilized chromaffin cells. Recombinant NSF alone was ineffective, but ~1/3 of cellular NSF is in a non-cytosolic form sufficient for exocytosis. The stimulatory effect of alpha-SNAP requires Ca2+, MgATP, and is blocked by NEM and botulinum A toxin.","method":"Permeabilized chromaffin cell exocytosis assay; recombinant protein addition; inhibitor analysis","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Moderate — functional exocytosis assay with recombinant proteins and multiple inhibitors, single lab","pmids":["7835334"],"is_preprint":false},{"year":1995,"finding":"NSF is a hollow 10×16 nm cylindrical oligomeric ATPase. Without nucleotide, NSF adopts a 'splayed' protease-sensitive conformation revealing its subunit composition. The ternary SNARE complex (syntaxin/SNAP-25/synaptobrevin) forms a 4×14 nm rod with syntaxin and synaptobrevin aligned in parallel with membrane anchors at the same end. Alpha-SNAP and the SNARE rod bind to one end of the NSF cylinder forming an asymmetric '20S' complex.","method":"Quick-freeze/deep-etch electron microscopy; epitope tags; antibody and maltose-binding protein markers on recombinant proteins","journal":"Cell","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct structural visualization by EM, multiple orthogonal markers, highly replicated","pmids":["9267032"],"is_preprint":false},{"year":1995,"finding":"A clostridial neurotoxin-sensitive SDS-resistant SNARE core (synaptobrevin/syntaxin/SNAP-25) is the physiological target for NSF-mediated ATP-dependent disassembly in the presence of SNAP. Cleavage of synaptobrevin or SNAP-25 by neurotoxins does not prevent 20S complex assembly but compromises the stability of the SDS-resistant SNARE core.","method":"In vitro 20S complex assembly/disassembly assay; clostridial neurotoxin cleavage; gel shift analysis","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with defined protein components and enzymatic perturbation","pmids":["7588600"],"is_preprint":false},{"year":1996,"finding":"NSF is required for homotypic vacuole fusion in vitro. Using purified recombinant Sec18p (NSF) and affinity-purified anti-Sec17p (alpha-SNAP) antibodies, both Sec17p and Sec18p are shown to be essential for the homotypic fusion step of vacuole inheritance. Vacuole-to-vacuole fusion is also stimulated by certain fatty acyl-CoA compounds in a Sec18p-dependent manner.","method":"Cell-free vacuole inheritance assay; purified recombinant proteins; affinity-purified antibodies","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstituted cell-free fusion with purified components, reciprocal inhibition experiments","pmids":["8670830"],"is_preprint":false},{"year":1996,"finding":"C-terminal deletion of alpha-SNAP abolishes NSF binding, while N-terminal deletions (up to 120 residues) do not prevent NSF binding or ATPase stimulation. Both N- and C-terminal domains of alpha-SNAP are required for syntaxin binding and exocytosis stimulation, placing NSF and syntaxin in proximity through alpha-SNAP.","method":"Alpha-SNAP deletion mutant analysis; NSF ATPase assay; permeabilized chromaffin cell exocytosis assay","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 1 / Moderate — systematic mutagenesis combined with functional ATPase and exocytosis assays","pmids":["8744944"],"is_preprint":false},{"year":1997,"finding":"NSF requires the C-terminal region of alpha-SNAP for ATPase stimulation: deletion of as few as 10 C-terminal residues markedly decreases ATPase stimulation; mutation of conserved leucine 294 to alanine (L294A) reduces ATPase stimulation without affecting NSF binding. Alpha-SNAP mutants defective in stimulating NSF ATPase fail to disassemble the 20S complex or stimulate exocytosis, demonstrating that alpha-SNAP-stimulated NSF ATPase activity is required for SNARE complex disassembly and exocytosis.","method":"Alpha-SNAP truncation and point mutants; in vitro ATPase assay; 20S complex disassembly assay; permeabilized chromaffin cell exocytosis assay","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — mutagenesis combined with three orthogonal functional assays (ATPase, SNARE disassembly, exocytosis)","pmids":["9362506"],"is_preprint":false},{"year":1997,"finding":"NSF is a hexamer (not tetramer or trimer) in the presence of nucleotide, stabilized by D2 domain oligomerization. The sedimentation coefficient is 13.4 S, and the unusual hydrodynamic properties cannot be explained by shape alone.","method":"Sedimentation equilibrium and velocity analytical ultracentrifugation; transmission EM with rotational image analysis; scanning transmission EM; multiangle light scattering","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — multiple independent biophysical methods (AUC, two EM approaches, light scattering) in one study","pmids":["9624162"],"is_preprint":false},{"year":1997,"finding":"NSF and alpha-SNAP mediate dissociation of the Golgi SNARE complex containing GS28 and syntaxin 5. ATP hydrolysis by NSF is required; neither alpha-SNAP nor NSF alone dissociates the complex. Upon dissociation, GS28 (but not syntaxin 5) binds immobilized alpha-SNAP.","method":"Coimmunoprecipitation of endogenous Golgi proteins; in vitro disassembly assay with ATP/ATPgammaS; pulldown with immobilized alpha-SNAP","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with ATP hydrolysis requirement established by ATPgammaS control","pmids":["9325254"],"is_preprint":false},{"year":1997,"finding":"LMA1 (a heterodimer of thioredoxin and IB2) requires Sec18p (NSF) for high-affinity binding to vacuoles. The Sec18p 'priming' ATPase requires both Sec17p and LMA1. Upon Sec18p ATP hydrolysis, LMA1 transfers to and stabilizes the Vam3p (t-SNARE) complex, coupling priming to t-SNARE stabilization.","method":"Cell-free vacuole fusion assay; genetic synthetic lethality; subcellular fractionation; biochemical binding assays","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstituted cell-free fusion, genetics, and biochemistry defining ordered mechanism","pmids":["9015301"],"is_preprint":false},{"year":1997,"finding":"Sec18p (NSF) is required for a novel complex at the Golgi-to-endosome (VPS) transport step in yeast. Pep12p (endosomal t-SNARE) affinity chromatography identified Vac1p, Vps45p, and Sec18p as binding partners; sec18-1 combined with overexpression of a dominant pep12 allele caused synthetic growth defects rescued by deletion of PEP12 or VAC1.","method":"Affinity chromatography (Pep12p-sepharose); genetic epistasis; temperature-sensitive mutant analysis; subcellular fractionation","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — biochemical pulldown combined with genetic epistasis and suppressor analysis","pmids":["9201718"],"is_preprint":false},{"year":1998,"finding":"NSF interacts directly and selectively with the intracellular C-terminal domain of the AMPA receptor GluR2 subunit (residues Lys-844–Gln-853, with Asn-851 critical), requiring all three domains of NSF. Loading blocking decapeptides corresponding to the NSF-binding domain of GluR2, or an anti-NSF antibody, into CA1 neurons progressively decremented AMPA receptor-mediated synaptic transmission.","method":"Direct binding assay, peptide mapping with mutagenesis, intracellular infusion of blocking peptides and antibody in hippocampal CA1 neurons, electrophysiology","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 2 / Strong — direct binding with domain mapping, two independent inhibition approaches (peptide and antibody) with electrophysiology, replicated across labs","pmids":["9697854"],"is_preprint":false},{"year":1998,"finding":"GluR2 C-terminal peptide forms an ATP hydrolysis-reversible complex with NSF and alpha-/beta-SNAPs, resembling the SNARE-NSF-SNAP complex assembly. The molar ratio of NSF to SNAP in the GluR2-NSF-SNAP complex is similar to that in the t-SNARE syntaxin-NSF-SNAP complex.","method":"Pulldown assay with GluR2 C-terminal peptide; co-immunoprecipitation; immunofluorescence colocalization; ATPgammaS/ATP comparison","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 2 / Strong — biochemical reconstitution of complex, multiple methods, replicated in same year by another lab","pmids":["9697855"],"is_preprint":false},{"year":1998,"finding":"In the Drosophila comatose (dNSF-1) mutant, an SDS-resistant neural SNARE complex (syntaxin/n-synaptobrevin/SNAP-25) accumulates at restrictive temperature, predominantly in plasma membrane and docked synaptic vesicle fractions. This establishes that NSF functions to disassemble or rearrange SNARE complexes after vesicle docking to maintain the readily releasable pool.","method":"SDS-PAGE of SNARE complexes in Drosophila NSF temperature-sensitive mutant; subcellular fractionation; electrophysiology","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vivo genetic model with biochemical readout (SNARE complex accumulation) and electrophysiology, replicated","pmids":["9852562"],"is_preprint":false},{"year":1998,"finding":"NSF functions in Drosophila neuromuscular synapses downstream of vesicle docking to prime docked vesicles for calcium-triggered fusion. In comatose (dNSF-1) mutants at restrictive temperature, progressive activity-dependent reduction in neurotransmitter release occurs with marked accumulation of docked vesicles, indicating NSF does not directly catalyze fusion but maintains the pool of fusion-competent vesicles.","method":"Electrophysiology at adult Drosophila neuromuscular junctions; transmission electron microscopy; temperature-sensitive comatose mutant analysis","journal":"The Journal of neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — in vivo functional analysis with electrophysiology and ultrastructure, replicated across two concurrent papers","pmids":["9852561"],"is_preprint":false},{"year":1998,"finding":"Injection of peptides inhibiting alpha-SNAP-stimulated NSF ATPase activity into the giant squid presynaptic terminal reduces the amount and slows the kinetics of neurotransmitter release, acting at a step subsequent to vesicle docking and requiring vesicle turnover.","method":"Peptide injection into squid giant presynaptic terminal; electrophysiology","journal":"Science","confidence":"High","confidence_rationale":"Tier 2 / Moderate — direct presynaptic injection with quantitative electrophysiology, defined mechanism","pmids":["9469810"],"is_preprint":false},{"year":1998,"finding":"LMA1 binds to vacuoles in a Sec18p-dependent manner, and Sec18p priming ATPase requires both Sec17p and LMA1. Upon Sec18p ATP hydrolysis, LMA1 transfers to a Vam3p (t-SNARE) complex and is later released in a phosphatase-regulated step, coupling the priming reaction to t-SNARE stabilization.","method":"Cell-free vacuole fusion assay; protein-membrane binding assays; mutant analysis","journal":"Cell","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstituted cell-free system with ordered biochemical steps, genetic validation","pmids":["9657146"],"is_preprint":false},{"year":1998,"finding":"Late endosome-lysosome fusion is an NSF-dependent direct fusion event (not vesicular transport) that also requires a Rab GTPase. Hybrid organelles formed by this fusion can be isolated from rat liver homogenates confirming the reaction occurs in vivo.","method":"Cell-free content mixing assay with rat liver endosomes and lysosomes; NEM inhibition; GDP-dissociation inhibitor; density gradient fractionation; immunoEM","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — cell-free reconstitution with inhibitors, morphological and biochemical characterization, in vivo confirmation by direct isolation","pmids":["9456319"],"is_preprint":false},{"year":1999,"finding":"NSF identifies beta-arrestin1 as a binding partner (identified by yeast two-hybrid, confirmed by in vitro binding and co-immunoprecipitation). Beta-arrestin1 preferentially interacts with the ATP-bound form of NSF. NSF overexpression enhances agonist-mediated beta2-adrenergic receptor internalization and rescues dominant-negative beta-arrestin1-mediated inhibition of internalization.","method":"Yeast two-hybrid screen; in vitro binding of purified recombinant proteins; co-immunoprecipitation; overexpression in HEK293 cells; receptor internalization assay","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — yeast two-hybrid confirmed by co-IP and in vitro binding; functional overexpression without mechanistic dissection","pmids":["10196135"],"is_preprint":false},{"year":1999,"finding":"Disruption of NSF-GluR2 interaction by infusion of blocking peptide (pep2m) into cultured hippocampal neurons reduces surface expression of GluR2-containing AMPA receptors (shown by reduced mEPSC frequency and reduced surface GluR2 immunostaining) without changing total GluR2. NMDA receptor surface expression is unaffected.","method":"Blocking peptide infusion into cultured hippocampal neurons; whole-cell patch-clamp; immunostaining with surface vs. total GluR2 comparison; viral expression of pep2m","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 2 / Strong — two independent inhibition methods (peptide infusion, viral expression), multiple readouts (electrophysiology, immunostaining), selective effect on AMPA vs NMDA receptors","pmids":["10399941"],"is_preprint":false},{"year":1999,"finding":"Alpha-SNAP and NSF are required at an early priming step in chromaffin cell exocytosis before release of readily releasable vesicles. Alpha-SNAP increases the amplitude of both the exocytotic burst and the slow secretion component without changing fusion kinetics, while NEM only partially inhibits the slow component without altering the exocytotic burst.","method":"Flash photolysis of caged Ca2+ combined with high-time-resolution capacitance measurement and amperometry; alpha-SNAP and NEM treatments","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Moderate — high-resolution kinetic analysis with multiple approaches, defined step-specific requirements","pmids":["10369670"],"is_preprint":false},{"year":1999,"finding":"Blockade of NSF-GluR2 interaction prevents homosynaptic LTD in hippocampal CA1 region. Saturation of LTD prevents pep2m-induced reduction in AMPAR EPSCs. Both pep2m and LTD cause changes in quantal size and content without changes in AMPAR single-channel conductance or EPSC kinetics, suggesting an NSF-GluR2-dependent pool of AMPARs is specifically removed during LTD.","method":"Intracellular peptide infusion (pep2m); whole-cell patch clamp; LTD induction; minimal stimulation experiments in hippocampal slices","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 2 / Strong — pharmacological dissection with saturation experiment, multiple electrophysiological readouts, replicated","pmids":["10571232"],"is_preprint":false},{"year":2000,"finding":"Trans-SNARE complexes (SNAREpins) assembled between opposing membranes are functionally resistant to disruption by NSF and alphaSNAP, becoming so at the moment of formation; this resistance allows fusion to proceed despite NSF activity in the surrounding environment that normally dismantles cis-SNARE complexes.","method":"Reconstituted liposome fusion assay with isolated SNARE proteins; NSF/alphaSNAP addition to trans- vs cis-SNARE complexes","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro reconstitution with purified components, direct demonstration of differential NSF sensitivity","pmids":["10831610"],"is_preprint":false},{"year":2001,"finding":"In Saccharomyces cerevisiae, Sec18p (NSF) and SNAREs (including Vti1p) are required for fusion of autophagosomes with the vacuole but are not involved in autophagosome formation itself.","method":"Temperature-shift experiments with sec18 yeast mutant; monitoring of autophagy flux and vacuolar delivery","journal":"Molecular biology of the cell","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic loss-of-function with defined step (formation vs fusion) distinction, single lab","pmids":["11694599"],"is_preprint":false},{"year":2001,"finding":"NSF ATPase activity and alpha-/beta-SNAPs disassemble the AMPA receptor GluR2-PICK1 complex. GluR2, PICK1, NSF, and alpha-/beta-SNAPs form a complex in the presence of ATPgammaS; NSF ATPase disrupts PICK1-GluR2 interactions. Alpha- and beta-SNAP have differential effects, and SNAP overexpression in hippocampal neurons alters AMPAR trafficking by acting on GluR2-PICK1 complexes. This is the first non-SNARE substrate identified for NSF disassembly activity.","method":"In vitro complex assembly with ATPgammaS; ATPase-dependent disassembly assay; SNAP overexpression in cultured neurons with AMPAR trafficking readout","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution of disassembly with ATPase requirement demonstrated, combined with neuronal functional assay","pmids":["11931741"],"is_preprint":false},{"year":2001,"finding":"Ergosterol is required for the Sec18p (NSF)-mediated priming step of homotypic vacuole fusion. Ergosterol ligands (filipin, nystatin, amphotericin B) block in vitro vacuole fusion specifically at the priming stage, inhibiting Sec17p release from vacuoles, and their action is prevented by a reversible delay in Sec18p action.","method":"In vitro vacuole fusion assay; lipid manipulation with ergosterol ligands; genetic deletion of ERG genes; reversible inhibition kinetics","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstituted cell-free fusion with multiple pharmacological and genetic approaches, step-specific dissection","pmids":["11483507"],"is_preprint":false},{"year":2001,"finding":"The ionic layer of the SNARE complex (specifically, the glutamine residue of syntaxin) is required for efficient alpha-SNAP/NSF-mediated disassembly. Mutation of this glutamine allows SNARE complex binding to alpha-SNAP and NSF and ATP hydrolysis but prevents dissociation into SNARE monomers, indicating the ionic layer couples ATP hydrolysis to complex dissociation.","method":"SNARE complex mutagenesis; in vitro NSF disassembly assay with ATPgammaS/ATP; gel-shift analysis","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 / Strong — site-directed mutagenesis with reconstituted in vitro disassembly, mechanistically informative separation of binding from disassembly","pmids":["11762430"],"is_preprint":false},{"year":2001,"finding":"SNARE complex disassembly by NSF follows (rather than precedes) synaptic vesicle fusion in Drosophila. Genetic interaction studies show that blocking evoked fusion delays accumulation of assembled SNARE complexes in comatose mutants. Double comatose/shibire mutants can deplete the entire vesicle pool, demonstrating NSF activity is not required for the fusion step itself.","method":"Drosophila genetic epistasis (comatose × para and comatose × shibire double mutants); behavioral paralysis assay; biochemical SNARE complex accumulation","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis with multiple allele combinations, behavioral and biochemical readouts, mechanistic ordering","pmids":["11593041"],"is_preprint":false},{"year":2002,"finding":"AP2 (clathrin adaptor) associates with GluR2 at a region overlapping the NSF binding site. Dissecting NSF vs AP2 binding with specific GluR2 mutants shows AP2 mediates NMDA-induced (but not ligand-dependent) AMPA receptor internalization and is essential for LTD, while NSF maintains synaptic AMPAR responses but is not required for NMDA receptor-mediated internalization or LTD.","method":"GluR2 mutant constructs dissociating NSF vs AP2 binding; co-immunoprecipitation; receptor internalization assays; hippocampal LTD recordings","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 2 / Strong — specific separation-of-function mutants distinguishing NSF and AP2 roles, multiple orthogonal readouts","pmids":["12441055"],"is_preprint":false},{"year":2002,"finding":"Ablation of NSF binding to GluR2 results in increased AMPA receptor endocytosis in response to AMPA or NMDA compared to wild-type, while loss of GRIP/ABP binding stabilizes an intracellular pool of internalized AMPARs and inhibits recycling, defining distinct roles for NSF (preventing excess endocytosis) vs GRIP/ABP (preventing recycling from intracellular stores).","method":"Epitope-tagged GluR2 mutants lacking NSF or PDZ binding; surface expression assays; endocytosis measurements in neurons","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — domain-specific GluR2 mutants with surface/endocytosis measurements, single lab","pmids":["12011465"],"is_preprint":false},{"year":2002,"finding":"NSF has an ATPase-independent function distinct from SNARE disassembly that is essential for Golgi membrane fusion. The Golgi-reassembly-defective mammalian NSF G274E mutant and Drosophila comatose NSF bind but cannot disassemble SNARE complexes and have almost no ATPase activity, yet retain activity in Golgi reassembly. NSF/alpha-SNAP catalyze binding of GATE-16 to GOS-28 (a Golgi v-SNARE) in an ATP-dependent but hydrolysis-independent manner, protecting the v-SNARE from binding its t-SNARE.","method":"Mammalian NSF mutant characterization; cell-free Golgi reassembly assay; SNARE disassembly assay; GATE-16/GOS-28 binding assay","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstituted cell-free assay with mechanistic separation of ATPase-dependent vs independent functions, replicated with Drosophila comatose mutant","pmids":["12070132"],"is_preprint":false},{"year":2003,"finding":"Dominant-interfering ATP hydrolysis-deficient NSF(E329Q) disrupts Golgi stack structure into dispersed vesicular elements and inhibits intra-Golgi transport (glycosaminoglycan sulfation), while dominant-interfering p97(E578Q) does not affect Golgi structure or function. This establishes that only NSF (not p97) is directly required for Golgi membrane fusion.","method":"Expression of ATP hydrolysis-deficient dominant-negative mutants NSF(E329Q) and p97(E578Q) in mammalian cells; Golgi morphology by immunofluorescence; glycosaminoglycan sulfation assay; VSV-G transport assay","journal":"Molecular biology of the cell","confidence":"High","confidence_rationale":"Tier 2 / Strong — parallel comparison of dominant-negative mutants with multiple pathway readouts, direct mechanistic comparison of NSF vs p97","pmids":["14617820"],"is_preprint":false},{"year":2005,"finding":"NSF and PICK1 are specifically required for calcium-permeable AMPA receptor plasticity (CARP), the dynamic exchange of GluR2-lacking and GluR2-containing receptors at synapses. NSF, but not PICK1, is required for receptor stabilization at synapses; PICK1, but not NSF, regulates formation of extrasynaptic GluR2-containing receptor pools that are laterally mobilized into synapses during CARP.","method":"Dominant-negative NSF and PICK1 interference; GluR2 subunit tracking; electrophysiology; fluorescence imaging in hippocampal neurons","journal":"Neuron","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional dissection of NSF vs PICK1 roles with electrophysiology and imaging, single lab","pmids":["15797551"],"is_preprint":false},{"year":2005,"finding":"NSF interaction with the GluR2 C-terminal domain is necessary and sufficient for rapid direct synaptic insertion of AMPA receptors. Wild-type GluR2 inserts rapidly into plasma membrane from intracellular compartments and accumulates at synaptic sites; a GluR2 mutant defective in NSF binding (DeltaA849-Q853) or GluR3 (which does not interact with NSF) show slower kinetics and initial extrasynaptic insertion. Introducing the NSF-binding site into GluR3 confers GluR2-like kinetics and synaptic targeting.","method":"Cell-surface thrombin cleavage assay; GluR2 mutants and chimeras; live imaging of receptor surface delivery in hippocampal neurons","journal":"Molecular and cellular neurosciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — gain-of-function and loss-of-function with direct surface insertion assay, single lab","pmids":["15797712"],"is_preprint":false},{"year":2005,"finding":"There is a SEC18/NSF-independent protein sorting pathway from the yeast cortical ER to the plasma membrane, mediated by the C-terminal domain of Ist2p. This pathway operates independently of COPII vesicle formation and overrides other sorting signals.","method":"Temperature-sensitive sec18 yeast mutant; chimeric protein constructs; fluorescence microscopy of protein localization","journal":"The Journal of cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic loss-of-function with defined chimeric constructs, negative result regarding NSF requirement is mechanistically informative","pmids":["15911878"],"is_preprint":false},{"year":2006,"finding":"NSF interacts directly with the GABAB receptor (GBR) heterodimer, forming a ternary complex in rat brain synaptosomes and CHO cells regulated by agonist stimulation. NSF functions as a priming factor required for agonist-promoted GBR desensitization independently of receptor internalization: inhibition of NSF binding (via TAT-Pep-27) abolished desensitization and prevented both PKC recruitment and receptor phosphorylation.","method":"Co-immunoprecipitation from synaptosomes and CHO cells; TAT peptide inhibition; Ca2+ mobilization assay; hippocampal slice electrophysiology; PKC recruitment assay","journal":"The EMBO journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP confirmed in native tissue and heterologous cells; functional dissection with peptide, multiple signaling readouts, single lab","pmids":["16724110"],"is_preprint":false},{"year":2006,"finding":"In zebrafish, nsf is required cell-autonomously in neurons for organization of nodes of Ranvier (sodium channel clustering) and myelin basic protein expression, independent of its role in synaptic vesicle fusion. Neural activity and chemical synapse function are not required for sodium channel clustering in the larval nervous system.","method":"Forward genetic screen in zebrafish; chimeric larval analysis (transplantation); pharmacological inhibition of neural activity and synaptic transmission; immunostaining","journal":"Current biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — chimeric transplantation establishing cell autonomy, pharmacological separation of functions, genetic null","pmids":["16581508"],"is_preprint":false},{"year":2009,"finding":"Alpha-SNAP contains a conserved membrane attachment site (an extended loop with two phenylalanine residues in the N-terminal domain) that facilitates NSF-driven disassembly of membrane-bound (but not soluble) SNARE complexes. Mutation of these phenylalanines prevents SNAPs from supporting disassembly of membrane-anchored SNARE complexes.","method":"In vitro SNARE disassembly assay comparing soluble vs membrane-bound substrates; site-directed mutagenesis of alpha-SNAP phenylalanines; liposome binding assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — mutagenesis combined with in vitro reconstitution of disassembly on soluble vs membrane substrates","pmids":["19762473"],"is_preprint":false},{"year":2010,"finding":"NSF-binding site within GluR2 intracellular domain is required for plasma membrane insertion of GluR2-containing AMPA receptors. RNA editing of the Q/R site in the ion channel region also plays a key role in GluR2 plasma membrane insertion. These two structural elements act in the same pathway for GluA2 and heteromeric GluA2/3 receptor delivery.","method":"pHluorin-tagged GluA2 with TIRF microscopy to visualize individual plasma membrane fusion events; GluA2 mutants lacking NSF binding or with Q/R editing changes","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 / Moderate — direct single-vesicle visualization of insertion events with domain-specific mutants","pmids":["20534470"],"is_preprint":false},{"year":2010,"finding":"Polo-like kinase 2 (Plk2), an activity-inducible kinase, directly interacts with NSF through a specific motif (independent of canonical polo box sites), disrupts NSF-GluA2 interaction, promotes loss of surface GluA2, increases GluA2 association with PICK1 and GRIP1, and decreases synaptic AMPAR current. Plk2 engagement of NSF (not Plk2 kinase activity) is required for this homeostatic reduction in surface AMPAR.","method":"Co-immunoprecipitation; pulldown with Plk2 mutants; surface biotinylation; whole-cell patch clamp in hippocampal neurons; dominant-negative and deletion constructs","journal":"Nature neuroscience","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple binding/functional assays, separation-of-function (binding vs kinase activity), electrophysiology","pmids":["20802490"],"is_preprint":false},{"year":2012,"finding":"Cryo-EM structures of NSF hexamer in ATPgammaS, ADP-AlFx, and ADP states reveal parallel arrangement of D1 and D2 domains and nucleotide-dependent conformational changes. The 20S particle structure shows the SNARE complex held at two interaction interfaces around the C-terminus and N-terminal half of the SNARE complex.","method":"Single-particle cryo-EM and negative stain EM; 3D reconstruction of NSF hexamer and 20S particle","journal":"Nature structural & molecular biology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — cryo-EM structural determination of multiple nucleotide states and 20S complex","pmids":["22307055"],"is_preprint":false},{"year":2013,"finding":"NSF-mediated disassembly of all tested SNARE complexes is initiated by a conserved 1:1 interaction between alpha-SNAP and the ternary SNARE complex (not influenced by N-terminal SNARE domains). This 1:1 alpha-SNAP:SNARE complex is confirmed by multiangle light scattering; NSF binding follows.","method":"SNARE-stimulated ATP hydrolysis rate measurements; Michaelis-Menten kinetics; SNAP-SNARE binding constants; multiangle light scattering; four different SNARE complexes tested","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro enzymatic reconstitution with multiple SNARE complexes, quantitative biophysical characterization","pmids":["23836889"],"is_preprint":false},{"year":2015,"finding":"NSF disassembles a single SNARE complex in one round of ATP turnover using a 'spring-loaded' mechanism: upon ATP cleavage, the NSF hexamer develops internal tension with phosphate dissociation, then releases the tension in a burst within 20 ms resulting in SNARE disassembly and immediate release of SNARE proteins.","method":"Single-molecule fluorescence spectroscopy; magnetic tweezers; real-time monitoring of single SNARE complex disassembly","journal":"Science","confidence":"High","confidence_rationale":"Tier 1 / Strong — single-molecule reconstitution with two orthogonal methods (fluorescence and magnetic tweezers), directly demonstrates mechanism","pmids":["25814585"],"is_preprint":false},{"year":2015,"finding":"Sec17 (alpha-SNAP) can trigger fusion of trans-SNARE paired membranes without Sec18 (NSF) by binding to trans-SNARE complexes and inserting apolar loops into apposed membranes; Sec18 does not substitute for Sec17 in this fusion-triggering role. Sec17 thus has two functions: stimulating Sec18-mediated cis-SNARE disassembly and independently triggering trans-SNARE-dependent fusion.","method":"Proteoliposome fusion assay with SNARE proteins; Sec17 and Sec18 mutants (L291A/L292A, F21S/M22S) dissociating the two functions; liposome binding assays","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 separation-of-function mutants, multiple orthogonal assays","pmids":["25902545"],"is_preprint":false},{"year":2016,"finding":"LRRK2 phosphorylates NSF at threonine 645 in the ATP-binding pocket of the D2 domain. NSF phosphorylated by LRRK2 displays enhanced ATPase activity and increased rate of SNARE complex disassembly. Substitution of Thr645 with alanine abrogates LRRK2-mediated increased ATPase activity.","method":"In vitro kinase assay with LRRK2 and full-length NSF; phosphosite mapping; ATPase assay; SNARE complex disassembly assay; alanine substitution mutagenesis","journal":"Molecular neurodegeneration","confidence":"High","confidence_rationale":"Tier 1 / Strong — in vitro kinase assay identifying phosphosite, mutagenesis confirming specificity, two orthogonal functional readouts (ATPase and SNARE disassembly)","pmids":["26758690"],"is_preprint":false},{"year":2017,"finding":"Sec17 (alpha-SNAP) and Sec18 (NSF) act twice in the vacuolar fusion cycle: first binding to trans-SNARE complexes to stimulate fusion (without requiring ATP hydrolysis), and then hydrolyzing ATP to disassemble cis-SNARE complexes. At physiological protein levels, Sec17 stimulates fusion through its central residues binding the 0-layer of the SNARE complex and its N-terminal apolar loop for membrane binding.","method":"Yeast vacuole fusion assay with Sec17 mutants; proteoliposome fusion with asymmetric SNARE arrangement; cis-SNARE disassembly assay; transmembrane-anchored Sec17 chimera","journal":"eLife","confidence":"High","confidence_rationale":"Tier 1 / Strong — reconstituted fusion and disassembly assays with domain-separation mutants and chimeric proteins","pmids":["28718762"],"is_preprint":false},{"year":2018,"finding":"Cryo-EM structure of the 20S supercomplex (NSF/2×alphaSNAP/neuronal SNARE complex) at ~3.9 Å reveals: two alphaSNAP molecules interface with a specific surface of the SNARE complex via electrostatic interactions; 15 N-terminal residues of SNAP-25A are loaded into the D1 ring pore of NSF via spiral interactions between a conserved NSF tyrosine residue and SNAP-25A backbone atoms, preceding ATP hydrolysis.","method":"Electron cryo-microscopy of 20S supercomplex; near-atomic resolution structure determination","journal":"eLife","confidence":"High","confidence_rationale":"Tier 1 / Strong — near-atomic resolution cryo-EM structure with specific contact identification, defining substrate loading mechanism","pmids":["30198481"],"is_preprint":false},{"year":2018,"finding":"NSF disassembles ternary SNARE complexes in a single step within 100 ms; complexin-1 competes with alphaSNAP binding to the SNARE complex, reducing disassembly rate and increasing failed disassembly events, suggesting complexin differentially regulates cis vs trans SNARE complex disassembly. NSF also disassembles anti-parallel SNARE complexes, implicating it in quality control.","method":"Single-molecule FRET assay monitoring repeated rounds of NSF-mediated SNARE complex disassembly and reassembly; complexin-1 competition assay","journal":"eLife","confidence":"High","confidence_rationale":"Tier 1 / Moderate — single-molecule reconstitution with quantitative kinetics, competition assays with complexin","pmids":["29985126"],"is_preprint":false},{"year":2019,"finding":"Formation of trans-SNARE complexes in the presence of NSF-alphaSNAP requires both Munc18-1 and Munc13-1, and is facilitated by synaptotagmin-1. Munc18-1, Munc13-1, complexin-1, and likely synaptotagmin-1 also contribute to maintaining assembled trans-SNARE complexes in the presence of NSF-alphaSNAP, preventing de-priming.","method":"Reconstituted proteoliposome system with defined protein components; SNARE complex formation assays with and without NSF-alphaSNAP; co-flotation and co-sedimentation assays","journal":"eLife","confidence":"High","confidence_rationale":"Tier 1 / Moderate — reconstituted in vitro system with defined components identifying protective factors against NSF-mediated disassembly","pmids":["30657450"],"is_preprint":false}],"current_model":"NSF (SEC18) is a homo-hexameric AAA+ ATPase that functions as a universal SNARE chaperone: together with its adaptor proteins (SNAPs/Sec17p), it recognizes assembled cis-SNARE complexes via a 1:1 alphaSNAP:SNARE interaction that loads the N-terminus of SNAP-25 into its D1 ring pore, then uses a 'spring-loaded' ATP hydrolysis mechanism to disassemble the complex in a single burst within ~20 ms, recycling SNAREs for subsequent fusion rounds; trans-SNARE complexes (SNAREpins) are resistant to NSF disassembly, allowing fusion to proceed, and are protected by accessory factors (Munc18-1, Munc13-1, complexin); beyond SNARE recycling, NSF also directly interacts with non-SNARE substrates including the GluR2 subunit of AMPA receptors (stabilizing their surface expression by disrupting inhibitory GluR2-PICK1 complexes), the GABAB receptor heterodimer (priming agonist-induced desensitization), and beta-arrestin1, and its activity can be post-translationally regulated by LRRK2-mediated phosphorylation at Thr645, which enhances ATPase activity and SNARE disassembly rate."},"narrative":{"mechanistic_narrative":"NSF (yeast SEC18) is a hexameric AAA+ ATPase that serves as the universal engine for recycling SNARE proteins after membrane fusion, originally defined as an essential factor for secretory transport between the ER, Golgi, and cell surface [PMID:3054509, PMID:2071670]. It operates with soluble NSF attachment proteins (alpha-, beta-, gamma-SNAP; yeast Sec17p), which recruit NSF to membranes, bind the SNARE substrate, and stimulate its ATPase activity by lowering the Km of the low-affinity catalytic site, thereby acting as a molecular switch [PMID:2111733, PMID:8455721, PMID:7961908, PMID:9362506]. Structurally, NSF is a hollow nucleotide-stabilized hexamer whose D1 ring engages the assembled cis-SNARE complex within an asymmetric '20S' particle; disassembly is initiated by a conserved 1:1 alpha-SNAP:SNARE interaction, after which the N-terminus of SNAP-25 is loaded into the D1 pore prior to ATP hydrolysis [PMID:9267032, PMID:9624162, PMID:22307055, PMID:23836889, PMID:30198481]. NSF couples ATP hydrolysis to dissociation through the SNARE ionic layer and executes disassembly of a single complex in one 'spring-loaded' burst within ~20 ms [PMID:11762430, PMID:25814585]. This activity recycles SDS-resistant cis-SNARE cores formed by syntaxin/SNAP-25/synaptobrevin [PMID:7588600, PMID:9852562], while trans-SNARE complexes (SNAREpins) become resistant to NSF at the moment of formation, allowing fusion to proceed; this protection is reinforced by Munc18-1, Munc13-1, complexin-1, and synaptotagmin-1 [PMID:10831610, PMID:29985126, PMID:30657450]. Genetic studies in Drosophila and squid place NSF action after vesicle docking, priming docked vesicles for calcium-triggered release rather than catalyzing fusion itself [PMID:9852562, PMID:9852561, PMID:9469810, PMID:11593041]. NSF supports a broad range of fusion events, including Golgi reassembly, basolateral TGN-to-plasma-membrane transport, homotypic vacuole fusion, late endosome-lysosome fusion, and autophagosome-vacuole fusion [PMID:7758111, PMID:7553851, PMID:8670830, PMID:9456319, PMID:11694599]; at the Golgi it additionally has an ATPase-independent function in which NSF/alpha-SNAP catalyze GATE-16 binding to the v-SNARE GOS-28 [PMID:12070132, PMID:14617820]. Beyond SNAREs, NSF directly binds the AMPA receptor GluR2 subunit and, using its ATPase, disassembles the inhibitory GluR2-PICK1 complex to stabilize surface AMPA receptors and maintain synaptic transmission [PMID:9697854, PMID:10399941, PMID:11931741, PMID:12441055]; it also binds beta-arrestin1 to promote receptor internalization and the GABAB receptor heterodimer to prime agonist-induced desensitization [PMID:10196135, PMID:16724110]. NSF activity is post-translationally tuned by LRRK2 phosphorylation at Thr645, which enhances its ATPase rate and SNARE disassembly [PMID:26758690].","teleology":[{"year":1988,"claim":"Established that NSF/SEC18 is an essential, cytoplasmic factor for secretory transport, framing the central question of how a soluble ATPase drives membrane traffic.","evidence":"Gene cloning by complementation and disruption in yeast with subcellular fractionation","pmids":["3054509"],"confidence":"High","gaps":["Molecular substrate of NSF unknown","Mechanism of membrane association undefined"]},{"year":1990,"claim":"Identified SNAP adaptors that bridge NSF to membranes, defining the conserved NSF/SNAP fusion machinery across species.","evidence":"Protein purification from brain cytosol, in vitro Golgi transport assay, yeast sec17 complementation","pmids":["2111733"],"confidence":"High","gaps":["Membrane receptor for the SNAP-NSF complex not yet identified","Catalytic role of NSF ATPase unresolved"]},{"year":1993,"claim":"Showed SNAP isoforms act through membrane-specific SNARE receptors, introducing the concept that fusion specificity is encoded downstream of NSF.","evidence":"cDNA cloning, in vitro Golgi transport, tissue expression analysis","pmids":["8455721"],"confidence":"High","gaps":["Identity of the relevant SNARE receptors at each step incomplete"]},{"year":1994,"claim":"Defined SNAPs as activators that lower NSF's ATPase Km ~100-fold, establishing them as a molecular switch for NSF activity at physiological ATP.","evidence":"In vitro ATPase kinetics with recombinant NSF and SNAPs","pmids":["7961908"],"confidence":"High","gaps":["How ATP hydrolysis is coupled to a downstream conformational event not yet shown"]},{"year":1995,"claim":"Resolved NSF architecture and the 20S complex, showing alpha-SNAP and the SNARE rod bind one end of the NSF cylinder, and identified the SDS-resistant SNARE core as the physiological substrate.","evidence":"Quick-freeze/deep-etch EM with epitope markers; in vitro 20S assembly/disassembly with neurotoxin cleavage","pmids":["9267032","7588600"],"confidence":"High","gaps":["Oligomeric state ambiguous at this stage","Atomic contacts within the 20S particle unresolved"]},{"year":1997,"claim":"Established NSF as a nucleotide-stabilized hexamer and mapped the alpha-SNAP C-terminus as the determinant required to stimulate NSF ATPase and thereby drive SNARE disassembly and exocytosis.","evidence":"Analytical ultracentrifugation and EM; alpha-SNAP truncation/point mutants in ATPase, disassembly, and chromaffin exocytosis assays","pmids":["9624162","9362506","8744944","9325254"],"confidence":"High","gaps":["Whether NSF acts before or after fusion not yet ordered","Non-SNARE substrates not yet considered"]},{"year":1998,"claim":"Genetic and physiological studies in Drosophila and squid placed NSF action downstream of vesicle docking, priming docked vesicles rather than catalyzing fusion.","evidence":"comatose temperature-sensitive mutants with SNARE accumulation, EM, and NMJ electrophysiology; squid presynaptic peptide injection","pmids":["9852562","9852561","9469810"],"confidence":"High","gaps":["Whether SNARE disassembly precedes or follows fusion not definitively ordered until later epistasis"]},{"year":1998,"claim":"Discovered the first non-SNARE NSF partner, the AMPA receptor GluR2 subunit, linking NSF directly to synaptic receptor trafficking and transmission.","evidence":"Direct binding with peptide mapping/mutagenesis; blocking peptide and antibody infusion in CA1 neurons with electrophysiology","pmids":["9697854","9697855"],"confidence":"High","gaps":["Mechanism by which NSF acts on GluR2 (disassembly of what complex) unknown at this point"]},{"year":1998,"claim":"Extended NSF requirement to homotypic vacuole fusion and late endosome-lysosome fusion as direct fusion events, defining an ordered priming reaction coupled to t-SNARE stabilization via LMA1.","evidence":"Cell-free vacuole and endosome-lysosome fusion assays with purified Sec18p, antibodies, and LMA1 transfer experiments","pmids":["8670830","9015301","9657146","9456319"],"confidence":"High","gaps":["Lipid and cofactor requirements of priming not fully mapped"]},{"year":1999,"claim":"Demonstrated NSF-GluR2 interaction maintains surface AMPA receptors and is required for LTD-related receptor pools, and identified beta-arrestin1 as an ATP-state-dependent NSF partner in receptor internalization.","evidence":"Blocking peptide/viral pep2m in neurons with electrophysiology and surface immunostaining; yeast two-hybrid, co-IP, and HEK293 internalization assays","pmids":["10399941","10571232","10196135"],"confidence":"High","gaps":["Molecular substrate of the NSF-GluR2 reaction still undefined","beta-arrestin1 finding is Co-IP/two-hybrid without mechanistic dissection"]},{"year":2000,"claim":"Resolved how fusion proceeds despite NSF: trans-SNARE complexes become NSF-resistant at the moment of formation, while cis-SNARE complexes are dismantled.","evidence":"Reconstituted liposome fusion with NSF/alphaSNAP applied to trans- vs cis-SNARE complexes","pmids":["10831610"],"confidence":"High","gaps":["Factors actively protecting trans-SNARE complexes not yet identified"]},{"year":2001,"claim":"Identified the GluR2-PICK1 complex as the first non-SNARE substrate of NSF's ATPase-driven disassembly and established the ionic layer as the coupling element for disassembly.","evidence":"In vitro ATPgammaS/ATP disassembly assays with GluR2-PICK1 and SNARE ionic-layer mutants; SNAP overexpression in neurons","pmids":["11931741","11762430","11483507","11593041"],"confidence":"High","gaps":["How NSF discriminates SNARE vs non-SNARE substrates unresolved"]},{"year":2002,"claim":"Revealed an ATPase-independent NSF function essential for Golgi membrane fusion and separated NSF-dependent receptor stabilization from AP2-dependent internalization in synaptic plasticity.","evidence":"G274E/comatose NSF mutants in Golgi reassembly and GATE-16/GOS-28 binding; GluR2 separation-of-function mutants in internalization and LTD assays","pmids":["12070132","12441055","12011465"],"confidence":"High","gaps":["Structural basis of the ATPase-independent Golgi activity unknown"]},{"year":2003,"claim":"Distinguished NSF from the related ATPase p97 as the factor directly required for Golgi membrane fusion in cells.","evidence":"Dominant-negative NSF(E329Q) vs p97(E578Q) expression with Golgi morphology and transport readouts","pmids":["14617820"],"confidence":"High","gaps":["Division of labor between NSF and p97 at other organelles not addressed"]},{"year":2006,"claim":"Expanded NSF's direct receptor partnerships to the GABAB receptor heterodimer and showed a cell-autonomous neuronal role in node-of-Ranvier organization independent of synaptic vesicle fusion.","evidence":"Co-IP from synaptosomes/CHO cells with TAT-peptide inhibition and signaling readouts; zebrafish forward genetics with chimeric transplantation","pmids":["16724110","16581508"],"confidence":"Medium","gaps":["GABAB finding from single lab without structural definition of interaction","Mechanism linking NSF to sodium channel clustering unknown"]},{"year":2009,"claim":"Mapped a membrane-attachment loop in alpha-SNAP required specifically for disassembly of membrane-bound SNARE complexes, connecting SNAP membrane contact to NSF function.","evidence":"In vitro disassembly comparing soluble vs membrane-bound SNAREs with alpha-SNAP phenylalanine mutants","pmids":["19762473"],"confidence":"High","gaps":["Contribution of this loop to in vivo fusion cycles not directly tested here"]},{"year":2013,"claim":"Defined the universal initiation step of disassembly as a conserved 1:1 alpha-SNAP:SNARE interaction independent of N-terminal SNARE domains, with NSF binding thereafter.","evidence":"Kinetic and multiangle light scattering analysis across four SNARE complexes","pmids":["23836889"],"confidence":"High","gaps":["Stoichiometry of alpha-SNAP in the active 20S particle later revised to two"]},{"year":2015,"claim":"Established the kinetic mechanism (single-complex disassembly in one spring-loaded burst within 20 ms) and uncovered a SNARE-disassembly-independent role for Sec17 in directly triggering trans-SNARE fusion.","evidence":"Single-molecule fluorescence and magnetic tweezers; proteoliposome fusion with Sec17/Sec18 separation-of-function mutants","pmids":["25814585","25902545"],"confidence":"High","gaps":["Atomic-resolution view of substrate loading still pending"]},{"year":2016,"claim":"Identified LRRK2 phosphorylation of NSF at Thr645 as a post-translational regulator that enhances ATPase activity and SNARE disassembly rate.","evidence":"In vitro kinase assay, phosphosite mapping, T645A mutagenesis, ATPase and disassembly assays","pmids":["26758690"],"confidence":"High","gaps":["Physiological/in vivo consequence of NSF Thr645 phosphorylation not established"]},{"year":2018,"claim":"Near-atomic cryo-EM of the 20S supercomplex resolved two alpha-SNAP molecules contacting the SNARE complex and the SNAP-25A N-terminus loaded into the D1 pore before hydrolysis, defining the substrate-engagement mechanism; single-molecule work showed complexin competes with alpha-SNAP and NSF can disassemble anti-parallel complexes for quality control.","evidence":"Cryo-EM of the 20S supercomplex at ~3.9 A; single-molecule FRET with complexin-1 competition","pmids":["30198481","29985126"],"confidence":"High","gaps":["Dynamics of pore translocation during the hydrolysis burst not fully captured"]},{"year":2019,"claim":"Identified the accessory factors (Munc18-1, Munc13-1, complexin-1, synaptotagmin-1) that build and protect trans-SNARE complexes against NSF-alphaSNAP de-priming, integrating NSF into the priming/fusion cycle.","evidence":"Reconstituted proteoliposome system with defined components, co-flotation/co-sedimentation assays","pmids":["30657450"],"confidence":"High","gaps":["Quantitative competition between protection and NSF disassembly in vivo unresolved"]},{"year":null,"claim":"How NSF achieves substrate selectivity between SNARE and diverse non-SNARE targets, and how its phosphoregulation and accessory-factor protection are integrated in vivo, remains open.","evidence":"No single experiment in the corpus resolves substrate discrimination across SNARE and non-SNARE clients","pmids":[],"confidence":"Medium","gaps":["No unified model for substrate recognition across SNARE and non-SNARE clients","In vivo regulatory role of LRRK2 phosphorylation undefined","Structural basis of ATPase-independent Golgi function unknown"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140657","term_label":"ATP-dependent activity","supporting_discovery_ids":[5,14,49,51]},{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[5,33,49]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[10,31,33,37]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[18,31,42]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0,1]},{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[1,7,37,38]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[6,20,26]},{"term_id":"GO:0005773","term_label":"vacuole","supporting_discovery_ids":[11,16,32]}],"pathway":[{"term_id":"R-HSA-5653656","term_label":"Vesicle-mediated transport","supporting_discovery_ids":[0,2,6,7]},{"term_id":"R-HSA-9609507","term_label":"Protein localization","supporting_discovery_ids":[2,6]},{"term_id":"R-HSA-112316","term_label":"Neuronal System","supporting_discovery_ids":[20,21,26,28]},{"term_id":"R-HSA-9612973","term_label":"Autophagy","supporting_discovery_ids":[30]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[25,42]}],"complexes":["20S SNARE disassembly complex (NSF/alphaSNAP/SNARE)","NSF homohexamer"],"partners":["NAPA","GRIA2","PICK1","ARRB1","GABBR1","LRRK2","PLK2","STX5"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P46459","full_name":"Vesicle-fusing ATPase","aliases":["N-ethylmaleimide-sensitive fusion protein","NEM-sensitive fusion protein","Vesicular-fusion protein NSF"],"length_aa":744,"mass_kda":82.6,"function":"Required for vesicle-mediated transport. Catalyzes the fusion of transport vesicles within the Golgi cisternae. Is also required for transport from the endoplasmic reticulum to the Golgi stack. Seems to function as a fusion protein required for the delivery of cargo proteins to all compartments of the Golgi stack independent of vesicle origin. Interaction with AMPAR subunit GRIA2 leads to influence GRIA2 membrane cycling (By similarity)","subcellular_location":"Cytoplasm","url":"https://www.uniprot.org/uniprotkb/P46459/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":true,"resolved_as":"","url":"https://depmap.org/portal/gene/NSF","classification":"Common Essential","n_dependent_lines":1208,"n_total_lines":1208,"dependency_fraction":1.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"BET1L","stoichiometry":10.0},{"gene":"BNIP1","stoichiometry":10.0},{"gene":"GOLT1B","stoichiometry":10.0},{"gene":"GOSR1","stoichiometry":10.0},{"gene":"GOSR2","stoichiometry":10.0},{"gene":"NAPA","stoichiometry":10.0},{"gene":"SCAMP2","stoichiometry":10.0},{"gene":"STX18","stoichiometry":10.0},{"gene":"STX5","stoichiometry":10.0},{"gene":"VTI1A","stoichiometry":10.0}],"url":"https://opencell.sf.czbiohub.org/search/NSF","total_profiled":1310},"omim":[{"mim_id":"620033","title":"DEVELOPMENTAL AND EPILEPTIC ENCEPHALOPATHY 107; DEE107","url":"https://www.omim.org/entry/620033"},{"mim_id":"619340","title":"DEVELOPMENTAL AND EPILEPTIC ENCEPHALOPATHY 96; DEE96","url":"https://www.omim.org/entry/619340"},{"mim_id":"615417","title":"BET1-LIKE PROTEIN; BET1L","url":"https://www.omim.org/entry/615417"},{"mim_id":"612679","title":"CUGBP- AND ELAV-LIKE FAMILY, MEMBER 4; CELF4","url":"https://www.omim.org/entry/612679"},{"mim_id":"611745","title":"VCP/p47 COMPLEX-INTERACTING PROTEIN 1;   VCPIP1","url":"https://www.omim.org/entry/611745"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Golgi apparatus","reliability":"Supported"},{"location":"Cytosol","reliability":"Supported"},{"location":"Acrosome","reliability":"Additional"},{"location":"Equatorial segment","reliability":"Additional"},{"location":"Mid piece","reliability":"Additional"},{"location":"Principal piece","reliability":"Additional"},{"location":"End piece","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"brain","ntpm":145.0}],"url":"https://www.proteinatlas.org/search/NSF"},"hgnc":{"alias_symbol":["SKD2","SEC18"],"prev_symbol":[]},"alphafold":{"accession":"P46459","domains":[{"cath_id":"2.40.40.20","chopping":"3-82","consensus_level":"medium","plddt":89.7531,"start":3,"end":82},{"cath_id":"3.10.330.10","chopping":"91-195","consensus_level":"medium","plddt":84.6335,"start":91,"end":195},{"cath_id":"3.40.50.300","chopping":"214-393","consensus_level":"medium","plddt":83.3078,"start":214,"end":393},{"cath_id":"1.10.8.60","chopping":"399-486","consensus_level":"medium","plddt":84.8018,"start":399,"end":486},{"cath_id":"3.40.50.300","chopping":"495-665","consensus_level":"high","plddt":90.9556,"start":495,"end":665},{"cath_id":"1.10.8.60","chopping":"669-736","consensus_level":"high","plddt":90.339,"start":669,"end":736}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P46459","model_url":"https://alphafold.ebi.ac.uk/files/AF-P46459-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P46459-F1-predicted_aligned_error_v6.png","plddt_mean":85.62},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=NSF","jax_strain_url":"https://www.jax.org/strain/search?query=NSF"},"sequence":{"accession":"P46459","fasta_url":"https://rest.uniprot.org/uniprotkb/P46459.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P46459/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P46459"}},"corpus_meta":[{"pmid":"9267032","id":"PMC_9267032","title":"Structure 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neurosciences","url":"https://pubmed.ncbi.nlm.nih.gov/15797712","citation_count":37,"is_preprint":false},{"pmid":"9378758","id":"PMC_9378758","title":"NSF is required for transport from early to late endosomes.","date":"1997","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/9378758","citation_count":37,"is_preprint":false},{"pmid":"23836889","id":"PMC_23836889","title":"Disassembly of all SNARE complexes by N-ethylmaleimide-sensitive factor (NSF) is initiated by a conserved 1:1 interaction between α-soluble NSF attachment protein (SNAP) and SNARE complex.","date":"2013","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/23836889","citation_count":37,"is_preprint":false},{"pmid":"7730397","id":"PMC_7730397","title":"Reconstitution of vesiculated Golgi membranes into stacks of cisternae: requirement of NSF in stack formation.","date":"1995","source":"The Journal of cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/7730397","citation_count":37,"is_preprint":false},{"pmid":"22073277","id":"PMC_22073277","title":"Both pre- and postsynaptic activity of Nsf prevents degeneration of hair-cell synapses.","date":"2011","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/22073277","citation_count":35,"is_preprint":false},{"pmid":"9325254","id":"PMC_9325254","title":"N-Ethylmaleimide-sensitive factor (NSF) and alpha-soluble NSF attachment proteins (SNAP) mediate dissociation of GS28-syntaxin 5 Golgi SNAP receptors (SNARE) complex.","date":"1997","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/9325254","citation_count":34,"is_preprint":false},{"pmid":"24603302","id":"PMC_24603302","title":"NSF workshop report: discovering general principles of nervous system organization by comparing brain maps across species.","date":"2014","source":"Brain, behavior and evolution","url":"https://pubmed.ncbi.nlm.nih.gov/24603302","citation_count":34,"is_preprint":false},{"pmid":"12244131","id":"PMC_12244131","title":"NSF regulates membrane traffic along multiple pathways in Paramecium.","date":"2002","source":"Journal of cell science","url":"https://pubmed.ncbi.nlm.nih.gov/12244131","citation_count":33,"is_preprint":false},{"pmid":"28747507","id":"PMC_28747507","title":"Roles of Cellular NSF Protein in Entry and Nuclear Egress of Budded Virions of Autographa californica Multiple Nucleopolyhedrovirus.","date":"2017","source":"Journal of virology","url":"https://pubmed.ncbi.nlm.nih.gov/28747507","citation_count":32,"is_preprint":false},{"pmid":"2005096","id":"PMC_2005096","title":"Structure of Saccharomyces cerevisiae alg3, sec18 mutant oligosaccharides.","date":"1991","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/2005096","citation_count":32,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":43350,"output_tokens":13894,"usd":0.16923,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":26141,"output_tokens":6503,"usd":0.14664,"stage2_stop_reason":"end_turn"},"total_usd":0.31587,"stage1_batch_id":"msgbatch_013a8chtv3AWyTqv4z4sEF4C","stage2_batch_id":"msgbatch_01AHsuW63vinsvuTgzmQ3n62","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1988,\n      \"finding\": \"SEC18 (yeast NSF) is essential for yeast cell growth and is required for secretory protein transport between the ER and Golgi complex. The protein is hydrophilic, lacks signal sequence or transmembrane anchor, resides in the cytoplasm, and associates transiently with a 100,000 x g pellet fraction consistent with small vesicles.\",\n      \"method\": \"Gene cloning by complementation, gene disruption, subcellular fractionation, in vitro transcription/translation\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — gene disruption with growth phenotype, biochemical fractionation, replicated in subsequent studies\",\n      \"pmids\": [\"3054509\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1990,\n      \"finding\": \"Three soluble NSF attachment proteins (alpha-, beta-, gamma-SNAP) were purified from bovine brain cytosol and shown to bind NSF to Golgi membranes, forming a SNAP-NSF-membrane complex required for the membrane fusion stage of intra-Golgi transport. Yeast SEC17 encodes a functional homolog of alpha-SNAP, establishing evolutionary conservation of the NSF/SNAP fusion mechanism.\",\n      \"method\": \"Protein purification, in vitro Golgi transport assay, complementation with yeast sec17 mutant cytosol\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstituted in vitro transport, purified components, cross-species complementation, replicated widely\",\n      \"pmids\": [\"2111733\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1991,\n      \"finding\": \"Yeast Sec18p/NSF function is required sequentially for protein transport from the ER to the Golgi, through multiple Golgi compartments, and from the Golgi to the cell surface, defining at least three functionally distinct Golgi compartments.\",\n      \"method\": \"Temperature-shift experiments with sec18 and sec23 yeast mutants tracking transport of alpha-factor and CPY biosynthetic intermediates\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic loss-of-function with defined transport phenotypes at multiple pathway steps, replicated with multiple substrates\",\n      \"pmids\": [\"2071670\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1992,\n      \"finding\": \"NSF and alpha-SNAP are required during the formation of functional transport vesicles from Golgi membranes, not only at the attachment/fusion step; after vesicle formation, the NEM-sensitive function of NSF is no longer required.\",\n      \"method\": \"Cell-free Golgi transport assay measuring functional vesicle formation; immunodepletion of NSF/SNAP\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — cell-free reconstitution assay, single lab, dissection of step-specific requirements\",\n      \"pmids\": [\"1522110\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1993,\n      \"finding\": \"Alpha- and gamma-SNAP are ubiquitously expressed and act synergistically in intra-Golgi transport; beta-SNAP is a brain-specific isoform of alpha-SNAP. SNAPs enable NSF to bind to target membranes, and their action at specific fusion sites is controlled by SNARE receptors particular to the membranes being fused.\",\n      \"method\": \"cDNA cloning, in vitro Golgi transport assay, tissue expression analysis\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — biochemical reconstitution, cloning with functional assay, replicated across labs\",\n      \"pmids\": [\"8455721\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"NSF ATPase activity is regulated by alpha- and gamma-SNAPs. Immobilized (but not soluble) SNAPs enhance NSF ATPase activity in a dose-dependent manner, primarily by decreasing the Km of the low-affinity ATPase site ~100-fold, thereby acting as a molecular switch to activate NSF at physiological ATP concentrations.\",\n      \"method\": \"In vitro ATPase assay with recombinant His6-tagged NSF and SNAPs; enzyme kinetics analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro enzymatic assay with purified recombinant proteins, kinetic analysis of both ATPase domains\",\n      \"pmids\": [\"7961908\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"NSF mediates basolateral (but not apical) transport from the trans-Golgi network to the plasma membrane in MDCK epithelial cells. Anti-NSF antibodies and alpha-SNAP inhibit/stimulate basolateral transport, while apical transport is insensitive to NSF, Rab-GDI, and neurotoxins.\",\n      \"method\": \"In vitro transport assay with streptolysin O-permeabilized MDCK cells; anti-NSF antibodies; toxin inhibition\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal inhibitors (antibody, alpha-SNAP, neurotoxins, Rab-GDI) in cell-free system, single lab\",\n      \"pmids\": [\"7758111\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"NSF together with SNAPs and p115 (a vesicle docking protein) restores cisternal regrowth from mitotic Golgi fragments in a cell-free system, while p97 (an NSF-like ATPase) also restores regrowth but produces morphologically distinct cisternae, indicating distinct roles in rebuilding Golgi after mitosis.\",\n      \"method\": \"Cell-free Golgi reassembly assay; NEM or salt-washing inhibition; reconstitution with purified proteins\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — cell-free reconstitution with purified proteins, morphological readout, comparison of NSF vs p97\",\n      \"pmids\": [\"7553851\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"Alpha- and gamma-SNAP stimulate Ca2+-dependent exocytosis in digitonin-permeabilized chromaffin cells. Recombinant NSF alone was ineffective, but ~1/3 of cellular NSF is in a non-cytosolic form sufficient for exocytosis. The stimulatory effect of alpha-SNAP requires Ca2+, MgATP, and is blocked by NEM and botulinum A toxin.\",\n      \"method\": \"Permeabilized chromaffin cell exocytosis assay; recombinant protein addition; inhibitor analysis\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional exocytosis assay with recombinant proteins and multiple inhibitors, single lab\",\n      \"pmids\": [\"7835334\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"NSF is a hollow 10×16 nm cylindrical oligomeric ATPase. Without nucleotide, NSF adopts a 'splayed' protease-sensitive conformation revealing its subunit composition. The ternary SNARE complex (syntaxin/SNAP-25/synaptobrevin) forms a 4×14 nm rod with syntaxin and synaptobrevin aligned in parallel with membrane anchors at the same end. Alpha-SNAP and the SNARE rod bind to one end of the NSF cylinder forming an asymmetric '20S' complex.\",\n      \"method\": \"Quick-freeze/deep-etch electron microscopy; epitope tags; antibody and maltose-binding protein markers on recombinant proteins\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct structural visualization by EM, multiple orthogonal markers, highly replicated\",\n      \"pmids\": [\"9267032\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"A clostridial neurotoxin-sensitive SDS-resistant SNARE core (synaptobrevin/syntaxin/SNAP-25) is the physiological target for NSF-mediated ATP-dependent disassembly in the presence of SNAP. Cleavage of synaptobrevin or SNAP-25 by neurotoxins does not prevent 20S complex assembly but compromises the stability of the SDS-resistant SNARE core.\",\n      \"method\": \"In vitro 20S complex assembly/disassembly assay; clostridial neurotoxin cleavage; gel shift analysis\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with defined protein components and enzymatic perturbation\",\n      \"pmids\": [\"7588600\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"NSF is required for homotypic vacuole fusion in vitro. Using purified recombinant Sec18p (NSF) and affinity-purified anti-Sec17p (alpha-SNAP) antibodies, both Sec17p and Sec18p are shown to be essential for the homotypic fusion step of vacuole inheritance. Vacuole-to-vacuole fusion is also stimulated by certain fatty acyl-CoA compounds in a Sec18p-dependent manner.\",\n      \"method\": \"Cell-free vacuole inheritance assay; purified recombinant proteins; affinity-purified antibodies\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstituted cell-free fusion with purified components, reciprocal inhibition experiments\",\n      \"pmids\": [\"8670830\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"C-terminal deletion of alpha-SNAP abolishes NSF binding, while N-terminal deletions (up to 120 residues) do not prevent NSF binding or ATPase stimulation. Both N- and C-terminal domains of alpha-SNAP are required for syntaxin binding and exocytosis stimulation, placing NSF and syntaxin in proximity through alpha-SNAP.\",\n      \"method\": \"Alpha-SNAP deletion mutant analysis; NSF ATPase assay; permeabilized chromaffin cell exocytosis assay\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — systematic mutagenesis combined with functional ATPase and exocytosis assays\",\n      \"pmids\": [\"8744944\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"NSF requires the C-terminal region of alpha-SNAP for ATPase stimulation: deletion of as few as 10 C-terminal residues markedly decreases ATPase stimulation; mutation of conserved leucine 294 to alanine (L294A) reduces ATPase stimulation without affecting NSF binding. Alpha-SNAP mutants defective in stimulating NSF ATPase fail to disassemble the 20S complex or stimulate exocytosis, demonstrating that alpha-SNAP-stimulated NSF ATPase activity is required for SNARE complex disassembly and exocytosis.\",\n      \"method\": \"Alpha-SNAP truncation and point mutants; in vitro ATPase assay; 20S complex disassembly assay; permeabilized chromaffin cell exocytosis assay\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — mutagenesis combined with three orthogonal functional assays (ATPase, SNARE disassembly, exocytosis)\",\n      \"pmids\": [\"9362506\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"NSF is a hexamer (not tetramer or trimer) in the presence of nucleotide, stabilized by D2 domain oligomerization. The sedimentation coefficient is 13.4 S, and the unusual hydrodynamic properties cannot be explained by shape alone.\",\n      \"method\": \"Sedimentation equilibrium and velocity analytical ultracentrifugation; transmission EM with rotational image analysis; scanning transmission EM; multiangle light scattering\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — multiple independent biophysical methods (AUC, two EM approaches, light scattering) in one study\",\n      \"pmids\": [\"9624162\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"NSF and alpha-SNAP mediate dissociation of the Golgi SNARE complex containing GS28 and syntaxin 5. ATP hydrolysis by NSF is required; neither alpha-SNAP nor NSF alone dissociates the complex. Upon dissociation, GS28 (but not syntaxin 5) binds immobilized alpha-SNAP.\",\n      \"method\": \"Coimmunoprecipitation of endogenous Golgi proteins; in vitro disassembly assay with ATP/ATPgammaS; pulldown with immobilized alpha-SNAP\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with ATP hydrolysis requirement established by ATPgammaS control\",\n      \"pmids\": [\"9325254\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"LMA1 (a heterodimer of thioredoxin and IB2) requires Sec18p (NSF) for high-affinity binding to vacuoles. The Sec18p 'priming' ATPase requires both Sec17p and LMA1. Upon Sec18p ATP hydrolysis, LMA1 transfers to and stabilizes the Vam3p (t-SNARE) complex, coupling priming to t-SNARE stabilization.\",\n      \"method\": \"Cell-free vacuole fusion assay; genetic synthetic lethality; subcellular fractionation; biochemical binding assays\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstituted cell-free fusion, genetics, and biochemistry defining ordered mechanism\",\n      \"pmids\": [\"9015301\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"Sec18p (NSF) is required for a novel complex at the Golgi-to-endosome (VPS) transport step in yeast. Pep12p (endosomal t-SNARE) affinity chromatography identified Vac1p, Vps45p, and Sec18p as binding partners; sec18-1 combined with overexpression of a dominant pep12 allele caused synthetic growth defects rescued by deletion of PEP12 or VAC1.\",\n      \"method\": \"Affinity chromatography (Pep12p-sepharose); genetic epistasis; temperature-sensitive mutant analysis; subcellular fractionation\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — biochemical pulldown combined with genetic epistasis and suppressor analysis\",\n      \"pmids\": [\"9201718\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"NSF interacts directly and selectively with the intracellular C-terminal domain of the AMPA receptor GluR2 subunit (residues Lys-844–Gln-853, with Asn-851 critical), requiring all three domains of NSF. Loading blocking decapeptides corresponding to the NSF-binding domain of GluR2, or an anti-NSF antibody, into CA1 neurons progressively decremented AMPA receptor-mediated synaptic transmission.\",\n      \"method\": \"Direct binding assay, peptide mapping with mutagenesis, intracellular infusion of blocking peptides and antibody in hippocampal CA1 neurons, electrophysiology\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — direct binding with domain mapping, two independent inhibition approaches (peptide and antibody) with electrophysiology, replicated across labs\",\n      \"pmids\": [\"9697854\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"GluR2 C-terminal peptide forms an ATP hydrolysis-reversible complex with NSF and alpha-/beta-SNAPs, resembling the SNARE-NSF-SNAP complex assembly. The molar ratio of NSF to SNAP in the GluR2-NSF-SNAP complex is similar to that in the t-SNARE syntaxin-NSF-SNAP complex.\",\n      \"method\": \"Pulldown assay with GluR2 C-terminal peptide; co-immunoprecipitation; immunofluorescence colocalization; ATPgammaS/ATP comparison\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — biochemical reconstitution of complex, multiple methods, replicated in same year by another lab\",\n      \"pmids\": [\"9697855\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"In the Drosophila comatose (dNSF-1) mutant, an SDS-resistant neural SNARE complex (syntaxin/n-synaptobrevin/SNAP-25) accumulates at restrictive temperature, predominantly in plasma membrane and docked synaptic vesicle fractions. This establishes that NSF functions to disassemble or rearrange SNARE complexes after vesicle docking to maintain the readily releasable pool.\",\n      \"method\": \"SDS-PAGE of SNARE complexes in Drosophila NSF temperature-sensitive mutant; subcellular fractionation; electrophysiology\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vivo genetic model with biochemical readout (SNARE complex accumulation) and electrophysiology, replicated\",\n      \"pmids\": [\"9852562\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"NSF functions in Drosophila neuromuscular synapses downstream of vesicle docking to prime docked vesicles for calcium-triggered fusion. In comatose (dNSF-1) mutants at restrictive temperature, progressive activity-dependent reduction in neurotransmitter release occurs with marked accumulation of docked vesicles, indicating NSF does not directly catalyze fusion but maintains the pool of fusion-competent vesicles.\",\n      \"method\": \"Electrophysiology at adult Drosophila neuromuscular junctions; transmission electron microscopy; temperature-sensitive comatose mutant analysis\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — in vivo functional analysis with electrophysiology and ultrastructure, replicated across two concurrent papers\",\n      \"pmids\": [\"9852561\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Injection of peptides inhibiting alpha-SNAP-stimulated NSF ATPase activity into the giant squid presynaptic terminal reduces the amount and slows the kinetics of neurotransmitter release, acting at a step subsequent to vesicle docking and requiring vesicle turnover.\",\n      \"method\": \"Peptide injection into squid giant presynaptic terminal; electrophysiology\",\n      \"journal\": \"Science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct presynaptic injection with quantitative electrophysiology, defined mechanism\",\n      \"pmids\": [\"9469810\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"LMA1 binds to vacuoles in a Sec18p-dependent manner, and Sec18p priming ATPase requires both Sec17p and LMA1. Upon Sec18p ATP hydrolysis, LMA1 transfers to a Vam3p (t-SNARE) complex and is later released in a phosphatase-regulated step, coupling the priming reaction to t-SNARE stabilization.\",\n      \"method\": \"Cell-free vacuole fusion assay; protein-membrane binding assays; mutant analysis\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstituted cell-free system with ordered biochemical steps, genetic validation\",\n      \"pmids\": [\"9657146\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Late endosome-lysosome fusion is an NSF-dependent direct fusion event (not vesicular transport) that also requires a Rab GTPase. Hybrid organelles formed by this fusion can be isolated from rat liver homogenates confirming the reaction occurs in vivo.\",\n      \"method\": \"Cell-free content mixing assay with rat liver endosomes and lysosomes; NEM inhibition; GDP-dissociation inhibitor; density gradient fractionation; immunoEM\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — cell-free reconstitution with inhibitors, morphological and biochemical characterization, in vivo confirmation by direct isolation\",\n      \"pmids\": [\"9456319\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"NSF identifies beta-arrestin1 as a binding partner (identified by yeast two-hybrid, confirmed by in vitro binding and co-immunoprecipitation). Beta-arrestin1 preferentially interacts with the ATP-bound form of NSF. NSF overexpression enhances agonist-mediated beta2-adrenergic receptor internalization and rescues dominant-negative beta-arrestin1-mediated inhibition of internalization.\",\n      \"method\": \"Yeast two-hybrid screen; in vitro binding of purified recombinant proteins; co-immunoprecipitation; overexpression in HEK293 cells; receptor internalization assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — yeast two-hybrid confirmed by co-IP and in vitro binding; functional overexpression without mechanistic dissection\",\n      \"pmids\": [\"10196135\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Disruption of NSF-GluR2 interaction by infusion of blocking peptide (pep2m) into cultured hippocampal neurons reduces surface expression of GluR2-containing AMPA receptors (shown by reduced mEPSC frequency and reduced surface GluR2 immunostaining) without changing total GluR2. NMDA receptor surface expression is unaffected.\",\n      \"method\": \"Blocking peptide infusion into cultured hippocampal neurons; whole-cell patch-clamp; immunostaining with surface vs. total GluR2 comparison; viral expression of pep2m\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — two independent inhibition methods (peptide infusion, viral expression), multiple readouts (electrophysiology, immunostaining), selective effect on AMPA vs NMDA receptors\",\n      \"pmids\": [\"10399941\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Alpha-SNAP and NSF are required at an early priming step in chromaffin cell exocytosis before release of readily releasable vesicles. Alpha-SNAP increases the amplitude of both the exocytotic burst and the slow secretion component without changing fusion kinetics, while NEM only partially inhibits the slow component without altering the exocytotic burst.\",\n      \"method\": \"Flash photolysis of caged Ca2+ combined with high-time-resolution capacitance measurement and amperometry; alpha-SNAP and NEM treatments\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — high-resolution kinetic analysis with multiple approaches, defined step-specific requirements\",\n      \"pmids\": [\"10369670\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Blockade of NSF-GluR2 interaction prevents homosynaptic LTD in hippocampal CA1 region. Saturation of LTD prevents pep2m-induced reduction in AMPAR EPSCs. Both pep2m and LTD cause changes in quantal size and content without changes in AMPAR single-channel conductance or EPSC kinetics, suggesting an NSF-GluR2-dependent pool of AMPARs is specifically removed during LTD.\",\n      \"method\": \"Intracellular peptide infusion (pep2m); whole-cell patch clamp; LTD induction; minimal stimulation experiments in hippocampal slices\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — pharmacological dissection with saturation experiment, multiple electrophysiological readouts, replicated\",\n      \"pmids\": [\"10571232\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Trans-SNARE complexes (SNAREpins) assembled between opposing membranes are functionally resistant to disruption by NSF and alphaSNAP, becoming so at the moment of formation; this resistance allows fusion to proceed despite NSF activity in the surrounding environment that normally dismantles cis-SNARE complexes.\",\n      \"method\": \"Reconstituted liposome fusion assay with isolated SNARE proteins; NSF/alphaSNAP addition to trans- vs cis-SNARE complexes\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro reconstitution with purified components, direct demonstration of differential NSF sensitivity\",\n      \"pmids\": [\"10831610\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"In Saccharomyces cerevisiae, Sec18p (NSF) and SNAREs (including Vti1p) are required for fusion of autophagosomes with the vacuole but are not involved in autophagosome formation itself.\",\n      \"method\": \"Temperature-shift experiments with sec18 yeast mutant; monitoring of autophagy flux and vacuolar delivery\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic loss-of-function with defined step (formation vs fusion) distinction, single lab\",\n      \"pmids\": [\"11694599\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"NSF ATPase activity and alpha-/beta-SNAPs disassemble the AMPA receptor GluR2-PICK1 complex. GluR2, PICK1, NSF, and alpha-/beta-SNAPs form a complex in the presence of ATPgammaS; NSF ATPase disrupts PICK1-GluR2 interactions. Alpha- and beta-SNAP have differential effects, and SNAP overexpression in hippocampal neurons alters AMPAR trafficking by acting on GluR2-PICK1 complexes. This is the first non-SNARE substrate identified for NSF disassembly activity.\",\n      \"method\": \"In vitro complex assembly with ATPgammaS; ATPase-dependent disassembly assay; SNAP overexpression in cultured neurons with AMPAR trafficking readout\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution of disassembly with ATPase requirement demonstrated, combined with neuronal functional assay\",\n      \"pmids\": [\"11931741\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Ergosterol is required for the Sec18p (NSF)-mediated priming step of homotypic vacuole fusion. Ergosterol ligands (filipin, nystatin, amphotericin B) block in vitro vacuole fusion specifically at the priming stage, inhibiting Sec17p release from vacuoles, and their action is prevented by a reversible delay in Sec18p action.\",\n      \"method\": \"In vitro vacuole fusion assay; lipid manipulation with ergosterol ligands; genetic deletion of ERG genes; reversible inhibition kinetics\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstituted cell-free fusion with multiple pharmacological and genetic approaches, step-specific dissection\",\n      \"pmids\": [\"11483507\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"The ionic layer of the SNARE complex (specifically, the glutamine residue of syntaxin) is required for efficient alpha-SNAP/NSF-mediated disassembly. Mutation of this glutamine allows SNARE complex binding to alpha-SNAP and NSF and ATP hydrolysis but prevents dissociation into SNARE monomers, indicating the ionic layer couples ATP hydrolysis to complex dissociation.\",\n      \"method\": \"SNARE complex mutagenesis; in vitro NSF disassembly assay with ATPgammaS/ATP; gel-shift analysis\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — site-directed mutagenesis with reconstituted in vitro disassembly, mechanistically informative separation of binding from disassembly\",\n      \"pmids\": [\"11762430\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"SNARE complex disassembly by NSF follows (rather than precedes) synaptic vesicle fusion in Drosophila. Genetic interaction studies show that blocking evoked fusion delays accumulation of assembled SNARE complexes in comatose mutants. Double comatose/shibire mutants can deplete the entire vesicle pool, demonstrating NSF activity is not required for the fusion step itself.\",\n      \"method\": \"Drosophila genetic epistasis (comatose × para and comatose × shibire double mutants); behavioral paralysis assay; biochemical SNARE complex accumulation\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis with multiple allele combinations, behavioral and biochemical readouts, mechanistic ordering\",\n      \"pmids\": [\"11593041\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"AP2 (clathrin adaptor) associates with GluR2 at a region overlapping the NSF binding site. Dissecting NSF vs AP2 binding with specific GluR2 mutants shows AP2 mediates NMDA-induced (but not ligand-dependent) AMPA receptor internalization and is essential for LTD, while NSF maintains synaptic AMPAR responses but is not required for NMDA receptor-mediated internalization or LTD.\",\n      \"method\": \"GluR2 mutant constructs dissociating NSF vs AP2 binding; co-immunoprecipitation; receptor internalization assays; hippocampal LTD recordings\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — specific separation-of-function mutants distinguishing NSF and AP2 roles, multiple orthogonal readouts\",\n      \"pmids\": [\"12441055\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Ablation of NSF binding to GluR2 results in increased AMPA receptor endocytosis in response to AMPA or NMDA compared to wild-type, while loss of GRIP/ABP binding stabilizes an intracellular pool of internalized AMPARs and inhibits recycling, defining distinct roles for NSF (preventing excess endocytosis) vs GRIP/ABP (preventing recycling from intracellular stores).\",\n      \"method\": \"Epitope-tagged GluR2 mutants lacking NSF or PDZ binding; surface expression assays; endocytosis measurements in neurons\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — domain-specific GluR2 mutants with surface/endocytosis measurements, single lab\",\n      \"pmids\": [\"12011465\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"NSF has an ATPase-independent function distinct from SNARE disassembly that is essential for Golgi membrane fusion. The Golgi-reassembly-defective mammalian NSF G274E mutant and Drosophila comatose NSF bind but cannot disassemble SNARE complexes and have almost no ATPase activity, yet retain activity in Golgi reassembly. NSF/alpha-SNAP catalyze binding of GATE-16 to GOS-28 (a Golgi v-SNARE) in an ATP-dependent but hydrolysis-independent manner, protecting the v-SNARE from binding its t-SNARE.\",\n      \"method\": \"Mammalian NSF mutant characterization; cell-free Golgi reassembly assay; SNARE disassembly assay; GATE-16/GOS-28 binding assay\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstituted cell-free assay with mechanistic separation of ATPase-dependent vs independent functions, replicated with Drosophila comatose mutant\",\n      \"pmids\": [\"12070132\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Dominant-interfering ATP hydrolysis-deficient NSF(E329Q) disrupts Golgi stack structure into dispersed vesicular elements and inhibits intra-Golgi transport (glycosaminoglycan sulfation), while dominant-interfering p97(E578Q) does not affect Golgi structure or function. This establishes that only NSF (not p97) is directly required for Golgi membrane fusion.\",\n      \"method\": \"Expression of ATP hydrolysis-deficient dominant-negative mutants NSF(E329Q) and p97(E578Q) in mammalian cells; Golgi morphology by immunofluorescence; glycosaminoglycan sulfation assay; VSV-G transport assay\",\n      \"journal\": \"Molecular biology of the cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — parallel comparison of dominant-negative mutants with multiple pathway readouts, direct mechanistic comparison of NSF vs p97\",\n      \"pmids\": [\"14617820\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"NSF and PICK1 are specifically required for calcium-permeable AMPA receptor plasticity (CARP), the dynamic exchange of GluR2-lacking and GluR2-containing receptors at synapses. NSF, but not PICK1, is required for receptor stabilization at synapses; PICK1, but not NSF, regulates formation of extrasynaptic GluR2-containing receptor pools that are laterally mobilized into synapses during CARP.\",\n      \"method\": \"Dominant-negative NSF and PICK1 interference; GluR2 subunit tracking; electrophysiology; fluorescence imaging in hippocampal neurons\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional dissection of NSF vs PICK1 roles with electrophysiology and imaging, single lab\",\n      \"pmids\": [\"15797551\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"NSF interaction with the GluR2 C-terminal domain is necessary and sufficient for rapid direct synaptic insertion of AMPA receptors. Wild-type GluR2 inserts rapidly into plasma membrane from intracellular compartments and accumulates at synaptic sites; a GluR2 mutant defective in NSF binding (DeltaA849-Q853) or GluR3 (which does not interact with NSF) show slower kinetics and initial extrasynaptic insertion. Introducing the NSF-binding site into GluR3 confers GluR2-like kinetics and synaptic targeting.\",\n      \"method\": \"Cell-surface thrombin cleavage assay; GluR2 mutants and chimeras; live imaging of receptor surface delivery in hippocampal neurons\",\n      \"journal\": \"Molecular and cellular neurosciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — gain-of-function and loss-of-function with direct surface insertion assay, single lab\",\n      \"pmids\": [\"15797712\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"There is a SEC18/NSF-independent protein sorting pathway from the yeast cortical ER to the plasma membrane, mediated by the C-terminal domain of Ist2p. This pathway operates independently of COPII vesicle formation and overrides other sorting signals.\",\n      \"method\": \"Temperature-sensitive sec18 yeast mutant; chimeric protein constructs; fluorescence microscopy of protein localization\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic loss-of-function with defined chimeric constructs, negative result regarding NSF requirement is mechanistically informative\",\n      \"pmids\": [\"15911878\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"NSF interacts directly with the GABAB receptor (GBR) heterodimer, forming a ternary complex in rat brain synaptosomes and CHO cells regulated by agonist stimulation. NSF functions as a priming factor required for agonist-promoted GBR desensitization independently of receptor internalization: inhibition of NSF binding (via TAT-Pep-27) abolished desensitization and prevented both PKC recruitment and receptor phosphorylation.\",\n      \"method\": \"Co-immunoprecipitation from synaptosomes and CHO cells; TAT peptide inhibition; Ca2+ mobilization assay; hippocampal slice electrophysiology; PKC recruitment assay\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP confirmed in native tissue and heterologous cells; functional dissection with peptide, multiple signaling readouts, single lab\",\n      \"pmids\": [\"16724110\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"In zebrafish, nsf is required cell-autonomously in neurons for organization of nodes of Ranvier (sodium channel clustering) and myelin basic protein expression, independent of its role in synaptic vesicle fusion. Neural activity and chemical synapse function are not required for sodium channel clustering in the larval nervous system.\",\n      \"method\": \"Forward genetic screen in zebrafish; chimeric larval analysis (transplantation); pharmacological inhibition of neural activity and synaptic transmission; immunostaining\",\n      \"journal\": \"Current biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — chimeric transplantation establishing cell autonomy, pharmacological separation of functions, genetic null\",\n      \"pmids\": [\"16581508\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Alpha-SNAP contains a conserved membrane attachment site (an extended loop with two phenylalanine residues in the N-terminal domain) that facilitates NSF-driven disassembly of membrane-bound (but not soluble) SNARE complexes. Mutation of these phenylalanines prevents SNAPs from supporting disassembly of membrane-anchored SNARE complexes.\",\n      \"method\": \"In vitro SNARE disassembly assay comparing soluble vs membrane-bound substrates; site-directed mutagenesis of alpha-SNAP phenylalanines; liposome binding assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — mutagenesis combined with in vitro reconstitution of disassembly on soluble vs membrane substrates\",\n      \"pmids\": [\"19762473\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"NSF-binding site within GluR2 intracellular domain is required for plasma membrane insertion of GluR2-containing AMPA receptors. RNA editing of the Q/R site in the ion channel region also plays a key role in GluR2 plasma membrane insertion. These two structural elements act in the same pathway for GluA2 and heteromeric GluA2/3 receptor delivery.\",\n      \"method\": \"pHluorin-tagged GluA2 with TIRF microscopy to visualize individual plasma membrane fusion events; GluA2 mutants lacking NSF binding or with Q/R editing changes\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct single-vesicle visualization of insertion events with domain-specific mutants\",\n      \"pmids\": [\"20534470\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Polo-like kinase 2 (Plk2), an activity-inducible kinase, directly interacts with NSF through a specific motif (independent of canonical polo box sites), disrupts NSF-GluA2 interaction, promotes loss of surface GluA2, increases GluA2 association with PICK1 and GRIP1, and decreases synaptic AMPAR current. Plk2 engagement of NSF (not Plk2 kinase activity) is required for this homeostatic reduction in surface AMPAR.\",\n      \"method\": \"Co-immunoprecipitation; pulldown with Plk2 mutants; surface biotinylation; whole-cell patch clamp in hippocampal neurons; dominant-negative and deletion constructs\",\n      \"journal\": \"Nature neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple binding/functional assays, separation-of-function (binding vs kinase activity), electrophysiology\",\n      \"pmids\": [\"20802490\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Cryo-EM structures of NSF hexamer in ATPgammaS, ADP-AlFx, and ADP states reveal parallel arrangement of D1 and D2 domains and nucleotide-dependent conformational changes. The 20S particle structure shows the SNARE complex held at two interaction interfaces around the C-terminus and N-terminal half of the SNARE complex.\",\n      \"method\": \"Single-particle cryo-EM and negative stain EM; 3D reconstruction of NSF hexamer and 20S particle\",\n      \"journal\": \"Nature structural & molecular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — cryo-EM structural determination of multiple nucleotide states and 20S complex\",\n      \"pmids\": [\"22307055\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"NSF-mediated disassembly of all tested SNARE complexes is initiated by a conserved 1:1 interaction between alpha-SNAP and the ternary SNARE complex (not influenced by N-terminal SNARE domains). This 1:1 alpha-SNAP:SNARE complex is confirmed by multiangle light scattering; NSF binding follows.\",\n      \"method\": \"SNARE-stimulated ATP hydrolysis rate measurements; Michaelis-Menten kinetics; SNAP-SNARE binding constants; multiangle light scattering; four different SNARE complexes tested\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro enzymatic reconstitution with multiple SNARE complexes, quantitative biophysical characterization\",\n      \"pmids\": [\"23836889\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"NSF disassembles a single SNARE complex in one round of ATP turnover using a 'spring-loaded' mechanism: upon ATP cleavage, the NSF hexamer develops internal tension with phosphate dissociation, then releases the tension in a burst within 20 ms resulting in SNARE disassembly and immediate release of SNARE proteins.\",\n      \"method\": \"Single-molecule fluorescence spectroscopy; magnetic tweezers; real-time monitoring of single SNARE complex disassembly\",\n      \"journal\": \"Science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — single-molecule reconstitution with two orthogonal methods (fluorescence and magnetic tweezers), directly demonstrates mechanism\",\n      \"pmids\": [\"25814585\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Sec17 (alpha-SNAP) can trigger fusion of trans-SNARE paired membranes without Sec18 (NSF) by binding to trans-SNARE complexes and inserting apolar loops into apposed membranes; Sec18 does not substitute for Sec17 in this fusion-triggering role. Sec17 thus has two functions: stimulating Sec18-mediated cis-SNARE disassembly and independently triggering trans-SNARE-dependent fusion.\",\n      \"method\": \"Proteoliposome fusion assay with SNARE proteins; Sec17 and Sec18 mutants (L291A/L292A, F21S/M22S) dissociating the two functions; liposome binding assays\",\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 separation-of-function mutants, multiple orthogonal assays\",\n      \"pmids\": [\"25902545\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"LRRK2 phosphorylates NSF at threonine 645 in the ATP-binding pocket of the D2 domain. NSF phosphorylated by LRRK2 displays enhanced ATPase activity and increased rate of SNARE complex disassembly. Substitution of Thr645 with alanine abrogates LRRK2-mediated increased ATPase activity.\",\n      \"method\": \"In vitro kinase assay with LRRK2 and full-length NSF; phosphosite mapping; ATPase assay; SNARE complex disassembly assay; alanine substitution mutagenesis\",\n      \"journal\": \"Molecular neurodegeneration\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — in vitro kinase assay identifying phosphosite, mutagenesis confirming specificity, two orthogonal functional readouts (ATPase and SNARE disassembly)\",\n      \"pmids\": [\"26758690\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Sec17 (alpha-SNAP) and Sec18 (NSF) act twice in the vacuolar fusion cycle: first binding to trans-SNARE complexes to stimulate fusion (without requiring ATP hydrolysis), and then hydrolyzing ATP to disassemble cis-SNARE complexes. At physiological protein levels, Sec17 stimulates fusion through its central residues binding the 0-layer of the SNARE complex and its N-terminal apolar loop for membrane binding.\",\n      \"method\": \"Yeast vacuole fusion assay with Sec17 mutants; proteoliposome fusion with asymmetric SNARE arrangement; cis-SNARE disassembly assay; transmembrane-anchored Sec17 chimera\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — reconstituted fusion and disassembly assays with domain-separation mutants and chimeric proteins\",\n      \"pmids\": [\"28718762\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Cryo-EM structure of the 20S supercomplex (NSF/2×alphaSNAP/neuronal SNARE complex) at ~3.9 Å reveals: two alphaSNAP molecules interface with a specific surface of the SNARE complex via electrostatic interactions; 15 N-terminal residues of SNAP-25A are loaded into the D1 ring pore of NSF via spiral interactions between a conserved NSF tyrosine residue and SNAP-25A backbone atoms, preceding ATP hydrolysis.\",\n      \"method\": \"Electron cryo-microscopy of 20S supercomplex; near-atomic resolution structure determination\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — near-atomic resolution cryo-EM structure with specific contact identification, defining substrate loading mechanism\",\n      \"pmids\": [\"30198481\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"NSF disassembles ternary SNARE complexes in a single step within 100 ms; complexin-1 competes with alphaSNAP binding to the SNARE complex, reducing disassembly rate and increasing failed disassembly events, suggesting complexin differentially regulates cis vs trans SNARE complex disassembly. NSF also disassembles anti-parallel SNARE complexes, implicating it in quality control.\",\n      \"method\": \"Single-molecule FRET assay monitoring repeated rounds of NSF-mediated SNARE complex disassembly and reassembly; complexin-1 competition assay\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — single-molecule reconstitution with quantitative kinetics, competition assays with complexin\",\n      \"pmids\": [\"29985126\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Formation of trans-SNARE complexes in the presence of NSF-alphaSNAP requires both Munc18-1 and Munc13-1, and is facilitated by synaptotagmin-1. Munc18-1, Munc13-1, complexin-1, and likely synaptotagmin-1 also contribute to maintaining assembled trans-SNARE complexes in the presence of NSF-alphaSNAP, preventing de-priming.\",\n      \"method\": \"Reconstituted proteoliposome system with defined protein components; SNARE complex formation assays with and without NSF-alphaSNAP; co-flotation and co-sedimentation assays\",\n      \"journal\": \"eLife\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — reconstituted in vitro system with defined components identifying protective factors against NSF-mediated disassembly\",\n      \"pmids\": [\"30657450\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"NSF (SEC18) is a homo-hexameric AAA+ ATPase that functions as a universal SNARE chaperone: together with its adaptor proteins (SNAPs/Sec17p), it recognizes assembled cis-SNARE complexes via a 1:1 alphaSNAP:SNARE interaction that loads the N-terminus of SNAP-25 into its D1 ring pore, then uses a 'spring-loaded' ATP hydrolysis mechanism to disassemble the complex in a single burst within ~20 ms, recycling SNAREs for subsequent fusion rounds; trans-SNARE complexes (SNAREpins) are resistant to NSF disassembly, allowing fusion to proceed, and are protected by accessory factors (Munc18-1, Munc13-1, complexin); beyond SNARE recycling, NSF also directly interacts with non-SNARE substrates including the GluR2 subunit of AMPA receptors (stabilizing their surface expression by disrupting inhibitory GluR2-PICK1 complexes), the GABAB receptor heterodimer (priming agonist-induced desensitization), and beta-arrestin1, and its activity can be post-translationally regulated by LRRK2-mediated phosphorylation at Thr645, which enhances ATPase activity and SNARE disassembly rate.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"NSF (yeast SEC18) is a hexameric AAA+ ATPase that serves as the universal engine for recycling SNARE proteins after membrane fusion, originally defined as an essential factor for secretory transport between the ER, Golgi, and cell surface [#0, #2]. It operates with soluble NSF attachment proteins (alpha-, beta-, gamma-SNAP; yeast Sec17p), which recruit NSF to membranes, bind the SNARE substrate, and stimulate its ATPase activity by lowering the Km of the low-affinity catalytic site, thereby acting as a molecular switch [#1, #4, #5, #13]. Structurally, NSF is a hollow nucleotide-stabilized hexamer whose D1 ring engages the assembled cis-SNARE complex within an asymmetric '20S' particle; disassembly is initiated by a conserved 1:1 alpha-SNAP:SNARE interaction, after which the N-terminus of SNAP-25 is loaded into the D1 pore prior to ATP hydrolysis [#9, #14, #47, #48, #53]. NSF couples ATP hydrolysis to dissociation through the SNARE ionic layer and executes disassembly of a single complex in one 'spring-loaded' burst within ~20 ms [#33, #49]. This activity recycles SDS-resistant cis-SNARE cores formed by syntaxin/SNAP-25/synaptobrevin [#10, #20], while trans-SNARE complexes (SNAREpins) become resistant to NSF at the moment of formation, allowing fusion to proceed; this protection is reinforced by Munc18-1, Munc13-1, complexin-1, and synaptotagmin-1 [#29, #54, #55]. Genetic studies in Drosophila and squid place NSF action after vesicle docking, priming docked vesicles for calcium-triggered release rather than catalyzing fusion itself [#20, #21, #22, #34]. NSF supports a broad range of fusion events, including Golgi reassembly, basolateral TGN-to-plasma-membrane transport, homotypic vacuole fusion, late endosome-lysosome fusion, and autophagosome-vacuole fusion [#6, #7, #11, #24, #30]; at the Golgi it additionally has an ATPase-independent function in which NSF/alpha-SNAP catalyze GATE-16 binding to the v-SNARE GOS-28 [#37, #38]. Beyond SNAREs, NSF directly binds the AMPA receptor GluR2 subunit and, using its ATPase, disassembles the inhibitory GluR2-PICK1 complex to stabilize surface AMPA receptors and maintain synaptic transmission [#18, #26, #31, #35]; it also binds beta-arrestin1 to promote receptor internalization and the GABAB receptor heterodimer to prime agonist-induced desensitization [#25, #42]. NSF activity is post-translationally tuned by LRRK2 phosphorylation at Thr645, which enhances its ATPase rate and SNARE disassembly [#51].\",\n  \"teleology\": [\n    {\n      \"year\": 1988,\n      \"claim\": \"Established that NSF/SEC18 is an essential, cytoplasmic factor for secretory transport, framing the central question of how a soluble ATPase drives membrane traffic.\",\n      \"evidence\": \"Gene cloning by complementation and disruption in yeast with subcellular fractionation\",\n      \"pmids\": [\"3054509\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular substrate of NSF unknown\", \"Mechanism of membrane association undefined\"]\n    },\n    {\n      \"year\": 1990,\n      \"claim\": \"Identified SNAP adaptors that bridge NSF to membranes, defining the conserved NSF/SNAP fusion machinery across species.\",\n      \"evidence\": \"Protein purification from brain cytosol, in vitro Golgi transport assay, yeast sec17 complementation\",\n      \"pmids\": [\"2111733\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Membrane receptor for the SNAP-NSF complex not yet identified\", \"Catalytic role of NSF ATPase unresolved\"]\n    },\n    {\n      \"year\": 1993,\n      \"claim\": \"Showed SNAP isoforms act through membrane-specific SNARE receptors, introducing the concept that fusion specificity is encoded downstream of NSF.\",\n      \"evidence\": \"cDNA cloning, in vitro Golgi transport, tissue expression analysis\",\n      \"pmids\": [\"8455721\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of the relevant SNARE receptors at each step incomplete\"]\n    },\n    {\n      \"year\": 1994,\n      \"claim\": \"Defined SNAPs as activators that lower NSF's ATPase Km ~100-fold, establishing them as a molecular switch for NSF activity at physiological ATP.\",\n      \"evidence\": \"In vitro ATPase kinetics with recombinant NSF and SNAPs\",\n      \"pmids\": [\"7961908\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How ATP hydrolysis is coupled to a downstream conformational event not yet shown\"]\n    },\n    {\n      \"year\": 1995,\n      \"claim\": \"Resolved NSF architecture and the 20S complex, showing alpha-SNAP and the SNARE rod bind one end of the NSF cylinder, and identified the SDS-resistant SNARE core as the physiological substrate.\",\n      \"evidence\": \"Quick-freeze/deep-etch EM with epitope markers; in vitro 20S assembly/disassembly with neurotoxin cleavage\",\n      \"pmids\": [\"9267032\", \"7588600\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Oligomeric state ambiguous at this stage\", \"Atomic contacts within the 20S particle unresolved\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Established NSF as a nucleotide-stabilized hexamer and mapped the alpha-SNAP C-terminus as the determinant required to stimulate NSF ATPase and thereby drive SNARE disassembly and exocytosis.\",\n      \"evidence\": \"Analytical ultracentrifugation and EM; alpha-SNAP truncation/point mutants in ATPase, disassembly, and chromaffin exocytosis assays\",\n      \"pmids\": [\"9624162\", \"9362506\", \"8744944\", \"9325254\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether NSF acts before or after fusion not yet ordered\", \"Non-SNARE substrates not yet considered\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Genetic and physiological studies in Drosophila and squid placed NSF action downstream of vesicle docking, priming docked vesicles rather than catalyzing fusion.\",\n      \"evidence\": \"comatose temperature-sensitive mutants with SNARE accumulation, EM, and NMJ electrophysiology; squid presynaptic peptide injection\",\n      \"pmids\": [\"9852562\", \"9852561\", \"9469810\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether SNARE disassembly precedes or follows fusion not definitively ordered until later epistasis\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Discovered the first non-SNARE NSF partner, the AMPA receptor GluR2 subunit, linking NSF directly to synaptic receptor trafficking and transmission.\",\n      \"evidence\": \"Direct binding with peptide mapping/mutagenesis; blocking peptide and antibody infusion in CA1 neurons with electrophysiology\",\n      \"pmids\": [\"9697854\", \"9697855\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which NSF acts on GluR2 (disassembly of what complex) unknown at this point\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Extended NSF requirement to homotypic vacuole fusion and late endosome-lysosome fusion as direct fusion events, defining an ordered priming reaction coupled to t-SNARE stabilization via LMA1.\",\n      \"evidence\": \"Cell-free vacuole and endosome-lysosome fusion assays with purified Sec18p, antibodies, and LMA1 transfer experiments\",\n      \"pmids\": [\"8670830\", \"9015301\", \"9657146\", \"9456319\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Lipid and cofactor requirements of priming not fully mapped\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Demonstrated NSF-GluR2 interaction maintains surface AMPA receptors and is required for LTD-related receptor pools, and identified beta-arrestin1 as an ATP-state-dependent NSF partner in receptor internalization.\",\n      \"evidence\": \"Blocking peptide/viral pep2m in neurons with electrophysiology and surface immunostaining; yeast two-hybrid, co-IP, and HEK293 internalization assays\",\n      \"pmids\": [\"10399941\", \"10571232\", \"10196135\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular substrate of the NSF-GluR2 reaction still undefined\", \"beta-arrestin1 finding is Co-IP/two-hybrid without mechanistic dissection\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Resolved how fusion proceeds despite NSF: trans-SNARE complexes become NSF-resistant at the moment of formation, while cis-SNARE complexes are dismantled.\",\n      \"evidence\": \"Reconstituted liposome fusion with NSF/alphaSNAP applied to trans- vs cis-SNARE complexes\",\n      \"pmids\": [\"10831610\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Factors actively protecting trans-SNARE complexes not yet identified\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Identified the GluR2-PICK1 complex as the first non-SNARE substrate of NSF's ATPase-driven disassembly and established the ionic layer as the coupling element for disassembly.\",\n      \"evidence\": \"In vitro ATPgammaS/ATP disassembly assays with GluR2-PICK1 and SNARE ionic-layer mutants; SNAP overexpression in neurons\",\n      \"pmids\": [\"11931741\", \"11762430\", \"11483507\", \"11593041\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How NSF discriminates SNARE vs non-SNARE substrates unresolved\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Revealed an ATPase-independent NSF function essential for Golgi membrane fusion and separated NSF-dependent receptor stabilization from AP2-dependent internalization in synaptic plasticity.\",\n      \"evidence\": \"G274E/comatose NSF mutants in Golgi reassembly and GATE-16/GOS-28 binding; GluR2 separation-of-function mutants in internalization and LTD assays\",\n      \"pmids\": [\"12070132\", \"12441055\", \"12011465\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of the ATPase-independent Golgi activity unknown\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Distinguished NSF from the related ATPase p97 as the factor directly required for Golgi membrane fusion in cells.\",\n      \"evidence\": \"Dominant-negative NSF(E329Q) vs p97(E578Q) expression with Golgi morphology and transport readouts\",\n      \"pmids\": [\"14617820\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Division of labor between NSF and p97 at other organelles not addressed\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Expanded NSF's direct receptor partnerships to the GABAB receptor heterodimer and showed a cell-autonomous neuronal role in node-of-Ranvier organization independent of synaptic vesicle fusion.\",\n      \"evidence\": \"Co-IP from synaptosomes/CHO cells with TAT-peptide inhibition and signaling readouts; zebrafish forward genetics with chimeric transplantation\",\n      \"pmids\": [\"16724110\", \"16581508\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"GABAB finding from single lab without structural definition of interaction\", \"Mechanism linking NSF to sodium channel clustering unknown\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Mapped a membrane-attachment loop in alpha-SNAP required specifically for disassembly of membrane-bound SNARE complexes, connecting SNAP membrane contact to NSF function.\",\n      \"evidence\": \"In vitro disassembly comparing soluble vs membrane-bound SNAREs with alpha-SNAP phenylalanine mutants\",\n      \"pmids\": [\"19762473\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Contribution of this loop to in vivo fusion cycles not directly tested here\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Defined the universal initiation step of disassembly as a conserved 1:1 alpha-SNAP:SNARE interaction independent of N-terminal SNARE domains, with NSF binding thereafter.\",\n      \"evidence\": \"Kinetic and multiangle light scattering analysis across four SNARE complexes\",\n      \"pmids\": [\"23836889\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Stoichiometry of alpha-SNAP in the active 20S particle later revised to two\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Established the kinetic mechanism (single-complex disassembly in one spring-loaded burst within 20 ms) and uncovered a SNARE-disassembly-independent role for Sec17 in directly triggering trans-SNARE fusion.\",\n      \"evidence\": \"Single-molecule fluorescence and magnetic tweezers; proteoliposome fusion with Sec17/Sec18 separation-of-function mutants\",\n      \"pmids\": [\"25814585\", \"25902545\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Atomic-resolution view of substrate loading still pending\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Identified LRRK2 phosphorylation of NSF at Thr645 as a post-translational regulator that enhances ATPase activity and SNARE disassembly rate.\",\n      \"evidence\": \"In vitro kinase assay, phosphosite mapping, T645A mutagenesis, ATPase and disassembly assays\",\n      \"pmids\": [\"26758690\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Physiological/in vivo consequence of NSF Thr645 phosphorylation not established\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Near-atomic cryo-EM of the 20S supercomplex resolved two alpha-SNAP molecules contacting the SNARE complex and the SNAP-25A N-terminus loaded into the D1 pore before hydrolysis, defining the substrate-engagement mechanism; single-molecule work showed complexin competes with alpha-SNAP and NSF can disassemble anti-parallel complexes for quality control.\",\n      \"evidence\": \"Cryo-EM of the 20S supercomplex at ~3.9 A; single-molecule FRET with complexin-1 competition\",\n      \"pmids\": [\"30198481\", \"29985126\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Dynamics of pore translocation during the hydrolysis burst not fully captured\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Identified the accessory factors (Munc18-1, Munc13-1, complexin-1, synaptotagmin-1) that build and protect trans-SNARE complexes against NSF-alphaSNAP de-priming, integrating NSF into the priming/fusion cycle.\",\n      \"evidence\": \"Reconstituted proteoliposome system with defined components, co-flotation/co-sedimentation assays\",\n      \"pmids\": [\"30657450\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Quantitative competition between protection and NSF disassembly in vivo unresolved\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How NSF achieves substrate selectivity between SNARE and diverse non-SNARE targets, and how its phosphoregulation and accessory-factor protection are integrated in vivo, remains open.\",\n      \"evidence\": \"No single experiment in the corpus resolves substrate discrimination across SNARE and non-SNARE clients\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unified model for substrate recognition across SNARE and non-SNARE clients\", \"In vivo regulatory role of LRRK2 phosphorylation undefined\", \"Structural basis of ATPase-independent Golgi function unknown\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140657\", \"supporting_discovery_ids\": [5, 14, 49, 51]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [5, 33, 49]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [10, 31, 33, 37]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [18, 31, 42]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [1, 7, 37, 38]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [6, 20, 26]},\n      {\"term_id\": \"GO:0005773\", \"supporting_discovery_ids\": [11, 16, 32]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-5653656\", \"supporting_discovery_ids\": [0, 2, 6, 7]},\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [2, 6]},\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [20, 21, 26, 28]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [30]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [25, 42]}\n    ],\n    \"complexes\": [\"20S SNARE disassembly complex (NSF/alphaSNAP/SNARE)\", \"NSF homohexamer\"],\n    \"partners\": [\"NAPA\", \"GRIA2\", \"PICK1\", \"ARRB1\", \"GABBR1\", \"LRRK2\", \"PLK2\", \"STX5\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"tie","faith_supported":9,"faith_total":9,"faith_pct":100.0}}