F8

Summary: Retain copper coordination as a supporting structural facet of the FVIII cofactor.

Reason: The mapped human cupredoxin-like domains are corroborated by the active recombinant human B-domain-deleted FVIII structure in PMID:17965321 (Methods; Results, Bound metal ions; Figure 2 caption). Anomalous diffraction supports copper coordination in A1 and A3. These domain-associated sites support the architecture of the nonenzymatic cofactor, so copper binding is retained within the same core unit rather than treated as peripheral merely because it is structural. The article relates metal binding to domain association, but the structure itself is not a copper-depletion/reconstitution experiment and does not establish a fixed occupancy for every expression system or product. No oxidation-reduction chemistry is assigned to FVIII. The engineered heterodimer is distinct from natural F8B.

Summary: Retain the source-specific human FVIII–VWF association without replacing its partner by ADAMTS13.

Reason: The imported IPI context names VWF (UniProtKB:P04275). In PMID:18492805, Figure 5 and the binding ELISA Methods directly compare recombinant human FVIII-SQ with an a3-deleted derivative: loss of a3 impairs VWF binding. The same paper separately reports shear-dependent VWF cleavage by ADAMTS13, a modest direct ADAMTS13 interaction and peptide-substrate enhancement. Those observations remain biologically relevant, but they do not change this row's VWF partner into ADAMTS13 or establish its independent FIXa-cofactor instance. Retain the supported carrier association as non-core under the standing generic-binding exception; the current targeted search did not establish an exact VWF-binding MF, and generic complex binding would not resolve this role. Complete main Methods/Results were available and selected passages were read; supplementary figures and pixels were not inspected. Human full-length and engineered B-domain/a3 constructs are not equated with natural F8B.

Summary: Human B-domain-deleted FVIII and engineered furin-site variants bind plasma-derived human VWF.

Reason: The original Methods, Table 1 and supplementary Figure S5 caption identify human FVIII-BDD and furin-site deletion variants produced in BHK cells, with binding to immobilized full-length human plasma VWF measured by surface plasmon resonance. Background-subtracted curves were fitted to a 1:1 model; the BDD comparator has a reported dissociation constant of 0.7 nM and the tested variants retain binding. This is positive carrier association, not evidence that FVIII itself stabilizes or transports VWF. The intrinsic-tenase assays elsewhere in the paper test a separate cofactor role and do not convert every VWF-binding measurement into endopeptidase activation. Targeted current-term searches did not establish a VWF-specific binding term; generic protein-containing-complex binding would merely restate multimer contact. Retain this supported interaction as non-core under the standing campaign exception for experimentally supported generic binding. The BDD comparator and furin deletion variants are engineered proteins, not the naturally spliced F8B product; single-chain versus processed heterodimer forms also do not define natural splice isoforms.

Summary: Human FVIII–VWF binding is retained with the original assay-access limitation stated.

Reason: The verified original abstract describes binding of human FVIII to plasma VWF from healthy donors and severe hemophilia A patients, including solid-phase, gel-filtration and VWF–gold fluid-phase measurements. It reports saturable, reversible binding and warns that surface immobilization changes apparent stoichiometry. Publisher and linked PDF attempts did not recover the complete original Methods, so reagent processing and product-specific attribution are not treated as independently verified here. Nevertheless, the same human interaction is established by the independently inspected FVIII–VWF assays in PMID:18492805 and PMID:27749002. Retain the experimentally supported interaction as non-core under the campaign generic-binding exception, without asserting that the old paper tested either current natural product or that FVIII performs VWF carrier activity. No exact VWF-binding GO term was established by the targeted current search; the cofactor and enzyme-activation assays have separate mechanistic contexts and are not automatically substituted for this binding experiment.

Summary: Retain inherited extracellular localization of functional FVIII.

Reason: The actual PANTHER v19 tree places the exact 2351-residue human target PTN002555836 below the asserted extracellular node PTN009099846, with the corresponding positive IBD and no relevant target-path NOT. Current UniProt family PTHR46806 and v19 PTHR24543 are explicitly different source versions; no family identity is silently rewritten. Donor count is not the basis for acceptance. Independent human plasma-derived FVIII and secreted recombinant FVIII provide positive extracellular evidence. This does not assert secretion of every natural product, including F8B.

Summary: Retain broad extracellular localization with an explicit rule-version limit.

Reason: The combined pipeline joins ARBA00027128 and UniProt SL-0112. The captured current ARBA rule has no fully matching human condition set; the target FunFam pair occurs in a reptile-specific set, so a historical human rule match is not claimed. SL-0112 maps to GO:0005576, although its own narrower vocabulary definition excludes freely circulating blood proteins. The broad GO term itself is independently correct for human plasma FVIII and secreted recombinant FVIII. Acceptance therefore rests on the actual target evidence and broad GO definition, not on treating the current ARBA conditions or the narrower location wording as experimentally verified.

Summary: F8 is explicitly present in the combined human plasma-protein source list.

Reason: The inspected original author-upload excerpts include Table II, where P00451 is explicitly listed as coagulation factor VIII with positive literature and LCMS1 source entries. The accompanying Methods identify the LCMS1 input as a human serum peptide-proteomics dataset; this is not an assertion that all four datasets detected F8. That target-specific record supports extracellular residence, independently consistent with the secreted human FVIII proteins isolated from conditioned medium in the inspected biochemical studies. Keep the broad extracellular-region term, which accommodates the soluble carrier-bound pool without inferring microparticle localization. Only the named original Methods/table excerpts were recovered, not a complete independently read article or peptide-level reassignment; the list does not distinguish the 2351-residue precursor, its processed products and natural F8B.

Summary: Retain extracellular FVIII in its VWF-associated circulating pool.

Reason: The actual R-HSA-158118 graph places P00451 heavy chain 20–1332 and light chain 1668–2351 in extracellular region, free and in VWF-containing complexes. Their own compartments, not merely the event compartment, are explicit. Human FVIII–VWF binding and secreted recombinant preparations corroborate this location. The model’s selected processing form and complex stoichiometry do not define all circulating forms or the natural F8B product.

Summary: Retain extracellular FVIII during thrombin-dependent activation.

Reason: R-HSA-158137 includes extracellular P00451 precursor chains and the resulting A1, A2, light-chain, B-domain and acidic-peptide products. Thrombin performs the cleavage; FVIII is its substrate in this event. The imported cellular-component claim is valid without assigning thrombin protease activity to F8. The released B-domain segment is a proteolytic product, not the separately encoded 216-residue F8B isoform.

Summary: Retain extracellular FVIII without treating the granule route as independently resolved.

Reason: R-HSA-481007 models native P00451 alpha-granule entity 114591 releasing extracellular entity 54601. Independent human plasma-derived and secreted recombinant FVIII establish the broad extracellular pool. The exact native FVIII granule identification behind this event remains unresolved: the recovered releasate main text lacks the target supplementary protein table, and historical factor VIII-related antigen wording cannot automatically be equated with F8. Those limits affect the separate granule-lumen claim, not the independently supported extracellular location.

Summary: Retain extracellular FVIII and its inactivation products.

Reason: R-HSA-5607002 explicitly places the human FVIII input and cleaved fragments in extracellular region. Activated protein C is the cleaving enzyme, with protein S in its regulatory context; F8 is the substrate. This source supports the target location and processing state, not an F8 protease or protease-inhibitor activity.

Summary: Retain the soluble extracellular FVIII pool before membrane recruitment.

Reason: R-HSA-5607043 distinguishes extracellular FVIII from its membrane-associated output. The extracellular input is a positive circulating pool, while the membrane output is separately refined to the external plasma-membrane face. Human FVIII supports FIXa-mediated factor X activation in solution/lipid and activated-platelet systems; these are distinct states of the same cofactor rather than mutually exclusive locations.

Summary: Retain extracellular FVIII as the product of secretion.

Reason: R-HSA-9661625 connects ER-lumen precursor FVIII to extracellular human heavy and light chains. F8 is cargo/product in the secretion model, not the machinery that transports or cleaves it. Actual secreted human recombinant FVIII corroborates the extracellular pool. The model does not establish secretion of F8B or functional equivalence of all F8 products.

Summary: Accept extracellular FVIII localization while retaining the model-specific variant context.

Reason: The actual R-HSA-9665809 target routes contain native heavy chain 158250 (20–1332) alongside its variant light-chain set. These P00451 entities have their own GO:0005576 compartment; the location is not borrowed from another participant. Extracellular FVIII is a core location independently supported by human biochemical/serum observations, and a native companion in a disease model does not make that location non-core. The literal variant and processing coordinates remain source-specific: acceptance of the location does not establish wild-type binding, activation, stability or membrane association for each variant, or locate natural F8B.

Summary: Accept extracellular FVIII localization while retaining the model-specific variant context.

Reason: The actual R-HSA-9666383 target routes contain native light chain 158299 (1668–2351) and heavy chain 158250 (20–1332) in alternative complexes with cleavage-site variants. These P00451 entities have their own GO:0005576 compartment; the location is not borrowed from another participant. Extracellular FVIII is a core location independently supported by human biochemical/serum observations, and a native companion in a disease model does not make that location non-core. The literal variant and processing coordinates remain source-specific: acceptance of the location does not establish wild-type binding, activation, stability or membrane association for each variant, or locate natural F8B.

Summary: Retain extracellular native FVIII chains during cofactor dissociation.

Reason: R-HSA-9670014 models dissociation of native activated FVIII into extracellular subunits. These explicit P00451 participants preserve a normal extracellular cofactor lifecycle. Dissociation is not an additional catalytic activity of F8, and this record does not imply that all subunits or natural isoforms retain intact-tenase cofactor activity.

Summary: Accept extracellular FVIII localization while retaining the model-specific variant context.

Reason: The actual R-HSA-9670049 target routes contain native light chain 158271 (1709–2351) and released A2 chain 158199 (392–759), alongside S308L/A303E A1 variants. These P00451 entities have their own GO:0005576 compartment; the location is not borrowed from another participant. Extracellular FVIII is a core location independently supported by human biochemical/serum observations, and a native companion in a disease model does not make that location non-core. The literal variant and processing coordinates remain source-specific: acceptance of the location does not establish wild-type binding, activation, stability or membrane association for each variant, or locate natural F8B.

Summary: Accept extracellular FVIII localization while retaining the model-specific variant context.

Reason: The actual R-HSA-9670054 target routes contain native A1 chain 158290 (20–391) and light chain 158271 (1709–2351), alongside the A2 variant set. These P00451 entities have their own GO:0005576 compartment; the location is not borrowed from another participant. Extracellular FVIII is a core location independently supported by human biochemical/serum observations, and a native companion in a disease model does not make that location non-core. The literal variant and processing coordinates remain source-specific: acceptance of the location does not establish wild-type binding, activation, stability or membrane association for each variant, or locate natural F8B.

Summary: Accept extracellular FVIII localization while retaining the model-specific variant context.

Reason: The actual R-HSA-9670189 target routes contain native A1 chain 158290 (20–391) and A2 chain 158199 (392–759), alongside light-chain A2220P/deletion and Q2330P variants. These P00451 entities have their own GO:0005576 compartment; the location is not borrowed from another participant. Extracellular FVIII is a core location independently supported by human biochemical/serum observations, and a native companion in a disease model does not make that location non-core. The literal variant and processing coordinates remain source-specific: acceptance of the location does not establish wild-type binding, activation, stability or membrane association for each variant, or locate natural F8B.

Summary: Retain extracellular FVIII in the tissue-factor-associated activation route.

Reason: R-HSA-9822522 models extracellular FVIII cleavage by the TF:FVIIa:FXa-associated system. The target P00451 chains and fragments carry their own extracellular compartment. F8 is the activation substrate, not the protease catalyst or an independent initiator of the extrinsic pathway. The event’s B-domain fragment must not be relabeled as natural F8B.

Summary: Retain extracellular FVIII in the VWF-cleavage cofactor context.

Reason: R-HSA-9934645 places FVIII in an extracellular VWF-containing complex during ADAMTS13 cleavage. The actual human experiments in PMID:18492805 show FVIII-dependent enhancement of VWF cleavage and a smaller direct enhancement of ADAMTS13 peptide-substrate activity, with appropriate no-FVIII and metal-chelation controls. These are cofactor effects; ADAMTS13 performs proteolysis. This supports the extracellular location without treating every FVIII construct or product as equivalent.

Summary: Retain ER-lumen FVIII as biosynthetic cargo.

Reason: R-HSA-203973 resolves human P00451 entity 5689449 in the ER lumen and COPII output entity 5689796. The target is secretory cargo assembled with its transport receptors, not a COPII coat enzyme or the cofactor acting on FIXa in the ER. Retain this explicit biosynthetic pool as contextual rather than denying ER residence.

Summary: Retain ER-lumen FVIII in the cargo-receptor assembly context.

Reason: R-HSA-204008 places the actual human FVIII cargo entity 5689449 in the ER lumen. The receptor complex and FVIII have distinct roles; inclusion in its transport assembly does not establish an intracellular tenase reaction. The source location is retained as a biosynthetic context.

Summary: Retain ER-lumen FVIII in the modeled receptor-dependent transport step.

Reason: R-HSA-5694417 contains P00451 cargo 5689449 with its own ER-lumen compartment. Its linkage to the transport complex is verified through actual participant objects. This is positive secretory-pathway residence, not evidence that FVIII is the transport machinery or has an ER catalytic function.

Summary: Retain ER-lumen FVIII during secretory cargo handling.

Reason: R-HSA-5694431 resolves the native P00451 precursor cargo in ER lumen. Preserve this model-supported location and distinguish receptor/coat actions from the transported FVIII molecule. The biosynthetic pool is contextual to the extracellular cofactor role.

Summary: Retain the ER-lumen cargo pool in this transport event.

Reason: R-HSA-5694522 includes the human FVIII precursor through explicit cargo/receptor participant links and assigns the FVIII entity itself to ER lumen. This supports residence during biosynthesis without assigning cargo sorting or vesicle formation as an activity performed by F8.

Summary: Retain ER-lumen FVIII in the modeled trafficking assembly.

Reason: R-HSA-5694527 contains the same explicitly localized human P00451 ER cargo. The annotation is retained for the biosynthetic state, while the model’s assembly and transport reactions belong to the corresponding machinery. No natural-product-wide secretion or processing equivalence follows.

Summary: Retain the native ER precursor preceding secretion.

Reason: R-HSA-9661625 explicitly connects an ER-lumen FVIII precursor to extracellular processed chains. The ER input is a genuine biosynthetic context and the extracellular output is separately core. This does not locate the intrinsic-tenase reaction in the ER or make F8 the performer of its own secretion.

Summary: Retain variant-retention context with a narrow F8B compartment query.

Reason: R-HSA-9661980 is a heterogeneous ER-retention model with explicit human FVIII variant participants. These are not collectively rejected. One member, 9666368, uses A20_M2143delinsMRIQDPGK notation corresponding in sequence to the short F8B product after the modeled mature-chain boundary. The actual PMID:24037092 Methods distinguish F8B’s eight-residue alternative N terminus, which lacks a recognizable leader, from the signal-containing long inversion product. Results show intracellular expression and nonsecretion, but do not resolve F8B to ER lumen with an ER marker. Retain the general variant-retention context and query this member’s precise compartment; sequence agreement alone does not establish natural-product localization.

Summary: Retain Golgi-lumen FVIII during tyrosine sulfation.

Reason: R-HSA-9668023 connects native FVIII precursor 9668037 to sulfated product 9668036 in Golgi lumen. TPST1/TPST2 perform the sulfation; F8 is the substrate. This positive biosynthetic compartment is retained as contextual and does not transfer sulfotransferase activity to FVIII.

Summary: Retain the Golgi-lumen sulfation-variant context.

Reason: R-HSA-9668148 explicitly places Y1699F FVIII entity 9668150 in Golgi lumen. The modeled defect concerns a sulfation-dependent VWF-binding determinant, not FVIII performing the sulfation. Retain the source-specific biosynthetic/variant location without generalizing it to all natural F8 products.

Summary: Specify the extracellular face of the tenase-supporting membrane.

Reason: R-HSA-158164 catalystActivity 158179 resolves to the FVIIIa:FIXa complex 158392, with P00451 A1/A2/light-chain participants 158121/158144/158388 on the membrane. FIXa is the protease and FVIIIa its cofactor. Actual human FVIII-dependent factor X activation on washed activated platelets and phospholipid surfaces supports peripheral extracellular-face association. Current GO:0009897 includes externally attached or peripheral proteins; no integral membrane topology is implied. The PROS1 regulatedBy branch was also traversed and does not change the target role.

Proposed replacements: external side of plasma membrane

Summary: Specify external-face FVIIIa in intrinsic-tenase assembly.

Reason: R-HSA-158278 assembles the three human FVIIIa chains with FIXa on the plasma membrane. Their extracellular cofactor/surface context and the independent human activated-platelet assay support GO:0009897 more precisely than broad plasma membrane. This identifies the external peripheral pool, not a transmembrane F8 protein or activity of the 216-residue product.

Proposed replacements: external side of plasma membrane

Summary: Specify external-face recruitment of circulating FVIII.

Reason: R-HSA-5607043 links the soluble extracellular FVIII pool to membrane-associated native chains. Human plasma-derived FVIII-dependent tenase activity on externally supplied washed platelets supports the external face. GO:0009897 includes peripheral attachment, so this refinement does not require membrane insertion or rewrite the separately valid extracellular input.

Proposed replacements: external side of plasma membrane

Summary: Specify the external face of the F9-variant tenase complex.

Reason: R-HSA-9668253 models a hyperactive F9 R384L protease context while its three F8 chains are native. The source’s membrane complex operates on extracellular factor X; the independently tested human FVIII cofactor pool is peripheral on activated platelets. Refine the location to the external face without calling the F8 participants mutants or transferring the F9 catalytic defect to F8.

Proposed replacements: external side of plasma membrane

Summary: Specify external-face localization within the FVIII-variant complex.

Reason: R-HSA-9668365 includes A2 variants R546W, I585T, S577F, V578A and D579A with native companion F8 chains in a membrane tenase model. These are extracellular cofactor assemblies on the outer membrane face, rather than integral membrane proteins. Refine the positive location while preserving the disease-specific functional impairment; a surface-location refinement does not assert wild-type activity for each variant.

Proposed replacements: external side of plasma membrane

Summary: Specify external-face FVIII in the protein-S-regulated complex.

Reason: R-HSA-9669959 places native FVIIIa chains in a membrane-associated FIXa complex regulated by protein S. The target is the cofactor component at the extracellular surface; protein S/FIXa regulatory chemistry is not assigned to F8. Current GO:0009897 captures this peripheral external-face pool, corroborated by the independent human platelet assay.

Proposed replacements: external side of plasma membrane

Summary: Specify the external face of the variant-FIXa cofactor assembly.

Reason: R-HSA-9670874 contains variant F9-associated tenase but native P00451 A1, A2 and light chains. The external substrate/cofactor setting and human platelet-supported FVIII evidence justify GO:0009897. Preserve the F9-versus-F8 product distinction and avoid treating a membrane model as evidence of an integral F8 chain.

Proposed replacements: external side of plasma membrane

Summary: FVIII participates in intrinsic coagulation through its activated cofactor role.

Reason: The cited genetic study is verified as the human F8 inversion/Southern-blot study; its accessible abstract establishes disruption associated with severe hemophilia A, while complete operative Methods were not recovered. The performed coagulation role is supported independently by the inspected human FVIII-BDD study: after thrombin activation and hirudin quenching, FVIIIa is added to plasma-derived human FIXa and human FX with phosphatidylcholine/phosphatidylserine vesicles, and generated FXa is measured with a chromogenic readout (PMID:27749002, supplementary Figures S1–S2). FVIIIa supplies cofactor function; FIXa carries out FX proteolysis. Refine broad blood coagulation to GO:0007597, whose current definition explicitly includes the FIXa-to-FXa step and whose typed ancestry reaches blood coagulation. This does not require all physiological initiation to proceed through FXII. The genetic paper is not recast as an isolated biochemical assay, and engineered BDD/furin-site constructs do not establish coagulation activity of natural F8B.

Proposed replacements: blood coagulation, intrinsic pathway

Summary: Retain inherited intrinsic-tenase participation.

Reason: The exact human target descends from PTN002815617 in the actual v19 tree, and the positive GO:0007597 IBD is grounded in rat F8 donor RGD:727845, without relevant target-path NOT. The rat PMID:2513867 abstract reports secreted active FVIII from cultured sinusoidal endothelial cells, but its full Methods were unavailable. Independent human FVIII-dependent factor X activation in PMID:6804496 and human B-domain-deleted FVIIIa/FIXa/FX reconstitution in PMID:27749002 establish the performed cofactor step directly. FVIIIa enhances FIXa proteolysis; it is not itself the protease or merely the substrate being activated.

Summary: Remove oxidoreductase activity overgeneralized from the cupredoxin-like domain.

Reason: IPR011706 genuinely occurs in FVIII and currently maps to GO:0016491, whose definition requires catalysis of an oxidation-reduction reaction with substrate oxidation-state changes. Actual human FVIII structure establishes copper coordination, while functional experiments establish enhancement of FIXa-mediated proteolysis. Neither is an oxidation-reduction reaction. Transfer of the generic oxidoreductase function of this domain family to the nonenzymatic coagulation cofactor is therefore inappropriate. This rejects the electronic functional propagation, not the valid domain match or copper binding, and does not overrule an unread experimental oxidoreductase annotation.

Summary: Retain the rule-supported COPII cargo compartment as contextual.

Reason: Current ARBA00027486 condition set 4 matches the actual target’s two FunFam features and Haplorrhini lineage. Independent Reactome target routes place FVIII cargo 5689796 in COPII-coated ER-to-Golgi vesicles. This supports a biosynthetic cargo location, not coat assembly or transport catalysis by FVIII. The current rule match is provenance rather than a new experimental assay.

Summary: Retain COPII-vesicle FVIII after ER budding.

Reason: R-HSA-203973 explicitly links ER-lumen FVIII 5689449 to COPII cargo 5689796. The output target’s own compartment supports the vesicle location. FVIII is transported cargo, so this contextual annotation does not assign coat formation or an intracellular tenase reaction to it.

Summary: Retain COPII-vesicle FVIII in the transport-receptor cycle.

Reason: R-HSA-5694409 contains human P00451 cargo 5689796 with its own COPII-vesicle compartment. The participant chain is verified independently of event names. This is a positive biosynthetic location, not evidence that FVIII is a coat or trafficking catalyst.

Summary: Retain COPII-vesicle FVIII during carrier handling.

Reason: R-HSA-5694418 resolves the human FVIII cargo to entity 5689796 in a COPII-coated ER-to-Golgi transport vesicle. The location is retained for this secretory intermediate while the transport machinery’s activities remain assigned to their actual performers.

Summary: Retain COPII-vesicle FVIII in the modeled cargo assembly.

Reason: R-HSA-5694439 explicitly contains human P00451 cargo 5689796 in the COPII-vesicle compartment. Retain this biosynthetic pool; association with cargo receptors does not establish a new transport activity or equivalent trafficking of F8B.

Summary: Retain the COPII transport-intermediate FVIII pool.

Reason: R-HSA-5694441 includes the same explicitly localized human FVIII cargo through the complete participant graph. This supports the imported compartment as a secretory-pathway context, without equating FVIII with the coat proteins or assigning its extracellular cofactor reaction to the vesicle.

Summary: Retain COPII cargo preceding ERGIC delivery.

Reason: R-HSA-5694446 contains COPII FVIII cargo 5689796 and receptor-associated ERGIC FVIII 5689798. Their distinct own compartments are preserved. The vesicle location is a biosynthetic intermediate; the event does not make FVIII a fusion catalyst or a transmembrane receptor.

Summary: Defer the precise native FVIII alpha-granule lumen claim.

Reason: ARBA00084788 condition set 2 matches the target FunFam pair and Haplorrhini lineage, so the current rule provenance is real. A matching rule does not independently resolve the native target identification behind the location. Current native FVIII granule-lumen attribution remains unresolved at the target-protein level. The recovered human releasate article PMID:23640497 has complete main text and assay Methods, but the supplementary protein tables needed to verify P00451 were not recovered. Its absence from searchable main text is not evidence of a negative experiment. The older PMID:6457647 abstract uses factor VIII-related antigen terminology, which cannot automatically be equated with F8 rather than VWF; its full original and the PMID:8467233 review remain unavailable. Preserve uncertainty instead of declaring the curated localization false or importing engineered platelet-FVIII results as native evidence.

Summary: Defer target-level verification of native FVIII in alpha-granule lumen.

Reason: R-HSA-481007 explicitly includes P00451 entity 114591 in alpha-granule lumen, so this is not a compartment borrowed from another participant. Current native FVIII granule-lumen attribution remains unresolved at the target-protein level. The recovered human releasate article PMID:23640497 has complete main text and assay Methods, but the supplementary protein tables needed to verify P00451 were not recovered. Its absence from searchable main text is not evidence of a negative experiment. The older PMID:6457647 abstract uses factor VIII-related antigen terminology, which cannot automatically be equated with F8 rather than VWF; its full original and the PMID:8467233 review remain unavailable. Preserve uncertainty instead of declaring the curated localization false or importing engineered platelet-FVIII results as native evidence.

Summary: Retain receptor-associated ERGIC cargo as contextual.

Reason: Current ARBA00092682 condition set 0 matches the actual target FunFam pair and Primates lineage. The independent Reactome route places FVIII cargo 5689798 in the ERGIC membrane-associated receptor assembly. Membrane association here does not imply that F8 itself spans the membrane; it is a biosynthetic transport state, not the extracellular tenase reaction.

Summary: Retain the ERGIC receptor-associated FVIII cargo pool.

Reason: R-HSA-5694446 delivers FVIII from COPII cargo 5689796 to entity 5689798 in the ERGIC membrane compartment. The target’s own location is explicit, but its role is receptor-associated cargo. Retain that contextual association without inferring integral membrane topology, universal natural-product trafficking, or FVIII-mediated vesicle fusion.

Summary: Activated human FVIIIa is a nonenzymatic activator of FIXa in intrinsic tenase.

Reason: The proposed MF is grounded primarily in the directly performed human reaction of PMID:6804496, not inferred from hemophilia or from the VWF-binding row. Its human FIXa/human FX initial-rate experiments compare reactions with and without activated human FVIII: increased maximum velocity and reduced apparent Km demonstrate cofactor work. The original Methods and Figure 5 identify this human-substrate series separately from the bovine-FX experiments; the VWF-containing FVIII preparation is an explicit limitation. PMID:27749002 independently corroborates activity with thrombin-activated human B-domain-deleted FVIII and an engineered Delta3 comparator. Its main Methods refer to earlier assay protocols, while the actual separate official supplement JTH-15-110-s001.docx, Figure S1 and S2 legends, explicitly specifies hirudin quenching, plasma-derived human FIXa and FX, and PC/PS vesicles; those reagent details come from the inspected supplement, not the abbreviated supplementary listing in the cached main article. Generated FXa reports the supported reaction. The direct public supplement URL is recorded in the source guide; no supplementary figure pixels were inspected. FVIIIa supplies activation/assembly support while FIXa cleaves FX. Current GO:0061133 requires binding to and increasing endopeptidase activity; its only current is_a child specifies cysteine-type enzymes and does not fit FIXa. Human/mouse F5/F8 MF comparator absence remains a caution, not evidence of an overlooked gap. Direct human molecular experiments and the literal term definition support this NEW; no parent activator term or new process is added. The tested processed/engineered proteins do not establish natural F8B activity.