ELN

Summary: Retain the curated outflow-tract morphogenesis annotation as a contextual developmental role of elastin.

Reason: PMID:8132745 identifies a roughly 100 kb deletion disrupting the 3-prime ELN region in two affected members of a human family with supravalvular aortic stenosis. All seven original scanned pages were examined. The human genetic and structural vascular phenotype supports retaining the BHF-UCL curator’s developmental interpretation as non-core, alongside the independently established arterial morphogenesis role. This is deference to the existing IMP interpretation rather than a claim that the paper directly measured an embryonic outflow-tract mechanism or the mutant protein.

Summary: Elastin contributes to postnatal aortic-valve architecture through its matrix role.

Reason: The literal mouse donor P54320 is linked to ENSMUSP00000015138 in the official UniProt record, and the current Ensembl gene-level relationship to human ELN is one-to-one orthology. The exact mouse GO:0003180 IMP record cites PMID:20576933. Its operative main text shows normal neonatal valve measurements followed by altered hinge/cusp architecture and disorganized elastic matrix during postnatal valve maturation. The protein contributes structural material to this organization; the evidence is not an early cushion-formation or human developmental assay. Retain this contextual process as non-core. Detailed supplemental Methods were not recovered, and orthology does not establish identical function of all 13 human products.

Summary: Elastin contributes to postnatal aortic-valve architecture through its matrix role.

Reason: The literal mouse donor P54320 is linked to ENSMUSP00000015138 in the official UniProt record, and the current Ensembl gene-level relationship to human ELN is one-to-one orthology. The exact mouse GO:0003180 IMP record cites PMID:20576933. Its operative main text shows normal neonatal valve measurements followed by altered hinge/cusp architecture and disorganized elastic matrix during postnatal valve maturation. The protein contributes structural material to this organization; the evidence is not an early cushion-formation or human developmental assay. Retain this contextual process as non-core. Detailed supplemental Methods were not recovered, and orthology does not establish identical function of all 13 human products.

Summary: The tropoelastin-family structural role can be refined to elasticity.

Reason: The current InterPro IPR003979 family maps to structural matrix constituent and includes an authenticated match spanning residues 1–782 of the 786-aa displayed human reference. Its official member-family identity is PTHR24018, ELASTIN. The general matrix structural function is correct; the verified is_a descendant GO:0030023 captures the established recoil-producing role supported by human elastic-material observations and the reviewed elastic-fiber architecture. A family match is not an assay of every natural splice product. The replacement GO:0030023 is already present in four other imported annotations for ELN.

Proposed replacements: extracellular matrix constituent conferring elasticity

Summary: The conserved elastin structural function is specifically elasticity-conferring.

Reason: The source names mouse P54320. Current donor GOA contains a general structural IEA and more specific experimental elasticity evidence, including PMID:20576933, whose mouse aortic mechanical tests and matrix morphology were read. The human structural evidence in PMID:9580666 independently supports the same functional refinement. Preserve the literal ISS source and use GO:0030023, a verified is_a child of GO:0005201; do not describe the current donor general IEA as an experimental measurement or the mouse experiment as a human product assay. The replacement GO:0030023 is already present in four other imported annotations for ELN.

Proposed replacements: extracellular matrix constituent conferring elasticity

Summary: Elastin is a matrix structural constituent with an established elasticity-conferring role.

Reason: PMID:25037231 identifies ELN in ECM-enriched human colon, colon-tumor, liver-metastasis and normal-liver preparations. Additional file 2, sheets A and B, row 25 contains 31 distinct peptides overall and a protein group with P15502-2 as the principal accession plus numerous other ELN accessions. This is protein-group detection, not isoform-2-specific identification or a mechanical elasticity assay. The computational structural classification is retained and refined to GO:0030023 by integration with the independent human elastic-material evidence in PMID:9580666. Neither the historical principal sequence nor shared peptides authenticate the current full precursor or every natural splice product. The replacement GO:0030023 is already present in four other imported annotations for ELN.

Proposed replacements: extracellular matrix constituent conferring elasticity

Summary: Elastin is an extracellular matrix constituent that confers elasticity.

Reason: PMID:9580666 reports mutant tropoelastin expression, abnormal elastic material and reduced elastin deposition in human skin. The positive structural claim is retained and refined to the verified elasticity-specific descendant GO:0030023. The authentic abstract and partial original were read; complete Methods remain unavailable. This refinement does not assign the patient mutation or measured behavior to every natural splice product. The replacement GO:0030023 is already present in four other imported annotations for ELN.

Proposed replacements: extracellular matrix constituent conferring elasticity

Summary: Refine the supported fibulin-5 interaction to extracellular matrix binding using the combined evidence.

Reason: The authentic abstract of PMID:11805834 positively reports calcium-dependent fibulin-5–elastin binding; Q9WVH8 is the imported mouse fibulin-5 partner. Complete operative Methods and the exact ELN species/preparation in this study remain unavailable. The positive report and existing curator assertion are retained. Independently inspected human tropoelastin–fibulin-5/fibrillin assembly experiments in PMID:15790312 and PMID:19570982 establish the more informative GO:0050840 claim for ELN. This is a synthesis-based refinement, not a claim that the missing Methods were recovered or that all natural splice products were tested.

Proposed replacements: extracellular matrix binding

Summary: Human tropoelastin binds fibrillin-1 fragments in an elastic-matrix assembly context.

Reason: PMID:15790312 measured binding of human fibrillin-1 fragments PF2 and PF7 to immobilized human tropoelastin, with BSA controls and with or without fibulin-5 (Methods: Inhibition binding assays; Figure 3C/D). This is direct binding to an established structural component of the elastic-fiber microfibrillar template, supporting GO:0050840. The assay uses fragments, not intact fibrillin-1, and the tropoelastin insert is not mapped to all 13 current products. The caption ends with an inconsistent PF5 label; the Methods and panel descriptions identify PF2/PF7.

Proposed replacements: extracellular matrix binding

Summary: Human tropoelastin binds fibulin-5 during elastic-matrix assembly.

Reason: PMID:15790312 directly measured the human fibulin-5–tropoelastin interaction by solid-phase binding and SPR, using immobilized tropoelastin and a blank-capped reference channel (Methods: BIAcore analysis; Results and Figure 3). The paper places this interaction in deposition of elastin onto a fibrillin-rich matrix, supporting extracellular matrix binding rather than a refinement based only on a partner name. The precise experimental tropoelastin splice product is unresolved.

Proposed replacements: extracellular matrix binding

Summary: Tropoelastin associates with fibulin-4 as part of elastic-matrix assembly.

Reason: PMID:16478991 demonstrates reciprocal co-immunoprecipitation of human tropoelastin and human fibulin-4 in transfected 293T lysates, with single-transfection controls (Methods and Figure 8C). Its purified solid-phase assay instead used bovine tropoelastin and mouse fibulin-4. Together with the human recombinant binding and assembly experiments in PMID:19570982, this supports extracellular matrix binding. The human co-immunoprecipitation is not claimed to be purified binary contact, and no exact natural ELN insert sequence or all-isoform equivalence is established.

Proposed replacements: extracellular matrix binding

Summary: Refine the supported fibulin-5 interaction to extracellular matrix binding using the combined evidence.

Reason: The authentic abstract and partial original Results preview of PMID:17035250 positively report wild-type/mutant human fibulin-5 binding to tropoelastin; Q9UBX5 is the imported human partner. Complete operative Methods and the exact ELN species/preparation in this study remain unavailable. The positive report and existing curator assertion are retained. Independently inspected human tropoelastin–fibulin-5/fibrillin assembly experiments in PMID:15790312 and PMID:19570982 establish the more informative GO:0050840 claim for ELN. This is a synthesis-based refinement, not a claim that the missing Methods were recovered or that all natural splice products were tested.

Proposed replacements: extracellular matrix binding

Summary: Human tropoelastin shows weak binding to mouse fibulin-3 in a solid-phase assay.

Reason: PMID:17324935 uses recombinant human tropoelastin and mouse fibulin-3, matching the imported cross-species partner. Methods and Figure 5D establish a positive concentration-dependent interaction, but saturation was not reached at 1 micromolar. Retain the supported generic interaction as non-core. This paper does not establish a specific role for that weak pair in elastin assembly, so the partner’s extracellular identity alone is not used to refine the molecular function. The supplied tropoelastin insert is not sequenced or mapped to a current splice product. The distinction from fibulin-4/5 is the demonstrated assembly role, not assay format or the partner’s matrix membership alone.

Summary: Human tropoelastin directly binds fibulin-4 in elastic-matrix assembly experiments.

Reason: PMID:19570982 measures binding of human recombinant tropoelastin to fibulin-4 by SPR and solid-phase assays (Figure 3), and shows LOX-dependent modulation of that interaction (Figure 7). These experiments examine assembly of an extracellular structural matrix and support GO:0050840. The tropoelastin preparation lacks domain 26A; its complete correspondence to a current ELN splice product was not established. The historic fibulin-4 residue bounds are retained as reported and not silently remapped.

Proposed replacements: extracellular matrix binding

Summary: Human tropoelastin directly binds its cross-linking enzyme LOX in a solid-phase assay.

Reason: PMID:19570982 reports binding of soluble recombinant human LOX to immobilized human tropoelastin in the solid-phase assay (Methods; Figure 6B), despite no detectable interaction in the reported SPR configuration. Preserve this method-dependent positive interaction as non-core. Tropoelastin supplies the substrate and structural material; LOX performs oxidative chemistry. Neither enzyme activity nor an enzyme-regulator subtype is transferred to ELN from the partner class. The tropoelastin preparation lacks domain 26A and is not mapped to all natural products.

Summary: Human tropoelastin binds fibulin-5 in a matrix-deposition mechanism.

Reason: PMID:19570982 establishes direct fibulin-5 binding to human tropoelastin by SPR and solid-phase assays, maps several fibulin-5 binding regions, and tests competition with fibrillin-1 (Figures 3 and 7). The independent assembly experiments support extracellular matrix binding, beyond a generic partner-class label. Rat fibroblast depletion experiments are separate from the human recombinant assays. Tropoelastin lacking domain 26A was used; exact correspondence to a current natural ELN product is unresolved.

Proposed replacements: extracellular matrix binding

Summary: Direct interaction of recombinant human tropoelastin with LOXL2 is supported, but this generic enzyme–substrate binding annotation is non-core.

Reason: PMID:30676771 directly measured binding of recombinant human tropoelastin, described as isoform 2, to immobilized full-length LOXL2 by surface plasmon resonance, with an activated and blocked reference channel lacking LOXL2 (Methods: Surface plasmon resonance; Results: LOXL2 and tropoelastin interaction; Figure 5 caption). The reported steady-state dissociation constant is 146 ± 16 nM (n = 4). The subsequent oxidation and cross-linking experiments identify tropoelastin as the substrate and LOXL2 as the oxidase. They do not establish an ELN enzyme-regulator activity or a more specific binding function from the partner identity alone. Retain the supported generic interaction as non-core under the campaign convention; preserve the imported P15502-2 assay designation. The Methods describe human isoform 2 produced in E. coli but do not authenticate the complete experimental insert against the current 724-residue UniProt product, so no exact precursor-sequence or all-isoform generalization is made.

Summary: Extracellular elastin is a substrate of the modeled degradation reaction.

Reason: R-HSA-1566962 has input polymer 2161232, whose repeated unit 1454880 resolves to human P15502 through reference entity 54272 and carries GO:0005576. Its cleaved output also resolves to P15502 fragments. The catalyst is a separate extracellular proteinase set, not ELN. Retain extracellular region for the substrate and products without transferring protease activity or assuming the cleaved material remains in a mature elastic fiber. This broad location is retained as non-core context; the core structural location is the elastic fiber.

Summary: The modeled ELN component belongs to an elastic fiber during fibulin association.

Reason: R-HSA-1592387 explicitly has an elastic-fiber input (2161360) and an elastic-fiber–fibulin output (2395337). Both trace through elastin polymer 2161232 to human P15502 at entity 1454880. Refine the broad extracellular-region location to GO:0071953 because this particular curated context explicitly supplies the fiber assembly state. This is a database component-chain inference, not a newly read localization experiment or a claim that soluble tropoelastin always resides in a mature fiber.

Proposed replacements: elastic fiber

Summary: Tropoelastin aggregates participate in extracellular microfibril association.

Reason: R-HSA-2129353 traces its tropoelastin aggregate 2161342 and aggregate-containing output 2161254 to human P15502 entity 1454880 with extracellular-region compartment. The model depicts an assembly intermediate rather than exclusively mature elastic fibers, so the broad location remains appropriate. The ten repeated aggregate components are modeled stoichiometry, not ten independent observations. Non-target fibrillin and fibulin branches were not exhaustively expanded. This broad location is retained as non-core context; the core structural location is the elastic fiber.

Summary: Elastin material is extracellular during lysyl-oxidase-mediated cross-linking.

Reason: R-HSA-2129375 is a Polymerisation event with a tropoelastin-aggregate input and elastic-fiber output, both traced to human P15502. The exact target entities carry extracellular region. The separate catalyst 2022088 has protein-lysine 6-oxidase activity and resolves to a lysyl-oxidase complex; ELN supplies structural substrate rather than that enzymatic activity. Preserve the broad location across the modeled precursor-to-fiber transition. This broad location is retained as non-core context; the core structural location is the elastic fiber.

Summary: The modeled ELN component is within an elastic fiber binding additional matrix proteins.

Reason: R-HSA-2161282 contains elastic-fiber complexes on both sides. The input 2396077 and output 2161325 trace through 2395337 and elastic-fiber complex 2161360 to elastin polymer 2161232 and human P15502 entity 1454880. This specific component chain supports refinement from extracellular region to GO:0071953. Associated-protein branches are not represented as additional direct ELN binding experiments, and no natural splice-product equivalence is inferred.

Proposed replacements: elastic fiber

Summary: Tropoelastin coacervates in the extracellular region.

Reason: R-HSA-2161293 has human P15502 entity 1454880 as the repeated input and as ten components of aggregate 2161342. The entity spans reported coordinates 27–786, consistent with the displayed-reference signal-peptide boundary, but it is not a separate natural splice-product assertion. The model concerns extracellular aggregate formation before mature-fiber organization. Repeated entries are preserved as model stoichiometry rather than deduplicated or counted as independent evidence. This broad location is retained as non-core context; the core structural location is the elastic fiber.

Summary: Extracellular elastin is an input to a membrane-associated proteolysis model.

Reason: R-HSA-2514790 traces its elastin input and cleaved output to human P15502 entities bearing GO:0005576. The event also includes plasma membrane because its catalyst is membrane associated; that event-level location is not transferred to ELN. The separate catalyst activity is metalloendopeptidase activity, not an ELN function. Broad extracellular location remains supported across the intact and cleaved substrate states. This broad location is retained as non-core context; the core structural location is the elastic fiber.

Summary: Human elastin is extracellular in the curated cross-species emilin/fibulin association.

Reason: R-NUL-2426460 is explicitly chimeric: complexes 2426508 and 2426553 contain human elastin polymer 2161232 together with mouse Fbln5 and Emilin1 entities. The ELN branch resolves to human P15502 entity 1454880 with extracellular-region compartment. Retain the positive human-component location while preserving the mixed-species assembly context. The R-NUL identifier is not treated as a failed source or a mouse-only ELN assertion. This broad location is retained as non-core context; the core structural location is the elastic fiber.

Summary: Elastin contributes structural recoil to respiratory tissues.

Reason: PMID:9873040 characterizes human cutis laxa mutations and fibroblast transcripts, with clinical upper-airway obstruction and limited cardiopulmonary involvement; it is not a direct gas-exchange assay. The physiological claim is retained at contextual strength by integration with the explicit pulmonary elastic-fiber role in PMID:23962539: elastin-containing networks permit respiratory expansion and recoil. GO:0007585 includes exchange through ventilated lungs and is not restricted to a catalytic gas-transfer step. No alveolar diffusion measurement, tested natural isoform or respiratory enzyme activity is attributed to the 1999 study.

Summary: Elastin-containing arterial matrix contributes to normal blood flow.

Reason: PMID:8096434 reports a human translocation disrupting ELN that cosegregates with supravalvular aortic stenosis. Only its authentic abstract was accessible, so no unseen hemodynamic experiment or protein construct is claimed. The contextual circulation annotation is consistent with the independently reviewed arterial structural role: elastic lamellae provide recoil and maintain arterial geometry, described in PMID:23962539 and experimentally disrupted in the mouse arterial study PMID:9607766. The product performs structural work in the vessel wall; this does not assign cardiac pumping or a direct human signaling assay to ELN.

Summary: Elastin supports circulation through the mechanical properties of elastic vessels.

Reason: The complete operative text of PMID:9873040 concerns human cutis laxa mutations and fibroblast RNA, with largely spared cardiopulmonary function and limited clinical vascular findings. It does not directly measure circulation. Retain the broad physiological role as non-core using the independent arterial-matrix evidence in PMID:9607766 and the elastic-lamella mechanics summarized in PMID:23962539. This preserves the original TAS citation while distinguishing the normal structural contribution from the measured scope of that particular mutation study.

Summary: Elastin-containing extracellular matrix contributes to organ shape and tissue architecture.

Reason: PMID:9580666 reports human cutis laxa, abnormal elastic material and reduced elastin deposition, but only an authentic abstract and partial original were accessible. Its broad organ-morphogenesis claim is retained as a contextual structural role, supported independently by the mouse arterial morphogenesis experiments in PMID:9607766. Elastin supplies material and matrix organization rather than merely being a consumed substrate. No human embryonic organ assay or equivalence of every natural splice product is inferred.

Summary: Elastin supplies the elasticity-conferring material of elastic matrix.

Reason: The exact mouse donor GO:0030023 IDA record cites PMID:20576933. Its main Methods/Results describe Eln haploinsufficiency, altered elastic matrix and increased aortic tensile stiffness at juvenile and adult stages. This tissue-level evidence is consistent with the human elastic-material role, rather than a purified single-molecule or human isoform-specific assay. Official UniProt and Ensembl records authenticate the named donor and orthology; no self-donor or evidence-count objection applies.

Summary: The elasticity-related role is consistent with ELN detection in human atrial matrix preparations.

Reason: PMID:27559042 Table 1 identifies Elastin in the guanidine-hydrochloride input extract of human atrial appendages. The glycoprotein-enrichment and direct-glycopeptide columns for Elastin are blank, so those modalities are not claimed as positive ELN measurements. The paper provides proteomic identification and computational matrix classification rather than a direct test of elastic mechanics; the established structural role is supported independently by human elastic-material observations in PMID:9580666. Preserve the RCA annotation without treating decorin-specific cleavage, glycosylation or myostatin experiments as ELN assays.

Summary: The existing RCA classification agrees with elastin’s established matrix elasticity function.

Reason: PMID28327460 identifies ELN in decellularized human cell-derived ECM: Supplementary Table I row 36 is positive for bone-marrow MSC donors 3–5, and Table II row 27 is positive for adipose-derived ECM. These are gene-level proteomic summaries, not a mechanical recoil assay. Retain the RCA functional classification because it is consistent with the independently supported structural role of elastin, including the human elastic-material observations in PMID9580666; do not infer elasticity solely from detection. The study’s serum/shared-peptide and residual-cellular-material limitations remain explicit, and no natural-product equivalence is assigned.

Summary: The existing RCA classification is biologically consistent with elastin’s elasticity role.

Reason: PMID28675934 supplies six human P15502 protein-summary rows in omental ECM preparations, with one reported unique peptide per row. It examines extraction and proteomic detection, not ELN-dependent recoil or cross-link mechanics. Retain the existing computational functional classification using established ELN structural biology, including PMID9580666, without relabeling the tissue proteomics as a direct elasticity assay. The records do not resolve ELN splice products or establish tumor-specific function.

Summary: ELN is detected in extracellular-matrix-enriched human tissue fractions.

Reason: PMID:25037231 uses sequential extraction to deplete cytosolic, nuclear, membrane and cytoskeletal proteins, followed by analysis of the insoluble ECM-enriched fraction. The authentic Additional file 2 workbook identifies ELN in sheets A and B, row 25, with 31 distinct peptides overall and positive measurements across all 16 sample or pool preparations. These are repeated tissue samples and liver pools, not 16 independent patients. The principal P15502-2 belongs to a multi-accession protein group, so no isoform-specific detection is inferred. The broad ECM location is directly supported; these fraction measurements do not establish exclusive localization or the assembly state of each detected molecule. This broad location is retained as non-core context; the core structural location is the elastic fiber.

Summary: ELN is detected in a human atrial extracellular-matrix extract.

Reason: PMID:27559042 Table 1 lists Elastin as detected in the GuHCl input fraction. Operative Methods describe human atrial tissue and sequential 0.5 M NaCl, 0.1% SDS and 4 M guanidine-hydrochloride extraction, followed by LC-MS/MS against a human database. This supports the broad extracellular-matrix location at the preparation level. Blank enrichment and glycopeptide cells are not converted into positive findings, and no individual ELN splice product, glycosylation site, exclusive location or mature-fiber topology is assigned. The detailed online supplement and ELN peptide spectra were not inspected. This broad location is retained as non-core context; the core structural location is the elastic fiber.

Summary: ELN is detected in decellularized cell-derived ECM preparations.

Reason: The genuine PMID28327460 supplement contains positive ELN protein measurements in bone-marrow MSC ECM and adipose-derived ECM. Human cells were cultured for 14 days, decellularized, and the retained matrix was digested for LC-MS/MS. This supports the broad extracellular-matrix annotation. Residual intracellular proteins and shared human/bovine peptides were acknowledged by the authors; the ELN summary does not provide peptide sequences to resolve those species or splice-product limits. No exclusive compartment or assembled elastic-fiber architecture is inferred from the protein digests. This broad location is retained as non-core context; the core structural location is the elastic fiber.

Summary: Human ELN/P15502 is present in ECM-enriched omental tissue fractions.

Reason: The PMID28675934 ACS workbook identifies P15502/ELN_HUMAN in C. Omentum_Unfrac. row 618 and D. Omentum_Frac. rows 11, 2162, 6241, 6493 and 7036. These comprise normal and metastatic omental samples processed as crude, urea-soluble or pellet fractions. The original Methods describe sequential enrichment followed by digestion and human-database LC-MS/MS identification. Retain broad extracellular-matrix location; one reported unique peptide per row and the absence of peptide sequences here do not establish a specific ELN splice product, sample purity or elastic-fiber architecture. This broad location is retained as non-core context; the core structural location is the elastic fiber.

Summary: The elastin-family matrix location can be refined to elastic fibers.

Reason: The literal IPR003979 family has a current GO:0031012 mapping and an authenticated match to human P15502. The prediction is biologically correct but broad for the established structural product. Independent human fiber-localization observations in PMID:10424889 and PMID:7534784 and the architecture reviewed in PMID:23962539 justify GO:0071953. This refinement of a general family prediction does not imply that every soluble precursor, degradation fragment or proteomic digest has been shown in a mature fiber.

Proposed replacements: elastic fiber

Summary: Elastin is a structural component of elastic fibers in the extracellular matrix.

Reason: PMID:9580666 positively reports altered elastin within elastic fibers in human skin by electron microscopy and immunocytochemistry. The broad extracellular matrix location is refined to GO:0071953, whose definition includes the polymerized tropoelastin core. Only the authentic abstract and partial original were accessible; no complete Methods or figure-pixel reading is claimed. This is a location refinement, not evidence that every splice product incorporates identically.

Proposed replacements: elastic fiber

Summary: Elastin-containing arterial matrix regulates smooth-muscle proliferation.

Reason: PMID:9607766 directly tests mouse Eln loss, with increased aortic smooth-muscle proliferation and luminal obstruction in vivo and in 24-hour aortic organ culture without blood flow (Results, Figure 5 and Methods). This supports a contextual regulatory role of arterial elastin rather than a purely hemodynamic consequence. Retain it as non-core relative to the matrix structural function. The experiment does not identify a human ELN receptor pathway or an isolated human splice-product activity.

Summary: Tropoelastin binds extracellular matrix components during elastic-matrix assembly.

Reason: The current mouse donor GO:0050840 IDA record cites PMID:18757743. Its genuine main text establishes a mouse-cDNA screen with GFP-tagged proteins and controlled binding assays, but the target-specific ELN pilot result lies in Table S2, whose supplement was not recovered. That limitation is preserved rather than inventing a specific mouse pair. Independent human experiments in PMID:15790312 and PMID:19570982 directly demonstrate tropoelastin binding to fibrillin/fibulin matrix components in assembly contexts, supporting the existing functional claim. The validated donor identity and orthology do not establish identical activity of every splice product.

Summary: Elastin is a component of elastic fibers.

Reason: The authentic abstract of PMID:10424889 explicitly reports immunoelectron localization of MAGP-36 with tropoelastin in human and bovine tissues, distinguishing early and mature elastic fibers from elastin-free microfibrils. This is a positive target-relevant localization observation even though another matrix protein is foregrounded. Complete operative Methods and figure pixels were not recovered, so exact antibodies, preparation details and a product-specific assignment are not reconstructed. The established ELN location and explicit positive report support retaining the curated IDA annotation.

Summary: Elastin occupies the amorphous core of human elastic fibers.

Reason: PMID:7534784 explicitly reports human tissue fibers that are positive for elastin and fibrillin-1, with ultrastructural localization in skin and saphenous vein. Its fibulin-1 emphasis does not exclude the ELN localization control. The authentic abstract was read; complete original Methods and figure pixels remain unavailable. Retain the positive curated IDA location without assigning a particular ELN splice product or claiming newly inspected ultrastructure.

Summary: Elastin is a structural component of elastic fibers.

Reason: The donor chain is authenticated, but the source-specific species boundary matters: the current mouse P54320 IDA cites PMID:17099216, whose original Methods and Results use EGFP-tagged bovine tropoelastin in mouse MEF 3T3 hosts and state that parental cells do not express tropoelastin. This is not represented as a direct endogenous mouse ELN localization assay. The biological location is independently established in human tissues by PMID:10424889 and PMID:7534784 and synthesized in PMID:23962539, so it is retained without rejecting the conserved location because of that donor-preparation discrepancy. No exact human splice-product equivalence is inferred.

Summary: Polymerized tropoelastin forms the core of elastic fibers.

Reason: PMID:23962539 is a review whose genuine publisher PDF describes the cross-linked elastin core and surrounding microfibrils, and distinguishes tropoelastin coacervation from LOX-catalyzed cross-link chemistry. Relevant pages 1, 3, 10 and 11 were read. This directly supports the TAS elastic-fiber location as a biological synthesis, not as a newly performed localization assay. The review also discusses alternative splicing, which does not establish equal incorporation of all 13 current products.

Summary: Tropoelastin contributes directly to elastic-fiber assembly through self-association and matrix incorporation.

Reason: The exact mouse donor GO:0085029 IMP record cites PMID:20576933, which documents altered postnatal valve matrix organization in Eln-haploinsufficient mice. The broader assembly claim can be refined using independent mechanistic evidence: tropoelastin coacervates, binds the microfibrillar assembly machinery and supplies the polymerized core described in PMID:23962539 and the human binding/assembly study PMID:19570982. GO:0048251 is a verified is_a child of GO:0085029. ELN performs structural self-assembly work; LOX performs the oxidative cross-link chemistry. This is not a transfer of enzyme activity, a claim that necessity alone proves participation, or an assignment to every natural product.

Proposed replacements: elastic fiber assembly

Summary: Tropoelastin contributes directly to elastic-fiber assembly through self-association and matrix incorporation.

Reason: The exact mouse donor GO:0085029 IMP record cites PMID:20576933, which documents altered postnatal valve matrix organization in Eln-haploinsufficient mice. The broader assembly claim can be refined using independent mechanistic evidence: tropoelastin coacervates, binds the microfibrillar assembly machinery and supplies the polymerized core described in PMID:23962539 and the human binding/assembly study PMID:19570982. GO:0048251 is a verified is_a child of GO:0085029. ELN performs structural self-assembly work; LOX performs the oxidative cross-link chemistry. This is not a transfer of enzyme activity, a claim that necessity alone proves participation, or an assignment to every natural product.

Proposed replacements: elastic fiber assembly

Summary: Elastin is a non-collagenous structural component of interstitial matrix.

Reason: PMID:36399478 describes the MatrisomeDB proteomic resource and matrix classification; its main text does not itself provide a target-specific ELN spectrum or isoform assignment. The current GO:0140149 definition explicitly includes elastin within this non-collagenous interstitial component, consistent with the independently established elastic-matrix structure in PMID:23962539. Retain this broad TAS matrix classification without pretending that a resource paper measured each ELN molecule in a mature elastic fiber. GO:0071953 is part_of this compartment; that edge is not misrepresented as is_a. This broad location is retained as non-core context; the core structural location is the elastic fiber.