EVC2 (limbin) is a single-pass membrane protein that associates with EVC in a specialized region of proximal ciliary membrane. This assembly promotes Hedgehog signaling downstream of Smoothened and regulates GLI activator and repressor responses. The EVC2 C-terminal region engages EFCAB7, linking the EVCβEVC2 assembly to the EFCAB7βIQCE module that restricts its position within the cilium. Pathogenic EVC2 variants cause Ellisβvan Creveld syndrome and Weyers acrofacial dysostosis.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005634 nucleus | HDA PMID:21630459 Proteomic characterization of the human sperm nucleus. | KEEP AS NON CORE | Summary: EVC2 was detected in a human sperm nuclear proteomics preparation. Reason: The source-specific positive identification is recoverable in coauthor Judit Castillo CorullΓ³n's 2014 thesis: Results 4.2.1 (printed page 130) explicitly links its 403-protein list to the Supporting Information of PMID:21630459, and Annex 8.2, Supplementary Table 8.1 (page 199) reports EVC2/Limbin, UniProt Q86UK5, with 3.7% protein coverage and three peptides. The thesis describes CTAB-isolated nuclei from human normozoospermic samples. This supports retaining the reported nuclear association as a specialized non-core localization. The journal's complete text remains unavailable; the accessible author-restated protocol and reproduced target table are distinguished from it. Individual peptide sequences, peptide uniqueness for this target, EVC2-specific imaging and discrimination among the three natural UniProt products were not established in the material read. No nuclear mechanism or universal localization is inferred. Supporting Evidence: |
| GO:0005634 nucleus | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: Retain the ortholog-supported nuclear pool as a contextual localization. Reason: SL-0191 correctly maps to nucleus. ENSMUSP00000055130 is the mouse Evc2 translation and exactly matches the current 1,220-residue Q8K1G2 sequence. The current mouse Q8K1G2 donor carries IDA PMID:21356043. In that original, Results Figure 7 and nuclear-fractionation Methods detect endogenous full-length Evc2 in wild-type mouse MEF nuclear and cytoplasmic fractions, with Evc2-null cells and c-Jun/alpha-tubulin controls. Evc is a separate protein and is not detected in the nuclear fraction. The authors did not observe Evc2 nuclear accumulation by their immunofluorescence or overexpression experiments, so neither a nuclear transport mechanism nor nuclear transcriptional activity is established. Retain the conserved nuclear pool as a non-core localization context; these mouse assays do not resolve localization or processing of the three human natural products. Propagation Review Root cause: NO FAILURE NON CORE Sources checked: UniProtKB:Q8K1G2 SUPPORTS TRANSFER Current IDA PMID:21356043 and its actual knockout-controlled fractionation support the nuclear context. ensembl:ENSMUSP00000055130 SUPPORTS TRANSFER Current mouse translation identity and exact Q8K1G2 sequence verified. UniProtKB-SubCell:SL-0191 SUPPORTS TRANSFER Official nucleus vocabulary mapping verified. Supporting Evidence: |
| GO:0005634 nucleus | ISS GO_REF:0000024 | KEEP AS NON CORE | Summary: Retain the experimentally grounded mouse-to-human nuclear localization inference as non-core. Reason: The current mouse Q8K1G2 donor carries IDA PMID:21356043. In that original, Results Figure 7 and nuclear-fractionation Methods detect endogenous full-length Evc2 in wild-type mouse MEF nuclear and cytoplasmic fractions, with Evc2-null cells and c-Jun/alpha-tubulin controls. Evc is a separate protein and is not detected in the nuclear fraction. The authors did not observe Evc2 nuclear accumulation by their immunofluorescence or overexpression experiments, so neither a nuclear transport mechanism nor nuclear transcriptional activity is established. Retain the conserved nuclear pool as a non-core localization context; these mouse assays do not resolve localization or processing of the three human natural products. Propagation Review Root cause: NO FAILURE NON CORE Sources checked: UniProtKB:Q8K1G2 SUPPORTS TRANSFER The proximate source is mouse IDA PMID:21356043, not an inference from a nuclear-domain prediction. Supporting Evidence: |
| GO:0005886 plasma membrane | IEA GO_REF:0000044 | MODIFY | Summary: Refine the broad plasma-membrane mapping to the supported ciliary membrane. Reason: SL-0039 correctly maps to plasma membrane but is broader than the supported compartment. Mouse Evc2 localization and selective-permeabilization experiments in PMID:21356043 Figures 3β4 resolve ciliary membrane topology; PMID:24582806 places EVC2 at its proximal EvC zone. Native human Q86UK5 is also explicitly modeled in ciliary membrane in Reactome R-HSA-5633051. GO:0060170 retains that positive evidence. The mouse constructs and human model have the distinct species and processing limits detailed in the source guide. Propagation Review Root cause: TERM SCOPING PROBLEM Sources checked: UniProtKB-SubCell:SL-0039 SUPPORTS TRANSFER Correct broad mapping; actual target-family membrane localization and human participant support the finer compartment. Proposed replacements: ciliary membrane |
| GO:0005886 plasma membrane | ISS GO_REF:0000024 | MODIFY | Summary: Refine the mouse-supported plasma-membrane assertion to ciliary membrane. Reason: The mouse Q8K1G2 donor carries EXP PMID:21356043 for plasma membrane. Its Evc2-specific localization and topology experiments (Figures 3β4), together with PMID:24582806 and the explicit human Reactome participant, support the more precise ciliary membrane. This conserved location does not establish equivalent localization or processing of all three human products. Propagation Review Root cause: TERM SCOPING PROBLEM Sources checked: UniProtKB:Q8K1G2 SUPPORTS TRANSFER Actual donor EXP PMID:21356043 includes Evc2-specific localization and topology assays. Proposed replacements: ciliary membrane |
| GO:0005929 cilium | IEA GO_REF:0000120 | MODIFY | Summary: Refine the combined broad cilium mapping to ciliary membrane. Reason: SL-0066 maps to cilium, and ENSMUSP00000055130 exactly matches the mouse Q8K1G2 donor carrying IDA PMID:21356043. Evc2-specific localization and selective permeabilization in that original (Figures 3β4), corroborated by PMID:24582806 and human Reactome R-HSA-5633051, resolve the ciliary membrane. GO:0060170 is part of both cilium and plasma membrane; the refinement relies on positive topology evidence, with mouse construct and human-model limits retained in the source guide. Propagation Review Root cause: TERM SCOPING PROBLEM Sources checked: UniProtKB:Q8K1G2 SUPPORTS TRANSFER Actual mouse localization/topology supports the membrane subcompartment. ensembl:ENSMUSP00000055130 SUPPORTS TRANSFER Exact current donor translation verified. UniProtKB-SubCell:SL-0066 SUPPORTS TRANSFER Correct broad cilium vocabulary mapping. Proposed replacements: ciliary membrane |
| GO:0005929 cilium | ISS GO_REF:0000024 | MODIFY | Summary: Refine the conserved ciliary location to its membrane compartment. Reason: Mouse Q8K1G2 carries cilium IDA PMID:21356043. Its localization and membrane-topology experiments (Figures 3β4) support the ciliary membrane refinement, with independent proximal-zone localization in PMID:24582806 and concordant human Reactome modeling. The conserved location is not an assertion that an engineered mouse Weyers deletion represents any natural human splice product. Propagation Review Root cause: TERM SCOPING PROBLEM Sources checked: UniProtKB:Q8K1G2 SUPPORTS TRANSFER The actual mouse original resolves ciliary localization and membrane topology. Proposed replacements: ciliary membrane |
| GO:0007224 smoothened signaling pathway | IEA GO_REF:0000120 | ACCEPT | Summary: Retain EVC2 participation in Smoothened signaling within the ciliary EVCβEVC2 assembly. Reason: The actual human IPR022076 and IPR026501 matches map to GO:0007224, and the mouse/Ensembl sources resolve to Evc2. PMID:21356043 Figure 1 tests mouse Evc2 depletion and null cells downstream of the Smoothened agonist purmorphamine. PMID:24582806 Figures 1β4 and 6 places EVC2 within the ciliary signaling assembly and shows impaired SAG-induced Gli1/Ptch1 activation and GLI3-repressor regulation after Evc2 loss. Together, assembly and pathway-response evidence supports conserved participation in the signals generated after Smoothened activation. Positive regulation is a compatible additional role, not a replacement for this pathway claim. These mouse experiments do not assay each natural human product. Propagation Review Root cause: NO FAILURE CORE Sources checked: InterPro:IPR022076 SUPPORTS TRANSFER Actual human target family match and pathway mapping verified; its cited original directly tests mouse Evc2 signaling. InterPro:IPR026501 SUPPORTS TRANSFER Broader EVC/EVC2 family match verified; no EVC-only function is mechanically transferred. UniProtKB:Q8K1G2 SUPPORTS TRANSFER Current IMP PMID:21356043 provides the proximate mouse functional source. ensembl:ENSMUSP00000055130 SUPPORTS TRANSFER Exact mouse Evc2 translation verified. |
| GO:0007224 smoothened signaling pathway | ISS GO_REF:0000024 | ACCEPT | Summary: Retain EVC2 participation in Smoothened signaling within the ciliary EVCβEVC2 assembly. Reason: Mouse Q8K1G2 carries GO:0007224 IMP from PMID:21356043. Its Evc2-specific knockdown/null experiments reduce purmorphamine-induced Gli reporter and Ptch1 responses (Figure 1). Independent Evc2-null NIH/3T3 experiments in PMID:24582806 Figure 6C establish defective SAG-induced target-gene activation and GLI3-repressor control within the characterized EVCβEVC2 signaling assembly. Retain the conserved pathway participation; the positive direction does not invalidate the donorβs pathway term. This is mouse-to-human inference with the construct and product limits recorded in the source guide, not a human isoform-specific assay. Propagation Review Root cause: NO FAILURE CORE Sources checked: UniProtKB:Q8K1G2 SUPPORTS TRANSFER Actual Evc2-specific mouse pathway-response and complex experiments support the imported pathway participation as well as a positive regulatory role. |
| GO:0060170 ciliary membrane | IBA GO_REF:0000033 | ACCEPT | Summary: Retain PAINT-supported ciliary membrane localization. Reason: The actual PTHR16795 tree places the sequence-verified human Q86UK5 leaf PTN002497664 below PTN000423571, with the relevant positive IBD and no target-path NOT. The mouse donor identities and aligned sequences were verified. Evc2-specific ciliary localization/topology in PMID:21356043 Figures 3β4 and proximal-zone localization in PMID:24582806 support the inherited membrane location; Reactome independently models native human Q86UK5 there. This supports the node placement without extending the assays to all human products. Propagation Review Root cause: NO FAILURE CORE Sources checked: PANTHER:PTN000423571 SUPPORTS TRANSFER The GO:0060170 IBD lies on the verified target path; original mouse Evc2 localization supports this inherited location. |
| GO:0060170 ciliary membrane | IEA GO_REF:0000120 | ACCEPT | Summary: Retain the ciliary-membrane location supported by mapped ortholog and vocabulary sources. Reason: Mouse Q8K1G2 carries ciliary-membrane IDA PMID:24582806, and SL-0305 maps to that compartment. The original identifies EVC2 at the proximal ciliary membrane and tests its redistribution after EFCAB7 loss (Figure 6EβG); PMID:21356043 Figures 3β4 separately resolves Evc2 membrane topology. These are mouse experiments, with a concordant human Reactome model rather than direct testing of every human product. Propagation Review Root cause: NO FAILURE CORE Sources checked: UniProtKB:Q8K1G2 SUPPORTS TRANSFER Actual mouse Evc2 IDA source and its original localization experiments were inspected. ensembl:ENSMUSP00000055130 SUPPORTS TRANSFER Exact mouse donor sequence verified. UniProtKB-SubCell:SL-0305 SUPPORTS TRANSFER Official exact ciliary-membrane mapping verified. |
| GO:0060170 ciliary membrane | TAS Reactome:R-HSA-5633051 | ACCEPT | Summary: The human Reactome EVC2 participant is explicitly located in ciliary membrane. Reason: Actual event 5633051 has input EVC2:EVC complex 5633041, whose native EVC2 participant 5633038 resolves to Q86UK5 reference entity 94287, human taxon 9606, modeled residues 27β1308 and GO:0060170. EVC2 is present in a binding/assembly event with EFCAB7:IQCE, not assigned an enzyme reaction. The cited PMID:24582806 uses mouse EvC constructs, including those in human HEK293T hosts; it distinguishes stable EVCβEVC2 and EFCAB7βIQCE subcomplexes. The modeled human compartment is supported without calling the experimental proteins human or treating EVC2 as the EFCAB7 adaptor. |
| GO:0098797 plasma membrane protein complex | IBA GO_REF:0000033 | ACCEPT | Summary: Retain the PAINT-supported plasma-membrane protein-complex membership. Reason: The sequence-verified human Q86UK5 leaf descends from PTN000423571, where the actual PAINT IBD supports membrane-complex membership with no target-path NOT. PMID:24582806 Figures 1β4 identifies endogenous mouse EVC2-containing assemblies and distinguishes the stable EVCβEVC2 and EFCAB7βIQCE subcomplexes. This supports GO:0098797 at the ciliary membrane without assigning EFCAB7βs adaptor activity to EVC2 or imposing fixed four-subunit stoichiometry in every condition. The W-peptide constructs and natural human products remain distinct. Propagation Review Root cause: NO FAILURE CORE Sources checked: PANTHER:PTN000423571 SUPPORTS TRANSFER The GO:0098797 IBD is ancestral to the exact target; original mouse Evc/Evc2 complex experiments substantiate its biological scope. |
| GO:0098797 plasma membrane protein complex | IEA GO_REF:0000107 | ACCEPT | Summary: Retain the ortholog-supported membrane-complex role. Reason: ENSMUSP00000055130 exactly matches mouse Q8K1G2, whose complex annotation is IDA PMID:24582806. Native co-IP, tagged reconstitution and membrane fractionation (Figures 1β2) support EVC2-containing membrane-complex membership, concordant with native human Q86UK5 in Reactome R-HSA-5633051. The separate source query concerns UniProt interface wording, not the validity of this complex annotation. EFCAB7 supplies the mapped adaptor connection to IQCE; no equivalent activity or product-wide assay is assigned to EVC2. Propagation Review Root cause: NO FAILURE CORE Sources checked: UniProtKB:Q8K1G2 SUPPORTS TRANSFER The actual mouse IDA source tests Evc2-containing complexes. ensembl:ENSMUSP00000055130 SUPPORTS TRANSFER Current mouse translation is exactly Q8K1G2; source transfer remains product-bounded. |
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Download this section (compressed HTML)Q: Which EVC2-specific molecular step links the positioned EVCβEVC2 assembly to GLI regulation, beyond maintaining its association with EVC and EFCAB7?
Q: Which of the three source-described human products are endogenously expressed, processed and incorporated into a signaling-competent ciliary complex?
Q: Where within the nuclear preparation is human EVC2 located, and does that pool contain the full-length protein or a distinct processed product?
Q: Should the EVCβEVC2 and EFCAB7βIQCE assemblies have a more specific complex representation than GO:0098797, distinguishing the two stable subcomplexes from their experimentally associated EvC assembly? The current annotation remains supported without assuming invariant four-subunit stoichiometry.
Experiment: In ciliated human cells, compare endogenous EVC2 loss with matched-expression rescue and interaction-guided separation-of-function variants. Quantify EVC and EFCAB7 association, ciliary abundance and proximal-zone restriction together with Smoothened-agonist responses, GLI1/PTCH1 transcription and GLI processing or localization. Include a downstream GLI bypass control. Test any proposed scaffold, adaptor or catalytic step directly before assigning that molecular activity to EVC2.
Hypothesis: EVC2-dependent signaling can be experimentally separated from its complex incorporation and restriction to the proximal ciliary membrane.
Type: Controlled genetic rescue with interaction, localization and signaling assays
Experiment: Establish endogenous product-specific transcripts and peptides for Q86UK5-1, Q86UK5-2 and Q86UK5-3 before comparing their signal-peptide processing, membrane topology, EVC/EFCAB7 association and ciliary signaling at matched abundance. Keep the natural 1,308-, 1,228- and 1,246-residue sequences distinct from engineered mouse EVC2ΞW and motif mutants; an overexpression phenotype alone does not establish a physiological isoform role.
Hypothesis: The natural N-terminal deletion and C-terminal replacement alter processing, complex engagement or signaling differently from the engineered mouse Weyers truncation.
Type: Product-resolved transcriptomics and proteomics with controlled functional rescue
Experiment: Combine endogenous tagging and loss-of-function controls with rigorously separated nuclear-envelope, nucleoplasmic and cytoplasmic fractions in appropriate human cells. Use orthogonal compartment markers, microscopy and product-discriminating peptides to identify EVC2 and distinguish intact protein from processing products. For sperm preparations, verify target peptide uniqueness and the correspondence of the detected form to the reported nuclear association before testing a nuclear mechanism.
Hypothesis: The reported nuclear EVC2 signal represents a reproducible compartment-associated pool whose molecular form can be resolved independently of bulk nuclear isolation.
Type: Orthogonal localization and molecular-form analysis with genetic specificity controls
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