id: A0A0D2WRB3 gene_symbol: coITGB2 aliases: - CAOG_005058 - CAOG_05058 - integrin beta 2 - integrin beta2 - D7PE19 - GU320673 product_type: PROTEIN status: DRAFT taxon: id: NCBITaxon:595528 label: Capsaspora owczarzaki ATCC 30864 description: >- Integrin beta 2 (CAOG_05058) is one of four integrin beta subunits of the amoeboid filasterean Capsaspora owczarzaki, a close unicellular relative of animals, and the most highly expressed of them. It is a 1056-residue single-pass type I membrane protein. It has a signal peptide, a vWA-like beta-I domain with conserved MIDAS, ADMIDAS and LIMBS cation-binding sites, a PSI domain, a cysteine-rich EGF-like stalk that is longer than in animal integrins, a transmembrane helix, and a short cytoplasmic tail with the alpha-subunit-interacting region and NPxY-type motifs that bind talin in animals. Capsaspora also encodes integrin alpha subunits and the main intracellular adhesome proteins (talin, vinculin, paxillin, the ILK-PINCH-parvin complex, FAK and Src), so the protein presumably forms alpha/beta heterodimers, although this has not been tested. In adherent cells, integrin beta 2 is found on the cell body and in distinct patches along the actin-dependent filopodia that attach the cells to surfaces, partly overlapping with vinculin. Mammalian fibronectin increases adhesion and the amount of integrin beta 2 in filopodia. An antibody against its ligand-binding beta-I domain strongly reduces adhesion to fibronectin-coated surfaces, so the protein mediates cell-substrate adhesion. Capsaspora has no fibronectin ortholog, and its natural ligand is unknown; candidates include secreted Capsaspora proteins with fibronectin-type domains or RGD sequences. Whether integrin beta 2 also signals or takes part in cell-cell adhesion during aggregation has not been examined. existing_annotations: - term: id: GO:0005178 label: integrin binding evidence_type: IEA original_reference_id: GO_REF:0000118 qualifier: enables supporting_entities: - PANTHER:PTN002560695 review: summary: >- TreeGrafter transfer from PTN002560695, the vertebrate integrin beta-like protein 1 (ITGBL1) node in PTHR10082. The term is inherited there from the integrin-beta family root, so it is a family-wide claim. For a beta subunit, the "integrin" it binds is its alpha partner. Capsaspora has four integrin alpha subunits, and the alpha-interacting tail motif is conserved in beta 2 [PMID:20479219], but heterodimer formation has not been tested. action: KEEP_AS_NON_CORE reason: >- The claim is plausible from conserved motifs and from the presence of alpha partners, and it is not specific to multicellular animals, since it concerns heterodimer assembly rather than any animal ligand. The authors who described the repertoire state explicitly that heterodimerisation is assumed, not shown. Kept as non-core, consistent with the human ITGB1 review, where the same IBA is kept as a non-core subunit-association term best captured by integrin complex. supported_by: - reference_id: PMID:20479219 supporting_text: >- Other key motifs in metazoan integrin β proteins are the cytoplasmic integrin α-interacting motif and the NPXY motif - reference_id: PMID:20479219 supporting_text: >- Thus, we can assume that they too work as heterodimers and that they interact and function similarly to metazoan homologs. Functional analysis will be needed to test this hypothesis. propagation_review: root_cause: NO_FAILURE_NON_CORE source_entities: - source_id: PANTHER:PTN002560695 source_label: PTHR10082:SF3 integrin beta-like protein 1, Euteleostomi node source_status: SUPPORTS_SOURCE_BUT_NOT_TARGET comment: >- Graft node is the vertebrate ITGBL1 clade (all leaves vertebrate ITGBL1), not an integrin beta orthology group containing Capsaspora; the PTHR10082 tree is rooted at Eumetazoa (PTN000801545) and has no unicellular sequences. The term itself is a family-root inheritance that fits a canonical integrin beta, so the outcome is acceptable despite the wrong graft. - term: id: GO:0005886 label: plasma membrane evidence_type: IEA original_reference_id: GO_REF:0000044 qualifier: located_in supporting_entities: - UniProtKB-SubCell:SL-0039 review: summary: >- UniProt subcellular-location mapping (Cell membrane; single-pass type I). The protein has a signal peptide and one transmembrane helix, and immunostaining places it on the cell body and in patches along filopodia [DOI:10.1101/2020.02.27.967653]. action: ACCEPT reason: >- Signal peptide plus a single transmembrane helix and filopodial staining are consistent with plasma membrane localization. Blocking adhesion by an antibody added to live cells also implies an exposed ectodomain. supported_by: - reference_id: file:CAPO3/coITGB2/coITGB2-uniprot.txt record_section: ["CC:SUBCELLULAR LOCATION"] supporting_text: Single-pass type I membrane protein - reference_id: DOI:10.1101/2020.02.27.967653 supporting_text: >- We observed that both antibodies stain the cell body and multiple distinct patches along filopodia - term: id: GO:0005925 label: focal adhesion evidence_type: IEA original_reference_id: GO_REF:0000118 qualifier: located_in supporting_entities: - PANTHER:PTN002560695 review: summary: >- TreeGrafter transfer from the vertebrate ITGBL1 node PTN002560695. In Capsaspora, integrin beta 2 and vinculin form distinct, partly overlapping patches along filopodia, which the authors suggest may be anchorage sites of adhesion [DOI:10.1101/2020.02.27.967653]. These patches have not been shown to be focal adhesions, which GO defines as cell-substrate junctions that anchor the cell to the extracellular matrix and terminate actin filaments. action: MARK_AS_OVER_ANNOTATED reason: >- Focal adhesions are a specific structure of animal cells, mature integrin adhesions at the ends of stress fibres. In Capsaspora the integrin and vinculin patches lie within filopodia, and the authors themselves describe this as an unexpected role for integrin adhesion within filopodia. They characterise the patches only as possible anchorage sites. The localization that is shown is captured by the NEW filopodium annotation. A focal-adhesion (or cell-substrate junction) assignment would need evidence of a junctional plaque, for example talin and paxillin co-recruitment and actin-filament termination. supported_by: - reference_id: DOI:10.1101/2020.02.27.967653 supporting_text: >- Taken together, these results suggest that the integrin and vinculin patches may represent anchorage sites of adhesion. - reference_id: DOI:10.1101/2020.02.27.967653 supporting_text: >- which is an unexpected role for integrin adhesion within filopodia propagation_review: root_cause: PROPAGATION_BAD failure_modes: - WRONG_ORTHOLOG_OR_PARALOG - LINEAGE_OR_TAXON_MISMATCH source_entities: - source_id: PANTHER:PTN002560695 source_label: PTHR10082:SF3 integrin beta-like protein 1, Euteleostomi node source_status: SUPPORTS_SOURCE_BUT_NOT_TARGET comment: >- Vertebrate ITGBL1 node in a Eumetazoa-rooted tree; focal adhesion is inherited from animal integrin betas (PTN000801545). Capsaspora sits outside that clade and its integrin adhesions are filopodial patches not characterised as focal adhesions. - term: id: GO:0007160 label: cell-matrix adhesion evidence_type: IEA original_reference_id: GO_REF:0000118 qualifier: involved_in supporting_entities: - PANTHER:PTN002560695 review: summary: >- TreeGrafter transfer from the vertebrate ITGBL1 node. Capsaspora integrin beta 2 does mediate substrate adhesion: an antibody to its beta-I domain inhibits adhesion to fibronectin-coated surfaces [PMID:32857975]. The surfaces are plastic coated with mammalian fibronectin or with material the cells secrete; Capsaspora has no fibronectin ortholog, and no Capsaspora extracellular matrix ligand has been identified [DOI:10.1101/2020.02.27.967653]. action: MODIFY reason: >- The process is supported, but "matrix" implies an extracellular matrix that has not been defined for Capsaspora. The experiments measure attachment to a coated substrate, which is exactly what cell-substrate adhesion (GO:0031589), the parent of cell-matrix adhesion, describes. The integrin is the adhesion receptor itself, so it does the work of the process. The antibody-blocking result (DOI:10.1101/2020.02.27.967653, PMID:32857975) is direct perturbation evidence for the replacement term. Revisit cell-matrix adhesion if the endogenous secreted ligand is identified. proposed_replacement_terms: - id: GO:0031589 label: cell-substrate adhesion supported_by: - reference_id: PMID:32857975 supporting_text: >- Finally, using a specific antibody for integrin β2, we inhibited cell adhesion to a fibronectin-coated surface. - reference_id: DOI:10.1101/2020.02.27.967653 supporting_text: >- Taken together, these results show that the major integrin β subunit in Capsaspora makes a substantial contribution to substrate adhesion. - reference_id: DOI:10.1101/2020.02.27.967653 supporting_text: >- This suggests that a protein secreted by Capsaspora sticks to the plastic substrate and provides a ligand for adhesion propagation_review: root_cause: TERM_SCOPING_PROBLEM failure_modes: - GRANULARITY_MISMATCH source_entities: - source_id: PANTHER:PTN002560695 source_label: PTHR10082:SF3 integrin beta-like protein 1, Euteleostomi node source_status: SUPPORTS_SOURCE_BUT_NOT_TARGET comment: >- Wrong graft (vertebrate ITGBL1 clade); the inherited family-root term presupposes an animal-type extracellular matrix that is not established in Capsaspora. The parent term is supported directly. - term: id: GO:0007229 label: integrin-mediated signaling pathway evidence_type: IEA original_reference_id: GO_REF:0000118 qualifier: involved_in supporting_entities: - PANTHER:PTN002560695 review: summary: >- TreeGrafter transfer from the vertebrate ITGBL1 node. Capsaspora encodes the intracellular signalling partners of animal integrins (FAK, Src, the ILK-PINCH-parvin complex) [PMID:20479219], and fibronectin increases filopodium number and integrin recruitment to filopodia [DOI:10.1101/2020.02.27.967653]. No signalling downstream of integrin beta 2 has been measured. action: UNDECIDED reason: >- The pathway is plausible, since the signalling components are present and ligand-dependent changes in filopodia are observed. But those changes could equally reflect adhesion mechanics, and no signalling output has been tested. The 2010 authors also caution that scaffold proteins may have had other ancestral roles. Left undecided pending, for example, FAK phosphorylation assays after ligand engagement. supported_by: - reference_id: PMID:20479219 supporting_text: >- bona fide FAK are only present in Metazoa and C. owczarzaki - reference_id: DOI:10.1101/2020.02.27.967653 supporting_text: >- These results suggest that Fibronectin promotes cell adhesion by increasing the number and length of filopodia as well as by promoting recruitment of integrin and vinculin to the filopodia. propagation_review: root_cause: UNRESOLVED source_entities: - source_id: PANTHER:PTN002560695 source_label: PTHR10082:SF3 integrin beta-like protein 1, Euteleostomi node source_status: UNRESOLVED comment: >- Wrong graft (vertebrate ITGBL1); the family-root signalling term may or may not apply to a Capsaspora integrin, which has the FAK/Src/IPP partners but no signalling data. - term: id: GO:0008305 label: integrin complex evidence_type: IEA original_reference_id: GO_REF:0000118 qualifier: part_of supporting_entities: - PANTHER:PTN002560695 review: summary: >- TreeGrafter transfer from the vertebrate ITGBL1 node. Capsaspora encodes four integrin alpha subunits with conserved FG-GAP repeats and cytoplasmic KXGFFXR-type motifs, and beta 2 has the alpha-interacting cytoplasmic motif [PMID:20479219]. action: ACCEPT reason: >- Membership of an alpha/beta heterodimer is the defining property of an integrin beta subunit. Every element needed for it is conserved, so the inference is sound even though the Capsaspora heterodimer has not been isolated. Note that the graft node itself (vertebrate ITGBL1, a TM-less protein) is a poor source for this term; the conclusion rests on the Capsaspora sequence features. supported_by: - reference_id: PMID:20479219 supporting_text: >- Both motifs are well conserved in C. owczarzaki integrin β1–β3 and Amastigomonas sp. integrin β - reference_id: PMID:20479219 supporting_text: >- we found four integrin β and four integrin α genes in C. owczarzaki propagation_review: root_cause: NO_FAILURE_CORE source_entities: - source_id: PANTHER:PTN002560695 source_label: PTHR10082:SF3 integrin beta-like protein 1, Euteleostomi node source_status: SUPPORTS_SOURCE_BUT_NOT_TARGET comment: >- Wrong graft (vertebrate ITGBL1 clade); the term is a family-root inheritance that fits the Capsaspora protein on its own sequence features. - term: id: GO:0009986 label: cell surface evidence_type: IEA original_reference_id: GO_REF:0000118 qualifier: located_in supporting_entities: - PANTHER:PTN002560695 review: summary: >- TreeGrafter transfer from the vertebrate ITGBL1 node. An antibody to the extracellular beta-I domain added to cells before plating blocks adhesion, which implies the ectodomain is exposed at the cell surface [DOI:10.1101/2020.02.27.967653]. action: KEEP_AS_NON_CORE reason: >- Correct for a type I transmembrane adhesion receptor and indirectly supported by the antibody-blocking experiment. It adds little beyond plasma membrane. supported_by: - reference_id: DOI:10.1101/2020.02.27.967653 supporting_text: >- Pre-incubation of this cells with this antibody prior to plating substantially reduced adhesion to fibronectin-treated surfaces propagation_review: root_cause: NO_FAILURE_NON_CORE source_entities: - source_id: PANTHER:PTN002560695 source_label: PTHR10082:SF3 integrin beta-like protein 1, Euteleostomi node source_status: SUPPORTS_SOURCE_BUT_NOT_TARGET comment: >- Wrong graft (vertebrate ITGBL1 clade); the generic location fits the Capsaspora protein independently. - term: id: GO:0016020 label: membrane evidence_type: IEA original_reference_id: GO_REF:0000044 qualifier: located_in supporting_entities: - UniProtKB-SubCell:SL-0162 review: summary: >- UniProt subcellular-location mapping (Membrane; single-pass type I). Correct but less informative than plasma membrane. action: KEEP_AS_NON_CORE reason: >- True (one transmembrane helix) but redundant with the more specific plasma membrane annotation. supported_by: - reference_id: file:CAPO3/coITGB2/coITGB2-uniprot.txt record_section: ["CC:SUBCELLULAR LOCATION"] supporting_text: Single-pass type I membrane protein - term: id: GO:0016477 label: cell migration evidence_type: IEA original_reference_id: GO_REF:0000118 qualifier: involved_in supporting_entities: - PANTHER:PTN002560695 review: summary: >- TreeGrafter transfer from the vertebrate ITGBL1 node. Capsaspora adherent cells attach by filopodia, but the cached papers report no measurement of cell migration or of any effect of integrin beta 2 inhibition on movement. The preprint notes that in animal cells filopodia are associated with dynamic exploration of the substrate, in contrast to the stable adhesive role seen in Capsaspora [DOI:10.1101/2020.02.27.967653]. action: UNDECIDED reason: >- Integrin traction is a plausible contributor to amoeboid crawling, but no data exist for Capsaspora. The process term should wait for a motility assay with the blocking antibody or a knockout. supported_by: - reference_id: DOI:10.1101/2020.02.27.967653 supporting_text: >- In animal cells filopodia are more generally associated with dynamic exploration of the substrate rather than forming stable adherent contacts propagation_review: root_cause: UNRESOLVED source_entities: - source_id: PANTHER:PTN002560695 source_label: PTHR10082:SF3 integrin beta-like protein 1, Euteleostomi node source_status: UNRESOLVED comment: >- Wrong graft (vertebrate ITGBL1 clade); family-root migration term untested in Capsaspora. - term: id: GO:0033627 label: cell adhesion mediated by integrin evidence_type: IEA original_reference_id: GO_REF:0000118 qualifier: involved_in supporting_entities: - PANTHER:PTN002560695 review: summary: >- TreeGrafter transfer from the vertebrate ITGBL1 node. Directly supported in Capsaspora: an antibody to the beta-I domain of integrin beta 2 inhibits cell adhesion to fibronectin-coated surfaces, whereas an antibody to the stalk does not [PMID:32857975; DOI:10.1101/2020.02.27.967653]. action: ACCEPT reason: >- The term (attachment of a cell to another cell or to a substrate via an integrin) matches the experiment. The integrin is the adhesion receptor, so it does the work of the process. The domain-specific antibody result (ligand-binding domain blocks, stalk does not) argues against a non-specific steric effect. supported_by: - reference_id: PMID:32857975 supporting_text: >- Our results suggest that adhesion to the substrate in C. owczarzaki is mediated by integrins. - reference_id: DOI:10.1101/2020.02.27.967653 supporting_text: >- in contrast to the antibody against the cysteine-rich stalk, which did not impair adhesion propagation_review: root_cause: NO_FAILURE_CORE source_entities: - source_id: PANTHER:PTN002560695 source_label: PTHR10082:SF3 integrin beta-like protein 1, Euteleostomi node source_status: SUPPORTS_SOURCE_BUT_NOT_TARGET comment: >- Wrong graft (vertebrate ITGBL1 clade); the family-root term is confirmed independently for the Capsaspora protein by antibody blocking. - term: id: GO:0098609 label: cell-cell adhesion evidence_type: IEA original_reference_id: GO_REF:0000118 qualifier: involved_in supporting_entities: - PANTHER:PTN002560695 review: summary: >- TreeGrafter transfer from the vertebrate ITGBL1 node. Capsaspora forms multicellular aggregates, so it has cell-cell adhesion, but no experiment links integrin beta 2 to it. The functional data concern adhesion to substrate, and the preprint names the aggregative stage as a subject for future work [DOI:10.1101/2020.02.27.967653]. In coYki knockouts, where CAOG_05058 is up-regulated, cell-substrate adhesion increases without a change in cell-cell adhesion [PMID:35659869]. action: MARK_AS_OVER_ANNOTATED reason: >- In animals, integrin-dependent cell-cell adhesion comes from binding to counter-receptors on other cells (for example ICAM and VCAM on leukocytes and endothelium). These counter-receptors are animal innovations, and none has been identified in Capsaspora. The term reaches this protein only through a family-root inheritance on a wrong (vertebrate ITGBL1) graft node. It should not be asserted until integrin involvement in aggregation is tested. supported_by: - reference_id: DOI:10.1101/2020.02.27.967653 supporting_text: >- Further investigation of integrin-mediated adhesion in Capsaspora, particularly during the aggregative stage, by examining its ligands and intracellular binding partners - reference_id: PMID:35659869 supporting_text: >- two integrin-β genes (CAOG_05058 and CAOG_01283) are upregulated in coYki -/- cells propagation_review: root_cause: PROPAGATION_BAD failure_modes: - WRONG_ORTHOLOG_OR_PARALOG - CONTEXT_OR_TISSUE_MISMATCH source_entities: - source_id: PANTHER:PTN002560695 source_label: PTHR10082:SF3 integrin beta-like protein 1, Euteleostomi node source_status: SUPPORTS_SOURCE_BUT_NOT_TARGET comment: >- Vertebrate ITGBL1 node in a Eumetazoa-rooted tree; integrin cell-cell adhesion in animals depends on animal-specific counter-receptors, and there is no Capsaspora evidence for it. - term: id: GO:0030175 label: filopodium evidence_type: IDA original_reference_id: PMID:32857975 qualifier: located_in review: summary: >- Immunostaining of adherent Capsaspora cells with antibodies against integrin beta 2 shows the protein in distinct patches along the actin-dependent filopodia, partly overlapping with vinculin. Its filopodial intensity increases on fibronectin [PMID:32857975; DOI:10.1101/2020.02.27.967653]. action: NEW reason: >- Direct localization evidence, stated in the cached abstract and detailed in the cached preprint; the antibodies were raised against CAOG_05058 regions. This is the most specific location shown for the protein. It replaces the unsupported focal-adhesion assignment. supported_by: - reference_id: PMID:32857975 supporting_text: >- We show that integrin β2 and its associated protein vinculin localize as distinct patches in the filopodia. - reference_id: DOI:10.1101/2020.02.27.967653 supporting_text: >- extracellular domain of the integrin β2 (CAOG_05058, aminoacid region 733-835) - term: id: GO:0098631 label: cell adhesion mediator activity evidence_type: IMP original_reference_id: PMID:32857975 qualifier: enables review: summary: >- An antibody against the ligand-binding beta-I domain of integrin beta 2, added to cells before plating, substantially reduces adhesion to fibronectin-coated surfaces; an antibody against the stalk does not [PMID:32857975; DOI:10.1101/2020.02.27.967653]. action: NEW reason: >- This is the molecular activity behind the accepted adhesion process terms: the cell-surface receptor binds an external substrate to attach the cell. Function-blocking antibody evidence is recorded as IMP. The term is deliberately generic because the substrate ligand is not known; it does not assert binding to fibronectin or any other animal extracellular matrix protein. supported_by: - reference_id: PMID:32857975 supporting_text: >- Finally, using a specific antibody for integrin β2, we inhibited cell adhesion to a fibronectin-coated surface. - reference_id: DOI:10.1101/2020.02.27.967653 supporting_text: >- Pre-incubation of this cells with this antibody prior to plating substantially reduced adhesion to fibronectin-treated surfaces core_functions: - description: >- Integrin beta subunit that acts as a cell-substrate adhesion receptor in filopodia of adherent Capsaspora cells. Its ligand-binding beta-I domain is needed for adhesion to fibronectin-coated surfaces, and it concentrates, together with vinculin, in patches along filopodia. The endogenous ligand is unknown; heterodimerisation with an integrin alpha subunit and coupling to talin through the NPxY tail are inferred from conserved motifs, not shown. molecular_function: id: GO:0098631 label: cell adhesion mediator activity directly_involved_in: - id: GO:0033627 label: cell adhesion mediated by integrin - id: GO:0031589 label: cell-substrate adhesion locations: - id: GO:0030175 label: filopodium - id: GO:0005886 label: plasma membrane in_complex: id: GO:0008305 label: integrin complex knowledge_gaps: - gap_statement: >- The integrin complex (GO:0008305) membership is inferred, not shown: no integrin alpha partner of integrin beta2 has been identified biochemically in Capsaspora, and talin coupling through the NPxY tail motif is predicted from sequence only. The endogenous ligand is also unknown. supported_by: - reference_id: PMID:32857975 supporting_text: >- Finally, using a specific antibody for integrin β2, we inhibited cell adhesion to a fibronectin-coated surface. - reference_id: PMID:32857975 supporting_text: >- We show that integrin β2 and its associated protein vinculin localize as distinct patches in the filopodia. - reference_id: DOI:10.1101/2020.02.27.967653 supporting_text: >- Taken together, these results show that the major integrin β subunit in Capsaspora makes a substantial contribution to substrate adhesion. suggested_questions: - question: >- What is the endogenous ligand of Capsaspora integrin beta 2? Candidates named by the authors are secreted Capsaspora proteins with fibronectin-type domains or RGD sequences; does adhesion depend on RGD, and on divalent cations at the conserved MIDAS site? - question: >- Which of the four Capsaspora integrin alpha subunits pairs with beta 2, and does the pair form in vivo? - question: >- Are the filopodial integrin-vinculin patches junctional plaques with talin and paxillin, comparable to animal nascent or focal adhesions, or a distinct filopodial adhesion structure? - question: >- Does integrin beta 2 contribute to cell-cell adhesion or aggregate shape during the aggregative stage, where adhesome genes are up-regulated? Is its up-regulation in coYki knockouts the cause of their increased substrate adhesion? - question: >- TreeGrafter grafts this and the other Capsaspora integrin betas onto the vertebrate ITGBL1 node (PTN002560695) of a Eumetazoa-rooted tree. Could PANTHER add a holozoan outgroup so that unicellular integrins graft at the family root instead? suggested_experiments: - hypothesis: Integrin beta 2 is required for substrate adhesion and filopodial adhesion patches. description: >- Knock out CAOG_05058 (genome editing now works in Capsaspora) and measure adhesion on uncoated and fibronectin-coated surfaces, filopodium number and length, and vinculin patch formation; rescue with wild-type and MIDAS-mutant transgenes. experiment_type: genetic knockout / complementation - hypothesis: Integrin beta 2 forms a heterodimer with a specific integrin alpha subunit. description: >- Immunoprecipitate integrin beta 2 with the beta-I antibody from adherent cells and identify co-precipitating alpha subunits, talin and other adhesome proteins by mass spectrometry. experiment_type: protein interaction / proteomics - hypothesis: Integrin beta 2 engagement triggers FAK/Src signalling. description: >- Plate cells on fibronectin with or without the beta-I blocking antibody and measure tyrosine phosphorylation of Capsaspora FAK and paxillin. experiment_type: biochemical signalling assay references: - id: GO_REF:0000044 title: Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt findings: [] - id: GO_REF:0000118 title: TreeGrafter-generated GO annotations findings: [] - id: PMID:32857975 title: Integrin-Mediated Adhesion in the Unicellular Holozoan Capsaspora owczarzaki. full_text_unavailable: true reference_review: relevance: HIGH correctness: VERIFIED review_notes: >- Primary functional paper; only the abstract is cached. The abstract states the filopodial localization of integrin beta 2 and vinculin, the fibronectin effect and antibody inhibition of adhesion. The mapping of "integrin beta 2" to CAOG_05058 comes from the methods of the cached bioRxiv preprint of the same study (DOI:10.1101/2020.02.27.967653). findings: - statement: Integrin beta 2 localizes as patches in filopodia, with vinculin. supporting_text: >- We show that integrin β2 and its associated protein vinculin localize as distinct patches in the filopodia. - statement: An integrin beta 2 antibody inhibits adhesion to fibronectin-coated surfaces. supporting_text: >- Finally, using a specific antibody for integrin β2, we inhibited cell adhesion to a fibronectin-coated surface. - id: DOI:10.1101/2020.02.27.967653 title: Integrin-mediated adhesion in the unicellular holozoan Capsaspora owczarzaki reference_review: relevance: HIGH correctness: VERIFIED review_notes: >- bioRxiv preprint (February 2020) of PMID:32857975, full text cached from the PDF. Its methods identify the antigen as integrin beta 2, CAOG_05058, which matches A0A0D2WRB3. It describes the two antibodies (stalk and beta-I domain), the substrate-coating assays and the blocking result, and states that Capsaspora has no fibronectin ortholog. Being a preprint, details may differ from the published version. findings: - statement: The antigen for the integrin beta 2 antibodies is CAOG_05058. supporting_text: >- extracellular domain of the integrin β2 (CAOG_05058, aminoacid region 733-835) - statement: >- An antibody against the beta-I domain reduces adhesion; an antibody against the stalk does not. supporting_text: >- substantially reduced adhesion to fibronectin-treated surfaces, in contrast to the antibody against the - statement: The natural adhesion ligand is unknown; a Capsaspora-secreted protein is proposed. supporting_text: >- This suggests that a protein secreted by Capsaspora sticks to the plastic substrate and provides a ligand for adhesion - id: PMID:20479219 title: Ancient origin of the integrin-mediated adhesion and signaling machinery. reference_review: relevance: HIGH correctness: VERIFIED review_notes: >- Full text cached. Deposited the four Capsaspora integrin beta cDNAs (GenBank GU320672-GU320675); GU320673 is "integrin beta 2 mRNA, complete cds", and its translation D7PE19 is identical in sequence to A0A0D2WRB3 (checked 2026-10-01). Reports conservation of the MIDAS/ADMIDAS/LIMBS sites, the expanded stalk, and the cytoplasmic alpha-interacting and NPXY motifs in beta 1-3. findings: - statement: Cation-binding sites are conserved in Capsaspora integrin betas except beta 4. supporting_text: >- are well conserved in the different nonmetazoan integrin β, except for C. owczarzaki integrin β4 - statement: The cDNAs were deposited in GenBank. supporting_text: >- New sequences were deposited in GenBank under accession nos. GU320672–GU320675 . - id: PMID:35659869 title: Genome editing in the unicellular holozoan Capsaspora owczarzaki suggests a premetazoan role for the Hippo pathway in multicellular morphogenesis. reference_review: relevance: LOW correctness: VERIFIED review_notes: >- coYki knockout paper (full text cached). Mentions CAOG_05058 only as an up-regulated integrin-beta gene in coYki knockout cells, which have increased substrate adhesion. findings: - statement: CAOG_05058 is up-regulated in coYki knockout cells. supporting_text: >- two integrin-β genes (CAOG_05058 and CAOG_01283) are upregulated in coYki -/- cells - id: file:CAPO3/coITGB2/coITGB2-uniprot.txt title: UniProt entry A0A0D2WRB3 findings: []