Affinage

INAVA

Innate immunity activator protein · UniProt Q3KP66

Length
663 aa
Mass
72.9 kDa
Annotated
2026-06-10
11 papers in source corpus 8 papers cited in narrative 8 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 5/6 claims corpus-supported (83%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

INAVA (C1orf106) is a multifunctional scaffold protein that couples epithelial barrier integrity to innate inflammatory signaling, both functions implicated in inflammatory bowel disease risk (PMID:29420262, PMID:28436939). At the lateral membrane it uses its CUPID (DUF3338) domain to stably bind the cytohesin ARF-GEF ARNO/cytohesin-1, limiting cytohesin-dependent ARF6 activation and driving lateral F-actin assembly that stabilizes adherens junctions and barrier function (PMID:29420262, PMID:30355448, PMID:31022698). INAVA controls cortical actin belt dynamics through a ROCK-dependent mechanism, with its loss producing stress fiber dysregulation, polarity defects, and impaired migration and permeability (PMID:40161582). Upon inflammatory stimulation (PRR ligands, IL-1β), INAVA relocates from junctions to cytosolic biomolecular condensates containing ubiquitin and the E3 ligase βTrCP2, where CUPID amplifies TRAF6-dependent polyubiquitination and downstream MAPK/NF-κB signaling, in part by recruiting 14-3-3τ, thereby enhancing cytokine secretion and bacterial clearance; ARNO binding to CUPID negatively regulates this inflammatory output (PMID:28436939, PMID:30355448, PMID:34251416). An IBD risk variant increases INAVA ubiquitination and turnover, impairing both barrier and immune functions (PMID:29420262). Beyond these intestinal/epithelial roles, INAVA has been linked in single-lab studies to thyroid cancer metastasis via FGF1/MMP9 (PMID:29632659) and to ovarian fibroblast activation via competitive binding of HMGA2 (PMID:40265981).

Mechanistic history

Synthesis pass · year-by-year structured walk · 8 steps
  1. 2017 High

    Established that INAVA functions in innate immunity, defining its requirement for PRR-induced inflammatory signaling and its mechanism of signal amplification via a partner adaptor.

    Evidence siRNA knockdown in primary human macrophages with Co-IP, cytokine ELISA, and MAPK/NF-κB and bacterial clearance assays

    PMID:28436939

    Open questions at the time
    • Did not define the structural basis of 14-3-3τ recruitment
    • Did not connect signaling role to epithelial barrier function
  2. 2018 High

    Identified the molecular basis of INAVA's barrier function, showing it stabilizes adherens junctions by limiting cytohesin-1/ARF6 activity, and linked the IBD risk variant to increased turnover.

    Evidence Knockout mouse model with cytohesin-1 degradation, ARF6 activation, and ubiquitination assays

    PMID:29420262

    Open questions at the time
    • Did not resolve which domain mediates cytohesin binding
    • E3 ligase driving variant-enhanced ubiquitination not identified here
  3. 2018 High

    Mapped the CUPID (DUF3338) domain as the interaction module unifying INAVA's two roles, showing ARNO binding drives GEF-independent F-actin assembly at junctions while the same domain amplifies inflammatory polyubiquitination upon IL-1β.

    Evidence Domain mapping, CUPID-ARNO Co-IP/pulldown, GEF and F-actin assays, polyubiquitination assays, and live-cell relocalization imaging in epithelial and macrophage contexts

    PMID:30355448

    Open questions at the time
    • Mechanism by which CUPID amplifies TRAF6-dependent ubiquitination not defined at atomic level
    • How IL-1β triggers junction-to-cytosol relocalization unresolved
  4. 2019 Medium

    Confirmed direct cytohesin binding and barrier relevance in vivo, showing C1orf106-deficient mice are hypersensitive to TNF-α-induced epithelial permeability.

    Evidence Direct interaction assay and TNF-α-induced permeability assay in C1orf106 KO mice

    PMID:31022698

    Open questions at the time
    • Single lab with two orthogonal methods
    • Did not address inflammatory signaling arm
  5. 2021 Medium

    Characterized the IL-1β-induced cytosolic puncta as dynamic biomolecular condensates with defined composition, linking INAVA to regulated proteostasis and identifying pathways controlling condensate resolution and junctional recruitment.

    Evidence Live-cell imaging of condensate dynamics, small-molecule screen, and co-localization of βTrCP2 and ubiquitin with INAVA puncta

    PMID:34251416

    Open questions at the time
    • Condensate composition defined by co-localization rather than reconstitution
    • Functional consequence of βTrCP2 within condensates not established
  6. 2025 Medium

    Defined the cytoskeletal effector pathway, demonstrating that INAVA regulates cortical actin belt dynamics, polarity, and barrier permeability through a ROCK-dependent mechanism, with the IBD-associated 333F variant recapitulating polarity defects in patient-derived spheroids.

    Evidence siRNA knockdown in colonic epithelial cells and hiPSC-derived intestinal spheroids with ROCK inhibitor rescue and immunofluorescence

    PMID:40161582

    Open questions at the time
    • Preprint, single lab
    • How INAVA mechanistically engages the ROCK pathway not resolved
  7. 2018 Low

    Proposed an oncogenic role outside the intestine, correlating INAVA upregulation with thyroid cancer invasion via an FGF1/MMP9 axis.

    Evidence Gain/loss-of-function assays, transcriptome resequencing, and in vitro/in vivo metastasis assays

    PMID:29632659

    Open questions at the time
    • Indirect mechanism without direct binding evidence
    • Not independently confirmed
    • Relationship to barrier/inflammatory functions unknown
  8. 2025 Medium

    Reported a distinct scaffold function in the tumor microenvironment, with INAVA competitively binding HMGA2 to block VRK1-mediated phosphorylation and stabilize HMGA2, activating fibroblasts via STAT3.

    Evidence Reciprocal Co-IP, phosphorylation site mapping, K48 ubiquitination assays, peptide competition, and orthotopic xenograft model

    PMID:40265981

    Open questions at the time
    • Single lab
    • Relationship to canonical CUPID/cytohesin functions not addressed

Open questions

Synthesis pass · forward-looking unresolved questions
  • How INAVA's two opposing activities — junction stabilization versus inflammatory amplification — are switched and coordinated at the molecular level, and how the disparate cancer-associated functions relate to the core epithelial/immune mechanism, remains unresolved.
  • No structural model of CUPID-ARNO or CUPID-TRAF6 engagement
  • Mechanism triggering junction-to-condensate relocalization undefined
  • Unified model spanning epithelial, immune, and cancer contexts lacking

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0008092 cytoskeletal protein binding 2 GO:0060090 molecular adaptor activity 2 GO:0098772 molecular function regulator activity 2
Localization
GO:0005886 plasma membrane 3 GO:0005829 cytosol 2
Pathway
R-HSA-1500931 Cell-Cell communication 2 R-HSA-162582 Signal Transduction 2 R-HSA-168256 Immune System 2

Evidence

Reading pass · 8 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2018 C1orf106/INAVA regulates adherens junction stability by controlling the degradation of cytohesin-1, a guanine nucleotide exchange factor. By limiting cytohesin-1-dependent ARF6 activation, C1orf106 stabilizes adherens junctions. The IBD risk variant increases C1orf106 ubiquitination and turnover, leading to impaired barrier function. C1orf106-/- mice exhibit defects in intestinal epithelial cell barrier. Knockout mouse model, degradation assays for cytohesin-1, ARF6 activation assays, ubiquitination assays Science (New York, N.Y.) High 29420262
2017 INAVA is required for optimal MAPK and NF-κB activation, cytokine secretion, and intracellular bacterial clearance upon PRR stimulation in primary human myeloid cells. INAVA recruits 14-3-3τ to form a signaling complex that amplifies downstream signals. INAVA also enhances bacterial clearance by regulating reactive oxygen species, reactive nitrogen species, and autophagy pathways. siRNA knockdown in primary human macrophages, Co-immunoprecipitation for 14-3-3τ recruitment, cytokine ELISA, MAPK/NF-κB pathway activation assays, bacterial clearance assays The Journal of clinical investigation High 28436939
2018 INAVA's DUF3338 domain (renamed CUPID) stably binds the cytohesin ARF-GEF ARNO to effect lateral membrane F-actin assembly underlying cell-cell junctions and barrier function. When bound to CUPID, ARNO affects F-actin dynamics independently of its canonical GEF activity. Upon IL-1β exposure, INAVA relocates to cytosolic puncta where CUPID amplifies TRAF6-dependent polyubiquitination and inflammatory signaling. ARNO binding to CUPID negatively regulates polyubiquitination and the inflammatory response. Domain mapping, Co-IP/pulldown of CUPID-ARNO interaction, F-actin assembly assays, GEF activity assays, polyubiquitination assays, live-cell imaging of INAVA relocalization, macrophage primary cell experiments eLife High 30355448
2018 C1ORF106 directly interacts with cytohesins to maintain functional epithelial cell junctions. C1orf106-deficient mice are hypersensitive to TNF-α-induced increase in epithelial permeability. Direct interaction assay (C1ORF106 with cytohesins), C1orf106 KO mouse model, TNF-α-induced permeability assay ImmunoHorizons Medium 31022698
2021 IL-1β-induced INAVA cytosolic puncta are biomolecular condensates that rapidly assemble and physiologically resolve. The condensates contain ubiquitin and the E3 ligase βTrCP2, and their formation correlates with amplified ubiquitination, suggesting a role in cellular proteostasis regulation. Inhibitors of p38α and mTOR pathways enhanced resolution of condensates, while inhibitors of the Rho-ROCK pathway recruited INAVA to newly assembled intercellular junctions. Live-cell imaging of condensate dynamics, small-molecule screen, co-localization of βTrCP2 and ubiquitin with INAVA puncta, pharmacological pathway inhibition The Journal of cell biology Medium 34251416
2025 C1ORF106 knockdown leads to impaired cortical actin belt dynamics, stress fiber dysregulation, increased cell constriction, impaired barrier permeability, cell polarity defects, and impaired cell migration. ROCK inhibition rescues the actin belt and cell polarity phenotypes in C1ORF106 KD cells, demonstrating that C1ORF106 regulates these phenotypes through a ROCK-dependent mechanism. Altered non-muscle myosin II phosphorylation (nmMYO2-P) localization was observed in C1ORF106 KD cells, associated with Vacuolar Apical Compartment (VAC) formation. The IBD-associated 333F variant in hiPSC-derived intestinal spheroids showed similar cell polarity impairments. siRNA knockdown in human colonic epithelial cells, hiPSC-derived intestinal spheroid cultures, immunofluorescence, western blots, permeability assays, ROCK inhibitor rescue experiments bioRxiv : the preprint server for biologypreprint Medium 40161582
2018 INAVA upregulation in papillary thyroid cancer cells promotes invasion, migration, and metastasis through elevated FGF1 expression, which in turn increases MMP9 expression. Gain- and loss-of-function assays, transcriptome resequencing, western blotting, in vitro and in vivo metastasis assays Cell & bioscience Low 29632659
2025 INAVA protein (translated from EV-delivered mRNA) competitively binds HMGA2 and inhibits its interaction with vaccinia-related kinase 1 (VRK1), leading to reduced HMGA2 phosphorylation at Ser105. This reduced phosphorylation stabilizes HMGA2 by blocking TRIM21-mediated K48-linked ubiquitylation, ultimately enhancing STAT3 transcription to activate normal ovarian fibroblasts. A cell-permeable peptide disrupting the INAVA-HMGA2 interaction attenuated fibroblast activation. Co-immunoprecipitation (INAVA-HMGA2 and HMGA2-VRK1), phosphorylation site mapping, ubiquitination assays (K48-linked), STAT3 transcription assays, peptide competition assay, orthotopic xenograft mouse model Advanced science (Weinheim, Baden-Wurttemberg, Germany) Medium 40265981

Source papers

Stage 0 corpus · 11 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2018 C1orf106 is a colitis risk gene that regulates stability of epithelial adherens junctions. Science (New York, N.Y.) 102 29420262
2017 An inflammatory bowel disease-risk variant in INAVA decreases pattern recognition receptor-induced outcomes. The Journal of clinical investigation 32 28436939
2018 INAVA-ARNO complexes bridge mucosal barrier function with inflammatory signaling. eLife 23 30355448
2018 INAVA promotes aggressiveness of papillary thyroid cancer by upregulating MMP9 expression. Cell & bioscience 18 29632659
2019 C1orf106, an innate immunity activator, is amplified in breast cancer and is required for basal-like/luminal progenitor fate decision. Science China. Life sciences 14 31376015
2018 Inflammatory Bowel Disease Susceptibility Gene C1ORF106 Regulates Intestinal Epithelial Permeability. ImmunoHorizons 13 31022698
2021 Small-molecule modulators of INAVA cytosolic condensate and cell-cell junction assemblies. The Journal of cell biology 10 34251416
2019 Association of polymorphisms in C1orf106, IL1RN, and IL10 with post-induction infliximab trough level in Crohn's disease patients. Gastroenterology report 9 33163192
2025 The INAVA mRNA in Extracellular Vesicles Activates Normal Ovarian Fibroblasts by Phosphorylation-Ubiquitylation Crosstalk of HMGA2. Advanced science (Weinheim, Baden-Wurttemberg, Germany) 3 40265981
2025 Inflammatory bowel disease risk gene C1ORF106 regulates actin dynamics in intestinal epithelial cells. bioRxiv : the preprint server for biology 1 40161582
2025 The Expression and Clinical Significance of C1orf106 in Low-Grade Serous Ovarian Cancer. The journal of obstetrics and gynaecology research 1 41126651

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