Affinage

RADIL

Ras-associating and dilute domain-containing protein · UniProt Q96JH8

Length
1075 aa
Mass
117.5 kDa
Annotated
2026-06-10
28 papers in source corpus 13 papers cited in narrative 13 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 6/6 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

RADIL is a Ras-association (RA)- and PDZ-domain adaptor protein that functions as an effector of GTP-bound Rap1, coupling GTPase activation to integrin-dependent cell adhesion, spreading, and migration (PMID:17704304, PMID:23097489, PMID:21540295). Upon receptor-driven Rap1a activation, RADIL assembles with Gβγ subunits and active Rap1a and translocates from the cytoplasm to sites of cell-matrix contact at the plasma membrane, where it drives inside-out activation of β1- and β2-integrins and downstream FAK activation (PMID:20048162, PMID:23097489). In neural crest and other cells this pathway acts downstream of upstream cues including Protogenin to confer high-affinity integrin conformations and migratory capacity (PMID:17704304, PMID:23744351). At endothelial junctions RADIL cooperates with its relative Rasip1 and recruits the RhoGAP ArhGAP29 into a multimeric plasma-membrane complex that suppresses Rho-mediated stress fiber formation and promotes barrier function (PMID:23798437, PMID:25963656). RADIL activity is negatively regulated at two levels: KIF14 tethers RADIL on microtubules through its PDZ domain to restrain Rap1-mediated integrin activation, and Gαi-GTP acts downstream of Rap1a/RADIL but upstream of integrins to reverse RADIL-driven adhesion (PMID:23209302, PMID:29259127). RADIL also binds all three Ras isoforms via its RA domain, preferentially GTP-bound KRas, and supports Ras-MEK-ERK signaling, proliferation, and invasion, consistent with a role in breast cancer metastasis (PMID:23209302, PMID:33482197).

Mechanistic history

Synthesis pass · year-by-year structured walk · 13 steps
  1. 2005 Low

    Established that the uncharacterized KIAA1849 protein bears a Ras-association domain and physically engages GTP-bound Rap1, raising the question of whether it is a functional Rap effector.

    Evidence Co-immunoprecipitation and overexpression adhesion assay in T cells

    PMID:16051602

    Open questions at the time
    • Single pulldown with a negative functional adhesion result
    • Effector function and cellular role not demonstrated
    • No domain-mapping of the binding interface
  2. 2007 Medium

    Defined RADIL as a genuine Rap effector required for cell adhesion and migration, and linked it in vivo to neural crest migration, establishing its developmental and cellular relevance.

    Evidence Rap-binding affinity assay plus morpholino knockdown in zebrafish with neural crest phenotyping

    PMID:17704304

    Open questions at the time
    • Molecular mechanism connecting RADIL to migration not resolved
    • Single lab
    • Downstream effectors at the membrane not identified
  3. 2010 Medium

    Showed how RADIL is brought to its site of action by demonstrating that Gβγ and activated Rap1a form a complex with RADIL that drives plasma-membrane translocation and inside-out integrin activation downstream of receptor stimulation.

    Evidence Reciprocal Co-IP, membrane translocation assay, integrin activation assay, RNAi

    PMID:20048162

    Open questions at the time
    • Structural basis of the Gβγ–Rap1a–RADIL complex unknown
    • How the complex activates integrins mechanistically not defined
  4. 2011 Medium

    Resolved which Rap effector mediates spreading by showing RADIL is uniquely required, among tested effectors, for Rap1-induced cell spreading but not basal adhesion, establishing pathway specificity.

    Evidence siRNA effector screen with Rap1-induced spreading assay in A549 cells

    PMID:21540295

    Open questions at the time
    • Distinction between spreading and adhesion machinery not mechanistically explained
    • Single cell type
  5. 2012 High

    Provided thorough mechanistic dissection in neutrophils, placing RADIL downstream of Rap1a-GTP for translocation and showing it controls β1/β2-integrin and FAK activation, chemotaxis, and adhesion.

    Evidence Overexpression/RNAi, live-cell translocation imaging, integrin/FAK assays, RapGAP epistasis, integrin antibody rescue

    PMID:23097489

    Open questions at the time
    • Direct biochemical step linking RADIL to talin/integrin not isolated
    • In vivo neutrophil function not tested
  6. 2012 High

    Identified a negative regulator: KIF14 binds the RADIL PDZ domain and sequesters it on microtubules to restrain Rap1-mediated integrin activation, and tied RADIL to breast cancer proliferation and metastasis.

    Evidence PDZ-domain Co-IP, KIF14 knockdown spreading/adhesion/migration assays, in vivo mouse metastasis model

    PMID:23209302

    Open questions at the time
    • How microtubule release of RADIL is triggered unknown
    • Mechanism by which RADIL promotes metastasis not fully defined
  7. 2013 Medium

    Extended RADIL function to endothelial biology, showing it cooperates with Rasip1 to inhibit Rho-mediated stress fibers, promote spreading via ArhGAP29, and regulate junctional barrier function.

    Evidence FRET interaction, siRNA, spreading and endothelial barrier assays

    PMID:23798437

    Open questions at the time
    • Stoichiometry and order of Rasip1/RADIL/ArhGAP29 assembly unresolved at this stage
    • Direct ArhGAP29 recruitment by RADIL not yet shown
  8. 2013 Medium

    Placed RADIL downstream of Protogenin in inside-out integrin activation, identifying an upstream receptor input that drives RADIL membrane translocation and α5β1-integrin activation in neural crest cells.

    Evidence Yeast two-hybrid, translocation assay, RNAi epistasis, integrin activation and transwell migration assays

    PMID:23744351

    Open questions at the time
    • Direct vs indirect nature of Prtg–RADIL coupling at the membrane unclear
    • Generality beyond neural crest cells not established
  9. 2015 High

    Clarified complex assembly by showing Rap1 independently recruits Rasip1 and a RADIL-ArhGAP29 complex to the membrane, forming a multimeric assembly that inhibits Rho signaling and strengthens the endothelial barrier.

    Evidence Live-cell translocation imaging, Co-IP, endothelial barrier assay, siRNA

    PMID:25963656

    Open questions at the time
    • Structural architecture of the multimeric complex unknown
    • Dynamics of complex turnover not characterized
  10. 2017 Medium

    Positioned a second negative regulator, showing Gαi-GTP acts downstream of Rap1a/RADIL but upstream of integrins/talin to reverse RADIL-driven adhesion, with specificity for the RADIL (not RIAM) pathway.

    Evidence Constitutively active mutant epistasis (Rap1a G12V, RADIL, Gαi1 Q204L), spreading/adhesion assays

    PMID:29259127

    Open questions at the time
    • Biochemical target of Gαi-GTP within the pathway not identified
    • Mechanism of RADIL-pathway specificity unexplained
  11. 2018 Medium

    Defined a parallel Rho-independent endothelial barrier route in which AF6/FGD5/RADIL drives Cdc42-mediated actin tension, distinguishing it from the RADIL/Rasip1/ArhGAP29 Rho-inhibitory arm.

    Evidence Co-IP, siRNA, endothelial barrier electrical resistance measurement

    PMID:29388865

    Open questions at the time
    • RADIL's specific contribution inferred from complex membership rather than direct assay
    • Relationship between the two parallel pathways not resolved
  12. 2021 Medium

    Broadened RADIL's GTPase repertoire beyond Rap, showing RA-domain binding to GTP-bound Ras isoforms (preferentially KRas) and a role in MEK-ERK signaling, proliferation, invasion, and mesenchymal phenotype.

    Evidence Affinity pulldown with mass spectrometry, Co-IP, MEK/ERK kinase assay, RNAi with proliferation/invasion/adhesion assays

    PMID:33482197

    Open questions at the time
    • Whether Ras and Rap binding are mutually exclusive unknown
    • How RADIL feeds into the MEK-ERK cascade mechanistically not defined
  13. 2021 Medium

    Identified the RADIL PDZ domain as a micromolar binder of the SARS-CoV-2 E protein PDZ-binding motif, with specificity over SARS-CoV E, flagging a potential viral hijacking interaction.

    Evidence High-throughput quantitative affinity profiling against the full human PDZome with KD measurement

    PMID:33864728

    Open questions at the time
    • No functional consequence for RADIL demonstrated
    • Interaction not validated in infected cells

Open questions

Synthesis pass · forward-looking unresolved questions
  • How RADIL integrates competing inputs — Rap versus Ras GTPase binding, positive membrane recruitment versus KIF14/Gαi negative regulation — into a single decision controlling adhesion, spreading, and barrier function remains unresolved.
  • No structure of RADIL or its multimeric complexes
  • Switch between Rap-adhesion and Ras-ERK functions not defined
  • Physiological signals controlling KIF14 release and Gαi action unknown

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0060090 molecular adaptor activity 3 GO:0098772 molecular function regulator activity 3
Localization
GO:0005886 plasma membrane 3 GO:0005829 cytosol 2
Pathway
R-HSA-162582 Signal Transduction 3 R-HSA-1266738 Developmental Biology 2 R-HSA-1500931 Cell-Cell communication 2
Partners
ARHGAP29FGD5KIF14KRASMLLT4PRTGRAP1ARASIP1
Complex memberships
AF6-FGD5-RADIL complexRADIL-Rasip1-ArhGAP29 complexRap1a-Gβγ-RADIL complex

Evidence

Reading pass · 13 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2007 RADIL was identified as a novel effector of the small GTPase Rap, required for cell adhesion and migration. Knockdown of radil in zebrafish caused defects in neural crest-derived lineages (cartilage, pigment cells, enteric neurons) primarily due to diminished migratory capacity of neural crest cells, establishing RADIL as a Rap-pathway regulator of neural crest migration. Affinity interaction assay (Rap binding), morpholino knockdown in zebrafish with phenotypic analysis of neural crest migration Genes & development Medium 17704304
2010 Gβγ subunits of heterotrimeric G proteins form a protein complex with activated Rap1a and Radil. This complex is required downstream of receptor stimulation for inside-out integrin activation and positive modulation of cell-matrix adhesiveness. Gβγ and activated Rap1a promote translocation of Radil to the plasma membrane at sites of cell-matrix contacts. Co-immunoprecipitation, plasma membrane translocation assay, integrin activation assay, RNAi knockdown The Journal of biological chemistry Medium 20048162
2012 Radil regulates neutrophil adhesion and motility by controlling β1- and β2-integrin activation downstream of Rap1a. On neutrophil activation, Radil translocates from cytoplasm to the plasma membrane in a Rap1a-GTP-dependent manner. Overexpression increases cell adhesion and FAK activation; knockdown inhibits β2-integrin activation and chemotaxis. Inhibition of Rap activity by RapGAP abolishes Radil-mediated integrin and FAK activation. Overexpression and RNAi knockdown in neutrophil-like cells, integrin/FAK activation assays, live-cell imaging of Radil translocation, β2-integrin inhibitory antibody rescue Molecular biology of the cell High 23097489
2012 KIF14 associates with the PDZ domain of Radil and negatively regulates Rap1-mediated inside-out integrin activation by tethering Radil on microtubules. Depletion of KIF14 leads to increased cell spreading, altered focal adhesion dynamics, and inhibition of cell migration and invasion. Radil is important for breast cancer cell proliferation and metastasis in mice. Co-immunoprecipitation (PDZ domain interaction), KIF14 knockdown with cell spreading/adhesion/migration assays, in vivo mouse metastasis model The Journal of cell biology High 23209302
2013 Rasip1 cooperates with its close relative Radil to inhibit Rho-mediated stress fiber formation and induce junctional tightening in endothelial cells. The Rap1-Rasip1 complex induces cell spreading by inhibiting Rho signaling through ArhGAP29, and Radil participates in the Rap1-mediated regulation of endothelial junctions controlling barrier function. FRET (active Rap1 interaction), siRNA knockdown, cell spreading assay, endothelial barrier function measurement Proceedings of the National Academy of Sciences of the United States of America Medium 23798437
2013 Protogenin (Prtg) interacts with Radil (identified by yeast two-hybrid). Overexpression of Prtg induces translocation of Radil from cytoplasm to cell membrane. Prtg and Radil together activate α5β1-integrins to high-affinity conformational forms; RNAi knockdown of Radil abolishes the effect of ERdj3/Prtg on α5β1-integrin activation, placing Radil downstream of Prtg in inside-out integrin activation in neural crest cells. Yeast two-hybrid, overexpression/translocation assay, RNAi knockdown, integrin activation assay, transwell migration assay Cell death & disease Medium 23744351
2015 Rap1 induces independent translocations of Rasip1 and a Radil-ArhGAP29 complex to the plasma membrane, resulting in formation of a multimeric protein complex required for Rap1-induced inhibition of Rho signaling and increased endothelial barrier function. Live-cell imaging of protein translocation, Co-immunoprecipitation, endothelial barrier function assay, siRNA knockdown Molecular and cellular biology High 25963656
2017 Constitutively active Gαi1(Q204L) reverses Radil-driven increases in cell spreading and adhesion to fibronectin, placing Gαi-GTP action downstream of Rap1a and Radil but upstream of integrins and talin. This negative regulation is specific to the Radil pathway, as Gαi1(Q204L) did not reverse RIAM-dependent adhesion. Expression of constitutively active mutants (Rap1a G12V, Radil, Gαi1 Q204L), cell spreading/adhesion assays, epistasis analysis The Journal of biological chemistry Medium 29259127
2018 AF6 forms a complex with FGD5 and Radil (by co-immunoprecipitation in HEK293T cells) and mediates Rap1-enhanced tension in circumferential actin cables via Cdc42, representing a Rho-independent pathway for endothelial barrier function that operates in parallel to the Radil/Rasip1/ArhGAP29 Rho-inhibitory complex. Co-immunoprecipitation, siRNA knockdown, endothelial barrier electrical resistance measurement Small GTPases Medium 29388865
2021 Radil interacts with all three Ras isoforms (HRas, NRas, KRas) via its Ras-association domain, with strongest interaction for KRas; interaction is preferential for GTP-bound Ras. Ectopic Radil expression transiently activates MEK and ERK; Radil knockdown weakens Ras downstream signaling, decreases cell proliferation and invasion, reduces mesenchymal markers, and decreases adhesion foci and actin filaments. Affinity pulldown with mass spectrometry, Co-immunoprecipitation, kinase activation assay (MEK/ERK), RNAi knockdown with proliferation/invasion/adhesion assays The Journal of biological chemistry Medium 33482197
2021 The PDZ domain of RADIL binds the SARS-CoV-2 E protein C-terminal PDZ-binding motif with measurable affinity (dissociation constant in the micromolar range), identified in a high-throughput screen of the full human PDZome; RADIL binding is specific to SARS-CoV-2 E and not shared with SARS-CoV E. High-throughput affinity profiling against full human PDZome (quantitative binding assay with KD measurement) The FEBS journal Medium 33864728
2011 In a siRNA screen, only Radil (among tested Rap effectors) blocked Rap1-induced cell spreading in A549 lung epithelial cells, establishing Radil as a required effector specifically for the cell spreading (but not basal adhesion) response downstream of Rap1. siRNA knockdown screen, Rap1-induced cell spreading assay Journal of cell science Medium 21540295
2005 KIAA1849 (RADIL) contains a Ras association domain and interacted with Rap1 (GTP-bound form) but, unlike AF6, did not inhibit Rap1-induced cell adhesion when overexpressed in T cells. Co-immunoprecipitation, overexpression cell adhesion assay The Journal of biological chemistry Low 16051602

Source papers

Stage 0 corpus · 28 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2013 Rasip1 mediates Rap1 regulation of Rho in endothelial barrier function through ArhGAP29. Proceedings of the National Academy of Sciences of the United States of America 118 23798437
1996 Angiotensin II modulates glomerular capillary permselectivity in rat isolated perfused kidney. Journal of the American Society of Nephrology : JASN 97 8738798
2015 Rap1 Spatially Controls ArhGAP29 To Inhibit Rho Signaling during Endothelial Barrier Regulation. Molecular and cellular biology 71 25963656
2014 Rap1 signaling in endothelial barrier control. Cell adhesion & migration 68 24714377
2012 KIF14 negatively regulates Rap1a-Radil signaling during breast cancer progression. The Journal of cell biology 67 23209302
2021 Host PDZ-containing proteins targeted by SARS-CoV-2. The FEBS journal 63 33864728
2017 Rap1 in endothelial biology. Current opinion in hematology 59 28178039
1999 Different doses of adenoviral vector expressing IL-12 enhance or depress the immune response to a coadministered antigen: the role of nitric oxide. Journal of immunology (Baltimore, Md. : 1950) 54 10228002
2010 G protein betagamma subunits regulate cell adhesion through Rap1a and its effector Radil. The Journal of biological chemistry 41 20048162
2007 A Rap GTPase interactor, RADIL, mediates migration of neural crest precursors. Genes & development 40 17704304
2005 AF6 negatively regulates Rap1-induced cell adhesion. The Journal of biological chemistry 39 16051602
2020 Combined Proteomic and Genetic Interaction Mapping Reveals New RAS Effector Pathways and Susceptibilities. Cancer discovery 35 32727735
2011 Ezrin is required for efficient Rap1-induced cell spreading. Journal of cell science 28 21540295
2012 Radil controls neutrophil adhesion and motility through β2-integrin activation. Molecular biology of the cell 22 23097489
2018 Multiple Rap1 effectors control Epac1-mediated tightening of endothelial junctions. Small GTPases 20 29388865
2013 Protogenin prevents premature apoptosis of rostral cephalic neural crest cells by activating the α5β1-integrin. Cell death & disease 17 23744351
2015 Triple-layer dissection of the lung adenocarcinoma transcriptome: regulation at the gene, transcript, and exon levels. Oncotarget 15 26356813
2017 Activated heterotrimeric G protein αi subunits inhibit Rap-dependent cell adhesion and promote cell migration. The Journal of biological chemistry 10 29259127
2016 Structural Basis of Dimeric Rasip1 RA Domain Recognition of the Ras Subfamily of GTP-Binding Proteins. Structure (London, England : 1993) 10 27839947
2004 Recombinant adenovirus-transduced human dendritic cells engineered to secrete interleukin-10 (IL-10) suppress Th1-type responses while selectively activating IL-10-producing CD4+ T cells. Human immunology 10 15556685
2021 Identification of Radil as a Ras binding partner and putative activator. The Journal of biological chemistry 9 33482197
2023 Proteomic Mapping of the Interactome of KRAS Mutants Identifies New Features of RAS Signalling Networks and the Mechanism of Action of Sotorasib. Cancers 7 37627169
2022 A Proteomic Approach Identifies Isoform-Specific and Nucleotide-Dependent RAS Interactions. Molecular & cellular proteomics : MCP 6 35839996
2013 Epidemiological and phylogenetic analysis of institutional mouse parvoviruses. Experimental and molecular pathology 5 23545399
2023 Exploring shared genetics between maximal oxygen uptake and disease: the HUNT study. Physiological genomics 4 37575066
2008 Characterization of alpha helices interacting with nucleic acids. Computational biology and chemistry 4 18667362
2025 Multi-Omics Analysis Revealed the Molecular Mechanisms Affecting Average Daily Gain in Cattle. International journal of molecular sciences 3 40076961
2026 Long-term Survivors of Anaplastic Thyroid Cancer: A Genomic Predictive Model. The Journal of clinical endocrinology and metabolism 0 40663630

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