Affinage

ELMO2

Engulfment and cell motility protein 2 · UniProt Q96JJ3

Length
720 aa
Mass
82.6 kDa
Annotated
2026-04-28
30 papers in source corpus 21 papers cited in narrative 20 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

ELMO2 is an evolutionarily conserved scaffold protein that functions as an obligate partner of DOCK180 in a bipartite guanine nucleotide exchange factor (GEF) complex, integrating diverse upstream signals into Rac1 activation and actin cytoskeletal reorganization across multiple cellular contexts including phagocytosis, cell migration, myoblast fusion, and vascular smooth muscle cell organization (PMID:11595183, PMID:36400788, PMID:40456777). ELMO2 receives upstream signals through its Armadillo repeats (binding activated RhoG), its PH domain (mediating membrane and lipid interactions), and its RAE supramodule (engaging adhesion GPCRs such as BAI1), while its C-terminal SH3-binding motif recruits DOCK180; additional inputs from ILK, receptor tyrosine kinases (MET–AXL), and Gαi2 converge on ELMO2 to direct spatially polarized Rac1 activation at leading edges and cell–cell contacts (PMID:15620647, PMID:30604775, PMID:19439446, PMID:30108175, PMID:32292657). Through Rac1, ELMO2 controls downstream effectors including stathmin phosphorylation and GSK-3β inactivation to stabilize microtubules, promotes GLUT4 membrane translocation in insulin-responsive cells, and regulates recycling endosome positioning for E-cadherin delivery during epithelial differentiation (PMID:25995380, PMID:27226625, PMID:27627840). Loss-of-function mutations in ELMO2 cause autosomal recessive intraosseous vascular malformation in humans (PMID:27476657).

Mechanistic history

Synthesis pass · year-by-year structured walk · 11 steps
  1. 2001 High

    The fundamental question of how DOCK180 achieves Rac1 GEF activity was answered by demonstrating that CED-12/ELMO2 is an obligate binding partner that directly binds DOCK180 via its SH3-binding motif and PH domain, forming an evolutionarily conserved complex required for Rac1 activation, phagocytosis, and cell migration.

    Evidence Reciprocal co-IP/pulldown, C. elegans genetic epistasis, mammalian functional rescue, Rac1 activation assays across three independent studies

    PMID:11595183 PMID:11703939 PMID:11703940

    Open questions at the time
    • Structural basis of ELMO2–DOCK180 interface not resolved
    • Upstream activating signals for the complex unknown
  2. 2004 High

    The upstream activator linking RhoG to the ELMO–DOCK180 complex was identified: ELMO's Armadillo repeats directly bind GTP-loaded RhoG, establishing the TRIO→RhoG→ELMO→DOCK180→Rac1 signaling cascade for engulfment.

    Evidence Domain mapping, co-IP, C. elegans genetic epistasis, Rac1 activation assay

    PMID:15620647

    Open questions at the time
    • Role of other small GTPases in activating ELMO unclear
    • RhoG-independent activation mechanisms not explored
  3. 2009 High

    ELMO2 was shown to form a tripartite complex with ILK and RhoG (ERI complex) that localizes to lamellipodia and is essential for front-rear cell polarity and haptotactic migration, establishing ELMO2 as a spatial organizer of Rac1 signaling at the leading edge.

    Evidence Reciprocal co-IP, dominant-negative ELMO2 mutant, live-cell imaging, migration assays; extended by EGF-specific induction in keratinocytes

    PMID:19439446 PMID:22160594

    Open questions at the time
    • How ILK–ELMO2 interaction is regulated at the structural level
    • Whether other ELMO paralogs form equivalent ERI complexes
  4. 2015 High

    The ERI complex was found to regulate microtubule stability (not just actin) through Rac1-mediated stathmin phosphorylation and GSK-3β/CRMP2 inactivation, and ClipR-59 was identified as a novel ELMO2 PH-domain interactor promoting myoblast fusion, broadening ELMO2's downstream effector repertoire beyond actin reorganization.

    Evidence Conditional Ilk KO, microtubule dynamics imaging, phosphorylation assays; yeast two-hybrid validated by co-IP with myoblast fusion readout

    PMID:25572395 PMID:25995380

    Open questions at the time
    • Direct structural basis of ELMO2 PH domain–ClipR-59 interaction unresolved
    • Whether microtubule regulation occurs in non-epithelial contexts
  5. 2016 Medium

    Multiple studies revealed ELMO2's physiological breadth: loss-of-function mutations cause intraosseous vascular malformation (VMOS) in humans with DOCK1 destabilization; ELMO2 mediates insulin-stimulated GLUT4 translocation via Rac1; and ELMO2/ILK localize to Rab4/Rab11a recycling endosomes to direct E-cadherin delivery at cell junctions.

    Evidence Human exome sequencing with primary fibroblast analysis; siRNA KD with GLUT4/Rac1/Akt assays in adipocytes and muscle cells; fluorescence imaging and subcellular fractionation with KO/KD in keratinocytes; phagocytosis KD assays in trabecular meshwork cells

    PMID:27226625 PMID:27476657 PMID:27539661 PMID:27627840

    Open questions at the time
    • Mechanism by which ELMO2 loss destabilizes DOCK1 protein not determined
    • Whether vascular malformation is due to endothelial or smooth muscle cell defects
    • ELMO2's role on recycling endosomes versus plasma membrane not fully dissected
  6. 2019 High

    The crystal structure of the ELMO2 RBD-ARR-ELMO (RAE) supramodule bound to the BAI1 cytoplasmic tail provided the first atomic-resolution view of how adhesion GPCRs engage the ELMO–DOCK pathway, and disease mutations were mapped to this interface.

    Evidence X-ray crystallography, binding assays, site-directed mutagenesis at the BAI1–ELMO2 interface

    PMID:30604775

    Open questions at the time
    • Full-length ELMO2–DOCK180 complex structure not available
    • How BAI1 engagement triggers conformational activation of ELMO2 unknown
  7. 2018 Medium

    ELMO2 was placed downstream of receptor tyrosine kinases MET and AXL, which form a quaternary complex (MET–AXL–ELMO2–DOCK180) upon HGF stimulation to drive RAC1-dependent invasion in glioblastoma, and downstream of Gαi2 in CXCL12-stimulated pancreatic cancer chemotaxis.

    Evidence Co-IP with kinase inhibitor dissection, RAC1 activation, migration/invasion assays; membrane fractionation and chemotaxis assays

    PMID:30108175 PMID:32292657

    Open questions at the time
    • Gαi2–ELMO2 interaction awaits reciprocal validation and structural characterization
    • Whether MET–AXL directly phosphorylates ELMO2 unknown
  8. 2022 High

    In vivo genetic evidence established that ELMO2 conformational switching between closed (autoinhibited) and open (active) states controls myoblast fusion efficiency during muscle development and regeneration, with ELMO1 and ELMO2 showing functional redundancy.

    Evidence Mouse Elmo1/Elmo2 double KO and knock-in of open/closed ELMO2 conformation mutations, myoblast fusion quantification

    PMID:36400788

    Open questions at the time
    • Molecular trigger for autoinhibition release in physiological signaling not identified
    • Whether conformational regulation applies to non-muscle contexts
  9. 2024 Medium

    A candidate GAP domain in CED-12/ELMO was identified that is functionally separable from the DOCK-interacting GEF domain, with the predicted catalytic arginine specifically required for epidermal cell migration but dispensable for corpse engulfment, suggesting ELMO may both promote and inhibit distinct GTPases.

    Evidence Site-directed mutagenesis (R537A), C. elegans cell migration and engulfment phenotype analysis

    PMID:39083711

    Open questions at the time
    • GAP activity not demonstrated biochemically in vitro
    • Target GTPase of the putative GAP domain not identified
    • Not confirmed in mammalian ELMO2
  10. 2025 High

    Neural crest-specific Elmo2 deletion in mice demonstrated that ELMO2 is essential for vascular smooth muscle cell organization during pharyngeal arch artery development, with loss causing carotid aneurysms and midgestation lethality, providing a mechanistic basis for the human VMOS phenotype.

    Evidence Global and neural crest-conditional mouse KO, VSMC adhesion/spreading/contractility assays, Rac1 activation

    PMID:40456777

    Open questions at the time
    • Whether endothelial-autonomous ELMO2 function also contributes to vascular phenotype
    • Downstream Rac1 effectors responsible for VSMC contractility defect not identified
  11. 2026 Medium

    ELMO2 was linked to cell survival through FAK signaling: its suppression triggers excessive autophagy and cell death via FAK inhibition in mesenchymal-like cancer cells, with ELMO3 acting as a synthetic lethal paralog whose expression is repressed by ZEB1.

    Evidence siRNA/CRISPR KD/KO, FAK activity assay, autophagy assays, small molecule inhibitor (C52), ZEB1 KD

    PMID:41997974

    Open questions at the time
    • Not independently replicated
    • Whether FAK regulation is direct or via Rac1/integrin signaling
    • Applicability beyond mesenchymal-like lung cancer not tested

Open questions

Synthesis pass · forward-looking unresolved questions
  • Key unresolved questions include the full-length structure of the ELMO2–DOCK180 holoenzymatic complex, the precise molecular trigger for ELMO2 autoinhibition release in physiological contexts, whether the candidate GAP activity is conserved in mammalian ELMO2 and which GTPase it targets, and how ELMO2 coordinates its multiple upstream inputs (RhoG, BAI1, ILK, RTKs, Gαi2) at a single-molecule level.
  • Full-length ELMO2–DOCK180 cryo-EM or crystal structure not available
  • Biochemical reconstitution of GAP activity for mammalian ELMO2 lacking
  • Quantitative signaling hierarchy among multiple upstream inputs not determined

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0060090 molecular adaptor activity 5 GO:0098772 molecular function regulator activity 4
Localization
GO:0005886 plasma membrane 4 GO:0005829 cytosol 2 GO:0005856 cytoskeleton 2 GO:0031410 cytoplasmic vesicle 1
Pathway
R-HSA-162582 Signal Transduction 6 R-HSA-168256 Immune System 3 R-HSA-1266738 Developmental Biology 2 R-HSA-1500931 Cell-Cell communication 2 R-HSA-9612973 Autophagy 1
Partners
AXLBAI1CLIPR59DOCK1GNAI2ILKMETRHOG
Complex memberships
ELMO2–DOCK180 bipartite GEF complexMET–AXL–ELMO2–DOCK180 complexRhoG–ELMO2–ILK (ERI) tripartite complex

Evidence

Reading pass · 20 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2001 ELMO2 (and its C. elegans ortholog CED-12) binds directly to DOCK180 (CED-5), forming an evolutionarily conserved complex that stimulates Rac1 GEF activity, leading to Rac1 activation and cytoskeletal rearrangements required for phagocytosis of apoptotic cells and cell migration. Direct binding assay (co-immunoprecipitation/pulldown), genetic epistasis in C. elegans, functional rescue in mammalian cells, Rac1 activation assay Cell High 11595183 11703939 11703940
2001 CED-12/ELMO contains a pleckstrin homology (PH) domain and an SH3-binding motif, both required for function; the PH domain mediates membrane association and the SH3-binding motif mediates interaction with CED-5/DOCK180. Domain deletion/mutation analysis, co-immunoprecipitation, functional assay in C. elegans and mammalian fibroblasts Developmental cell High 11703939 11703940
2003 In C. elegans, the phosphatidylserine receptor PSR-1 acts upstream of CED-12 (ELMO) in the cell corpse engulfment pathway through direct interaction with CED-5 and CED-12. Genetic epistasis in C. elegans, in vitro binding assay (PSR-1 binding to phosphatidylserine), co-immunoprecipitation Science Medium 14645848
2004 ELMO/CED-12 contains evolutionarily conserved Armadillo (ARM) repeats that mediate direct interaction with activated RhoG (MIG-2 in C. elegans), linking the upstream TRIO/UNC-73→RhoG/MIG-2 signaling module to DOCK180-dependent Rac1 activation during engulfment. Domain identification, co-immunoprecipitation, genetic epistasis in C. elegans, Rac1 activation assay Current biology : CB High 15620647
2009 ELMO2 forms a tripartite complex with integrin-linked kinase (ILK) and RhoG; this RhoG-ELMO2-ILK complex localizes to leading lamellipodia of polarized cells and is essential for ILK-induced front-rear cell polarity and haptotactic migration, with RhoG binding to ELMO2 being required for the polarity function. Co-immunoprecipitation, dominant-negative ELMO2 mutant expression, live-cell imaging/localization, cell migration assay Molecular biology of the cell High 19439446
2011 EGF receptor stimulation induces formation of RhoG-ELMO2-ILK complexes that promote Rac1 activation, driving front-rear polarity and directional keratinocyte migration; this requires ILK, ELMO2, integrin β1, and Rac1, and is specific to EGF (not other growth factors). siRNA knockdown, co-immunoprecipitation, cell polarity assay, chemotaxis assay, Rac1 activation assay Molecular biology of the cell High 22160594
2011 In C. elegans, the myotubularin phosphatase MTM-1 acts upstream of the CED-2/CED-5/CED-12 ternary GEF complex during apoptotic cell clearance; the CED-12 PH domain can bind PtdIns(3,5)P2 (a product of MTM-1 phosphatase activity), suggesting MTM-1 regulates CED-12 membrane recruitment. Genetic epistasis in C. elegans, lipid-binding assay (CED-12 PH domain with phosphoinositides) Development Medium 21490059
2015 ELMO2-RhoG-ILK (ERI) tripartite complexes regulate microtubule dynamics in an integrin-independent manner in differentiated keratinocytes: ERI complexes promote microtubule stability through Rac1 activation, which inactivates stathmin (via phosphorylation) and GSK-3β (leading to CRMP2 activation), and absence of ERI complexes impairs Ca2+-mediated adherens junction formation. Conditional Ilk knockout, ELMO2/RhoG overexpression, microtubule dynamics imaging, Rac1 activation assay, phosphorylation assays Molecular biology of the cell High 25995380
2015 ClipR-59 interacts with ELMO2 through the atypical PH domain of ELMO2 and the Glu-Pro-rich domain of ClipR-59; this interaction is regulated by Rho-GTPase and enhances Rac1 activation to promote myoblast fusion. Yeast two-hybrid, co-immunoprecipitation, domain mapping, Rac1 activation assay, siRNA knockdown/overexpression with myoblast fusion readout The Journal of biological chemistry Medium 25572395
2016 Loss-of-function mutations in ELMO2 cause intraosseous vascular malformation (VMOS); absence of ELMO2 in patient fibroblasts correlates with downregulation of binding partner DOCK1 and deficient RAC1-dependent cell migration. Human genetics (exome sequencing), primary fibroblast analysis, DOCK1 protein level measurement, cell migration assay American journal of human genetics Medium 27476657
2016 ELMO2 is required for insulin-dependent GLUT4 membrane translocation in adipocytes and skeletal muscle cells through modulation of Rac1 activity; ELMO2 promotes insulin-induced Rac1 GTP loading and Akt membrane compartmentalization (but not Akt phosphorylation itself). siRNA knockdown, overexpression in 3T3-L1 and L6 cells, GLUT4 translocation assay, Rac1 GTP pull-down, Akt membrane fractionation The Journal of biological chemistry Medium 27226625
2016 ELMO2 and ILK localize to Rab4- and Rab11a-containing recycling endosomes during keratinocyte differentiation; ELMO2 or ILK deficiency disrupts positioning of Rab11a-positive endosomes at cell-cell contacts, impairing E-cadherin delivery to cell borders. Fluorescence imaging, subcellular fractionation, ELMO2/ILK KO/KD with functional readout (E-cadherin localization) Biochimica et biophysica acta Medium 27627840
2016 In human trabecular meshwork cells, phagocytosis is mediated by an ILK/RhoG/ELMO2 signaling pathway upstream of Rac1; knockdown of ELMO2, ILK, or RhoG each significantly inhibits phagocytosis. siRNA knockdown, Rac1 inhibitor, overexpression with phagocytosis assay Experimental cell research Medium 27539661
2019 Crystal structure of the ELMO2 RBD-ARR-ELMO (RAE) supramodule and its complex with the C-terminal cytoplasmic tail of BAI1 reveals the molecular basis of BAI adhesion GPCR/ELMO interactions; disease-causing mutations in BAI and ELMO were mapped to this interface and shown to affect complex formation. X-ray crystallography, binding assays, mutagenesis at the BAI1-ELMO2 interface Nature communications High 30604775
2018 HGF stimulation induces formation of a MET-AXL-ELMO2-DOCK180 complex on the plasma membrane that activates RAC1-dependent cytoskeletal reorganization, cell migration, and invasion in glioblastoma cells; this complex requires both MET and AXL kinase activities. Co-immunoprecipitation, kinase inhibitor treatment, RAC1 activation assay, migration/invasion assay, siRNA knockdown The Journal of biological chemistry Medium 30108175
2020 ELMO2 interacts with Gαi2 in pancreatic cancer cells; CXCL12 stimulation triggers Gαi2-dependent membrane translocation of ELMO2, promoting chemotaxis, migration, invasion, and F-actin polymerization. Co-immunoprecipitation, siRNA knockdown, membrane fractionation, chemotaxis/migration/invasion assay PeerJ Medium 32292657
2022 ELMO2 is required for myoblast fusion; a mutation conferring an open/active ELMO2 conformation increases myoblast fusion during development and in muscle regeneration, while a signaling-reduced ELMO2 mutation decreases fusion; Elmo1-/-;Elmo2-muscle-KO mice exhibit severe myoblast fusion defects. Mouse knockout, Elmo2 open/closed conformation knock-in mutations, muscle regeneration assay, myoblast fusion quantification Nature communications High 36400788
2024 CED-12 (ELMO ortholog) in C. elegans harbors a candidate GAP region distinct from the DOCK-interacting GEF region; mutagenesis of the predicted catalytic arginine (R537A) in the GAP region alters epidermal cell migration (but not corpse engulfment), while disrupting the CED-5 GEF domain abolishes both functions, suggesting CED-12 uses distinct domains to promote and inhibit F-actin via different GTPases. Site-directed mutagenesis, genetic epistasis, C. elegans embryonic phenotype analysis (cell migration and corpse engulfment assays) PLoS genetics Medium 39083711
2025 Global or neural crest-specific deletion of Elmo2 in mice causes midgestation lethality due to dilation of pharyngeal arch arteries and carotid aneurysms associated with vascular smooth muscle cell organization defects; in vitro, ELMO2 regulates vascular smooth muscle cell adhesion, spreading, and contractility through Rac1 activation and actin dynamics modulation. Conditional mouse knockout, in vitro VSMC adhesion/spreading/contractility assays, Rac1 activation assay Nature communications High 40456777
2026 ELMO2 suppression induces excessive autophagy and cell death via FAK activity inhibition in mesenchymal-like lung cancer cells; ELMO3 acts as a functional paralog compensating for ELMO2 loss, establishing a synthetic lethal interaction; ZEB1 represses ELMO3 transcription in mesenchymal-like cells, sensitizing them to ELMO2 blockade. siRNA/CRISPR knockdown/knockout, FAK activity assay, autophagy assays, structure-based small molecule screening (C52 inhibitor), transcription factor (ZEB1) knockdown Nature communications Medium 41997974

Source papers

Stage 0 corpus · 30 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2001 CED-12/ELMO, a novel member of the CrkII/Dock180/Rac pathway, is required for phagocytosis and cell migration. Cell 470 11595183
2004 Phagocytosis of apoptotic cells is regulated by a UNC-73/TRIO-MIG-2/RhoG signaling module and armadillo repeats of CED-12/ELMO. Current biology : CB 168 15620647
2003 Cell corpse engulfment mediated by C. elegans phosphatidylserine receptor through CED-5 and CED-12. Science (New York, N.Y.) 164 14645848
2001 The C. elegans PH domain protein CED-12 regulates cytoskeletal reorganization via a Rho/Rac GTPase signaling pathway. Developmental cell 141 11703939
2001 C. elegans CED-12 acts in the conserved crkII/DOCK180/Rac pathway to control cell migration and cell corpse engulfment. Developmental cell 136 11703940
2007 Drosophila ELMO/CED-12 interacts with Myoblast city to direct myoblast fusion and ommatidial organization. Developmental biology 72 18163987
2011 Epidermal growth factor induction of front-rear polarity and migration in keratinocytes is mediated by integrin-linked kinase and ELMO2. Molecular biology of the cell 38 22160594
2009 Integrin-linked kinase interactions with ELMO2 modulate cell polarity. Molecular biology of the cell 32 19439446
2019 Structure of BAI1/ELMO2 complex reveals an action mechanism of adhesion GPCRs via ELMO family scaffolds. Nature communications 31 30604775
2018 HGF-induced formation of the MET-AXL-ELMO2-DOCK180 complex promotes RAC1 activation, receptor clustering, and cancer cell migration and invasion. The Journal of biological chemistry 30 30108175
2011 The phosphoinositide phosphatase MTM-1 regulates apoptotic cell corpse clearance through CED-5-CED-12 in C. elegans. Development (Cambridge, England) 29 21490059
2016 Loss-of-Function Mutations in ELMO2 Cause Intraosseous Vascular Malformation by Impeding RAC1 Signaling. American journal of human genetics 26 27476657
2016 Involvement of Tiam1, RhoG and ELMO2/ILK in Rac1-mediated phagocytosis in human trabecular meshwork cells. Experimental cell research 25 27539661
2015 An ELMO2-RhoG-ILK network modulates microtubule dynamics. Molecular biology of the cell 25 25995380
2012 The Drosophila TRPP cation channel, PKD2 and Dmel/Ced-12 act in genetically distinct pathways during apoptotic cell clearance. PloS one 17 22347485
2018 Homozygous mutation in ELMO2 may cause Ramon syndrome. Clinical genetics 15 29095483
2012 Emerging role of ILK and ELMO2 in the integration of adhesion and migration pathways. Cell adhesion & migration 12 22568984
2022 Biasing the conformation of ELMO2 reveals that myoblast fusion can be exploited to improve muscle regeneration. Nature communications 10 36400788
2016 Elmo2 Is a Regulator of Insulin-dependent Glut4 Membrane Translocation. The Journal of biological chemistry 9 27226625
2015 ClipR-59 interacts with Elmo2 and modulates myoblast fusion. The Journal of biological chemistry 9 25572395
2016 Integrin-linked kinase and ELMO2 modulate recycling endosomes in keratinocytes. Biochimica et biophysica acta 8 27627840
2020 ELMO2 association with Gαi2 regulates pancreatic cancer cell chemotaxis and metastasis. PeerJ 6 32292657
2024 Planarians require ced-12/elmo-1 to clear dead cells by excretion through the gut. Cell reports 4 38165802
2022 Comparative Morphological, Metabolic and Transcriptome Analyses in elmo1 , elmo2 , and elmo3 Zebrafish Mutants Identified a Functional Non-Redundancy of the Elmo Proteins. Frontiers in cell and developmental biology 4 35874819
2024 ELMO2 biallelic pathogenic variants in a patient with gingival hypertrophy and cherubism phenotype: Case report and molecular review. American journal of medical genetics. Part A 3 38517102
2024 CED-5/CED-12 (DOCK/ELMO) can promote and inhibit F-actin formation via distinct motifs that may target different GTPases. PLoS genetics 2 39083711
2025 ELMO2 is an essential regulator of carotid artery development. Nature communications 1 40456777
2023 CED-5/CED-12 (DOCK/ELMO) can promote and inhibit F-actin formation via distinct motifs that target different GTPases. bioRxiv : the preprint server for biology 1 37873140
2026 ELMO2 is a therapeutic vulnerability in mesenchymal-like and drug-resistant non-small cell lung cancer. Nature communications 0 41997974
2025 Primary Intraosseous Vascular Malformation in a Child with ELMO2 Mutation: Diagnostic and Dental Management Challenges. Dentistry journal 0 41149120