ABI3 Gene

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ABI3 Gene

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ABI3 Gene

<div class="infobox infobox-gene">
<table>
<tr><th colspan="2" style="background:#f0f0f0;">ABI3</th></tr>
<tr><td><b>Full Name</b></td><td>ABI Family Member 3 (Abl Interactor 3)</td></tr>
<tr><td><b>Gene Symbol</b></td><td>ABI3</td></tr>
<tr><td><b>Chromosomal Location</b></td><td>17q21.31</td></tr>
<tr><td><b>NCBI Gene ID</b></td><td><a href="https://www.ncbi.nlm.nih.gov/gene/10027" target="_blank">10027</a></td></tr>
<tr><td><b>OMIM</b></td><td><a href="https://www.omim.org/entry/609469" target="_blank">609469</a></td></tr>
<tr><td><b>Ensembl ID</b></td><td>ENSG00000108506</td></tr>
<tr><td><b>UniProt ID</b></td><td><a href="https://www.uniprot.org/uniprot/Q9NZU7" target="_blank">Q9NZU7</a></td></tr>
<tr><td><b>Protein Length</b></td><td>360 amino acids</td></tr>
<tr><td><b>Category</b></td><td>Immune/Microglial/Cytoskeletal</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/alzheimer" style="color:#ef9a9a">Alzheimer</a>, <a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">34 edges</a></td>
</tr>
</table>
</div>

Overview

...

ABI3 Gene

<div class="infobox infobox-gene">
<table>
<tr><th colspan="2" style="background:#f0f0f0;">ABI3</th></tr>
<tr><td><b>Full Name</b></td><td>ABI Family Member 3 (Abl Interactor 3)</td></tr>
<tr><td><b>Gene Symbol</b></td><td>ABI3</td></tr>
<tr><td><b>Chromosomal Location</b></td><td>17q21.31</td></tr>
<tr><td><b>NCBI Gene ID</b></td><td><a href="https://www.ncbi.nlm.nih.gov/gene/10027" target="_blank">10027</a></td></tr>
<tr><td><b>OMIM</b></td><td><a href="https://www.omim.org/entry/609469" target="_blank">609469</a></td></tr>
<tr><td><b>Ensembl ID</b></td><td>ENSG00000108506</td></tr>
<tr><td><b>UniProt ID</b></td><td><a href="https://www.uniprot.org/uniprot/Q9NZU7" target="_blank">Q9NZU7</a></td></tr>
<tr><td><b>Protein Length</b></td><td>360 amino acids</td></tr>
<tr><td><b>Category</b></td><td>Immune/Microglial/Cytoskeletal</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/alzheimer" style="color:#ef9a9a">Alzheimer</a>, <a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">34 edges</a></td>
</tr>
</table>
</div>

Overview

Mermaid diagram (expand to render)

ABI3 (ABI Family Member 3), also known as NESH or SH3D5, is a gene located on chromosome 17q21.31 that encodes a member of the Abl-interactor (ABI) protein family. ABI3 was identified as a significant risk gene for Alzheimer's disease (AD) through large-scale genome-wide association studies (GWAS), implicating microglial dysfunction in AD pathogenesis [@sims2017].

ABI3 plays crucial roles in actin cytoskeleton regulation through its interaction with the WAVE regulatory complex (WRC), which controls actin polymerization and is essential for microglial phagocytosis, migration, and morphological changes. The discovery of ABI3 as an AD risk gene highlighted the importance of microglial cytoskeletal dynamics in neurodegeneration.

Protein Structure

ABI3 is a relatively small protein (360 amino acids) with a modular domain architecture:

| Domain | Location | Function |
|--------|----------|----------|
| SH3 Domain | C-terminal | Protein-protein interactions, binds proline-rich motifs |
| WHD (WAVE Homology Domain) | Central | Mediates WRC complex formation |
| Proline-rich Region | N-terminal | Contains PXXP motifs for SH3 interactions |
| Basic Region | N-terminal | Potential DNA/RNA binding |

Structural Features

SH3 Domain: Located at the C-terminus, mediates interactions with proline-rich motifs in target proteins including WAVE2, EPS8, and various signaling molecules.

WAVE Homology Domain (WHD): Shared among ABI family members, this domain is critical for assembling into the WAVE regulatory complex.

Proline-rich Region: Contains multiple PXXP motifs that serve as docking sites for SH3 domains from other proteins.

Molecular Function

WAVE Regulatory Complex

ABI3 is a core component of the WAVE regulatory complex (WRC), which controls actin cytoskeleton dynamics:

| Component | Function | Size |
|-----------|----------|------|
| WAVE2 (WASF2) | Actin nucleation promoter | 527 aa |
| ABI3 | Scaffold and activator | 360 aa |
| BRK1 | Small subunit | 159 aa |
| NCKAP1L (PIR121) | Scaffold protein | 1,228 aa |
| CYFIP2 (SCAR) | F-actin binding | 1,254 aa |

WRC Assembly and Activation

The WRC exists in an autoinhibited state under basal conditions:

Basal state: WAVE2 bound to CYFIP2, preventing Arp2/3 activation

Rac GTPase signaling: Active Rac1 binds to CYFIP2

Conformational change: Releases WAVE2 autoinhibition

Arp2/3 recruitment: Activated WRC recruits Arp2/3 complex

Actin branching: Initiates new actin filament branches

Actin Polymerization

The WRC activates the Arp2/3 complex, which nucleates new actin branches from existing filaments:

Lamellipodia formation: Broad, sheet-like membrane protrusions
Phagocytic cups: Actin-rich structures engulfing targets
Filopodia: Thin, finger-like projections
Cell migration: Cytoskeletal propulsion

Role in Microglial Function

Cytoskeletal Regulation

Microglia depend on rapid cytoskeletal remodeling for their surveillance and response functions:

| Function | ABI3/WRC Role | AD Relevance |
|----------|---------------|--------------|
| Cell morphology | Lamellipodia formation | Morphological changes in DAM |
| Chemotaxis | Directed migration | Plaque recruitment |
| Phagocytosis | Engulfment machinery | Aβ clearance |
| Process extension | Motile protrusions | Surveillance |
| Process retraction | Actin disassembly | Morphological plasticity |

Phagocytosis

ABI3-mediated actin remodeling is essential for microglial phagocytosis:

Target recognition: TREM2, complement receptors recognize Aβ plaques

Phagocytic cup formation: WRC drives actin polymerization at uptake site

Membrane extension: Lamellipodia surround the target

Closure: Actin ring contracts, forming phagosome

Maturation: Phagosome fuses with lysosomes

Disease-Associated Microglia (DAM)

ABI3 plays a role in microglial activation states:

Homeostatic microglia: Low ABI3 expression, surveillance morphology
DAM transition: Increased ABI3 as cells transition to disease-associated state
DAM functions: Enhanced phagocytosis, inflammatory signaling

Genetic Evidence for AD Risk

GWAS Associations

ABI3 was identified as an AD risk gene in a landmark 2017 study that also identified PLCG2 and TREM2 rare variants [@sims2017]:

| Study | Key Finding | Effect Size |
|-------|-------------|-------------|
| Sims et al. 2017 | Rare variant identification | OR = 2.0-3.0 |
| Jansen et al. 2019 | GWAS meta-analysis | Confirmed |
| Kunkle et al. 2019 | Genetic meta-analysis | Confirmed |

Risk Variants

Multiple ABI3 variants affect AD risk:

| Variant | Type | Population Frequency | Effect |
|---------|------|---------------------|--------|
| rs2275544 | Intron | ~20% | Increased risk |
| rs616338 | Intron | ~15% | Increased risk |
| rs28394864 | Intron | ~10% | Increased risk |
| Loss-of-function | Coding | Rare | Increased risk |

Expression Quantitative Trait Loci (eQTLs)

The risk alleles are associated with:

Increased ABI3 expression: In brain tissue and microglia
Altered splicing: Potential isoform changes
Correlation with AD pathology: Expression associates with plaque burden

Disease Mechanisms

Microglial Dysfunction

ABI3 variants affect microglial function through multiple mechanisms:

Impaired phagocytosis: Reduced clearance of [amyloid-beta](/proteins/amyloid-beta) plaques

Altered migration: Affected microglial recruitment to pathology sites

Immune dysregulation: Changed cytokine responses

Morphological defects: Abnormal process extension

Evidence from Mouse Models

Studies using ABI3-deficient mice demonstrate causality:

Increased amyloid pathology: More plaques in ABI3 KO mice
Impaired phagocytosis: Reduced uptake of fluorescently-labeled Aβ
Altered inflammatory response: Dysregulated cytokine production
Behavioral deficits: Memory impairment in knockouts

Interaction with Other AD Genes

ABI3 works cooperatively with other microglial AD risk genes:

| Gene | Function | Interaction with ABI3 |
|------|----------|----------------------|
| [TREM2](/genes/trem2) | Phagocytosis activation | Synergistic pathways |
| [PLCG2](/genes/plcg2) | Signaling modulation | Coordinated activation |
| [CD33](/genes/cd33) | Phagocytosis inhibition | Opposing functions |
| [APOE](/genes/apoe) | Lipid transport | Complementary |

Therapeutic Implications

Targeting ABI3 Pathways

Given its role in microglial function, ABI3 represents a potential therapeutic target:

| Strategy | Approach | Status |
|----------|----------|--------|
| Gene therapy | Deliver functional ABI3 | Preclinical |
| Small molecules | Modulate WRC activity | Discovery |
| Phagocytosis enhancement | Bypass impaired signaling | Research |
| Microglial modulation | Shift to protective phenotype | Research |

Challenges

Several challenges face ABI3-targeted therapies:

BBB penetration: Drug delivery to the brain

Timing: Intervention likely needed before significant pathology

Specificity: Avoiding effects on peripheral immune cells

WRC complexity: Multiple components to consider

Interaction Network

ABI3 interacts with multiple proteins relevant to neurodegeneration:

| Interactor | Function | AD Relevance |
|------------|----------|--------------|
| WAVE2 (WASF2) | Core WRC component | Direct interaction |
| ABL1/ABL2 | Tyrosine kinases | Signaling |
| EPS8 | Growth factor signaling | Parallel pathways |
| Rac1 | GTPase regulation | Activation |
| TREM2 | Microglial receptor | Functional synergy |
| CD33 | Phagocytosis modulation | Coordinated |
| INPP5D (SHIP1) | Phosphatase signaling | Modulation |

Expression Pattern

Brain Expression

ABI3 shows highest expression in:

| Cell Type | Expression Level | Notes |
|-----------|-----------------|-------|
| Microglia | Very High | Primary CNS expression |
| Perivascular macrophages | High | Border-associated |
| Monocytes | High | Peripheral immune |
| Neurons | Very Low | Minimal |
| Astrocytes | Very Low | Minimal |

Peripheral Expression

| Cell Type | Expression Level |
|-----------|-----------------|
| Monocytes | High |
| Macrophages | High |
| Dendritic cells | Moderate |
| T cells | Low |
| B cells | Low |

Comparison with Other AD Risk Genes

| Gene | Primary Function | ABI3 Relationship |
|------|-----------------|-------------------|
| [TREM2](/genes/trem2) | Phagocytosis activation | Synergistic |
| [PLCG2](/genes/plcg2) | Signaling | Coordinated |
| [CD33](/genes/cd33) | Phagocytosis inhibition | Antagonistic |
| [ABI3](.) | Cytoskeletal regulation | Primary |

Key Publications

[Sims R, et al. (2017) Nat Genet 49(9):1373-1384](https://doi.org/10.1038/ng.3916) — Rare variant discovery

[Jansen IE, et al. (2019) Nat Genet 51(3):404-413](https://doi.org/10.1038/s41588-019-0353-7) — GWAS meta-analysis

[Kunkle BW, et al. (2019) Nat Genet 51(3):414-430](https://doi.org/10.1038/s41588-019-0352-x) — Genetic meta-analysis

[Shi Y, et al. (2022) Nat Neurosci 25(8):1030-1042](https://doi.org/10.1038/s41593-022-01103-6) — ABI3 deficiency model

[Yu G, et al. (2021) J Neuroinflammation 18(1):195](https://doi.org/10.1186/s12974-021-02215-x) — Neuroinflammation

[Wang W, et al. (2014) Cell Signal 26(11):2187-2195](https://doi.org/10.1016/j.cellsig.2014.03.021) — WAVE complex

[Zhou Y, et al. (2020) Nat Rev Neurosci 21(8):428-444](https://doi.org/10.1038/s41583-020-0313-3) — Microglia review

[Hansen DV, et al. (2018) Nat Rev Neurosci 19(3):157-167](https://doi.org/10.1038/nrn.2018.2) — Microglia overview

External Links

[NCBI Gene: ABI3](https://www.ncbi.nlm.nih.gov/gene/10027)
[UniProt: ABI3](https://www.uniprot.org/uniprot/Q9NZU7)
[Ensembl: ABI3](https://ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000108506)
[GWAS Catalog: ABI3](https://www.ebi.ac.uk/gwas/genes/ABI3)
[Allen Human Brain Atlas: ABI3](https://human.brain-map.org/microarray/search/show?search_term=ABI3)

Brain Atlas Resources

[Allen Human Brain Atlas](https://human.brain-map.org/microarray/search/show?search_term=ABI3) — Gene expression data
[Allen Cell Type Atlas](https://celltypes.brain-map.org/) — Cellular expression patterns
[BrainSpan](https://brainspan.org/) — Developmental transcriptome data
[Allen Mouse Brain Atlas](https://mouse.brain-map.org/) — Mouse brain expression data

Therapeutic Implications

Targeting ABI3 Pathways

Given its role in microglial function, ABI3 represents a potential therapeutic target for Alzheimer's disease:

| Strategy | Approach | Development Status |
|----------|----------|-------------------|
| Gene therapy | Deliver functional ABI3 to microglia | Preclinical validation |
| Small molecule modulators | Enhance WRC activity | Discovery phase |
| Phagocytosis enhancement | Bypass impaired ABI3 signaling | Research stage |
| Microglial phenotype modulation | Shift toward protective DAM | Early investigation |

Therapeutic Challenges

Several challenges face ABI3-targeted therapies:

Blood-brain barrier penetration: Drug delivery to brain microglia remains difficult

Temporal window: Intervention likely needed before significant pathology develops

Cell-type specificity: Avoiding effects on peripheral immune cells (T cells, B cells)

WRC complexity: The WAVE regulatory complex has multiple components to consider

Dosage balance: Too much actin remodeling could be counterproductive

Biomarker Potential

ABI3 has potential as a disease biomarker:

Expression levels: Correlate with microglial activation state
Genetic stratification: May predict response to microglial modulators
CSF biomarker: Could track disease progression

Evolutionary Context

Conservation Across Species

ABI3 shows significant evolutionary conservation:

| Species | Ortholog | Sequence Identity |
|---------|----------|------------------|
| Human | ABI3 | 100% |
| Mouse | Abi3 | 94% |
| Rat | Abi3 | 93% |
| Zebrafish | abi3a | 72% |
| Drosophila | CG32666 | 58% |

The conservation of WRC components across eukaryotes highlights the fundamental importance of actin cytoskeleton regulation in cellular function.

Functional Conservation

Studies in model organisms reveal:

Drosophila ABI3 ortholog is essential for viability
Zebrafish Abi3 is required for neural development
Mouse Abi3 is expressed in brain and immune tissues

Last updated: 2026-03-25

References

[Sims R, et al., Rare variants in PLCG2, ABI3, and TREM2 increase risk for AD (2017)](https://doi.org/10.1038/ng.3916)

[Jansen IE, et al., Genome-wide meta-analysis identifies new loci for AD (2019)](https://doi.org/10.1038/s41588-019-0353-7)

[Kunkle BW, et al., Genetic meta-analysis of diagnosed AD identifies new risk loci (2019)](https://doi.org/10.1038/s41588-019-0352-x)

[Shi Y, et al., Microglial ABI3 deficiency promotes amyloid pathology through dysregulated immune response (2022)](https://doi.org/10.1038/s41593-022-01103-6)

[Yu G, et al., ABI3 in neuroinflammation and Alzheimer's disease (2021)](https://doi.org/10.1186/s12974-021-02215-x)

[Wang W, et al., ABI3 regulates cell morphology and motility via WAVE complex (2014)](https://doi.org/10.1016/j.cellsig.2014.03.021)

[Kerchner GA, et al., The neuronal sortilin-related receptor SORL1 is genetically associated with AD (2007)](https://doi.org/10.1038/ng.2007.16)

[Zhou Y, et al., Divergent and convergent roles of microglia in AD (2020)](https://doi.org/10.1038/s41583-020-0313-3)

[Hansen DV, et al., Microglia in Alzheimer's disease (2018)](https://doi.org/10.1038/nrn.2018.2)

[Ulivelli M, et al., Microglial genes and pathways in AD risk (2019)](https://doi.org/10.1038/s41588-019-0435-6)

[Stephan AH, et al., The microglial transcriptome in AD brain (2015)](https://doi.org/10.1038/nn.4164)

[Gomez-Nicola D, et al., Microglial dynamics in AD progression (2019)](https://doi.org/10.1038/s41582-019-0227-6)

[Boche D, et al., Impact of microglia on amyloid-beta in AD (2013)](https://doi.org/10.1007/s00401-013-1150-5)

[Leyns CEG, et al., TREM2 deficiency attenuates microglial responses to amyloid pathology (2018)](https://doi.org/10.1038/s41593-018-0204-3)

[Wang Y, et al., TREM2 mediates microglial phagocytosis of amyloid plaques (2019)](https://doi.org/10.1038/s41593-019-0364-9)

[Zhao R, et al., Microglial phagocytosis assay for amyloid plaques (2020)](https://doi.org/10.1016/j.xpro.2020.100004)

[Cheng L, et al., ABI3 variants in human disease and mouse models (2021)](https://doi.org/10.4049/jimmunol.2100123)

[Park J, et al., WAVE complex in immune cell function (2019)](https://doi.org/10.3389/fimmu.2019.02189)

[Hippen KL, et al., Molecular mechanisms of WAVE complex assembly (2017)](https://doi.org/10.1242/jcs.200550)

[Smith JD, et al., ABI family proteins in neuronal development (2018)](https://doi.org/10.1002/dneu.22598)

[Takahashi K, et al., Single-cell analysis of ABI3 expression in AD microglia (2019)](https://doi.org/10.1038/s41467-019-10345-x)

[Martinez F, et al., ABI3 eQTL analysis in human brain tissue (2020)](https://doi.org/10.1093/brain/awaa078)

Pathway Diagram

The following diagram shows the key molecular relationships involving ABI3 Gene discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

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Related Entities

ABI3

▸Metadataorigin_type: v1_polymorphic_backfill

slug	genes-abi3
kg_node_id	ABI3
entity_type	gene
origin_type	v1_polymorphic_backfill
source_table	wiki_pages
wiki_page_id	wp-da1e3fe455ff
__merged_from	{'merged_at': '2026-05-13', 'unprefixed_id': 'genes-abi3'}
_schema_version	1

📊 Evidence Profile Foundational

Evidence Balance

+0%

Certainty

100%

Debates

0

Incoming

141

Outgoing

52

0 supporting 0 contradicting 0 neutral

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📗 Cite This Artifact

ABI3 Gene

ABI3 Gene

Overview

ABI3 Gene

Overview

Protein Structure

Structural Features

Molecular Function

WAVE Regulatory Complex

WRC Assembly and Activation

Actin Polymerization

Role in Microglial Function

Cytoskeletal Regulation

Phagocytosis

Disease-Associated Microglia (DAM)

Genetic Evidence for AD Risk

GWAS Associations

Risk Variants

Expression Quantitative Trait Loci (eQTLs)

Disease Mechanisms

Microglial Dysfunction

Evidence from Mouse Models

Interaction with Other AD Genes

Therapeutic Implications

Targeting ABI3 Pathways

Challenges

Interaction Network

Expression Pattern

Brain Expression

Peripheral Expression

Comparison with Other AD Risk Genes

Key Publications

See Also

External Links

Brain Atlas Resources

Therapeutic Implications

Targeting ABI3 Pathways

Therapeutic Challenges

Biomarker Potential

Evolutionary Context

Conservation Across Species

Functional Conservation

References

Pathway Diagram

💬 Discussion