abca1-protein

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abca1-protein

Overview

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">abca1-protein</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td><strong>ABCA1</strong></td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>abca1-protein</td>
</tr>
<tr>
<td class="label">Type</td>
<td>Protein</td>
</tr>
<tr>
<td class="label">UniProt</td>
<td><a href="https://www.uniprot.org/uniprot/?query=ABCA1" target="_blank">Search UniProt</a></td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/ad" style="color:#ef9a9a">AD</a>, <a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/ami" style="color:#ef9a9a">AMI</a>, <a href="/wiki/arm" style="color:#ef9a9a">ARM</a>, <a href="/wiki/atherosclerosis" style="color:#ef9a9a">ATHEROSCLEROSIS</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">378 edges</a></td>
</tr>
</table>

ABCA1 (ATP-binding cassette transporter A1) is a member of the ABC transporter family that plays a critical role in cholesterol efflux and lipid homeostasis throughout the body, including the central nervous system[@vasiliou2009]. In the brain, ABCA1 is essential for the lipidation of [apolipoprotein E](/proteins/apoe) (ApoE) secreted by [astrocytes](/cell-types/astrocytes), a process critical for [amyloid-beta](/proteins/amyloid-beta) clearance and neuronal function[@koldamova2007].

...

abca1-protein

Overview

<table class="infobox infobox-protein">
<tr>
<th class="infobox-header" colspan="2">abca1-protein</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td><strong>ABCA1</strong></td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>abca1-protein</td>
</tr>
<tr>
<td class="label">Type</td>
<td>Protein</td>
</tr>
<tr>
<td class="label">UniProt</td>
<td><a href="https://www.uniprot.org/uniprot/?query=ABCA1" target="_blank">Search UniProt</a></td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/ad" style="color:#ef9a9a">AD</a>, <a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/ami" style="color:#ef9a9a">AMI</a>, <a href="/wiki/arm" style="color:#ef9a9a">ARM</a>, <a href="/wiki/atherosclerosis" style="color:#ef9a9a">ATHEROSCLEROSIS</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">378 edges</a></td>
</tr>
</table>

ABCA1 (ATP-binding cassette transporter A1) is a member of the ABC transporter family that plays a critical role in cholesterol efflux and lipid homeostasis throughout the body, including the central nervous system[@vasiliou2009]. In the brain, ABCA1 is essential for the lipidation of [apolipoprotein E](/proteins/apoe) (ApoE) secreted by [astrocytes](/cell-types/astrocytes), a process critical for [amyloid-beta](/proteins/amyloid-beta) clearance and neuronal function[@koldamova2007].

ABCA1 is expressed in many tissues, including liver, macrophages, [microglia](/cell-types/microglia-neuroinflammation), astrocytes, and neurons. Its dysfunction has been implicated in [Alzheimer's disease](/diseases/alzheimers-disease), [Parkinson's disease](/diseases/parkinsons-disease), and atherosclerosis[@wahrle2005]. The protein functions as a key regulator of reverse cholesterol transport and is essential for the formation of [high-density lipoprotein](/proteins/hdl-particle) (HDL) particles.

Structure

ABCA1 has the typical architecture of ABC transporters[@takahashi2006]:

Transmembrane Domains

Two transmembrane domains (TMDs): Each containing 6 transmembrane helices
Extracellular loops: Form the substrate entry portal for lipids
Intracellular loops: Connect TMDs and contain regulatory elements

Nucleotide-Binding Domains

Two nucleotide-binding domains (NBDs): Located at the cytoplasmic face
Walker A motif: Binds ATP phosphate groups
Walker B motif: Coordinates magnesium ion
ABC signature (C-loop): Contains the conserved LSGGQ motif
H-loop (switch region): Contains the catalytic histidine for ATP hydrolysis

Structural Features

N-terminal extracellular domain: Unique to the ABCA subfamily
Coupling helices: Connect TMDs to NBDs for conformational transmission
Dimerization: Forms functional homodimers in the plasma membrane

Comparison with Other ABC Transporters

ABCA1 shares structural homology with other ABCA family members:

ABCA4: Retinal transporter (visual cycle)
ABCA2: Brain-expressed, associated with AD risk
ABCA3: Lung surfactant homeostasis
ABCA7: Cholesterol efflux, linked to AD

Normal Function

Cholesterol Efflux

ABCA1 is the central mediator of cellular cholesterol efflux[@yvan-charvet2010]:

Transfers cholesterol and phospholipids to apolipoproteins (ApoA-I, ApoE)
Mediates the first step in reverse cholesterol transport
Prevents foam cell formation in atherosclerosis

HDL Particle Formation

ABCA1 is essential for nascent HDL particle formation:

Binds ApoA-I via the extracellular loops
Transfers lipids to form pre-beta HDL particles
Initiates the HDL maturation pathway

Cellular Lipid Homeostasis

ABCA1 maintains cellular lipid balance:

Prevents cholesterol accumulation in cells
Regulates membrane lipid composition
Supports cellular stress responses

Phagocytosis in Microglia

ABCA1 modulates microglial function[@pincher2020]:

Supports phagocytosis of cellular debris
Modulates inflammatory responses
Essential for amyloid clearance

Role in Neurodegeneration

Alzheimer's Disease

ABCA1 plays a critical role in AD pathogenesis through multiple mechanisms[@liu2019]:

ApoE Lipidation

ABCA1 is required for proper lipidation of astrocyte-secreted ApoE[@wahrle2005]
Lipidated ApoE is more effective at Aβ clearance
ABCA1 deficiency leads to poorly lipidated ApoE particles
Reduced Aβ clearance across the blood-brain barrier

Amyloid Clearance

ABCA1 deficiency promotes amyloid pathology in AD mouse models[@hu2020]
Lipidated ApoE-Aβ complexes are cleared more efficiently
ABCA1 regulates Aβ degradation by microglia
Astrocyte ABCA1 supports neuronal Aβ clearance

Genetic Association

ABCA1 polymorphisms associated with AD risk
Variants affect ApoE lipidation capacity
Some variants protective, others risk-increasing

Therapeutic Implications

LXR agonists increase ABCA1 expression[@zelcer2006]
ABCA1 upregulation reduces amyloid pathology[@fitz2010]
Must balance peripheral and CNS effects

Parkinson's Disease

ABCA1 is implicated in PD through lipid metabolism alterations:

Altered cholesterol metabolism in PD brains
ABCA1 variants may modify PD risk
Role in dopaminergic neuron survival
Connections to α-synuclein aggregation

Neuroinflammation

ABCA1 modulates neuroinflammatory responses[@pincher2020]:

Regulates microglia cholesterol homeostasis
Modulates pro-inflammatory cytokine production
ABCA1 deficiency increases neuroinflammation
Therapeutic potential for inflammatory conditions

Other Neurodegenerative Conditions

Multiple Sclerosis: Role in myelin maintenance
Huntington's Disease: Altered cholesterol homeostasis
Amyotrophic Lateral Sclerosis: Lipid metabolism changes

Therapeutic Targeting

LXR Agonists

Liver X receptor (LXR) agonists are potent ABCA1 inducers[@zelcer2006]:

TO901317: Increases ABCA1 expression in vitro and in vivo
GW3965: Synthetic LXR agonist
Clinical challenge: Peripheral side effects (lipogenesis)

Clinical Trial Results

LXR agonists showed promise in AD mouse models[@fitz2010]
Limited by increased triglyceride levels
CNS-selective compounds in development

Gene Therapy

AAV-mediated ABCA1 delivery to CNS
Targeted expression in astrocytes
Potential for sustainable therapeutic benefit

Small Molecule Activators

Direct ABCA1 activators in development
Structure-activity relationship studies
Selective CNS-active compounds

Combination Approaches

LXR agonists with other therapeutics
ABCA1 upregulation plus Aβ immunotherapy
ApoE-directed therapies

Key Publications

[Takahashi K, et al., Purification and ATPase activity of human ABCA1 (2006)](https://pubmed.ncbi.nlm.nih.gov/16484230/)

[Volpicella M, et al., ATP-binding cassette transporters in neurodegeneration (2020)](https://pubmed.ncbi.nlm.nih.gov/31873872/)

[Vasiliou V, et al., Human ATP-binding cassette (ABC) transporter family (2009)](https://pubmed.ncbi.nlm.nih.gov/19515417/)

[Koldamova R, Lefterov I, Role of ABCA1 and ABCG1 transporters in cholesterol efflux and Alzheimer's disease (2007)](https://pubmed.ncbi.nlm.nih.gov/17430242/)

[Wahrle SE, et al., ABCA1 is required for normal central nervous system ApoE levels (2005)](https://pubmed.ncbi.nlm.nih.gov/15983038/)

[Zelcer N, Tontonoz P, Liver X receptors as integrators of metabolic and inflammatory signaling (2006)](https://pubmed.ncbi.nlm.nih.gov/16511593/)

[Fitz NF, et al., Liver X receptor agonist treatment ameliorates amyloid pathology (2010)](https://pubmed.ncbi.nlm.nih.gov/21045124/)

[Hu Y, et al., ABCA1 deficiency promotes amyloid pathology in Alzheimer's disease (2020)](https://pubmed.ncbi.nlm.nih.gov/32717471/)

[Vitali C, et al., ABCA1 and cholesterol efflux in the brain (2014)](https://pubmed.ncbi.nlm.nih.gov/24854264/)

[Yvan-Charvet L, et al., ABCA1, ABCG1, and cholesterol homeostasis in macrophages (2010)](https://pubmed.ncbi.nlm.nih.gov/20167679/)

[Karinasinska JM, et al., ABCA1 deficiency and apoE metabolism in neurons (2013)](https://pubmed.ncbi.nlm.nih.gov/23418355/)

[Pincher A, et al., ABCA1 in microglia and neuroinflammation (2020)](https://pubmed.ncbi.nlm.nih.gov/32848178/)

[Liu Q, et al., ABCA1 and Alzheimer's disease: mechanisms and therapeutic potential (2019)](https://pubmed.ncbi.nlm.nih.gov/31372849/)

[Chen J, et al., ABCA1 and cholesterol efflux in neurons (2018)](https://pubmed.ncbi.nlm.nih.gov/28762176/)

Cross-Links

[ABCA1 Gene](/genes/abca1) - Gene page
[ApoE Protein](/proteins/apoe) - Key substrate
[Cholesterol Metabolism](/mechanisms/cholesterol-metabolism) - Pathway
[HDL Particle](/proteins/hdl-particle) - Product
[Alzheimer's Disease](/diseases/alzheimers-disease) - Disease
[Parkinson's Disease](/diseases/parkinsons-disease) - Disease
[Microglia](/cell-types/microglia-neuroinflammation) - Cell type

References

[Takahashi K, Kimura Y, Kioka N, et al, Purification and ATPase activity of human ABCA1 (2006)](https://pubmed.ncbi.nlm.nih.gov/16484230/)

[Volpicella M, Leoni C, Fanizza I, et al, ATP-binding cassette transporters in neurodegeneration (2020)](https://pubmed.ncbi.nlm.nih.gov/31873872/)

[Vasiliou V, Vasiliou K, Nebert DW, Human ATP-binding cassette (ABC) transporter family (2009)](https://pubmed.ncbi.nlm.nih.gov/19515417/)

[Koldamova R, Lefterov I, Role of ABCA1 and ABCG1 transporters in cholesterol efflux and Alzheimer's disease (2007)](https://pubmed.ncbi.nlm.nih.gov/17430242/)

[Wahrle SE, Jiang H, Parsadanian M, et al, ABCA1 is required for normal central nervous system ApoE levels and for lipidation of astrocyte-secreted ApoE (2005)](https://pubmed.ncbi.nlm.nih.gov/15983038/)

[Zelcer N, Tontonoz P, Liver X receptors as integrators of metabolic and inflammatory signaling (2006)](https://pubmed.ncbi.nlm.nih.gov/16511593/)

[Fitz NF, Cronican A, Pham T, et al, Liver X receptor agonist treatment ameliorates amyloid pathology and memory deficits (2010)](https://pubmed.ncbi.nlm.nih.gov/21045124/)

[Hu Y, Meuret C, Go C, et al, ATP-binding cassette transporter A1 deficiency promotes amyloid pathology in Alzheimer's disease (2020)](https://pubmed.ncbi.nlm.nih.gov/32717471/)

[Vitali C, Wellington C, Calabrese V, ABCA1 and cholesterol efflux in the brain (2014)](https://pubmed.ncbi.nlm.nih.gov/24854264/)

[Yvan-Charvet L, Wang N, Tall AR, ABCA1, ABCG1, and cholesterol homeostasis in macrophages (2010)](https://pubmed.ncbi.nlm.nih.gov/20167679/)

[Karasinska JM, et al, ABCA1 deficiency and apoE metabolism in neurons (2013)](https://pubmed.ncbi.nlm.nih.gov/23418355/)

[Pincher A, et al, ABCA1 in microglia and neuroinflammation (2020)](https://pubmed.ncbi.nlm.nih.gov/32848178/)

[Liu Q, et al, ABCA1 and Alzheimer's disease: mechanisms and therapeutic potential (2019)](https://pubmed.ncbi.nlm.nih.gov/31372849/)

[Chen J, et al, ABCA1 and cholesterol efflux in neurons (2018)](https://pubmed.ncbi.nlm.nih.gov/28762176/)

External Links

[UniProt: ABCA1](https://www.uniprot.org/uniprot/O95477)
[PubMed](https://pubmed.ncbi.nlm.nih.gov/) - Biomedical literature
[Alzheimer's Disease Neuroimaging Initiative](https://adni.loni.usc.edu/) - Research data
[Allen Brain Atlas](https://brain-map.org/) - Brain gene expression data

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Related Entities

ABCA1PROTEIN

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slug	proteins-abca1-protein
kg_node_id	ABCA1PROTEIN
entity_type	protein
origin_type	v1_polymorphic_backfill
source_table	wiki_pages
wiki_page_id	wp-e37ec2e037eb
__merged_from	{'merged_at': '2026-05-13', 'unprefixed_id': 'proteins-abca1-protein'}
_schema_version	1

📊 Evidence Profile Foundational

Evidence Balance

+0%

Certainty

100%

Debates

0

Incoming

202

Outgoing

215

0 supporting 0 contradicting 0 neutral

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📗 Cite This Artifact

abca1-protein

abca1-protein

Overview

abca1-protein

Overview

Structure

Transmembrane Domains

Nucleotide-Binding Domains

Structural Features

Comparison with Other ABC Transporters

Normal Function

Cholesterol Efflux

HDL Particle Formation

Cellular Lipid Homeostasis

Phagocytosis in Microglia

Role in Neurodegeneration

Alzheimer's Disease

ApoE Lipidation

Amyloid Clearance

Genetic Association

Therapeutic Implications

Parkinson's Disease

Neuroinflammation

Other Neurodegenerative Conditions

Therapeutic Targeting

LXR Agonists

Clinical Trial Results

Gene Therapy

Small Molecule Activators

Combination Approaches

Key Publications

Cross-Links

References

See Also

External Links

💬 Discussion