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ABCA1

ABCA1, or ATP-binding cassette subfamily A member 1, is a human gene located on chromosome 9q31.1 that encodes a transmembrane protein functioning as a major regulator of cellular cholesterol and phospholipid efflux.^[1] This protein facilitates the transport of cholesterol and phospholipids from cells to apolipoprotein A-I (apoA-I), the primary protein component of high-density lipoprotein (HDL) particles, thereby playing a crucial role in reverse cholesterol transport and preventing lipid accumulation in tissues.^[2] Expressed prominently in the liver, macrophages, and other tissues, ABCA1 is essential for maintaining lipid homeostasis and protecting against atherosclerosis by promoting the formation of HDL, often referred to as "good cholesterol."^[1] The ABCA1 protein belongs to the ATP-binding cassette (ABC) transporter superfamily, utilizing ATP hydrolysis to drive the unidirectional movement of lipids across cell membranes, particularly from the plasma membrane to extracellular lipid acceptors like apoA-I or nascent HDL.^[3] This efflux process is vital for macrophage cholesterol removal in vascular walls, reducing foam cell formation and inflammation associated with cardiovascular disease.^[4] Dysregulation of ABCA1 activity, often through genetic variants or environmental factors, impairs lipid export and contributes to systemic lipid imbalances.^[1] Mutations in ABCA1 are the primary cause of Tangier disease, a rare autosomal recessive disorder characterized by near-absent HDL levels, cholesterol accumulation in tissues leading to enlarged orange tonsils, neuropathy, and accelerated atherosclerosis.^[2] Heterozygous variants are linked to familial HDL deficiency, increasing the risk of premature coronary artery disease due to low HDL and altered lipid profiles.^[1] Beyond cardiovascular implications, emerging research highlights ABCA1's roles in Alzheimer's disease pathogenesis through amyloid-beta clearance and in cancer progression via tumor lipid metabolism modulation.^[5]^[6]

Genetics

Gene Structure and Location

The ABCA1 gene, encoding the ATP-binding cassette subfamily A member 1 transporter, is located on the long (q) arm of human chromosome 9 at cytogenetic band 9q31.1, spanning genomic coordinates 104,781,006 to 104,928,155 on the reverse strand.^[1]^[7] This positioning was confirmed through radiation hybrid mapping and sequence analysis, placing it between markers at 109.8 cM and 112.0 cM on chromosome 9.^[8] The gene encompasses approximately 149 kb of genomic DNA and comprises 50 exons ranging in size from 33 to 3,454 bp, with 49 introns containing 62 repetitive Alu sequences primarily in introns 1–49.^[8] Exon 1 partially encodes the 5' untranslated region (UTR), while exon 2 includes the initiation methionine and the first 21 amino acids of the protein; the largest exon, exon 50, encodes the C-terminal region.^[8] This organization supports the synthesis of a 6,783 bp open reading frame translating to a 2,261-amino-acid protein.^[9] The promoter region extends about 1,453 bp upstream of the transcription start site, which is 191 bp 5' to the ATG start codon, and features a TATA box 33 bp upstream along with binding sites for transcription factors such as Sp1, AP-1, and E-box motifs.^[8] Key regulatory elements include liver X receptor (LXR) response elements (LXREs), specifically a direct repeat 4 (DR4) motif located between -70 and -55 bp relative to the transcription start site, enabling LXR/retinoid X receptor (RXR) heterodimers to transactivate ABCA1 expression in response to oxysterol ligands. ABCA1 demonstrates strong evolutionary conservation across mammals, with the mouse ortholog on chromosome 4 exhibiting an identical 50-exon structure, comparable intron-exon boundaries, and over 90% sequence similarity in the promoter over 189 bp, including conserved Sp1, AP-1, and other motifs.^[8] The exons encoding the two ATP-binding cassette (ABC) domains—NBD1 (exons 18–22) and NBD2 (exons 34–38)—are particularly well-conserved, underscoring their essential role in the transporter's nucleotide hydrolysis and substrate translocation functions.^[10]^[8]

Mutations and Variants

Mutations in the ABCA1 gene are primarily loss-of-function variants that disrupt the protein's role in lipid transport, leading to conditions such as Tangier disease when occurring biallelically.^[11] These include nonsense, frameshift, splice-site, and missense mutations, with over 300 variants reported across the gene.^[12] For instance, the missense variant R230C has been identified in patients with reduced HDL cholesterol levels, demonstrating its pathogenic potential in altering ABCA1 function.^[13] Common polymorphisms in ABCA1, such as the R219K single nucleotide variant, occur at higher frequencies in the general population and are associated with modest increases in HDL cholesterol levels.^[14] This variant, located in exon 7, has been linked to decreased triglyceride levels and reduced atherosclerosis progression in population studies, highlighting its protective effects on lipid profiles.^[15] Recent genetic analyses up to 2025 have identified novel homozygous variants expanding the mutational spectrum of ABCA1. One such variant, c.4799A>G (p.His1600Arg), was reported, confirming its role in severe Tangier disease through whole-exome sequencing.^[16]^[17] For example, a novel splice-site variant c.1510-1G>C was identified in 2025 in a patient with premature cardiovascular disease and rapidly progressive neurodegenerative disorder.^[18] These discoveries underscore the genetic heterogeneity and the value of advanced sequencing in uncovering rare homozygous mutations. At the molecular level, many ABCA1 mutations exert their effects through premature stop codons, resulting in truncated proteins that lack essential domains for lipid efflux.^[9] Nonsense and frameshift variants often trigger nonsense-mediated decay, further reducing functional protein levels.^[19] Missense mutations, such as those in the extracellular loops, frequently impair protein trafficking from the endoplasmic reticulum to the plasma membrane, preventing proper localization and activity.^[20] These disruptions collectively contribute to diminished cholesterol efflux capacity and low HDL levels observed in affected individuals.^[11]

Protein Structure and Function

Molecular Structure

ABCA1 is a full-length ATP-binding cassette (ABC) transporter characterized by a modular architecture typical of the ABCA subfamily, consisting of two homologous halves that each include a transmembrane domain (TMD) and a nucleotide-binding domain (NBD). Specifically, TMD1 and TMD2 each span the membrane with six alpha-helices, facilitating lipid interaction, while NBD1 and NBD2 are located intracellularly and couple ATP hydrolysis to transport. Additionally, two large extracellular domains (ECDs)—ECD1 (residues 47–629, 583 amino acids) and ECD2 (residues 1369–1639, 270 amino acids)—extend from the TMDs, forming an elongated hydrophobic tunnel that connects the extracellular space to the membrane interface.^[21]^[22] The atomic structure of human ABCA1 was elucidated by cryo-electron microscopy (cryo-EM) in 2017, achieving an overall resolution of 4.1 Å and 3.9 Å for the ECDs, revealing a monomeric conformation with the TMDs adopting an inward-facing orientation and the ECDs positioned above the membrane. This structure highlights a shallow lipid-binding pocket within TMD1, lined by polar and charged residues from transmembrane helices 1, 2, and 5, which accommodates detergent or lipid molecules. The NBDs exhibit a nucleotide-free state, with key conserved residues in the Walker A motifs—lysine at position 939 (K939) in NBD1 and K1952 in NBD2—poised for ATP coordination and subsequent hydrolysis. Subsequent structural studies, including those from 2022, have refined these insights into ABCA1's conformational dynamics and lipid interaction sites.^[22]^[23] Post-translational modifications play a critical role in ABCA1 maturation and stability, particularly N-glycosylation, which occurs at seven confirmed sites primarily within the ECDs: N98, N400, N489, and N521 in ECD1, and N1453, N1504, and N1647 in ECD2. In the cryo-EM model, 12 sugar moieties were resolved at these sites, contributing to proper folding and trafficking of the protein to the plasma membrane. This domain organization and modification pattern underpin ABCA1's capacity to engage lipids at the cell surface.^[22]^[4]

Cholesterol Efflux Mechanism

ABCA1 functions as an ATP-binding cassette transporter that extracts phospholipids and free cholesterol from the outer leaflet of the plasma membrane and translocates them into an elongated extracellular hydrophobic tunnel in an ATP-dependent manner, acting as an extracellular translocase rather than a traditional floppase. This process involves the hydrolysis of ATP at the nucleotide-binding domains (NBDs), which powers conformational changes in the transmembrane domains (TMDs), enabling lipid extraction through a gateway and annulus structure.^[24]^[23] Once lipids are mobilized to the extracellular space, ABCA1 interacts directly with lipid-poor apolipoprotein A-I (apoA-I), the major protein component of high-density lipoprotein (HDL). This interaction allows apoA-I to solubilize the surface lipids, forming nascent or discoidal HDL particles through a process of lipidation where apoA-I wraps around the exported phospholipids and cholesterol. The binding of apoA-I to ABCA1 is transient and promotes the release of lipidated particles, preventing excessive membrane depletion.^[24]^[23] ABCA1-mediated cholesterol efflux constitutes the initial and rate-limiting step in the reverse cholesterol transport (RCT) pathway, whereby excess cholesterol from peripheral cells is exported to apoA-I for ultimate delivery to the liver for excretion. The kinetics of this efflux can be modeled as Efflux = k [ABCA1] [Cholesterol] [apoA-I], where k represents the rate constant reflecting the efficiency of the transporter-lipid-acceptor interaction. This equation highlights the dependence on cellular ABCA1 expression, intracellular cholesterol availability, and extracellular apoA-I concentration.^[24] Experimental evidence from cell-based assays, such as those using cholesterol-loaded mouse peritoneal macrophages or human fibroblasts, demonstrates ABCA1-specific efflux to apoA-I but minimal transfer to other lipid acceptors like albumin or mature HDL. For instance, in ABCA1-overexpressing HEK293 cells, efflux rates to apoA-I increase by up to 5-fold compared to controls, with mutations in the extracellular domains reducing this specificity by 65-95%. These assays often employ radiolabeled cholesterol tracers to quantify efflux, confirming the ATP-dependent and apoA-I-selective nature of the process.^[24]^[23]

Physiological Roles

Role in Lipid Homeostasis

ABCA1 plays a central role in maintaining lipid homeostasis by facilitating the efflux of excess cholesterol and phospholipids from peripheral cells, thereby preventing intracellular lipid accumulation. In macrophages, a key cell type prone to foam cell formation, ABCA1 promotes the removal of free cholesterol to extracellular acceptors, reducing the risk of cytotoxic cholesterol buildup that could impair cellular function.^[25] This efflux mechanism is particularly vital in cholesterol-rich environments, such as atherosclerotic lesions, where ABCA1 activity helps sustain cellular lipid balance and supports overall organismal cholesterol equilibrium.^[26] Recent studies as of 2025 have further elucidated ABCA1's physiological roles in other tissues. In endothelial cells, ABCA1 regulates membrane cholesterol content in response to shear stress, contributing to vascular homeostasis.^[27] Additionally, in the lungs, ABCA1 maintains cholesterol balance under normal conditions, supporting pulmonary lipid regulation.^[28] ABCA1 is highly expressed in specific tissues critical for lipid regulation, including the liver, intestine, and macrophages, where it coordinates systemic cholesterol distribution. In the liver and intestine, ABCA1 contributes to the initial lipidation of apolipoproteins, aiding in the maintenance of circulating lipid pools without promoting net accumulation.^[29] Macrophage-specific expression further ensures that peripheral immune cells do not retain excess lipids, integrating local cellular homeostasis with broader metabolic control.^[30] Through its integration into the reverse cholesterol transport (RCT) pathway, ABCA1 exports excess cholesterol from peripheral tissues to the liver for eventual biliary excretion, thus preventing systemic lipid overload. This process begins with ABCA1-mediated efflux from cells like macrophages to lipid-poor apolipoproteins, which then carry cholesterol to hepatic receptors for processing and elimination via bile.^[31] Studies in Abca1 knockout mice demonstrate this role, as these animals exhibit increased cellular free cholesterol in macrophages, accelerated foam cell formation, and heightened predisposition to atherosclerosis due to impaired RCT.^[32] Similarly, combined Abca1 and Abcg1 deficiencies in mouse models exacerbate foam cell accumulation and lesion development, underscoring ABCA1's non-redundant contribution to lipid homeostasis.^[33]

Role in HDL Biogenesis

ABCA1 plays a pivotal role in the initial steps of high-density lipoprotein (HDL) biogenesis by facilitating the efflux of cellular cholesterol and phospholipids to lipid-poor apolipoprotein A-I (apoA-I). This process begins with ABCA1 translocating phospholipids from the inner to the outer leaflet of the plasma membrane, creating microdomains of high lipid content that enable apoA-I binding. Upon interaction, ABCA1 promotes the transfer of unesterified cholesterol and phospholipids to apoA-I, resulting in the formation of discoidal pre-β-HDL particles, which serve as nascent HDL precursors.^[34]^[35] In certain tissues, such as macrophages and the brain, ABCA1 cooperates with ABCA7 to enhance phospholipid efflux during HDL formation. While ABCA1 primarily drives cholesterol export, ABCA7 complements this by specializing in phospholipid translocation to apoA-I, thereby supporting the lipidation process and contributing to the stability of nascent HDL particles in environments where phospholipid availability is limiting.^[36]^[37] ABCA1 deficiency profoundly impacts HDL subclass distribution, leading to the absence of mature α-HDL particles while preserving smaller pre-β-HDL. In conditions like Tangier disease, where ABCA1 function is impaired, the lack of efficient initial lipidation prevents the maturation of pre-β-HDL into spherical α-HDL subclasses, resulting in low circulating HDL levels and disrupted reverse cholesterol transport.^[34] ABCA1 mediates the majority of cellular cholesterol efflux to apoA-I in macrophages, underscoring its dominant role in this pathway and highlighting its efficiency in promoting HDL assembly from foam cells.^[38]

Clinical Significance

Tangier Disease

Tangier disease is a rare autosomal recessive disorder resulting from biallelic mutations in the ABCA1 gene, leading to severe deficiency of the ABCA1 transporter protein. It was first described in 1959 in two siblings from a kindred on Tangier Island in the Chesapeake Bay, Virginia, where low plasma cholesterol and high-density lipoprotein (HDL) levels were noted alongside characteristic clinical manifestations. The disease derives its name from the island, and subsequent studies identified affected individuals worldwide, though prevalence remains extremely low at approximately 1 in 1,000,000. The ABCA1 gene was localized to chromosome 9q31 and definitively linked to the disorder in 1999 through positional cloning efforts.^[39]^[40] The hallmark clinical features of Tangier disease include enlarged tonsils with a distinctive orange-yellow discoloration due to cholesterol ester deposits, which often require tonsillectomy in childhood for recurrent infections or airway obstruction. Patients exhibit profoundly low plasma HDL cholesterol concentrations, typically less than 5 mg/dL, accompanied by reduced apolipoprotein A-I levels and variable hypertriglyceridemia. Neurological involvement manifests as peripheral neuropathy, ranging from mild sensory deficits to severe demyelinating polyneuropathy with syringomyelia-like features, while systemic signs such as splenomegaly and hepatomegaly arise from lipid-laden macrophage infiltration. Premature atherosclerosis is a significant complication, with accelerated coronary artery disease and cerebrovascular events occurring in about 25-50% of cases, often by the fourth or fifth decade of life.^[41]^[42] Pathophysiologically, Tangier disease arises from defective ABCA1 function, which impairs the efflux of cholesterol and phospholipids from cells to lipid-poor apolipoproteins, thereby disrupting reverse cholesterol transport and HDL particle formation. This leads to intracellular accumulation of free cholesterol and esterified sterols in tissues, particularly within foamy macrophages of the reticuloendothelial system, tonsils, spleen, liver, and peripheral nerves. The resulting sterol deposition drives the characteristic organomegaly, neuropathy, and accelerated atherogenesis, as unesterified cholesterol buildup promotes foam cell formation and vascular inflammation.^[43]^[44] Diagnosis of Tangier disease relies on clinical suspicion prompted by low HDL levels and suggestive features, followed by confirmation through genetic sequencing identifying biallelic pathogenic variants in ABCA1, such as frameshift, nonsense, or missense mutations that abolish protein function. Biochemical assays showing absent or defective cholesterol efflux in fibroblasts can support diagnosis, but molecular testing remains the gold standard. Over 100 distinct ABCA1 mutations have been reported in Tangier disease cases.^[41]^[45]

Associations with Other Disorders

Common genetic variants in the ABCA1 gene have been associated with an increased risk of coronary artery disease (CAD), primarily through their impact on reducing high-density lipoprotein (HDL) cholesterol levels, which impairs reverse cholesterol transport and promotes atherosclerosis. For instance, heterozygous carriers of loss-of-function ABCA1 mutations exhibit approximately half-normal HDL levels, contributing to premature CAD in affected individuals. Studies have identified specific polymorphisms, such as those in the promoter region, that correlate with lower HDL and elevated CAD risk in population cohorts.^[46]^[47]^[48] ABCA1 plays a critical role in Alzheimer's disease (AD) pathogenesis, where reduced expression impairs amyloid-beta (Aβ) clearance from the brain by hindering the lipidation of apolipoprotein E (APOE), essential for Aβ transport across the blood-brain barrier. Genome-wide association studies (GWAS) up to 2022 have identified rare damaging variants in ABCA1 that significantly elevate AD risk, particularly in interaction with APOE4 alleles, as these variants disrupt cholesterol efflux and exacerbate Aβ accumulation. Loss-of-function mutations in ABCA1, occurring in about 1 in 500 individuals, are linked to low plasma APOE levels and heightened AD susceptibility, independent of HDL effects.^[49] Polymorphisms in ABCA1 are implicated in metabolic syndrome and type 2 diabetes (T2D), where they alter lipid profiles and insulin sensitivity by accumulating cholesterol in pancreatic beta cells, thereby reducing insulin secretion. For example, the ABCA1 C69T variant has been associated with dysglycemia and a decreased T2D incidence in some populations, while other single nucleotide polymorphisms (SNPs) correlate with hypertriglyceridemia and impaired glucose homeostasis in diabetic patients. Hepatocyte-specific ABCA1 deletion in models disrupts liver insulin signaling, mirroring human associations between ABCA1 SNPs and metabolic syndrome traits like dyslipidemia and insulin resistance.^[52]^[53]^[54] ABCA1 has also been implicated in cancer progression through its regulation of tumor lipid metabolism and cholesterol efflux. Dysregulated ABCA1 expression influences tumor cell proliferation, metastasis, and resistance to therapy in various cancers, including renal cell carcinoma and endometrial cancer. For instance, high ABCA1 expression may inhibit tumor spread, while certain variants promote oncogenic signaling. As of 2025, pan-cancer analyses suggest ABCA1 as a potential prognostic marker and therapeutic target.^[55]^[56]^[57] Recent research from 2023 to 2025 highlights ABCA1 as a promising therapeutic target for neurodegeneration, with agonists and inducers showing potential to enhance APOE lipidation and Aβ clearance in AD models. Nonlipogenic ABCA1 inducers have demonstrated efficacy in preclinical studies by promoting APOE function and reducing AD pathology, particularly in APOE4 carriers. Additionally, modulation of regulators like miR-33 to upregulate ABCA1 has improved microglial Aβ clearance and cognitive outcomes in mouse models of neurodegeneration.^[58]^[59]^[60]

Regulation and Interactions

Regulatory Mechanisms

The expression of ABCA1 is primarily regulated at the transcriptional level by the liver X receptor (LXR)/retinoid X receptor (RXR) heterodimers, which bind to LXR response elements in the ABCA1 promoter in response to oxysterols such as 25-hydroxycholesterol.^[61] This activation pathway is a key mechanism for sensing cellular cholesterol levels, as oxysterols are derived from cholesterol via the mevalonate pathway, thereby upregulating ABCA1 to promote cholesterol efflux under conditions of lipid excess.^[62] Seminal studies have demonstrated that LXR agonists, like T0901317, significantly induce ABCA1 transcription in hepatic and macrophage cells, highlighting the pathway's role in reverse cholesterol transport. Post-transcriptional regulation of ABCA1 involves microRNAs, particularly miR-33a and miR-33b, which are encoded within introns of the SREBP-2 gene and directly target the 3' untranslated region of ABCA1 mRNA to inhibit its translation.^[63] This repression fine-tunes cholesterol homeostasis by counteracting LXR-mediated induction, as SREBP-2 activation in response to sterol depletion promotes miR-33 expression, thereby reducing ABCA1 levels and limiting efflux.^[64] Inhibition of miR-33 has been shown to elevate ABCA1 expression and enhance HDL formation in preclinical models, underscoring its therapeutic potential.^[65] Post-translational modifications, including phosphorylation and ubiquitination, critically influence ABCA1 protein stability and membrane localization. Protein kinase A (PKA)-mediated phosphorylation at specific serine residues stabilizes ABCA1 at the plasma membrane, enhancing its lipid efflux capacity, while dephosphorylation accelerates its degradation.^[66] Ubiquitination, often triggered by cellular cholesterol levels, targets ABCA1 for lysosomal or proteasomal degradation via E3 ligases, thereby reducing its surface expression and preventing excessive efflux under low-cholesterol conditions.^[67] In contrast, the E3 ubiquitin ligase Listerin promotes K63-linked polyubiquitination of ABCA1, which stabilizes the protein, promotes its translocation to the cell membrane, and enhances cholesterol efflux in macrophages.^[68] These modifications ensure dynamic control, with LXR-mediated pathways modulating ubiquitination to balance ABCA1 turnover.^[69] In the liver, ABCA1 expression exhibits circadian rhythms, peaking during the active phase to align with diurnal fluctuations in lipid metabolism, as disruptions in clock genes like Clock reduce hepatic ABCA1 levels and impair cholesterol homeostasis.^[70] Dietary factors further modulate hepatic ABCA1; for instance, high-fat or atherogenic diets upregulate its expression to counteract lipid overload, promoting reverse cholesterol transport.^[71] These environmental influences integrate with intrinsic clocks to maintain lipid balance, with studies showing enhanced ABCA1 mRNA in response to cholesterol-rich feeding.^[72]

Protein and Pathway Interactions

ABCA1 primarily interacts with apolipoprotein A-I (apoA-I), the major protein component of high-density lipoprotein (HDL), to facilitate the lipidation of apoA-I and the generation of nascent HDL particles on the cell surface.^[73] This interaction involves the binding of lipid-poor apoA-I to ABCA1, which promotes the efflux of phospholipids and free cholesterol from cells, initiating HDL biogenesis.^[74] In addition, ABCA1 cooperates with ABCG1, another ATP-binding cassette transporter, to enhance cholesterol efflux from macrophages to HDL acceptors; studies show that combined deficiency of ABCA1 and ABCG1 substantially impairs net cholesterol export compared to individual deficiencies, highlighting their synergistic role in cellular lipid homeostasis.^[75] SR-BI, a scavenger receptor, complements ABCA1 and ABCG1 by mediating selective cholesterol uptake and efflux to mature HDL, contributing to the overall efficiency of cholesterol removal in peripheral tissues, particularly in hepatocytes and macrophages.^[76] Experimental identification of ABCA1's protein partners has relied on techniques such as co-immunoprecipitation (co-IP) and yeast two-hybrid (Y2H) screening. Co-IP assays have confirmed direct associations, for instance, between ABCA1 and apoA-I at the cell surface, as well as intracellular interactions with regulatory proteins like α1-syntrophin, which stabilizes ABCA1 by preventing its degradation.^[77] Y2H screens using the C-terminal domain of ABCA1 as bait have identified binding partners such as liver X receptor-β (LXR-β), which modulates ABCA1 expression, and PDZ-RhoGEF, demonstrating ABCA1's capacity to engage PDZ domain-containing scaffolds.^[78] These methods have been instrumental in mapping ABCA1's interactome, revealing both extracellular lipid acceptors and intracellular modulators that influence its trafficking and activity. Within the reverse cholesterol transport (RCT) pathway, ABCA1 serves as the initial efflux step, transferring cellular cholesterol and phospholipids to lipid-poor apoA-I to form discoidal nascent HDL particles.^[79] These nascent particles are subsequently remodeled by lecithin-cholesterol acyltransferase (LCAT), which esterifies free cholesterol to cholesteryl esters, promoting the maturation of HDL and enabling further cholesterol acquisition from peripheral cells via ABCG1 and SR-BI. This sequential integration positions ABCA1 upstream in the RCT cascade, ensuring efficient delivery of cholesterol to the liver for biliary excretion. Regulatory influences, such as LXR activation, can modulate these interactions to fine-tune efflux capacity under varying lipid loads.^[80] ABCA1 also participates in signaling pathways through interactions with PDZ domain proteins, exemplified by its binding to PDZ-RhoGEF via a C-terminal PDZ-binding motif, which activates RhoA signaling to enhance cholesterol efflux and prevent ABCA1 degradation.^[81] This interaction underscores ABCA1's role beyond transport, as a scaffold for cytoskeletal regulation in polarized cells, potentially influencing its localization and function in epithelial tissues.

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Jun 13, 2023 · DNA sequencing revealed 3 heterozygous variants in the ABCA1 gene, namely, p.G592G frameshift X37, p.A2028V, and p.R2081Q. The frameshift ...
[45]
Variations on a gene: rare and common variants in ABCA1 and their ...
Here we review genetic variation in ABCA1 and its critical role in cholesterol metabolism and atherosclerosis in the general population.
[46]
Exome sequencing identifies rare damaging variants in ATP8B4 and ...
Nov 21, 2022 · We observed a significant association of rare, predicted damaging variants in ATP8B4 and ABCA1 with AD risk, and a suggestive signal in ADAM10.
[47]
Loss-of-function mutation in ABCA1 and risk of Alzheimer's disease ...
A loss-of-function mutation in ABCA1, present in 1:500 individuals, was associated with low plasma levels of apoE and with high risk of AD and cerebrovascular ...Missing: GWAS | Show results with:GWAS
[48]
The role of ABCA1 gene sequence variants on risk of Alzheimer's ...
ABCA1 is a candidate risk gene for late onset Alzheimer's disease (LOAD) as a consequence of its role in cholesterol transport and metabolism.Missing: function | Show results with:function
[49]
ABCA1 C69T Gene Polymorphism Association with Dysglycemia in ...
Studies suggest that ATP-binding cassette transporter A1 (ABCA1 C69T) polymorphism is associated with a decreased incidence of type 2 diabetes mellitus (T2DM)
[50]
ATP-binding cassette sub-family a member1 gene mutation ...
Apr 22, 2019 · ABCA1 C69T gene mutation significantly reduced the risk of hypertriglyceridemia in diabetic patients than that in non-diabetic subjects.. The ...
[51]
Hepatocyte ABCA1 Deletion Impairs Liver Insulin Signaling and ...
Jun 6, 2017 · Mounting evidence suggests that ABCA1 SNPs are associated with type 2 diabetes and metabolic syndrome in humans (Daimon et al., 2005 ...
[52]
Nonlipogenic ABCA1 Inducers (NLAI) for Alzheimer's Disease ...
Therapeutics enhancing apolipoprotein (APOE) positive function are a priority, because APOE4 is the major genetic risk factor for Alzheimer's disease (AD).
[53]
Deletion of miR‐33, a regulator of the ABCA1–APOE pathway ...
Sep 30, 2024 · These results suggest that miR-33 might be a potential drug target by modulating ABCA1 level, apoE lipidation, Aβ level, and microglial function ...<|control11|><|separator|>
[54]
Enhancing of cerebral Abeta clearance by modulation of ABC ...
OAB-14, a bexarotene derivative, improves Alzheimer's disease-related pathologies and cognitive impairments by increasing β-amyloid clearance in APP/PS1 mice.Abstract · Introduction · ABC transporters involved in... · Discussion<|separator|>
[55]
Regulation of ATP-binding cassette transporter A1 transcription by ...
Cholesterol- and oxysterol-mediated up-regulation of ABCA1 transcription includes the binding of the liver X receptor and retinoid X receptor (LXR/RXR) ...
[56]
Regulation of ATP binding cassette transporter A1 (ABCA1 ...
Sep 25, 2020 · LXR forms a heterodimer with retinoid X receptor (RXR), and together they form a transcription factor that binds to the promoter element in the ...
[57]
miR-33 links SREBP-2 induction to repression of sterol transporters
Jul 6, 2010 · Here we show that miR-33 is encoded within SREBP-2 and that both mRNAs are coexpressed. We also identify sequences in the 3' UTR of ABCA1 and ABCG1.Missing: post- | Show results with:post-
[58]
Expression of miR-33 from an SREBP2 intron inhibits cholesterol ...
Oct 29, 2010 · In this study, we provide evidence that the primary transcript of SREBP2 contains an intronic miRNA (miR-33) that reduces cellular cholesterol export.
[59]
Involvement of Expression of miR33-5p and ABCA1 in Human ...
Aug 7, 2024 · Downregulation of miR-33a-5p and upregulation of ABCA1 were linked to a lower CAD risk. Atorvastatin upregulated ABCA1 mRNA, and metformin ...
[60]
Protein kinase A site-specific phosphorylation regulates ATP ...
Nov 1, 2002 · We show that ABCA1 is a constitutively phosphorylated protein in both RAW macrophages and in a human embryonic kidney cell line expressing ABCA1.
[61]
Cellular Cholesterol Regulates Ubiquitination and Degradation of ...
Plasma membrane localized ABCA1 can also be degraded by ubiquitin-dependent lysosomal proteolysis in human hepatoma cells and THP-1 macrophages (51).
[62]
E3 ubiquitin ligase Listerin regulates macrophage cholesterol efflux ...
Jun 17, 2025 · These findings collectively demonstrate Listerin's role in preserving ABCA1 membrane residency by blocking ESCRT-mediated lysosomal sorting.
[63]
Clock mutation facilitates accumulation of cholesterol in the liver of ...
The present findings indicate that normal circadian clock function is important for the regulation of CH homeostasis in the mouse liver.
[64]
ABCA1 mRNA and protein distribution patterns predict ... - PubMed
We also show that ABCA1 protein levels are up-regulated specifically in the liver after exposure to an atherogenic diet for 7 days, supporting a major role for ...Missing: hepatic | Show results with:hepatic
[65]
Estrogen-induced regulation of the ATP-binding cassette transporter ...
HF diet increased the hepatic ABCA1 mRNA 1.8-fold in WT, but lowered ABCA1 mRNA by 2-fold in A1-Tg mice, suggesting that ABCA1 levels did not correlate with ...<|control11|><|separator|>
[66]
Lipidation of apolipoprotein A-I by ATP-binding cassette transporter ...
Knock-down of ABCA1 inhibits the cellular binding at 4 degrees C of lipid-free apoA-I but not of HDL whereas suppression of ABCG1 or SR-BI reduces the binding ...
[67]
Role of apoA-I, ABCA1, LCAT, and SR-BI in the Biogenesis of HDL
Here we review the current status of the pathway of HDL biogenesis and mutations in apoA-I, ABCA1, and SR-BI that disrupt different steps of the pathway.
[68]
ABCA1 and ABCG1 Synergize to Mediate Cholesterol Export to ApoA-I
Dec 15, 2005 · Because ABCG1 is induced by the same transcriptional processes as ABCA1 and, like ABCA1 but unlike SR-BI, is upregulated in response to cellular ...
[69]
ABCA1, ABCG1 and SR-BI: hormonal regulation in primary rat ...
The results show that SR-BI, ABCA1 and ABCG1 mRNA expression increased in response to dexamethasone while insulin treatment reduced the expression in primary ...
[70]
α1-Syntrophin Modulates Turnover of ABCA1
To examine whether the functions of ABCA1 are modulated by associated proteins, a yeast two-hybrid library was screened with the C-terminal 120 amino acids of ...
[71]
Direct Interaction of Nuclear Liver X Receptor-β with ABCA1 ... - NIH
We performed a yeast two-hybrid screen to search for additional proteins associated with the C-terminal region of ABCA1. The screen identified a nuclear ...
[72]
Pivotal role of ABCA1 in reverse cholesterol transport influencing ...
Nov 1, 2001 · LCAT transfers a fatty acyl chain from phosphatidylcholine to cholesterol, forming cholesteryl ester. The cholesteryl ester partitions into the ...Molecular Components · Abca1 · Phospholipid Transfer...
[73]
Regulation of reverse cholesterol transport - Nutrition & Metabolism
Mar 29, 2012 · From macrophages cholesterol can be effluxed as free cholesterol either via ATP binding cassette transporter A1 (ABCA1) with poorly lipidated ...
[74]
Binding of PDZ-RhoGEF to ATP-binding Cassette Transporter A1 ...
Thus, the PDZ-RhoGEF and LARG interaction to ABCA1 implies that 1) ABCA1 may act not only as a lipid transporter but may also act as a receptor for RhoA ...Missing: PDZK1 apical