Cited by 182Retinal Development and DisordersRetinal Diseases and TreatmentsRetinoids in leukemia and cellular processes

The role of the photoreceptor ABC transporter ABCA4 in lipid transport and Stargardt macular degeneration

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Molday, Robert S., Zhong, Ming, Quazi, Faraz·2009·Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids

Abstract

ABCA4 is a member of the ABCA subfamily of ATP binding cassette (ABC) transporters that is expressed in rod and cone photoreceptors of the vertebrate retina. ABCA4, also known as the Rim protein and ABCR, is a large 2,273 amino acid glycoprotein organized as two tandem halves, each containing a single membrane spanning segment followed sequentially by a large exocytoplasmic domain, a multispanning membrane domain and a nucleotide binding domain. Over 500 mutations in the gene encoding ABCA4 are associated with a spectrum of related autosomal recessive retinal degenerative diseases including Stargardt macular degeneration, cone-rod dystrophy and a subset of retinitis pigmentosa. Biochemical studies on the purified ABCA4 together with analysis of abca4 knockout mice and patients with Stargardt disease have implicated ABCA4 as a retinylidene-phosphatidylethanolamine transporter that facilitates the removal of potentially reactive retinal derivatives from photoreceptors following photoexcitation. Knowledge of the genetic and molecular basis for ABCA4 related retinal degenerative diseases is being used to develop rationale therapeutic treatments for this set of disorders.

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Integrity signals

Registry

Crossref · 10.1016/j.bbalip.2009.02.004

Cites

127 of 127 references verified0 citation errors · 0 not checkable

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  • A2E cannot be further metabolized and RPE cells are postmitotic, so A2E and related bisretinoids accumulate in the RPE in the form of lipofuscin deposits.

    “As A2E can not be further metabolized and as RPE cells are postmitotic, A2E and related bisretinoids accumulate in the RPE in the form of lipofuscin deposits.”

    From The Role of Vitamin A in Retinal Diseases (2022) · cites this paper as [69]

    Section 8 states that A2E cannot be further metabolized and that A2E and related retinal compounds progressively accumulate as lipofuscin deposits in RPE cells. It does not state that RPE cells are postmitotic or give that as a reason for the accumulation. No page number is available in our copy. (LLM, conf=0.88)

    Experimental — accuracy not yet measured
  • In the membranes of outer photoreceptor segments, nonenzymatically formed toxic bisretinoids are converted upon phagocytosis in the acidic environment of RPE phagolysosomes to bisretinoid pyridinium compound A2E and related bisretinoids.

    “In the membranes of outer photoreceptor segments are nonenzymatically formed toxic bisretinoids. Upon phagocytosis, these bisretinoids are in the acidic environment of RPE phagolysosomes converted to bisretinoid pyridinium compound A2E and related bisretinoids [54,69,70,71,72,73,74].”

    From The Role of Vitamin A in Retinal Diseases (2022) · cites this paper as [69]

    Section 8 (page unavailable) says that A2PE and related compounds form in photoreceptor outer segments, that RPE cells phagocytose those segments, and that A2PE is hydrolyzed to A2E in the resulting phagolysosomes. Section 6 identifies A2E as a pyridinium compound. The copy does not specify that the phagolysosomes’ acidic environment drives the conversion, or that all the bisretinoids mentioned are converted to A2E. (LLM, conf=0.84)

    Experimental — accuracy not yet measured
  • ABCA4 dysfunction leads to the accumulation of vitamin A derivatives and toxic compounds in photoreceptor outer segments because they cannot be efficiently removed.

    “ABCA4 dysfunction leads to the accumulation of vitamin A derivatives and toxic compounds, as they cannot be efficiently removed from the photoreceptor outer segment.”

    From The Role of Vitamin A in Retinal Diseases (2022) · cites this paper as [69]

    The Conclusions state that loss of ABCA4 transport causes all-trans retinal and N-retinylidene-PE to accumulate in photoreceptor disc membranes, where potentially toxic compounds form. Section 8 distinguishes their location from the subsequent accumulation of A2E and related compounds in retinal pigment epithelial cells, so the claim overstates where the toxic compounds accumulate. (LLM, conf=0.84)

    Experimental — accuracy not yet measured
  • In STGD1, cone degeneration is more severe and occurs before rod degeneration.

    “In STGD1, cone degeneration is more severe and occurs before rod degeneration [69,94].”

    From The Role of Vitamin A in Retinal Diseases (2022) · cites this paper as [69]

    Section 7.1 says cone degeneration is more severe than rod degeneration in ABCA4-related cone-rod dystrophy, which it distinguishes from Stargardt disease. It describes photoreceptor atrophy in Stargardt disease but does not say that cone degeneration is more severe there or occurs before rod degeneration. Page numbers are unavailable in our copy. (LLM, conf=0.82)

    Experimental — accuracy not yet measured
  • A2E is insoluble, tends to aggregate, and accumulates as lipofuscin deposits in RPE cells, compromising RPE function and leading to cell death.

    “The latter are insoluble, have a tendency to aggregate and accumulate as lipofuscin deposits in the RPE cells, compromising RPE function and leading to cell death.”

    From The Role of Vitamin A in Retinal Diseases (2022) · cites this paper as [69]

    Section 8 (page not provided) says A2E progressively accumulates as lipofuscin deposits in RPE cells and can lead to loss of RPE function and cell death. The passages do not say that A2E is insoluble or tends to aggregate; searches for those properties found no supporting passage. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

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4 of the 131 references couldn’t be matched to a known paper.

Research works printed but not linked: 1

  1. [19]Oram JF ATP-binding cassette transporter A1 and cholesterol trafficking Curr Opin Lipidol 2002 13 373 381 12151852

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Authors
Molday, R. S., Zhong, M., & Quazi, F.
Affiliations
University of British Columbia (CA)
Corresponding author
Molday, Robert S.
Venue
Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids
Publisher
Elsevier BV
Published
2009-07
Volume
1791
Issue
7
Pages
573-583
ISSN
1388-1981 (ISSN-L)
OpenAlex
W2031287535
Cited by
182
References
131
Citations by year
2026: 5 · 2025: 7 · 2024: 7 · 2023: 6 · 2022: 11 · 2021: 11 · 2020: 13 · 2019: 22 · 2018: 15 · 2017: 8 · 2016: 9 · 2015: 11 · 2014: 5 · 2013: 7 · 2012: 11
FWCI
1.15
Type
journal article
Language
en
Open access
Locations
  • Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (acceptedVersion)
Funders
  • Macula Vision Research Foundation
  • National Eye Institute (EY02422, R01EY002422)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Retinal Development and Disorders
  • Health Sciences › Medicine › Ophthalmology › Retinal Diseases and Treatments
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Retinoids in leukemia and cellular processes
Keywords
ABCA4, ABC transporters, lipid transport, photoreceptors, retinal degeneration, cone-rod dystrophy, retinitis pigmentosa, ABCA4 mutations
MeSH terms
Amino Acid Sequence, Animals, Biological Transport, Humans, Macular Degeneration, Molecular Sequence Data, Mice, Knockout, ATP-Binding Cassette Transporters, Lipid Metabolism, Mice

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