Related Experiment Video

Updated: Apr 29, 2026

Author Spotlight: A Bicelle Crystallization Setup for ABC Transporter Membrane Proteins to Advance Drug Development
06:47

Author Spotlight: A Bicelle Crystallization Setup for ABC Transporter Membrane Proteins to Advance Drug Development

Published on: August 25, 2023

1.9K

3β,5α,6β-Cholestanetriol and 25-hydroxycholesterol accumulate in ATP-binding cassette transporter G1

Thomas Engel1, Manfred Fobker2, Jana Buchmann3

  • 1Leibniz-Institute for Arteriosclerosis Research at The Westphalian Wilhelms-University, 48149 Muenster, Germany.

Atherosclerosis
|May 17, 2014
PubMed
Abstract

Insights

ATP-binding cassette transporter G1 (ABCG1) efficiently removes cytotoxic oxysterols. This study identifies 25-hydroxycholesterol and 3β,5α,6β-cholestanetriol as key substrates, with their accumulation in Abcg1-deficient mice explaining cell death and inflammation.

Area of Science:

  • Biochemistry
  • Cell Biology
  • Molecular Biology

Background:

  • Oxysterols, oxidized sterols, regulate cellular functions but can be cytotoxic.
  • ATP-binding cassette transporter G1 (ABCG1) is crucial for oxysterol removal and cell survival.
  • The specific oxysterol species transported by ABCG1 remain incompletely understood.

Purpose of the Study:

  • To investigate the role of ABCG1 in the metabolism of various oxysterol species.
  • To determine which oxysterols accumulate in the absence of functional ABCG1.
  • To elucidate the cellular consequences of ABCG1 deficiency regarding oxysterol accumulation.

Main Methods:

  • Analysis of lung tissue oxysterol levels in Abcg1-deficient (Abcg1(-/-)) and wild-type mice.
  • Radiolabeled assays using HeLa cell lines with inducible ABCG1 expression to study oxysterol transport.
  • Measurement of mitochondrial membrane potential and reactive oxygen species production in response to 25-hydroxycholesterol.

Main Results:

  • Lung tissues of Abcg1(-/-) mice showed over 100-fold accumulation of 3β,5α,6β-cholestanetriol (CT) and 25-hydroxycholesterol (HC) compared to wild-type.
  • Elevated, but minor, levels of 24S-HC and 27-HC were also observed in Abcg1(-/-) mice.
  • 25-HC export via ABCG1 was confirmed in HeLa cells and could be inhibited by unlabeled 25-HC or 27-HC.
  • Low doses of 25-HC induced mitochondrial membrane potential changes and reactive oxygen species production.

Conclusions:

  • 25-hydroxycholesterol (25-HC) and 3β,5α,6β-cholestanetriol (CT) are identified as physiological substrates of ABCG1.
  • Excessive accumulation of these oxysterols in Abcg1-deficient models likely contributes to increased cell death and inflammatory phenotypes.
  • These findings highlight ABCG1's critical role in maintaining cellular homeostasis by regulating specific oxysterol levels.
Keywords:
25-Hydroxycholesterol3β,5α,6β-CholestanetriolATP-binding cassette transporter, G-subgroup, family member 1 (ABCG1)InflammationLipid effluxOxysterols

More Related Videos

Cholesterol Efflux Assay07:54

Cholesterol Efflux Assay

Published on: March 6, 2012

29.4K
Enrichment of Mammalian Tissues and Xenopus Oocytes with Cholesterol10:12

Enrichment of Mammalian Tissues and Xenopus Oocytes with Cholesterol

Published on: March 25, 2020

5.6K

Related Concept Videos

Cholesterol: Significance and Regulation01:29

Cholesterol: Significance and Regulation

Although not a source of energy, cholesterol plays a significant role as a foundational structure for bile salts, steroid hormones, and vitamin D, as well as being a crucial component of plasma membranes. Approximately 15% of blood cholesterol is derived from our diet, with the remainder synthesized from acetyl CoA by the liver and intestines. Cholesterol is eliminated from the body through its conversion into bile salts, which are eventually discarded in the feces.
Considering cholesterol and...
2.1K
Pharmacogenetics of Drug Transporters: P-Glycoprotein and Solute Carrier Transporters01:16

Pharmacogenetics of Drug Transporters: P-Glycoprotein and Solute Carrier Transporters

The pharmacogenetics of drug transporters is increasingly recognized as a critical factor influencing interindividual variability in drug absorption, distribution, and elimination. These membrane-bound proteins regulate drugs' movement across cellular barriers by actively pumping them out (efflux) or facilitating their uptake (influx). Among the major transporter families, ATP-binding cassette (ABC) and solute carrier (SLC) transporters play particularly prominent roles. Genetic polymorphisms...
189
Lipid Absorption01:24

Lipid Absorption

Dietary triglycerides from chyme in the duodenum are mixed with bile salts produced by the liver to emulsify fats. As a result, large droplets are broken down into smaller ones, increasing the surface area for enzymatic action. Once emulsified, pancreatic lipases hydrolyze the triglycerides into free fatty acids and monoglycerides.
These breakdown products bind with bile salts and lecithin to form micelles, which quickly pass between microvilli to come in close contact with the apical...
3.9K
Overview of Fatty Acid Metabolism01:28

Overview of Fatty Acid Metabolism

Lipids also are sources of energy that power cellular processes. Like carbohydrates, lipids are composed of carbon, hydrogen, and oxygen, but these atoms are arranged differently. Most lipids are nonpolar and hydrophobic. Major types include fats and oils, waxes, phospholipids, and steroids.
Fatty acids are catabolized in a process called beta-oxidation, which takes place in the matrix of the mitochondria and converts their fatty acid chains into two-carbon units of acetyl groups. The acetyl...
25.4K
ABC Transporters: Exporter01:31

ABC Transporters: Exporter

ATP-binding cassette or ABC transporter is the largest superfamily of integral membrane proteins. The transporters have transmembrane-binding domains (TMDs) and nucleotide-binding domains (NBDs). The TMDs are specific to their substrates, whereas the NBDs are similar to engines that complete ATP hydrolysis to complete the substrate transport. They can be full transporters consisting of two TMDs and NBDs, half transporters with one TMD and NBD, while some encoded with a single TMD or NBD are...
5.7K
Blood Studies for Cardiovascular System III: Serum Lipid Profile01:25

Blood Studies for Cardiovascular System III: Serum Lipid Profile

Understanding serum lipids is crucial for maintaining cardiovascular health and preventing heart disease and stroke.
Serum lipids are fats and fatty substances in the blood and are crucial for various bodily functions, including energy storage, cellular structure, and hormone production. Serum lipids consist of cholesterol, triglycerides, and phospholipids.
Cholesterol is a soft, fat-like substance found in all body cells. It is crucial for producing hormones, vitamin D, and substances that aid...
840