ABCG2

Overview

Diagram of ABCG2 in the plasma membrane

ABCG2 (ATP-binding cassette sub-family G member 2) is a protein that in humans is encoded by the ABCG2 gene. It is a member of the ATP-binding cassette transporter family, which is involved in the transport of various molecules across extra- and intracellular membranes.

Structure

ABCG2 is a half-transporter, meaning it consists of a single transmembrane domain and a single nucleotide-binding domain. It functions as a homodimer or homotetramer to transport substrates across the cell membrane.

Function

ABCG2 plays a critical role in the efflux of xenobiotics and endogenous substrates from cells. It is known to transport a wide variety of substrates, including drugs, metabolites, and lipids. This transporter is highly expressed in the placenta, liver, intestine, and blood-brain barrier, where it contributes to the protection of tissues from toxic substances.

Clinical Significance

ABCG2 is associated with multidrug resistance in cancer therapy. Overexpression of ABCG2 in cancer cells can lead to decreased intracellular accumulation of chemotherapeutic agents, resulting in treatment failure. It is also involved in the pharmacokinetics of various drugs, affecting their absorption, distribution, and elimination.

Genetic Variants

Several single nucleotide polymorphisms (SNPs) in the ABCG2 gene have been identified, which can influence the function of the transporter. These genetic variants can affect drug response and toxicity, making ABCG2 an important consideration in personalized medicine.

Research

Ongoing research is focused on understanding the regulation of ABCG2 expression and function, as well as its role in drug resistance and pharmacogenomics. Inhibitors of ABCG2 are being investigated as potential adjuvants in cancer therapy to overcome drug resistance.

Related Pages

• ATP-binding cassette transporter
• Multidrug resistance
• Pharmacogenomics
• Cell membrane