title: Human ABC transporters ABCG2 (BCRP) and ABCG4.
abstract: 1. The human ABC transporter ABCG2 is regarded as a member of the phase III system for xenobiotic metabolism, and it has been suggested that this efflux pump is responsible for protecting the body from toxic xenobiotics and for removing metabolites. 2. This review paper will address the new aspects of ABCG2 in terms of post-translational modifications (i.e., disulfide bond formation, ubiquitination, and endoplasmic reticulum-associated degradation) of ABCG2 protein, high-speed screening, and quantitative structure-activity relationship (QSAR) analysis to evaluate ABCG2-drug interactions, and genetic polymorphisms potentially associated with photosensitivity. 3. In addition, new aspects of human ABCG4 and mouse Abcg4 are presented with respect to their molecular properties and potential physiological roles. Considering a high sequence similarity between ABCG1 and ABCG4, both Abcg4 and ABCG4 may be involved in the transport of cholesterol from neurons and astrocytes. Furthermore, high expression of the mouse Abcg4 protein in the testis implicates its involvement in transport of certain sex hormones.
authors.affiliation: Department of Biomolecular Engineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Koshiba
authors.forename: R
authors.initials: R
authors.lastname: An
authors.forename: H
authors.initials: H
authors.lastname: Saito
authors.forename: K
authors.initials: K
authors.lastname: Wakabayashi
authors.forename: A
authors.initials: A
authors.lastname: Tamura
authors.forename: T
authors.initials: T
authors.lastname: Ishikawa
mesh_terms: D000070996:ATP Binding Cassette Transporter, Subfamily G; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001253:Astrocytes / Q000378:metabolism; D001693:Biological Transport, Active / Q000235:genetics; D002784:Cholesterol / Q000378:metabolism; D005260:Female; D012739:Gonadal Steroid Hormones / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D009363:Neoplasm Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D010787:Photosensitivity Disorders / Q000235:genetics / Q000378:metabolism; D011110:Polymorphism, Genetic; D011499:Protein Processing, Post-Translational; D017386:Sequence Homology, Amino Acid; D013737:Testis / Q000378:metabolism; D015262:Xenobiotics / Q000493:pharmacokinetics
chemical_list: C116614:ABCG2 protein, human; C439766:ABCG4 protein, human; D000070996:ATP Binding Cassette Transporter, Subfamily G; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; C486685:Abcg4 protein, mouse; D012739:Gonadal Steroid Hormones; D009363:Neoplasm Proteins; D015262:Xenobiotics; D002784:Cholesterol