ABC Transporters.pdf

ABC proteins are present in all living species, making up 4% of bacterial genomes and several dozen members in eukaryotes, recognized by a consensus ATP-binding region. They catalyze various physiological functions, mostly related to transport, with 61 phylogenetic families identified, correlating with substrate specificity. The topology of ABC transporters varies, with most containing one or two cytoplasmic ATP-binding domains and one or two transmembrane domains. In eukaryotes, ABC transporters are effluxers, transporting substrates out of the cell or into organelles, with 12 efflux families identified. The Human Genome Organization classification system groups human and mouse ABC proteins into seven families, while the Transporter Classification system categorizes prokaryotic ABC influx porters into 22 families and effluxers into 27 families. ABC transporters are involved in various diseases, including multidrug resistance, cystic fibrosis, and sulfonylurea receptor regulation.