ATP-Binding Cassette Transporter (ABC Transporter)

ATP-binding cassette (ABC) transporters are a large and diverse superfamily of integral membrane proteins found in all domains of life. They utilize the energy derived from ATP hydrolysis to translocate a wide variety of substrates across cellular membranes, including ions, lipids, peptides, drugs, and other small molecules. ABC transporters play essential roles in processes such as nutrient uptake, toxin efflux, antigen presentation, and drug resistance. They typically consist of two transmembrane domains (TMDs) and two nucleotide-binding domains (NBDs). The NBDs bind and hydrolyze ATP to drive conformational changes in the TMDs, facilitating substrate movement across the membrane. This mechanism supports both import into and export out of cells, depending on the transporter type. ABC transporters are implicated clinically in cancer drug resistance and genetic diseases like cystic fibrosis.

Inhibition of ATP binding/hydrolysis; substrate-competitive inhibition