Potassium channel regulation - Structural insights into the function of the nucleotide-binding domains of the human sulphonylurea receptor

The sulphonylurea receptor ( SUR) is a member of the ATP-binding cassette (ABC) family of membrane proteins. It functions as the regulatory subunit of the ATP-sensitive potassium (K-ATP) channel, which comprises SUR and Kir6.x proteins. Here, we review data demonstrating functional differences between the two nucleotide binding domains (NBDs) of SUR1. In addition, to explain the structural basis of these functional differences, we have constructed a molecular model of the NBD dimer of human SUR1. We discuss the experimental data in the context of this model, and show how the model can be used to design experiments aimed at elucidating the relationship between the structure and function of the K-ATP channel.