EVOLUTION OF ATP-BINDING CASSETTE TRANSPORTER GENES

The transport of molecules across lipid membranes is an essential func tion of all living organisms. One of the families of genes that have e volved to carry out this function is that which encodes the ATP-bindin g cassette proteins. These molecules use active transport to pump spec ific molecules across membranes, and the genes that encode them are fo und in abundance in the genomes of both prokaryotes and eukaryotes. By using gene disruption techniques and by studying homologous genes in model organisms, significant progress has been made during the last fe w years in evaluating the physiological functions of ABC proteins in h igher eukaryotes.