β Galactosidase Enzyme Fragment Complementation as A Novel Technology for High Throughput Screening

In this review, the applications of β galactosidase complementation are described. αComplementation is a naturally occurring process in bacteria and in engineered cells, and can also occur in eukaryotic cells. Two forms of α complementation have been used in high throughput screening (HTS), in which interacting fragments complement with either low or high affinity. Low affinity complementation is used to monitor protein protein interactions, such as those occurring in homodimerization of the epidermal growth factor receptor (EGFR), and provides a robust screen for detection of EGFR inhibitors. High affinity complementation provides the basis for several HTS assays, in which analytes, such as cAMP or IP3, are detected in crude cell lysates. A development of the latter approach is protein labeling, providing for measurement of cell protein expression and trafficking. Collectively, the use of β galactosidase complementation provides a novel and flexible technology for highly sensitive, homogeneous HTS assay development.