Question

Diagram the key steps in a GST pull-down assay. Is the GST-tagged protein the “bait” or the “prey”?

Answer 1

GST pull down assay is done to check if two proteins are interacting with each other. In this method, GST-tagged protein is 'prey' and GSH-coated beads are 'bait'. The illustration of the method is below :

We want to check if protein 1 and 2 interact with each other.

GST-tagged proteins binds to the GSH-coated beads and pulled down, if protein 2 is interacting with protein 1, the band intensity will be higher in lane #3 (mixture of two lysate)