Direct manipulation of the presence and absence of a specific protein of interest is a very powerful tool for analyzing protein function. The Retro-X ProteoTuner Shield System N (w/ ZsGreen1) uses a unique method to regulate the amount of protein of interest present in a cell, quickly and directly. It utilizes a ligand-dependent destabilization domain (DD) and its membrane permeable stabilizing ligand, Shield1. The DD is based on a 12 kDa mutant of the FKBP protein, which is expressed as a tag on the N-terminus of your protein of interest. In the presence of Shield1, the DD-tagged protein is stabilized and will accumulate inside the cell. This ligand-dependent stabilization occurs very quickly, and has been observed as soon as 15–30 minutes after the addition of Shield1. However, in the absence of the protective ligand Shield1, the DD-tagged protein of interest is rapidly degraded. Removing the Shield1 (by splitting the cells into media without Shield1) allows for protein destabilization, causing a fast degradation of the protein of interest. The process of stabilization via Shield1 is reversible, so it is possible to tune the amount of protein of interest present in the cell, by controlling the amount of the Shield1 ligand.

Overview