Figure 5.

p23-mediated affects on ligand efficacy for GR and AR occur with slow kinetics in animal and yeast cells. The effect of p23 (circles) or tsp23 (squares), at the indicated time points, on GR (open symbols) or AR (closed symbols) was determined in transiently transfected (A) HeLa cells. The data are presented as the fold change in receptor activity relative to receptor activity in the absence of a cotransfected p23 or tsp23 expression plasmid. The activity of GR (open symbols) or AR (closed symbols) was measured in (B) wild-type yeast (circles), Δp23 expressing exogenous Sba1p (squares), and wild-type expressing exogenous Sba1p (diamonds) at the indicated time points. The data are presented as the fold change in receptor activity relative to receptor activity in the Δp23 strain.