Figure 1.

Models of glucocorticoid receptor dynamics at hormone response elements. (A) The classic model of receptor binding posits long-term residency of the receptor at the promoter with subsequent recruitment of factors. (B) Direct observation of receptor binding in living cells by Hager and colleagues (McNally et al. 2000) revealed rapid exchange of the receptor (hit-and-run). Most cofactors that have been examined (x, y) also exchange dynamically at sites of receptor binding. (C) Some coregulatory proteins may have longer residence times at selected sites. GR, glucocorticoid receptor; Dex, dexamethasone.