Figure

10-24 Amino acid

sequences

from the literature that

comprise the nuclear translocation signal.

comprise the nuclear translocation signal.

Both the glucocorticoid and mineralocorticoid receptors are cytoplasmic in their unoccupied (by ligand) forms. The glucocorticoid receptor is complexed with a dimer of hsp 90 and a monomer of immunophilin p52. hsp 70 is also found in this complex, although not always as a stoichiometric partner, and is thought to play a role in the assembly of the oligomeric form shown in Figure 10-14. Interestingly, the oligomeric form of the glucocorticoid receptor generates a conformation that productively binds the steroidal ligand in cellular concentrations, whereas the free receptor monomer does not rebind the steroid well once the ligand has dissociated. In addition to generating the steroid-binding form of the receptor, the oligomer probably serves to anchor the receptor to a cytoplasmic skeletal element, such as tubulin or actin. Once the

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