MOLECULAR CHAPERONES AND SUBCELLULAR TRAFFICKING OF STEROID-RECEPTORS

Unliganded steroid receptors exist as heteromeric complexes comprised of heat shock and immunophilin proteins that associate either directly or indirectly with receptor carboxyl-terminal ligand-binding domains. Molecular chaperons, and other proteins associated with steroid recep tors, play an important role in the maturation of receptors to a hormo ne-binding competent state. Steroid receptor-associated 90 and 70 kDa heat shock proteins, hsp90 and hsp70, respectively, have well establis hed roles in protein folding in addition to participating in numerous subcellular trafficking pathways. In this review, we discuss the possi ble roles that molecular chaperons, such as hsp90, hsp70 and DnaJ prot eins, have in steroid receptor trafficking within two distinct subcell ular compartments, i.e. the cytoplasm and nucleus. (C) 1998 Elsevier S cience Ltd. All rights reserved.