All of the factors required for assembly of the glucocorticoid receptor into a functional heterocomplex with XXXX protein 90 are preassociated in a self-sufficient protein folding structure, a "foldosome".

@entity23118 @entity19 @entity1457 @entity95 @entity134 @entity187 @entity4338 @entity855
The hormone-binding domain of the glucocorticoid receptor must be bound to @entity1457 protein (hsp) 90 for it to have a high-affinity @entity134 binding conformation. We have recently demonstrated that @entity187 is required for cell-free assembly of the receptor. @entity23118 complex and concomitant activation of @entity134 binding activity (Hutchison, K.A., Dittmar, K.D., Czar, M.J., and Pratt, W. B. (1994) J. Biol. Chem. 269, 5043-5049). @entity23118 and @entity187 are known to exist together in a cytosolic complex containing several other proteins, and in this work we ask if all of the factors required for proper receptor folding and heterocomplex assembly are preassociated in this multiprotein complex. The multiprotein complex was immunoadsorbed to protein A-agarose from @entity95 reticulocyte lysate using the 3G3 monoclonal IgM directed against @entity23118 . When this immunopellet is mixed with immunadsorbed @entity19 glucocorticoid receptor and incubated at 30 degrees C with @entity855 /Mg2+ and @entity4338 , the receptor is converted to the @entity134 binding conformation. When the immunoadsorbed multiprotein @entity23118 complex is washed extensively, it loses a weakly bound protein (not @entity187 or @entity23118 ) that is required for receptor activation. This protein factor is contained in a Centricon C-100 filtrate of lysate which reconstitutes the receptor activating activity of the washed @entity23118 complex. The @entity23118 complex can be released from the 3G3 antibody, and in the presence of the protein factor in the Centricon C-100 filtrate it converts the receptor into a functional heterocomplex with @entity23118 . The results support the proposal that the various components of reticulocyte lysate that are required to refold the glucocorticoid receptor to the @entity134 binding state are preassociated with each other, acting as a self-sufficient protein folding machine.
