Association of prokaryotic and eukaryotic chaperone proteins with the human 1alpha,25-dihydroxyvitamin D(3) receptor.
Steroid hormone receptors (SHR) form complexes with heat shock proteins (hsps). The 1alpha,25-dihydroxyvitamin D(3) receptor (VDR) has not been previously shown to interact with hsps. During expression and purification of VDR-glutathione S-transferase (VDR-GST) fusion proteins encompassing full-length, DNA, and ligand-binding domains of the VDR (FL-VDR, DBD-VDR, and LBD-VDR), we observed binding of bacterial hsps with VDR-GST constructs. All VDR constructs bound DnaK in amounts greater than GST alone and bound smaller amounts of DnaJ or GrpE. GroEL bound only to FL-VDR. GroES did not bind to VDR. When VDR-GST constructs were incubated with a reticulocyte lysate system that has been used previously to examine SHR-hsp interactions, eukaryotic hsc70 was detected bound to FL-VDR and DBD-VDR. Binding of hsp90 to VDR was not detected. However, geldanamycin, an hsp90 inhibitor, reduced 1alpha,25-dihydroxyvitamin D(3)-mediated gene activation in osteoblasts. Our data show that the bacterial and eukaryotic hsps associate with the VDR and might be involved in VDR function.
Craig
T A
TA
Department of Medicine, Mayo Clinic/Foundation, Rochester, Minnesota, 55905, USA.
Lutz
W H
WH
Kumar
R
R
D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002117:Calcitriol / Q000378:metabolism*; D018833:Chaperonins / Q000378:metabolism*; D004247:DNA; D005057:Eukaryotic Cells / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D011387:Prokaryotic Cells / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014407:Tumor Cells, Cultured
D011993:Recombinant Fusion Proteins; D004247:DNA; D005982:Glutathione Transferase; D018833:Chaperonins; D002117:Calcitriol