Hsp70 Cochaperones HspBP1 and BAG-1M Differentially Regulate Steroid Hormone Receptor Function
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Hsp70 binding protein 1 (HspBP1) and Bcl2-associated athanogene 1 (BAG-1), the functional orthologous nucleotide exchange factors of the heat shock protein 70 kilodalton (Hsc70/Hsp70) chaperones, catalyze the release of ADP from Hsp70 while inducing different conformational changes of the ATPase domain of Hsp70. An appropriate exchange rate of ADP/ATP is crucial for chaperone-dependent protein folding processes. Among Hsp70 client proteins are steroid receptors such as the glucocorticoid receptor (GR), the mineralocorticoid receptor (MR), and the androgen receptor (AR). BAG-1 diversely affects steroid receptor activity, while to date the influence of HspBP1 on steroid receptor function is mostly unknown. Here, we compared the influence of HspBP1 and BAG-1M on Hsp70-mediated steroid receptor folding complexes and steroid receptor activity. Coimmunoprecipitation studies indicated preferential binding of Hsp40 and the steroid receptors to BAG-1M as compared to HspBP1. Furthermore, Hsp70 binding to the ligand-binding domain of GR was reduced in the presence of HspBP1 but not in the presence of BAG-1M as shown by pull-down assays. Reporter gene experiments revealed an inhibitory effect on GR, MR, and AR at a wide range of HspBP1 protein levels and at hormone concentrations at or approaching saturation. BAG-1M exhibited a transition from stimulatory effects at low BAG-1M levels to inhibitory effects at higher BAG-1M levels. Overall, BAG-1M and HspBP1 had differential impacts on the dynamic composition of steroid receptor folding complexes and on receptor function with important implications for steroid receptor physiology.
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Locascio A, Marques M, Garcia-Martinez G, Corratge-Faillie C, Andres-Colas N, Rubio L Plant Physiol. 2019; 181(3):1277-1294.
PMID: 31451552 PMC: 6836829. DOI: 10.1104/pp.19.00224.
Dong J, Wu Z, Wang D, Pascal L, Nelson J, Wipf P Mol Cancer Ther. 2018; 18(1):39-50.
PMID: 30297360 PMC: 6318070. DOI: 10.1158/1535-7163.MCT-18-0432.
Fries G, Gassen N, Rein T Int J Mol Sci. 2017; 18(12).
PMID: 29206196 PMC: 5751217. DOI: 10.3390/ijms18122614.
He Y, Fang J, Xue L, Wu J, Dawar F, Mei J Fish Physiol Biochem. 2017; 43(2):465-475.
PMID: 28243861 DOI: 10.1007/s10695-016-0303-6.