MMTV luciferase promoter assay in HeLa cells with MMTV luciferase construct, TK Renilla luciferase and ARLBD (amino acids 1C682), plus the indicated BAG domain name mutants. prostate malignancy, PSA: prostate specific antigen, HR: hazard ratio, 95% CI: 95% confidence intervals. a Univariate cox survival model. elife-27159-table1-data1.docx (47K) DOI:?10.7554/eLife.27159.033 Table 1source data 2: Clinical characteristics of patients at time of castration-resistant prostate malignancy biopsy. CRPC: castration-resistant prostate malignancy, ECOG PS: Eastern Cooperative Oncology Group overall performance status, IQR: interquartile range, SD: standard deviation, PSA: prostate specific antigen, n: number, pts: patients. at-test from linear regression model of Nuclear Bag-1 H-score at the time of CRPC biopsy bWald test from linear regression model of Nuclear Bag-1 H-score at the time of CRPC biopsy elife-27159-table1-data2.docx (61K) DOI:?10.7554/eLife.27159.034 Transparent reporting form. elife-27159-transrepform.docx (243K) DOI:?10.7554/eLife.27159.036 Abstract Targeting the activation function-1 (AF-1) domain name located in the N-terminus of the androgen receptor (AR) is an attractive therapeutic alternative to the current approaches to inhibit AR action in prostate cancer (PCa). Here we show that this AR AF-1 is usually bound by the cochaperone Bag-1L. Mutations in the AR conversation domain name or loss of Bag-1L abrogate AR signaling and reduce PCa growth. Clinically, Bag-1L protein levels increase with progression to castration-resistant PCa (CRPC) and high levels of Bag-1L in main PCa associate with a reduced clinical benefit from abiraterone when these tumors progress. Intriguingly, residues in Bag-1L important for its interaction with the AR AF-1 are within a potentially druggable pocket, implicating Bag-1L as a potential therapeutic target in Tianeptine sodium PCa. amino acid sequence of the BAG domain of Bag-1L (residues 219C345) with evolutionarily conserved residues highlighted in reddish and CMut (K231A/K232A/K279A) shown in blue. Residues involved in -helix formation are highlighted in grey. MMTV luciferase promoter assay in HeLa cells with MMTV luciferase construct, TK Renilla luciferase and ARLBD (amino acids 1C682), plus the indicated BAG domain mutants. The results are the mean of three impartial experiments??SD. Physique 2figure product 5. Open in a separate windows CBCACONH data of wild-type and CMut Bag-1L.Superposition of CBCACONH of Bag-1L WT (black) and the K231/232/279A mutant (Bag-1L CMut; reddish). 1H 13C planes were extracted from your 3D spectrum at the indicated 15N values. Physique 2figure product 6. Open in a separate windows 15N-HSQC spectra of wild-type and CMut Bag-1L.Superposition of 15N-HSQC spectra of the BAG domain of Bag-1L WT (black) and the K231/232/279A mutant (Bag-1L CMut; reddish). To test if mutations in the BAG domain name would disrupt the Tal1 integrity of associated biochemical complexes, we next employed quantitative, stable isotope labeling with amino acids in cell culture (SILAC) combined with quick immunoprecipitation mass spectrometry of endogenous proteins (RIME) (Mohammed et al., 2013) of LNCaP cells that stably express FLAG-HA-tagged wild-type or CMut Bag-1L. Association of AR, but not Hsp70 (HSPA1), was disrupted in Bag-1L biochemical complexes in the context of the triple mutation (Physique 2G); these data agree with the results of our GST pull-down (Physique 2C) and co-IP experiments (Physique 2D). Several proteins which exhibited decreased association with CMut Bag-1L (Physique 2source data 1) are annotated with functional roles in protein synthesis, localization, or other aspects of proteostasis (Capabilities and Balch, 2013; Taipale et al., 2014; Labbadia and Morimoto, 2015) (Physique 2source data 2). The dynamics we observed in the biochemical complex as a function of the Bag1L mutant is usually consistent with our hypothesis that Bag-1L is involved in the folding of AR (Figures 1G and ?and2F),2F), suggesting a broader role for the BAG domain in proteome homeostasis. The reduction of interactors for the mutant Bag-1L could, in theory, be the result of an altered BAG domain conformation brought about by the triple mutation. To test this, we recorded 13C correlation nuclear Tianeptine sodium magnetic resonance (NMR) spectra to compare C and C shifts (Sattler et al., 1999), Tianeptine sodium which are predominantly influenced by the secondary structure of a protein. Comparison of the C and Cshifts revealed no significant changes in the wild-type and mutant BAG domain name peptide (Physique 2figure product 5), suggesting that this extent of -helix formation is essentially unchanged for the two proteins. However, about one third of residues that make the three antiparallel, helix bundles of the wild-type BAG domain name (Briknarov et al., 2001) shifted to new positions or exhibited reduced transmission intensities in 1H15N-HSQC NMR spectra in response to the K231/232/279A mutations (Physique 2figure product 6). This is most likely due to a destabilization of the entire protein caused Tianeptine sodium by the three mutations, a consequence of which is a significant switch in the 3D-structure of Bag-1L and hence an altered interactome of CMut compared to wild-type Bag-1L (Physique 2G). The Bag-1L:AR conversation alters the structure of the AR NTD and is druggable Differences in the structural effects of the wild-type or mutant BAG domain.