Figure 5

CXCR7 colocalizes and physically interacts with AR in LNCaP prostate-tumor cells. (A) Immunofluorescence staining of CXCR7 and AR in semi-permeabilized AD-LNCaP cells treated with vehicle (0.1% BSA), 0.1, 1, or 10 nM R1881 for 96 hrs. The nuclei are labeled with DAPI. (B) Western blot analysis of crude cytosolic, membrane, and nuclear proteins isolated from LNCaP cells stably expressing streptavidin binding peptide tag (SBP) or CXCR7 with a SBP-tag on the C-terminus (C7-SBP) using antibodies to GM130 and Histone H3 (top panel). Silver-stained gel demonstrated equal protein loading across samples (bottom panel). (C) Western blot analysis of streptavidin affinity purified samples from detergent-solubilized microsomal protein fraction of SBP or C7-SBP cells using the SBP, and (D) AR antibody. Equal proportions (10 μl) of input, flow-through (void), and 5% (10 ul) of the biotin elution were loaded.