N-terminal domain of the androgen receptor contains a region that can promote cytoplasmic localization

Abstract

Nucleocytoplasmic trafficking of the androgen receptor (AR) represents an essential step in androgen action. To determine whether the amino-terminal domain (NTD) contains potential nuclear import and/or export signals, deletion mutants of the NTD tagged with green fluorescent protein (GFP) were generated and tested for their intracellular localization in both AR-negative and AR-positive cell lines. Subcellular localization analysis suggested a role of the NTD in regulating AR subcellular localization and revealed that the region of a.a. 50-250 of the NTD of AR (AR50-250) could promote cytoplasmic localization. Leptomycin B inhibited the activity of AR50-250, suggesting that AR50-250 export is mediated through exportin 1, either directly or indirectly. These observations argue for an important role of the NTD in regulating AR nucleocytoplasmic trafficking and will facilitate further investigation of interactions among different signals in regulating AR nucleocytoplasmic trafficking, which may lead to new approaches to inhibit AR nuclear localization.

The N-terminal domain of the androgen receptor drives its nuclear localization in castration-resistant prostate cancer cells

“…The presence of the NTD led to the cytoplasmic localization of full-length AR in COS-1 cells, whereas GFP-DBDH-LBD, which lacks NTD, was evenly distributed in COS-1 cells. This finding is consistent with the presence of a region, AR 50–250 , within the NTD capable of promoting cytoplasmic localization of the AR in PC3 cells (38). Furthermore, GFP-AR and GFP-AR Δ (294–556) were localized in the cytoplasm in virtually all of the transfected cells whereas GFP-AR Δ (1–293) was evenly distributed in PC3 cells (46).…”

“…This finding is consistent with the presence of a region, AR 50–250 , within the NTD capable of promoting cytoplasmic localization of the AR in PC3 cells (38). Furthermore, GFP-AR and GFP-AR Δ (294–556) were localized in the cytoplasm in virtually all of the transfected cells whereas GFP-AR Δ (1–293) was evenly distributed in PC3 cells (46). These observations suggest that a.a.294–556 of NTD is not sufficient to drive complete nuclear localization of AR in PC3 cells.…”

“…4B). Similarly, in the androgen-negative PC3 cells, both GFP-NTD and GFP-AR (294–556) exhibited even localization between the nucleus and the cytoplasm (38). These results suggest that a.a. 294–556 together with DBDH-LBD are essential for androgen-independent nuclear localization of AR in LAPC4, C4-2 and LNCaP cells.…”

Inhibition of Androgen Receptor Nuclear Localization and Castration-Resistant Prostate Tumor Growth by Pyrroloimidazole-based Small Molecules

“…Cells were transfected at >60% confluence in phenol red-free OptiMEM. The localization of GFP fusion proteins was imaged 16 h after transfection, or at the indicated times after exposure to small molecules dissolved in DMSO, or DMSO vehicle control, with fluorescence microscopy using either a Nikon TE 2000U, Nikon TS100, or Leica DM-IL microscope as described previously (22). Cytoplasmic localization in transfected cells was defined as GFP fluorescence that was both predominantly in the cytoplasm and more intense relative to nuclei.…”

Development and Implementation of a High-Throughput High-Content Screening Assay to Identify Inhibitors of Androgen Receptor Nuclear Localization in Castration-Resistant Prostate Cancer Cells

“…[21][22][23][24] In addition, the N-terminal domain of AR contains amino acid sequences that can modulate subcellular localization. 25,26 In androgen-sensitive cells, AR is localized to the cytoplasm in the absence of ligand. 27 On exposure to androgens, AR translocates to the nucleus where it binds to specific androgen response element DNA sequences to transactivate target genes.…”