The androgen receptor DNA-binding domain determines androgen selectivity of transcriptional response

2006 ◽  
Vol 34 (6) ◽  
pp. 1089-1094 ◽  
Author(s):  
G. Verrijdt ◽  
T. Tanner ◽  
U. Moehren ◽  
L. Callewaert ◽  
A. Haelens ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Dna Binding ◽  
Cellular Response ◽  
Hormone Receptors ◽  
Target Genes ◽  
Steroid Hormone ◽  
Prostate Gland ◽  
Steroid Hormone Receptors ◽  
Binding Motif

The AR (androgen receptor) is a hormone-dependent transcription factor that translates circulating androgen hormone levels into a physiological cellular response by directly regulating the expression of its target genes. It is the key molecule in e.g. the development and maintenance of the male sexual characteristics, spermatocyte production and prostate gland development and growth. It is also a major factor in the onset and maintenance of prostate cancer and a first target for pharmaceutical action against the further proliferation of prostate cancer cells. The AR is a member of the steroid hormone receptors, a group of steroid-inducible transcription factors sharing an identical consensus DNA-binding motif. The problem of how specificity in gene activation is achieved among the different members of this nuclear receptor subfamily is still unclear. In this report, we describe our investigations on how the AR can specifically activate its target genes, while the other steroid hormone receptors do not, despite having the same consensus monomeric DNA-binding motif. In this respect, we describe how the AR interacts with a newly identified class of steroid-response elements to which only the AR and not, for example, the glucocorticoid receptor can bind.

Comparative analysis of the influence of the high-mobility group box 1 protein on DNA binding and transcriptional activation by the androgen, glucocorticoid, progesterone and mineralocorticoid receptors

2001 ◽  
Vol 361 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Guy VERRIJDT ◽  
Annemie HAELENS ◽  
Erik SCHOENMAKERS ◽  
Wilfried ROMBAUTS ◽  
Frank CLAESSENS
Keyword(s):  
Androgen Receptor ◽  
Comparative Analysis ◽  
Dna Binding ◽  
Mineralocorticoid Receptor ◽  
Hormone Receptors ◽  
Steroid Hormone ◽  
High Mobility ◽  
Steroid Hormone Receptors ◽  
High Mobility Group ◽  
Mineralocorticoid Receptors

We performed a comparative analysis of the effect of high-mobility group box protein 1 (HMGB1) on DNA binding by the DNA-binding domains (DBDs) of the androgen, glucocorticoid, progesterone and mineralocorticoid receptors. The affinity of the DBDs of the different receptors for the tyrosine aminotransferase glucocorticoid response element, a classical high-affinity binding element, was augmented up to 7-fold by HMGB1. We found no major differences in the effects of HMGB1 on DNA binding between the different steroid hormone receptors. In transient transfection assays, however, HMGB1 significantly enhances the activity of the glucocorticoid and progesterone receptors but not the androgen or mineralocorticoid receptor. We also investigated the effect of HMGB1 on the binding of the androgen receptor DBD to a subclass of directly repeated response elements that is recognized exclusively by the androgen receptor and not by the glucocorticoid, progesterone or mineralocorticoid receptor. Surprisingly, a deletion of 26 amino acid residues from the C-terminal extension of the androgen receptor DBD does not influence DNA binding but destroys its sensitivity to HMGB1. Deletion of the corresponding fragment in the DBDs of the glucocorticoid, progesterone and mineralocorticoid receptor destroyed their DNA binding. This 26-residue fragment is therefore essential for the influence of HMGB1 on DNA recognition by all steroid hormone receptors that were tested. However, it is dispensable for DNA binding by the androgen receptor.

Molecular Biology of the Androgen Receptor

2002 ◽  
Vol 20 (13) ◽  
pp. 3001-3015 ◽  
Author(s):  
Edward P. Gelmann
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Ligand Binding ◽  
Dna Sequences ◽  
Hormone Receptors ◽  
Steroid Hormone ◽  
Three Dimensional ◽  
Intramolecular Interactions ◽  
Steroid Hormone Receptors ◽  
Dimensional Structure

ABSTRACT: Androgen receptor (AR) is a member of the steroid hormone receptor family of molecules. AR primarily is responsible for mediating the physiologic effects of androgens by binding to specific DNA sequences that influence transcription of androgen-responsive genes. The three-dimensional structure of the AR ligand-binding domain has shown it is similar to other steroid hormone receptors and that ligand binding alters the protein conformation to allow binding of coactivator molecules that amplify the hormone signal and mediate transcriptional initiation. However, AR also undergoes intramolecular interactions that regulate its interactions with coactivators and influence its activity. A large number of naturally occurring mutations of the human AR gene have provided important information about AR molecular structure and intermolecular interactions. AR is also a critical mediator of prostate cancer promotion, conferring growth signals to prostate cancer cells throughout the natural history of the disease. Late-stage prostate cancer, unresponsive to hormonal deprivation, sustains AR signaling through a diverse array of molecular strategies. Variations in the AR gene may also confer genetic predisposition to prostate cancer development and severity. Further understanding of AR action and new strategies to interfere with AR signaling hold promise for improving prostate cancer therapy.

scholarly journals E6-associated protein (E6-AP) is a dual function coactivator of steroid hormone receptors

2008 ◽  
Vol 6 (1) ◽  
pp. nrs.06006 ◽  
Author(s):  
Sivapriya Ramamoorthy ◽  
Zafar Nawaz
Keyword(s):  
Hormone Receptors ◽  
Target Genes ◽  
Steroid Hormone ◽  
Enzymatic Activities ◽  
Steroid Hormone Receptors ◽  
Dual Function ◽  
Biological Functions ◽  
Ubiquitin Proteasome Pathway ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway

Steroid hormone receptors (SHR) belong to a large family of ligand-activated transcription factors that perform their biological functions by enhancing the transcription of specific target genes. The transactivation functions of SHRs are regulated by a specialized group of proteins called coactivators. The SHR coactivators represent a growing class of proteins with various enzymatic activities that serve to modify the chromatin to facilitate the transcription of SHR target genes. The ubiquitin-proteasome pathway enzymes have also been added to the growing list of enzymatic activities that are recruited to the SHR target gene promoters during transcription. One such ubiquitin-proteasome pathway enzyme to be identified and characterized as a SHR coactivator was E6-associated protein (E6-AP). E6-AP is a hect (homologous to E6-associated protein carboxy-terminal domain) domain containing E3 ubiquitin ligase that possesses two independent separable functions; a coactivation function and an ubiquitin-protein ligase activity. Being a component of the ubiquitin-proteasome pathway, it is postulated that E6-AP may orchestrate the dynamics of steroid hormone receptor-mediated transcription by regulating the degradation of the transcriptional complexes. E6-AP has also been shown to be involved in the regulation of various aspects of reproduction such as prostate and mammary gland development. Furthermore, it has been demonstrated that E6-AP expression is down-regulated in breast and prostate tumors and that the expression of E6-AP is inversely associated with that of estrogen and androgen receptors. This review summarizes our current knowledge about the structures, molecular mechanisms, spatiotemporal expression patterns and biological functions of E6-AP.

scholarly journals Targeting steroid hormone receptors for ubiquitination and degradation in breast and prostate cancer

Oncogene ◽  
2008 ◽  
Vol 27 (57) ◽  
pp. 7201-7211 ◽  
Author(s):  
A Rodriguez-Gonzalez ◽  
K Cyrus ◽  
M Salcius ◽  
K Kim ◽  
C M Crews ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Hormone Receptors ◽  
Steroid Hormone ◽  
Steroid Hormone Receptors ◽  
Breast And Prostate Cancer

scholarly journals A Splicing Variant of the Androgen Receptor Detected in a Metastatic Prostate Cancer Exhibits Exclusively Cytoplasmic Actions

Endocrinology ◽  
2007 ◽  
Vol 148 (9) ◽  
pp. 4334-4343 ◽  
Author(s):  
Monika Jagla ◽  
Marie Fève ◽  
Pascal Kessler ◽  
Gaëlle Lapouge ◽  
Eva Erdmann ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Dna Binding ◽  
Cancer Progression ◽  
Metastatic Prostate Cancer ◽  
Transcriptional Activity ◽  
Target Genes ◽  
Nuclear Translocation ◽  
Splicing Variant ◽  
Activation Of Transcription

The androgen receptor (AR) is a ligand-activated transcription factor that displays genomic actions characterized by binding to androgen-response elements in the promoter of target genes as well as nongenomic actions that do not require nuclear translocation and DNA binding. In this study, we report exclusive cytoplasmic actions of a splicing variant of the AR detected in a metastatic prostate cancer. This AR variant, named AR23, results from an aberrant splicing of intron 2, wherein the last 69 nucleotides of the intronic sequence are retained, leading to the insertion of 23 amino acids between the two zinc fingers in the DNA-binding domain. We show that the nuclear entry of AR23 upon dihydrotestosterone (DHT) stimulation is impaired. Alternatively, DHT-activated AR23 forms cytoplasmic and perinuclear aggregates that partially colocalize with the endoplasmic reticulum and are devoid of genomic actions. However, in LNCaP cells, this cytoplasmic DHT-activated AR23 remains partially active as evidenced by the activation of transcription from androgen-responsive promoters, the stimulation of NF-κB transcriptional activity and by the decrease of AP-1 transcriptional activity. Our data reveal novel cytoplasmic actions for this splicing AR variant, suggesting a contribution in prostate cancer progression.

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