Post-translational modification of the androgen receptor in normal and disease conditions

Lead Research Organisation: MRC Human Reproductive Sciences Unit

Abstract

Testosterone is a steroid hormone which is important for human reproductive development and fertility. In the body, a protein known as an androgen receptor binds to testosterone, and this binding protein is regulated and controlled by the addition or removal of chemical groups called phosphate. ||Phosphates cover the binding protein with negative charge at specific positions. It is likely that the number and position of phosphate groups on the binding protein may change and this will control where in the cell the protein is found, how quickly it is destroyed, and how it interacts with neighbouring protein.||Our research aims to understand how the protein that binds testosterone can be regulated. We will use a range of antibodies, which act as molecular probes, to recognise the presence of phosphate groups at selected positions on the androgen receptor. We will use these probes to work out if the pattern of phosphate addition or removal changes during development or in diseases such as prostate cancer, which is now a leading cause of cancer-related death in UK men. This information will improve our understanding of how testosterone works in the body and may lead to better treatments for disease such as prostate cancer.

Technical Summary

The primary aim of this programme of research is to identify the pattern of phosphorylation of the androgen receptor in male and female reproductive target tissues and to determine if this pattern changes during development and/or in disease states. The second aim is to use appropriate cell models to understand the molecular basis for the observed pattern(s) of phosphorylation and to determine the functional consequences for androgen receptor signalling.| |The androgen receptor is a ligand activated transcription factor that binds and mediates the actions of the steroid hormones testosterone and dihydrotestosterone. The receptor is critical for normal male development in utero and at puberty and reproductive function in adulthood. Male infertility and prostate cancer are two major diseases that result from mutations in the androgen receptor. Genetic changes in the receptor also cause a neuromuscular degenerative condition called Kennedys disease. A better understand of the structure and function of the androgen receptor is therefore vital for developing novel or improving existing therapies for receptor-dependent diseases.||Post-translational modification of proteins represents an important cellular process for controlling protein function in the absence of de novo protein synthesis. The androgen receptor is subject to a range of modifications such as phosphorylation, acetylation and summoylation. To-date twelve phosphosphorylated residues have been identified in the androgen receptor. The majority of these sites map to serine residues in the structurally flexible N-terminal domain of the receptor, which has been shown to critical for receptor-dependent gene regulation. Phosphorylation is likely to control one or more steps in the androgen receptor signalling pathway, including intracellular location, interaction with binding partners and/or receptor stability and breakdown. However, despite considerable effort, using primarily the cancer cell line LNCaP, the role of phosphorylation in receptor action remains poorly understood. ||We will use a panel of anti-phospho specific androgen receptor antibodies to look directly in tissue sections for the phosphorylated receptor and to study if the pattern changes under defined pathophysiological conditions. Based on the outcomes of this analysis suitable cellular models will be used to dissect the signalling pathways responsible for specific phosphorylated residues and to determine the functional consequences for receptor action using a combination of biochemistry and cell biology methodologies.||The objectives of this research are to study the role phosphorylation plays in androgen receptor signalling in normal tissues and to characterise how this changes in specific disease states, such as prostate cancer.

Publications

10 25 50
 
Description Androgen Receptor Expression in the Human Fetal Adrenal Gland 
Organisation University of Edinburgh
Country United Kingdom 
Sector Academic/University 
PI Contribution I have jointly supervised a MSc student with Prof. Iain Mason investigating the expression levels of the androgen receptor (mRNA and protein) in adrenal and liver cell-lines and fetal tissue. The phosphorylation of the receptor was also studied using phospho-specific antibodies.
Collaborator Contribution Established a collaborative link with Prof. Ian Mason and expanded our analysis of androgen receptor post-translational modifications in different tissues and cell-lines.
Impact Preliminary data has been generated that will be used in planning further collaborative work leading to publocation.
Start Year 2009
 
Description Androgen Receptor Phosphorylation in the Ovary 
Organisation Medical Research Council (MRC)
Department MRC Human Reproductive Sciences Unit
Country United Kingdom 
Sector Academic/University 
PI Contribution Phospho-specific antibodies against the human androgen receptor have been used to identify and characterise the phosphorylation status of the receptor in the primate ovary. Collaboration involves Profs. Hamish Fraser and Philippa Saunders
Collaborator Contribution Allowed a new area of reaserch to be investiagted.
Impact Initial work has now been published.
Start Year 2008
 
Title Receptor phosphorylation in reproductive and non-reproductive tissues 
Description The androgen receptor is important for male and female reproductive health and is regulated by phosphorylation. We have shown for the first time that specific residues are modified in a range of reproductive (ovary, endometrium, prostate) and non-reproductive tissues (fetal adrenal, kidney) in vivo. 
IP Reference  
Protection Protection not required
Year Protection Granted 2008
Licensed No
Impact Advancement of knowledge on the regulation and function of a critical regulatory protein.