Specific N-terminal mutations in the human androgen receptor induce cytotoxicity

• Published in: Neurobiology of aging 2009-11, Vol.30 (11), p.1851-1864
• Main Authors: Funderburk, Sarah F, Shatkina, Liubov, Mink, Sigrun, Weis, Qun, Weg-Remers, Susanne, Cato, Andrew C.B
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Animals, Genetically Modified; Behavioral Symptoms - genetics; Behavioral Symptoms - pathology; Biological and medical sciences; Butyrates - pharmacology; CAG; Cercopithecus aethiops; COS Cells; Development. Senescence. Regeneration. Transplantation; Disease Models, Animal; Drosophila; Drosophila Proteins - genetics; Fundamental and applied biological sciences. Psychology; Humans; Internal Medicine; Kennedy's disease; Larva; Locomotion - drug effects; Locomotion - genetics; Melatonin; Melatonin - pharmacology; Misfolding; Mitogen-Activated Protein Kinase Kinases - metabolism; Muscular Atrophy, Spinal - genetics; Muscular Atrophy, Spinal - metabolism; Muscular Atrophy, Spinal - mortality; Muscular Atrophy, Spinal - physiopathology; Mutation - genetics; Neurodegeneration; Neurology; Peptide Fragments - genetics; Receptors, Androgen - chemistry; Receptors, Androgen - genetics; SBMA; Serine - genetics; Sodium butyrate; Survival Analysis; Transfection - methods; Trinucleotide Repeats - genetics; Vertebrates: nervous system and sense organs
• ISSN: 0197-4580; 1558-1497
• DOI: 10.1016/j.neurobiolaging.2007.12.023

Abstract Polyglutamine (polyQ) stretch amplification in different proteins causes neurodegenerative disease. These proteins form intracellular aggregates thought to be cytotoxic but differ in pathology and tissue specificity. Here, we demonstrate that specific sequences outside the polyQ stretch of the human androgen receptor contribute to polyQ pathology. An exchange of two N-terminal serine phosphorylation residues to alanine in the wild type androgen receptor (ARQ22dm) resulted in cytoplasmic accumulation and increased early hormone-dependent aggregation of the receptor. In a Drosophila model, the ARQ22dm was cytotoxic, and developing larvae expressing this receptor showed behavioral abnormalities and severely impaired locomotion. In contrast, the same double mutation in an androgen receptor with an extended polyQ stretch was less toxic. The response of the receptors to inhibitors of polyglutamine toxicity is altered by the amino acid exchanges suggesting that careful consideration is needed in the choice of potential therapies of disorders involving toxic polyQ species.