Antagonistic effect of cyclin-dependent kinases and a calcium-dependent phosphatase on polyglutamine expanded androgen receptor toxic gain of function
Spinal and bulbar muscular atrophy (SBMA) is a neurodegenerative disorder caused by the abnormal expansion of polyglutamine (PolyQ)-encoding CAG triplets in the androgen receptor (AR) gene. AR binds to testosterone and its more potent derivative dihydrotestosterone (DHT), which trigger the activation of androgen receptor and the transcription of genes responsive to testosterone. Several enzymes in the cells (called kinases) can add chemical modifications (phosphorylation) to transcription factors to tightly regulate specific gene expression programs. On the contrary, phosphatases do the opposite job and remove phosphorylation from these proteins. Working together in a concerted way, kinases and phosphatases modify stability, cellular localization and function of transcription factors.