Antagonistic effect of cyclin-dependent kinases and a calcium-dependent phosphatase on polyglutamine-expanded androgen receptor toxic gain of function

• DOI: 10.1126/sciadv.ade1694
• Publication Date: 2023-01-20T21:36:19Z
• Authors: Diana Piol; Laura Tosatto; Emanuela Zuccaro; Eric N. Anderson; Antonella Falconieri; Maria J. Polanco; Caterina Marchior...; Federica Lia; Joseph White; Elisa Bregolin; Giovanni Minervini; Sara Parodi; Xavier Salvatella; Giorgio Arrigoni; Andrea Ballabio; Albert R. La Spada; Silvio C. E. Tosatto; Fabio Sambataro; Diego L. Medina; Udai B. Pandey; Manuela Basso; Maria Pennuto
• Keywords: 0301 basic medicine; Muscular atrophy; Cyclin-Dependent Kinases; Phosphoric Monoester Hydrolases; Mice; 03 medical and health sciences; Receptors, Androgen; Gain of Function Mutation; Animals; Receptors cel·lulars; Calcium; MS; liquid chromatography-tandem mass spectrometry; m; z; mass; charge ratio; aa; amino acid;; Atròfia muscular; Cell receptors; Neuroscience

Spinal and bulbar muscular atrophy is caused by polyglutamine (polyQ) expansions in androgen receptor (AR), generating gain-of-function toxicity that may involve phosphorylation. Using cellular and animal models, we investigated what kinases and phosphatases target polyQ-expanded AR, whether polyQ expansions modify AR phosphorylation, and how this contributes to neurodegeneration. Mass spectrometry showed that polyQ expansions preserve native phosphorylation and increase phosphorylation at conserved sites controlling AR stability and transactivation. In small-molecule screening, we identified that CDC25/CDK2 signaling could enhance AR phosphorylation, and the calcium-sensitive phosphatase calcineurin had opposite effects. Pharmacologic and genetic manipulation of these kinases and phosphatases modified polyQ-expanded AR function and toxicity in cells, flies, and mice. Ablation of CDK2 reduced AR phosphorylation in the brainstem and restored expression of Myc and other genes involved in DNA damage, senescence, and apoptosis, indicating that the cell cycle–regulated kinase plays more than a bystander role in SBMA-vulnerable postmitotic cells.