Reduction of protein kinase A-mediated phosphorylation of ATXN1-S776 in Purkinje cells delays onset of Ataxia in a SCA1 mouse model.

Reduction of protein kinase A-mediated phosphorylation of ATXN1-S776 in Purkinje cells delays onset of Ataxia in a SCA1 mouse model. Neurobiol Dis. 2018 May 11;: Authors: Pérez Ortiz JM, Mollema N, Toker N, Adamski CJ, O'Callaghan B, Duvick L, Friedrich J, Walters MA, Strasser J, Hawkinson JE, Zoghbi HY, Henzler C, Orr HT, Lagalwar S Abstract Spinocerebellar ataxia type 1 (SCA1) is a polyglutamine (polyQ) repeat neurodegenerative disease in which a primary site of pathogenesis are cerebellar Purkinje cells. In addition to polyQ expansion of ataxin-1 protein (ATXN1), phosphorylation of ATXN1 at the serine 776 residue (ATXN1-pS776) plays a significant role in protein toxicity. Utilizing a biochemical approach, pharmacological agents and cell-based assays, including SCA1 patient iPSC-derived neurons, we examine the role of Protein Kinase A (PKA) as an effector of ATXN1-S776 phosphorylation. We further examine the implications of PKA-mediated phosphorylation at ATXN1-S776 on SCA1 through genetic manipulation of the PKA catalytic subunit Cα in Pcp2-ATXN1[82Q] mice. Here we show that pharmacologic inhibition of S776 phosphorylation in transfected cells and SCA1 patient iPSC-derived neuronal cells lead to a decrease in ATXN1. In vivo, reduction of PKA-mediated ATXN1-pS776 results in enhanced degradation of ATXN1 and improved cerebellar-dependent motor performance. These results provide evidence that PKA is a biologically important kinase ...
Source: Neurobiology of Disease - Category: Neurology Authors: Tags: Neurobiol Dis Source Type: research