Dopamine D₂ receptor signaling modulates mutant ataxin‐1 S776 phosphorylation and aggregation

Abstract

line transiently transfected with GFP-ataxin-1[82Q], we demonstrate that stimulation of the D2R/S100B pathway caused a reduction in mutant ataxin-1 S776 phosphorylation and ataxin-1 aggregation. Activation of PKA by forskolin resulted in an enhanced S776 phosphorylation and increased ataxin-1 nuclear aggregation, which was suppressed by treatment with D2R agonist bromocriptine and PKA inhibitor H89. Furthermore, treating SCA1 transgenic PC slice cultures with forskolin induced neurodegenerative morphological abnormalities in PC dendrites consistent with those observed in vivo. Taken together our data support a mechanism where PKA dependent mutant ataxin-1 phosphorylation and aggregation can be regulated by D2R/S100B signaling.

The design and delivery of a thermally responsive peptide to inhibit S100B-mediated neurodegeneration

“…Experiments were repeated at least three times and statistics taken. SHSY5Y stable cell lines were produced by transfecting with either GFP-ATXN1[82Q] or GFP-ATXN1[30Q] vectors (described previously (Hearst et al, 2010)) using Fugene 6 transfection reagent and selected by G418 (G418 sulfate 600 μg/ml, Sigma) resistance as previously described (Hearst et al, 2010). Cells were grown in 15% FBS in F-12/DMEM media and plated on 2 well Lab-Tek CC2 chamber slides (Fisher).…”

Does astroglial protein S100B contribute to West Nile neuro-invasive syndrome?

“…The cells were allowed to grow for 24 h. After 24 h, the cell were lysed using RIPA buffer (50 mM Tris-HCl, pH 7.5, 150 mM NaCl, 1 mM EDTA, 1% sodium deoxycholate and 1% NP-40, Sigma). These lysates were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (4-20% acrylamide gels) as described earlier [23]. Equal amounts of protein were loaded to the gels.…”

Beyond the Glutamine Expansion: Influence of Posttranslational Modifications of Ataxin-1 in the Pathogenesis of Spinocerebellar Ataxia Type 1

“…An initial study using tissue culture systems and Drosophila models of SCA1 suggested that AKR mouse thymoma (Akt) was the kinase responsible for ATXN1-S776 phosphorylation [15]. However, a later study proposed that cyclic AMP-dependent protein kinase (PKA), not Akt, is the kinase that phosphorylates ATXN1-S776 in the mouse cerebellum in vivo [25, 26]. This finding was based on the following observations: 1) PKA co-fractionates with the peak of ATXN1-S776 phosphorylation by gel-filtration chromatography.…”

“…And 4) activation of PKA by forskolin treatment enhances ATXN1-S776 phosphorylation in cultured cells and induces the degeneration of PCs in slice cultures. Furthermore, the dopamine receptor D2 (DRD2) signaling pathway is suggested to act upstream of PKA in SCA1 [26]. The expression level of DRD2 is reduced in the cerebellum of SCA1 transgenic mice (B05) [27].…”