| First Author | Ruegsegger C | Year | 2016 |
| Journal | Neuron | Volume | 89 |
| Issue | 1 | Pages | 129-46 |
| PubMed ID | 26748090 | Mgi Jnum | J:230877 |
| Mgi Id | MGI:5766408 | Doi | 10.1016/j.neuron.2015.11.033 |
| Citation | Ruegsegger C, et al. (2016) Impaired mTORC1-Dependent Expression of Homer-3 Influences SCA1 Pathophysiology. Neuron 89(1):129-46 |
| abstractText | Spinocerebellar ataxia type 1 (SCA1), due to the expansion of a polyglutamine repeat within the ubiquitously expressed Ataxin-1 protein, leads to the premature degeneration of Purkinje cells (PCs), the cause of which is poorly understood. Here, we identified the unique proteomic signature of Sca1(154Q/2Q) PCs at an early stage of disease, highlighting extensive alterations in proteins associated with synaptic functioning, maintenance, and transmission. Focusing on Homer-3, a PC-enriched scaffold protein regulating neuronal activity, revealed an early decline in its expression. Impaired climbing fiber-mediated synaptic transmission diminished mTORC1 signaling, paralleling Homer-3 reduction in Sca1(154Q/2Q) PCs. Ablating mTORC1 within PCs or pharmacological inhibition of mTORC1 identified Homer-3 as its downstream target. mTORC1 knockout in Sca1(154Q/2Q) PCs exacerbated and accelerated pathology. Reinstating Homer-3 expression in Sca1(154Q/2Q) PCs attenuated cellular dysfunctions and improved motor deficits. Our work reveals that impaired mTORC1-Homer-3 activity underlies PC susceptibility in SCA1 and presents a promising therapeutic target. |
