In Situ Structure of Neuronal C9orf72 Poly-GA Aggregates Reveals Proteasome Recruitment.Guo, Q., Lehmer, C., Martinez-Sanchez, A., Rudack, T., Beck, F., Hartmann, H., Perez-Berlanga, M., Frottin, F., Hipp, M.S., Hartl, F.U., Edbauer, D., Baumeister, W., Fernandez-Busnadiego, R.
(2018) Cell 172: 696-705.e12
- PubMed: 29398115
- DOI: https://doi.org/10.1016/j.cell.2017.12.030
- Primary Citation of Related Structures:
6EPC, 6EPD, 6EPE, 6EPF
- PubMed Abstract:
Protein aggregation and dysfunction of the ubiquitin-proteasome system are hallmarks of many neurodegenerative diseases. Here, we address the elusive link between these phenomena by employing cryo-electron tomography to dissect the molecular architecture of protein aggregates within intact neurons at high resolution. We focus on the poly-Gly-Ala (poly-GA) aggregates resulting from aberrant translation of an expanded GGGGCC repeat in C9orf72, the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia. We find that poly-GA aggregates consist of densely packed twisted ribbons that recruit numerous 26S proteasome complexes, while other macromolecules are largely excluded. Proximity to poly-GA ribbons stabilizes a transient substrate-processing conformation of the 26S proteasome, suggesting stalled degradation. Thus, poly-GA aggregates may compromise neuronal proteostasis by driving the accumulation and functional impairment of a large fraction of cellular proteasomes.
Department of Biophysics, Ruhr University Bochum, 44780 Bochum, Germany; NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Champaign, IL 61801, USA.