In particular, we have used cryo‐ET to show that amyloid‐like poly‐GA inclusions linked to C9orf72 ALS/FTD disrupt neuronal proteostasis by sequestering proteasomes in a rare transition state, suggesting the cyclic conformational changes required for substrate processing (Collins & Goldberg, 2017) are altered by the association with the inclusions (Guo et al, 2018). This evidence concerns the gene C9orf72 and frontotemporal dementia.