In Situ Architecture and Cellular Interactions of PolyQ Inclusions

• Published in: Cell Vol. 171; no. 1; pp. 179 - 187.e10
• Main Authors: Bäuerlein, Felix J.B., Saha, Itika, Mishra, Archana, Kalemanov, Maria, Martínez-Sánchez, Antonio, Klein, Rüdiger, Dudanova, Irina, Hipp, Mark S., Hartl, F. Ulrich, Baumeister, Wolfgang, Fernández-Busnadiego, Rubén
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 21-09-2017
• Subjects: Amyloid - chemistry; amyloid fibril; Animals; cryo-electron tomography; cryo-EM; cryo-focused ion beam milling; Cryoelectron Microscopy; endoplasmic reticulum; Endoplasmic Reticulum - metabolism; Endoplasmic Reticulum - pathology; Female; HeLa Cells; Humans; Huntingtin Protein - genetics; Huntingtin Protein - metabolism; Huntington Disease - pathology; Inclusion Bodies - chemistry; Inclusion Bodies - pathology; inclusion body; Male; membrane disruption; Mice; Mice, Inbred C57BL; Microscopy, Electron, Transmission; Mutation; Neurons - pathology; Neurons - ultrastructure; Peptides - metabolism; polyglutamine expansion; protein aggregation; Protein Aggregation, Pathological; Tomography - methods; inclusion body; cryo-focused ion beam milling; membrane disruption; polyglutamine expansion; protein aggregation; cryo-electron tomography; amyloid fibril; cryo-EM; endoplasmic reticulum
• ISSN: 0092-8674; 1097-4172
• DOI: 10.1016/j.cell.2017.08.009

Expression of many disease-related aggregation-prone proteins results in cytotoxicity and the formation of large intracellular inclusion bodies. To gain insight into the role of inclusions in pathology and the in situ structure of protein aggregates inside cells, we employ advanced cryo-electron tomography methods to analyze the structure of inclusions formed by polyglutamine (polyQ)-expanded huntingtin exon 1 within their intact cellular context. In primary mouse neurons and immortalized human cells, polyQ inclusions consist of amyloid-like fibrils that interact with cellular endomembranes, particularly of the endoplasmic reticulum (ER). Interactions with these fibrils lead to membrane deformation, the local impairment of ER organization, and profound alterations in ER membrane dynamics at the inclusion periphery. These results suggest that aberrant interactions between fibrils and endomembranes contribute to the deleterious cellular effects of protein aggregation.
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•Polyglutamine inclusions in intact neurons visualized with cryo-electron tomography•PolyQ inclusions in neurons consist of amyloid-like fibrils•PolyQ fibrils interact with cellular endomembranes•PolyQ fibrils deform ER membranes and alter ER organization and dynamics
Cryo-electron tomography shows that fibrils from polyglutamine inclusions distort organellar membranes and perturb membrane dynamics.