Superresolution Fluorescence Imaging of Mutant Huntingtin Aggregation in Cells.

Fluorescence-based nanoscopy methods (also known as "superresolution" microscopy) have substantially expanded our options to examine the distributions of molecules inside cells with nanometer-scale resolution and molecular specificity. In the biophysical analysis of aggregation-prone misfolded proteins and peptides, this has enabled the visualization of distinct populations of aggregated species such as fibrillar assemblies within intact neuronal cells, well below previous limits of sensitivity and resolution. With the Huntington's disease protein, polyglutamine-expanded mutant huntingtin, as an example, we provide sample preparation and imaging protocols for superresolution microscopy down to the ~30 nm-level.